# Habitat

HabitatName:
[Philine aperta] and [Virgularia mirabilis] in soft stable infralittoral mud

HabitatDescription:
Physically very stable muds, occasionally with small stones, with a high proportion of fine material (typically greater than 80 %) may contain the opisthobranch [Philine aperta] and the seapen [Virgularia mirabilis]. These muds typically occur in shallow water down to about 12-15 m where significant seasonal variation in temperature is presumed to occur. This habitat is restricted to the most sheltered basins in, for example, sealochs. Although most records suggest full salinity conditions are prevalent, some sites may be subject to variable salinity. [Philine aperta] is the most characteristic species of this habitat, occurring in high densities at many sites, whilst [Virgularia mirabilis], a species found more widely in muddy sediments, appears to reach its highest densities in this shallow mud but may not be present in all examples of this biotope. Other conspicuous species found in this shallow muddy habitat include [Cerianthus lloydii], [Pagurus bernhardus], [Sagartiogeton] spp. and [Hydractinia echinata]. Burrowing crustacean megafauna, characteristic of deeper mud, are rare or absent from this shallow sediment although [Nephrops norvegicus] may sometimes be recorded. This biotope has been primarily recorded on the basis of its epifauna and a few conspicuous infauna. Little data exists on the infaunal component of this biotope but it may include [Nephtys] spp., spionid polychaetes, [Ampelisca] spp. and the bivalves [Nucula] spp., [Thyasira flexuosa], [Mysella bidentata] and [Abra] spp. In the south of Great Britain, the polychaete [Sternaspis scutata] is also characteristic of this biotope. This polychaete is rare in Great Britain (Sanderson 1996). Indeed, this southern variant of the biotope is very restricted in the UK to Portland Harbour but is known to occur further south in the Gulf of Gascony and the Mediterranean (Glemarec 1973; Dauvin [et al]. 1994).
Temporal variation: It is possible that this biotope is a temporal variant of other subunits of A5.3. The key species, [Philine aperta], may be highly variable from year to year The sediment may also be covered by a diatom film at certain times of the year


HabitatName:
[Ocnus planci] aggregations on sheltered sublittoral muddy sediment

HabitatDescription:
Dense aggregations of [Ocnus planci [?brunneus]] on various substrata, typically muddy but occasionally with stones or shells, in sheltered conditions such as sealochs. [Philine aperta] also characterises this biotope but is present in lower abundances than in A5.343. Other associated species vary but are typical of very sheltered muddy habitats and include the ophiuroids [Ophiura] spp. and [Ophiothrix fragilis]. [Melanella alba], which parasitises holothurians, has been found in large numbers at one site.


HabitatName:
[Astarte crenata] beneath high salinity cold polar water


HabitatName:
Pontic mobile muds of the River Danube mouths


HabitatDescription:
Circalittoral, cohesive sandy mud, typically with over 20% silt/clay, generally in water depths of over 10 m, with weak or very weak tidal streams. This habitat is generally found in deeper areas of bays and marine inlets or offshore from less wave exposed coasts. Sea pens such as [Virgularia mirabilis] and brittlestars such as [Amphiura] spp. are particularly characteristic of this habitat whilst infaunal species include the tube building polychaetes [Lagis koreni] and [Owenia fusiformis], and deposit feeding bivalves such as [Mysella bidentata] and [Abra] spp.


HabitatName:
[Amphiura filiformis], [Mysella bidentata] and [Abra nitida] in circalittoral sandy mud

HabitatDescription:
Cohesive sandy mud off wave exposed coasts with weak tidal streams can be characterised by super-abundant [Amphiura filiformis] with [Mysella bidentata] and [Abra nitida]. This community occurs in muddy sands in moderately deep water (Hiscock 1984; Picton [et al]. 1994) and may be related to the 'off-shore muddy sand association' described by other workers (Jones 1951; Thorson 1957; Mackie 1990) and is part of the infralittoral etage described by Glemarec. This community is also characterised by the sipunculid [Thysanocardia procera] and the polychaetes [Nephtys incisa], [Phoronis] sp. and [Pholoe] sp., with cirratulids also common in some areas. Other taxa such as [Nephtys hombergii], [Echinocardium cordatum], [Nucula nitidosa], [Callianassa subterranea] and [Eudorella truncatula] may also occur in offshore examples of this biotope (e.g. Künitzer [et al]. 1992).


HabitatName:
[Thyasira] spp. and [Nuculoma tenuis] in circalittoral sandy mud

HabitatDescription:
Circalittoral cohesive sandy muds with small quantities of gravel, off sheltered or moderately exposed coasts may support populations characterised by [Thyasira] spp. and in particular [Thyasira flexuosa]. Other characteristic taxa may include [Nuculoma tenuis], [Goniada maculate] and in some areas [Rhodine gracilior]. [Mysella bidentata], [Abra alba], [Harpinia antennaria] and [Amphiura filiformis] may be abundant in some examples of this biotope. Whilst moderately diverse, animal abundances are often low and it is possible that the biotope is the result of sedimentary disturbance e.g. from trawling and is possibly an impoverished version of A5.353. Collectively the biotopes A5.351, A5.352, A5.353 and A5.272, may form the [Amphiura] dominated components of the 'off-shore muddy sand association' described by other workers (Jones 1951; Thorson 1957; Mackie 1990) and the infralittoral etage described by Glemarec (1973).


HabitatName:
[Amphiura filiformis] and [Nuculoma tenuis] in circalittoral and offshore muddy sand

HabitatDescription:
In cohesive and non-cohesive sandy mud, off moderately exposed coasts in deep water dense populations of [Amphiura filiformis] with the bivalve [Nuculoma tenuis] may occur. This biotope together with A5.351, A5.352 and A5.272 may be part of the [Amphiura filiformis] dominated infralittoral etage described by Glemarec (1973) and part of the 'off-shore muddy sand association' described by other workers (Jones 1951; Mackie 1990). Other species characteristic of this biotope may include the echinoderms [Ophiura albida] and [Echinocardium flavescens] and the bivalve [Mysella bidentata]. [Phaxas pellucidus], [Owenia fusiformis] and [Virgularia mirabilis] may also be present. At the sediment surface the hydroid [Sertularia argentea] may be present although only at very low abundances. Variations of this biotope exist in the northern North Sea (see below) and it is possible that more than one entity exists for this biotope.


HabitatName:
[Virgularia mirabilis] and [Ophiura] spp. with [Pecten maximus] on circalittoral sandy or shelly mud

HabitatDescription:
Circalittoral fine sandy mud may contain [Virgularia mirabilis] and [Ophiura] spp. A variety of species may occur, and species composition at a particular site may relate, to some extent, to the proportions of the major sediment size fractions. Several species are common to most sites including [Virgularia mirabilis] which is present in moderate numbers, [Ophiura albida] and [Ophiura ophiura] which are often quite common, and [Pecten maximus] which is usually only present in low numbers. [Virgularia mirabilis] is usually accompanied by occasional [Cerianthus lloydii], [Liocarcinus depurator] and [Pagurus bernhardus]. [Amphiura chiajei] and [Amphiura filiformis] may occur in some examples of this biotope. Polychaetes and bivalves are generally the main components of the infauna, although the nemerteans, [Edwardsia claparedii], [Phoronis muelleri] and [Labidoplax buski] may also be widespread. Of the polychaetes [Goniada maculata], [Nephtys incisa], [Minuspio cirrifera], [Chaetozone setosa], [Notomastus latericeus] and [Owenia fusiformis] are often the most widespread species whilst [Myrtea spinifera], [Lucinoma borealis], [Mysella bidentata], [Abra alba] and [Corbula gibba] are typical bivalves in this biotope. This biotope is primarily identified on the basis of its epifauna and may be an epibiotic overlay over other closely related biotopes such as A5.361, A5.351 and A5.353.
Situation: Such sediments are very common in sealochs, often occurring shallower than the finest mud or in somewhat more exposed parts of the lochs.


HabitatName:
[Virgularia mirabilis] and [Ophiura] spp. with [Pecten maximus], hydroids and ascidians on circalittoral sandy or shelly mud with shells or stones

HabitatDescription:
Circalittoral fine sandy mud with shell gravel and notable quantities of shells or small stones scattered over the sediment surface. These sediments, like A5.354, may contain [Virgularia mirabilis, Pecten maximus] and [Ophiura] spp. but shells and small stones scattered over the sediment surface provided sufficient stable substrata for a variety of sessile epifaunal species to occur. Of these the hydroids [Kirchenpaueria pinnata], [Nemertesia antennina] and [Nemertesia ramosa] are most common with solitary ascidians such as [Corella parallelogramma] and [Ascidia mentula] also present. The anemone [Cerianthus lloydii] is often found in the sediment together with occasional [Lanice conchilega]. The serpulids [Protula tubularia], [Serpula vermicularis] and [Pomatoceros triqueter] and the barnacles [Balanus balanus] and [Balanus crenatus] are also often present on pebbles and shells. [Munida rugosa] are occasionally found under larger stones. All these species are typical of more rocky habitats in such sheltered conditions. As with A5.354 this biotope is primarily identified on the basis of its epifauna and may be an epibiotic overlay over other closely related biotopes such as units A5.351 and A5.353.


HabitatName:
[Lagis koreni] and [Phaxas pellucidus] in circalittoral sandy mud

HabitatDescription:
In stable circalittoral sandy mud dense populations of the tube building polychaete [Lagis koreni] may occur. Other species found in this habitat typically include bivalves such as [Phaxas pellucidus], [Mysella bidentata] and [Abra alba] and polychaetes such as [Mediomastus fragilis], [Spiophanes bombyx], [Owenia fusiformis] and [Scalibregma inflatum]. At the sediment surface easily visible fauna include [Lagis koreni] and [Ophiura ophiura]. [Lagis koreni] is an important source of food for commercially important demersal fish, especially dab and plaice (Macer, 1967; Lockwood, 1980 and Basimi & Grove, 1985).

Temporal variation: In some areas e.g. Liverpool Bay, A5.261 and A5.355 have exhibited cyclical behaviour with the community periodically switching from one biotope to another - possibly in relation to dredge spoil disposal (Rees [et al]. 1992) along with other environmental and biological factors. Both [Lagis koreni] and [Phaxas pellucidus], are capable of tolerating sudden increases in the deposition of sediment and often dominate such areas following such an event. Indeed it is likely that the two biotopes are merely different aspects of the same community as [Lagis koreni] is often recorded with high densities of [Abra alba] (Eagle 1975; Rees and Walker 1983). Densities of mature populations of [L. koreni] may exceed 1000m-2


HabitatName:
Pontic circalittoral sandy muds with [Heteromastus filiformis], [Dipolydora quadrilobata] and [Nephthys hombergii]


HabitatDescription:
Sublittoral muds, occurring below moderate depths of 15-20 m, either on the open coast or in marine inlets such as sealochs. The seapens [Virgularia mirabilis] and [Pennatula phosphorea] are characteristic of this habitat type together with the burrowing anemone [Cerianthus lloydii] and the ophiuroid [Amphiura] spp. The relatively stable conditions often lead to the establishment of communities of burrowing megafaunal species, such as [Nephrops norvegicus].


HabitatDescription:
Plains of fine mud at depths greater than about 15 m may be heavily bioturbated by burrowing megafauna; burrows and mounds may form a prominent feature of the sediment surface with conspicuous populations of seapens, typically [Virgularia mirabilis] and [Pennatula phosphorea]. The burrowing crustacea present typically include [Nephrops norvegicus], which is frequently recorded from surface observations although grab sampling may fail to sample this species. Indeed, some forms of sampling may also fail to indicate seapens as characterising species. This biotope also seems to occur in deep offshore waters in the North Sea, where densities of [Nephrops norvegicus] may reach 68 per 10 m2 (see Dyer [et al]. 1982, 1983), and the Irish Sea. The burrowing anemone [Cerianthus lloydii] and the ubiquitous epibenthic scavengers [Asterias rubens], [Pagurus bernhardus] and [Liocarcinus depurator] are present in low numbers in this biotope whilst the brittlestars [Ophiura albida] and [Ophiura ophiura] are sometimes present, but are much more common in slightly coarser sediments. Low numbers of the anemone [Pachycerianthus multiplicatus] may also be found, and this species, which is scarce in the UK, appears to be restricted to this habitat (Plaza & Sanderson 1997). The infauna may contain significant populations of the polychaetes [Pholoe] spp., [Glycera] spp., [Nephtys] spp., spionids, [Pectinaria belgica] and [Terebellides stroemi], the bivalves [Nucula sulcata], [Corbula gibba] and [Thyasira flexuosa], and the echinoderm [Brissopsis lyrifera].

Situation: These soft mud habitats occur extensively throughout the more sheltered basins of sealochs and voes (narrow inlets) and are present in quite shallow depths (as little as 15 m) in these areas probably because they are very sheltered from wave action.


HabitatName:
Seapens, including [Funiculina quadrangularis], and burrowing megafauna in undisturbed circalittoral fine mud

HabitatDescription:
Deep muds, especially in sealochs, support forests of the nationally scarce [Funiculina quadrangularis], in addition to populations of the seapens [Virgularia mirabilis] and [Pennatula phosphorea]. The sediment is usually extensively burrowed by crustaceans, the most common of which is [Nephrops norvegicus], but [Calocaris macandreae] and [Callianassa subterranea] may also be present (the latter is likely to be under-recorded by grab sampling because it is deep burrowing). The burrowing anemone [Cerianthus lloydii] is present in low numbers in this biotope and the rare anemone [Pachycerianthus multiplicatus] may also be found occasionally. [Amphiura] spp. are also often present in high densities.


HabitatName:
Burrowing megafauna and [Maxmuelleria lankesteri] in circalittoral mud

HabitatDescription:
In circalittoral stable mud distinctive populations of megafauna may be found. These typically include [Nephrops norvegicus], [Calocaris macandreae] and [Callianassa subterranea]. Large mounds formed by the echiuran [Maxmuelleria lankesteri] are also frequent in this biotope. The seapen [Virgularia mirabilis] may occur occasionally in this biotope but not in the same abundance as A5.361 to which A5.362 is closely allied. Infaunal species may include [Nephtys hystricis], [Chaetozone setosa, Amphiura chiajei] and [Abra alba].


HabitatName:
[Brissopsis lyrifera] and [Amphiura chiajei] in circalittoral mud

HabitatDescription:
Mud in deep offshore, or shallower stable nearshore, waters can be characterised by the urchin [Brissopsis lyrifera] and the brittle star [Amphiura chiajei]. Where intense benthic dredge fishing activity occurs, populations of the indicator species, [Brissopsis lyrifera] may be depressed, although broken tests may still remain (E.I.S. Rees pers. comm. 1997; M. Costello pers. comm. 1997). Low numbers of the seapen [Virgularia mirabilis] may be found in many examples of this biotope. In addition, in certain areas of the UK such as the northern Irish Sea, this community may also contain [Nephrops norvegicus] and can consequently be the focus for fishing activity (Mackie, Oliver & Rees 1995). Infaunal species in this community are similar to those found in A5.361 and include the polychaetes [Nephtys hystricis], [Pectinaria belgica], [Glycera] spp. and [Lagis koreni] and the bivalves [Myrtea spinifera] and [Nucula sulcata]. This community is the 'Boreal Offshore Mud Association' and '[Brissopsis - Chiajei]' communities described by other workers (Petersen 1918; Jones 1950).


HabitatName:
Silty sediments > 140 m with polychaetes [Lumbrineris fragilis], [Levinsenia gracilis] and amphipods [Eriopisa elongata]


HabitatName:
[Spiochaetopterus] beneath high salinity Atlantic water


HabitatName:
[Macoma calcarea] in deep-water soft clayey mud


HabitatName:
Pontic very soft, organic-rich muds of the Danube front


HabitatName:
Very soft muds with [Nephthys hombergii]


HabitatName:
Soft muds with [Abra prismatica], [Acanthocardia paucicostata] and [Spisula subtruncata]


HabitatName:
Pontic circalittoral muds with [Acanthocardia paucicostata], [Papillicardium papillosum] and hydroids


HabitatName:
Pontic circalittoral muds with [Mya arenaria] and Spisula subtruncata


HabitatName:
Pontic circalittoral muds with [Mellina palmata] and [Aricidea claudiae]


HabitatDescription:
In mud and cohesive sandy mud in the offshore circalittoral zone, typically below 50-70 m, a variety of faunal communities may develop, depending upon the level of silt/clay and organic matter in the sediment. Communities are typically dominated by polychaetes but often with high numbers of bivalves such as [Thyasira] spp., echinoderms and foraminifera.


HabitatName:
[Ampharete falcata] turf with [Parvicardium ovale] on cohesive muddy sediment near margins of deep stratified seas

HabitatDescription:
Dense stands of [Ampharete falcata] tubes which protrude from muddy sediments, appearing as a turf or meadow in localised areas. These areas seem to occur on a crucial point on a depositional gradient between areas of tide-swept mobile sands and quiescent stratifying muds. Dense populations of the small bivalve [Parvicardium ovale] occur in the superficial sediment. Other infauna in this diverse biotope includes [Lumbrineris scopa], [Levinsenia] sp., [Prionospio steenstrupi], [Diplocirrus glaucus] and [Praxillella affinis] although a wide variety of other infaunal species may also be found. Both the brittlestars [Amphiura filiformis] and [Amphiura chiajei] may be present together with [Nephrops norvegicus] in higher abundance than the A5.363 or A5.351 biotopes. Substantial populations of mobile epifauna such as [Pandalus montagui] and smaller fish also occur, together with those that can cling to the tubes, such as [Macropodia] spp. A similar turf of worm tubes formed by the maldanid polychaete [Melinna cristata] has been recorded from Northumberland (Buchanan 1963). Nephrops trawling may severely damage this biotope and it is possible that such activity has destroyed examples of this biotope in the Irish Sea (E.I.S. Rees pers. comm. 2002).


HabitatName:
Foraminiferans and [Thyasira] spp. in deep circalittoral soft mud

HabitatDescription:
In deep water and soft muds of Boreal and Arctic areas, a community dominated by foraminiferans and the bivalve [Thyasira] sp. (e.g. [T. croulinensis and T. pygmaea]) may occur (Thorson 1957; Künitzer [et al]. 1992). Foraminiferans such as [Saccammina], [Psammosphaera], [Haplophragmoides], [Crithionina] and [Astorhiza] are important components of this community with dead tests numbering thousands per m2 (see Stephen 1923; McIntyre 1961) and sometimes visible from benthic photography (Mackie, Oliver & Rees 1995). It is likely that a community dominated by [Astorhiza] in fine sands in the Irish Sea may be another distinct biotope (E.I.S. Rees pers. comm. 2002). Polychaetes, e.g. [Paraonis gracilis], [Myriochele heeri], [Spiophanes kroyeri], [Tharyx] sp., [Lumbrineris tetraura], are also important components of this biotope. These communities appear to have no equivalent on the continental plateau further south (Glemarec 1973) but are known from the edge of the Celtic Deep in the Irish Sea (Mackie, Oliver & Rees 1995). The benthos in these offshore areas has been shown to be principally Foraminifera and similar, rich communities may exist in Scottish sealochs (McIntyre 1961). Communities from yet deeper (northern) waters at the extremes of the North Sea may be reminiscent, although dissimilar to A5.372  (see Pearson [et al]. 1996) reflecting a higher proportion of silt/clay. A fully Arctic version of this biotope has also been described (Thorson 1934, 1957) although it should be noted that Jones (1950) considered this Boreal foraminiferan community to be part of a 'Boreal Deep Mud Association'.

Situation: This community typically occurs in water deeper than 100 m in the northern North Sea (Knitzer [et al]. 1992) and have been referred to as 'Foraminifera communities' by other workers (e.g. Stephen 1923; Thorson 1957; McIntyre 1961).


HabitatName:
[Styela gelatinosa], [Pseudamussium septemradiatum] and solitary ascidians on sheltered deep circalittoral muddy sediment

HabitatDescription:
This biotope is known only from deep water in Loch Goil (Clyde sealochs) in fine mud at 65 m with terrigenous debris. Large numbers of solitary ascidians, including [Styela gelatinosa], [Ascidia conchilega], [Corella parallelogramma] and [Ascidiella] spp., are characteristic of this biotope together with the bivalve [Pseudamussium septemradiatum]. Terebellid worms, the bivalve [Abra alba] and the polychaete [Glycera tridactyla] may also occur. It is possibly an ice age relict biotope.


HabitatName:
[Capitella capitata] and [Thyasira] spp. in organically-enriched offshore circalittoral mud and sandy mud

HabitatDescription:
In circalittoral and deep offshore mud and sandy mud adjacent to oil or gas platforms, organic enrichment from drill cuttings leads to the development of communities dominated by the [Capitella capitata], an opportunist especially associated with organically enriched and polluted sediments as described for A5.336 (Warren 1977; Pearson & Rosenberg 1978). The bivalves [Thyasira flexuosa] or [Thyasira sarsi] may also be found in moderate numbers at some sites. Other taxa may be present in low numbers in areas of less severe enrichment including [Pholoe inornata], [Lagis koreni], [Philine scabra], [Anaitides groenlandica], [Mediomastus fragilis] and [Paramphinome jeffreysii].


HabitatName:
[Capitella capitata], [Thyasira] spp. and [Ophryotrocha dubia] inorganically-enriched offshore circalittoral mud or sandy mud

HabitatDescription:
In deep offshore sandy mud adjacent to oil or gas platforms, organic enrichment from drill cuttings leads to the development of communities dominated by the pollution tolerant opportunist [Capitella capitata] and the polychaete [Ophryotrocha dubia] (or other species of [Ophryotrocha]). These species are generally found in extremely high abundances and accompanied by [Thyasira] spp., [Raricirrus beryli], [Paramphinome jeffreysii] and [Chaetozone setosa]. Other taxa including [Exogone verugera], [Pholoe inornata] and [Idasola simpsoni] may also be present.


HabitatName:
[Levinsenia gracilis] and [Heteromastus filifirmis] in offshore circalittoral mud and sandy mud

HabitatDescription:
In deep offshore mud and sandy mud a community characterised by the polychaetes [Levinsenia gracilis] and [Heteromastus filiformis] may occur. Other important taxa may include [Paramphinome jeffreysii], [Nephtys hystricis] and [N. incisa], [Spiophanes kroyeri], [Orbinia norvegica], [Terebellides stroemi], [Thyasira gouldi] and [Thyasira equalis]. Burrowing megafauna such as [Calocaris macandreae] may also be found in this biotope. This biotope has been found in the central and northern North Sea. A similar community, dominated by [L. gracilis] but accompanied by [Glycera] spp. (particularly [Glycera rouxii]) and [Monticellina dorsobranchialis], has also been reported from the Irish Sea. This Irish community also contains [Calocaris macandreae], [Mediomastus fragilis], [Tubificoides amplivasatus], [Nephtys incisa], [Ancistrosyllis groenlandica], [Nucula sulcata], [Litocorsa stremma] and [Minuspio] sp. and it is not known at present whether this represents a separate biotope or whether it is a geographic variant of a wider [Levinsenia] biotope.
Situation: This biotope has been found in the central and northern North Sea and may also occur in the Irish Sea


HabitatName:
[Paramphinome jeffreysii], [Thyasira] spp. and [Amphiura filiformis] in offshore circalittoral sandy mud

HabitatDescription:
Deep, offshore cohesive sandy mud communities characterised by the polychaete [Paramphinome jeffreysii], bivalves such as [Thyasira equalis] and [Thyasira gouldi] and the brittlestar [Amphiura filiformis]. Other taxa may include Laonice cirrata, the sea cucumber Labidoplax buski and the polychaetes [Goniada maculata], [Spiophanes kroyeri] and [Aricidea catherinae]. [Amphiura chiajei] may be occasional in this biotope as may [Philine scabra], [Levinsenia gracilis] and [Pholoe inornata]. This biotope along with A5.351, A5.352, A5.353 and A5.272, may comprise the [Amphiura] dominated components of the 'off-shore muddy sand association' (Jones 1951; Mackie 1990) and the infralittoral etage described by Glemarec (1973).


HabitatName:
[Myrtea spinifera] and polychaetes in offshore circalittoral sandy mud

HabitatDescription:
Deep, offshore habitats with cohesive sandy mud (>20% mud) may support communities characterised by infaunal polychaetes and the bivalve [Myrtea spinifera]. Polychaetes typically include [Chaetozone setosa], [Paramphinome jeffreysii], [Levinsenia gracilis], [Aricidea catherinae] and [Prionospio malmgreni]. The bivalves [Thyasira] spp. and [Abra nitida] may also be found as may seapens, such as [Pennatula phosphorea]. Some examples of the unit A5.353 contain [Myrtea spinifera] (Mackie 1990) in lower numbers but these habitats are generally sandier than those in A5.377.

Situation: This biotope has been recorded in the northern North Sea but may also exist in the Irish Sea.


HabitatName:
Baltic muddy bottoms of the aphotic zone


HabitatName:
Pontic deep circalittoral muds with [Modiolula phaseolina]

HabitatDescription:
Discriminated by the mussel [Modiolula phaseolina]. The habitat is characterised by bulk of dead shells and shelly detritus of the same species, decreasing oxygen concentration and increasing salinity in comparison to coastal habitats. Other specific species are [Amphiura stepanovi] and [Notomastus profundus]. In Bulgarian waters the community is not present below 100m.


HabitatName:
Pontic deep circalittoral muds with [Terebellides stroemi] and [Amphiura] sp.


HabitatName:
Pontic deep circalittoral muds with [Pachycerianthus solitarius]


HabitatName:
Pontic periazoic white calcareous muds with [Bougainvillia ramosa] and nematodes


HabitatName:
Mediterranean communities of muddy detritic bottoms

HabitatDescription:
This biocenosis develops in areas where a detritus bottom is covered with mud formed by terrigenous deposits from rivers. The sediment is a very muddy sand or sandy mud, or even a rather compacted mud, rich in shell debris or valocanic fragments (scoriae); sedimentation is slow enough to allow the development of sessile epifauna. Gravel, sand and mud are mixed in varying quantities, but mud always predominates.


HabitatDescription:
This facies is exclusive to the muddy detritic biocenosis and is characterised by an unusual community of the brittlestar [Ophiothrix quinquemaculata] ([Ophiuroidea]). This species in some places forms an extremely dense population which is almost 90% ophiuran.


HabitatName:
Mediterranean communities of coastal terrigenous muds

HabitatDescription:
The sediment is always pure mud, more or less clayey, almost always of fluvial origin. Such coarse debris as may be deposited is quickly covered, with the result that no epifauna develops.


HabitatName:
Facies of soft muds with [Turritella tricarinata communis]

HabitatDescription:
This facies is characterised by presence of the gastropod [Turritella tricarinata].


HabitatName:
Facies of sticky muds with [Virgularia mirabilis] and [Pennatula phosphorea]

HabitatDescription:
This facies is characterised by the soft corals [Virgularia mirabilis] and [Pennatula phosphorea] on sticky muddy bottoms.


HabitatName:
Facies of sticky muds with [Alcyonium palmatum] and [Stichopus regalis]

HabitatDescription:
This facies is characterised by the soft coral [Alcyonium palmatum] and the echinoderm [Stichopus regalis] on sticky muddy bottoms.


HabitatDescription:
Sublittoral mixed (heterogeneous) sediments found from the extreme low water mark to deep offshore circalittoral habitats. These habitats incorporate a range of sediments including heterogeneous muddy gravelly sands and also mosaics of cobbles and pebbles embedded in or lying upon sand, gravel or mud. There is a degree of confusion with regard nomenclature within this complex as many habitats could be defined as containing mixed sediments, in part depending on the scale of the survey and the sampling method employed. The BGS trigon can be used to define truly mixed or heterogeneous sites with surficial sediments which are a mixture of mud, gravel and sand. However, another 'form' of mixed sediment includes mosaic habitats such as superficial waves or ribbons of sand on a gravel bed or areas of lag deposits with cobbles/pebbles embedded in sand or mud and these are less well defined and may overlap into other habitat or biological subtypes. These habitats may support a wide range of infauna and epibiota including polychaetes, bivalves, echinoderms, anemones, hydroids and Bryozoa. Mixed sediments with biogenic reefs or macrophyte dominated communities are classified separately in A5.6 and A5.5 respectively.


HabitatName:
Sublittoral mixed sediment in low or reduced salinity

HabitatDescription:
Shallow, muddy mixed sediments in areas of low or reduced, although stable, salinity (may vary annually) with largely ephemeral faunal communities. Characterised infaunally by oligochaetes, including [Heterochaeta costata] and members of the Enchytraeidae, polychaetes such as [Hediste diversicolor], [Polydora ciliata] and [Pygospio elegans],and bivalves such as [Mya arenaria] and the lagoon cockle [Cerastoderma glaucum]. These bivalve species may also form conspicuious members of the epifauna together with more ubiquitous species like the common goby [Pomatoschistus microps].


HabitatName:
Baltic level mixed sediment bottoms of the infralittoral photic zone with little or no macrophyte vegetation


HabitatName:
Baltic mixed sediment bottoms of the aphotic zone


HabitatDescription:
Shallow sublittoral mixed sediments in estuarine conditions, often with surface shells or stones, enabling the development of diverse epifaunal communities, e.g. [Crepidula fornicata] (A5.422), as well as infaunal communities. This habitat type is therefore often quite species rich, compared with purer sediments.


HabitatName:
[Aphelochaeta] spp. and [Polydora] spp. in variable salinity infralittoral mixed sediment

HabitatDescription:
In sheltered muddy mixed sediments in estuaries or marine inlets with variable or reduced/low salinity communities characterised by [Aphelochaeta marioni] and [Polydora ciliata] may be present. Other important taxa may include the polychaetes [Nephtys hombergii], [Caulleriella zetlandica] and [Melinna palmata], tubificid oligochaetes and bivalves such as [Abra nitida]. Conspicuous epifauna may include members of the bivalve family Cardiidae (cockles) and the slipper limpet [Crepidula fornicata]. This biotope is often found in polyhaline waters.


HabitatName:
[Crepidula fornicata] and [Mediomastus fragilis] in variable salinity infralittoral mixed sediment

HabitatDescription:
Variable salinity mixed sediment characterised by the slipper limpet [Crepidula fornicata] and the polychaetes [Mediomastus fragilis] and [Aphelochaeta marioni]. Other numerically important taxa include the oligochaetes [Tubificoides benedii], syllids such as [Exogone] [naidina] and [Sphaerosyllis], and [Nephtys hombergii]. [Lepidonotus squamatus] and [Scoloplos armiger] may also be common. Shell debris and cobbles are colonised by the ascidians [Ascidiella aspersa], [Ascidiella scabra], [Molgula] sp. and [Dendrodoa grossularia] (the ascidians may not be recorded adequately by remote infaunal survey techniques).
Situation: This biotope occurs in the lower estuary where currents allow a stable environment to develop. It is associated with oyster beds and relict oyster beds, (A5.435) in southern England and Wales. It may be found adjacent to or in conjunction with A5.322 and A5.421. It may be associated with A5.433 and possibly form a component of A5.332.


HabitatDescription:
Shallow mixed (heterogeneous) sediments in fully marine or near fully marine conditions, supporting various animal-dominated communities, with relatively low proportions of seaweeds. This habitat may include well mixed muddy gravelly sands or very poorly sorted mosaics of shell, cobbles and pebbles embedded in mud, sand or gravel. Due to the quite variable nature of the sediment type, a widely variable array of communities may be found, including those characterised by bivalves (A5.433, A5.431, and A5.435), polychaetes (A5.432) and file shells (A5.434). This has resulted in many species being described as characteristic of this habitat type all contributing only a small percentage to the overall similarity (see below). This habitat type may also include a newly proposed [Chaetopterus] biotope (Rees pers com.) recently found in the eastern English Channel. This biotope is characterised by an undescribed [Chaetopterus] sp. and small [Lanice conchilega]. Further sampling is need in order to assess and fully characterise this potential biotope. As a result, the Chaetopterus biotope has not been included in this revision. Infaunal data for this habitat type are limited to that described in the biotope A5.433 and so are not representative of the infaunal component of the whole habitat type.


HabitatName:
[Crepidula fornicata] with ascidians and anemones on infralittoral coarse mixed sediment

HabitatDescription:
Medium-coarse sands with gravel, shells, pebbles and cobbles on moderately exposed coasts may support populations of the slipper limpet [Crepidula fornicata] with ascidians and anemones. [C. fornicata] is common in this biotope though not as abundant as in the muddier estuarine biotope A5.422 to which this is related. Anemones such as [Urticina felina] and [Alcyonium digitatum] and ascidians such as [Styela clava] are typically found in this biotope. Bryozoans such as [Flustra foliacea] are also found along with polychaetes such as [Lanice conchilega]. Little information is available with regard the infauna of this biotope but given the nature of the sediment the infaunal communities are liable to resemble those in biotopes from A5.1 and subunits. As with A5.444 this biotope could be considered a superficial or epibiotic overlay but more data is required to support this.


HabitatName:
[Sabella pavonina] with sponges and anemones on infralittoral mixed sediment

HabitatDescription:
Muddy gravelly sand with pebbles off shallow, sheltered or moderately exposed coasts or embayments may support dense populations of the peacock worm [Sabella pavonina]. This community may also support populations of sponges such as [Esperiopsis fucorum], [Haliclona oculata] and [Halichondria panicea] and anemones such as [Sagartia elegans], [Cerianthus lloydii] and [Urticina felina]. Hydroids such as [Hydrallmania falcata] and the encrusting polychaete [Pomatoceros triqueter] are also important. This biotope may have an extremely diverse epifaunal community. Less is known about its infaunal component, although it is likely to include polychaetes such as Nephtys spp., [Harmothoe] spp., [Glycera] spp., syllid and cirratulid polychaetes, bivalves such as [Abra] spp., Aoridae amphipods and brittlestars such as [Amphipholis squamata].


HabitatName:
[Venerupis senegalensis], [Amphipholis squamata] and [Apseudes latreilli] in infralittoral mixed sediment

HabitatDescription:
Sheltered muddy sandy gravel and pebbles in marine inlets, estuaries or embayments with variable salinity or fully marine conditions, support large populations of the pullet carpet shell [Venerupis senegalensis] with the brittlestar [Amphipholis squamata] and the tanaid [Apseudes latreilli]. This biotope may be found at a range of depths from 5m to 30m although populations of [V. senegalensis] may also be found on the low shore. Other common species within this biotope include the gastropod [Calyptraea chinensis], a range of amphipod crustacea such as [Corophium sextonae] and [Maera grossimana] and polychaetes such as [Mediomastus fragilis], [Melinna palmata], [Aphelochaeta marioni], [Syllids] and tubificid oligochaetes. Many of the available records for this biotope are from southern inlets and estuaries such as Plymouth Sound and Milford Haven but [V. senegalensis] has a much wider distribution and it should be noted that northern versions of this biotope may a have a much lower species diversity than reported here.


HabitatName:
[Limaria hians] beds in tide-swept sublittoral muddy mixed sediment

HabitatDescription:
Mixed muddy gravel and sand often in tide-swept narrows in the entrances or sills of sealochs with beds or 'nests' of [Limaria hians]. The [Limaria] form woven 'nests' or galleries from byssus and fragments of seaweeds so that the animals themselves cannot be seen from above the seabed. [Modiolus modiolus] sometimes occur at the same sites lying over the top of the [Limaria] bed. Other fauna associated with this biotope include echinoderms ([Ophiothrix fragilis], [Ophiocomina nigra] and [Asterias rubens]), [Buccinum undatum], mobile crustaceans (e.g. [Pagurus bernhardus]), [Alcyonium digitatum] and hydroids such as [Plumularia setacea], [Kirchenpaueria pinnata] and [Nemertesia] spp. Sometimes red seaweeds such as [Phycodrys rubens] occur if the beds are in shallow enough water.


HabitatName:
Oyster beds on shallow sublittoral muddy mixed sediment

HabitatDescription:
Dense beds of the oyster [Ostrea edulis] can occur on muddy fine sand or sandy mud mixed sediments. There may be considerable quantities of dead oyster shell making up a substantial portion of the substratum. The clumps of dead shells and oysters can support large numbers of [Ascidiella aspersa] and [Ascidiella scabra]. Sponges such as [Halichondria bowerbanki] may also be present. Several conspicuously large polychaetes, such as [Chaetopterus variopedatus] and terebellids, as well as additional suspension-feeding polychaetes such as [Myxicola infundibulum] and [Sabella pavonina] may be important in distinguishing this biotope, whilst the Opisthobranch [Philine aperta] may also be frequent in some areas. A turf of seaweeds such as [Plocamium cartilagineum], [Nitophyllum punctatum] and [Spyridia filamentosa] may also be present. This biotope description may need expansion to account for oyster beds in England.


HabitatDescription:
Mixed (heterogeneous) sediment habitats in the circalittoral zone (generally below 15-20 m) including well mixed muddy gravelly sands or very poorly sorted mosaics of shell, cobbles and pebbles embedded in or lying upon mud, sand or gravel. Due to the variable nature of the seabed a variety of communities can develop which are often very diverse. A wide range of infaunal polychaetes, bivalves, echinoderms and burrowing anemones such as Cerianthus lloydii are often present in such habitat and the presence of hard substrata (shells and stones) on the surface enables epifaunal species to become established, particularly hydroids such as [Nemertesia] spp and [Hydrallmania falcata]. The combination of epifauna and infauna can lead to species rich communities. Coarser mixed sediment communities may show a strong resemblance, in terms of infauna, to biotopes within the A5.1. However, infaunal data for this habitat type is limited to that described under the biotope A5.443, and so are not representative of the infaunal component of this habitat type.


HabitatName:
[Cerianthus lloydii] and other burrowing anemones in circalittoral muddy mixed sediment

HabitatDescription:
Circalittoral plains of sandy muddy gravel may be characterised by burrowing anemones such as [Cerianthus lloydii]. Other burrowing anemones such as [Cereus pedunculatus], [Mesacmaea mitchellii] and [Aureliania heterocera] may be locally abundant. Relatively few conspicuous species are found in any great number in this biotope but typically they include ubiquitous epifauna such as [Asterias rubens], [Pagurus bernhardus] and [Liocarcinus depurator] with occasional terebellid polychaetes such as [Lanice conchilega] and also the clam [Pecten maximus]. [Ophiura albida] may be frequent in some areas, and where surface shell or stones are present ascidians such as [Ascidiella aspersa] may occur in low numbers.


HabitatName:
[Cerianthus lloydii] with [Nemertesia] spp. and other hydroids in circalittoral muddy mixed sediment

HabitatDescription:
In sheltered muddy sandy gravel with appreciable quantities of surficial cobbles, pebbles and shells a community similar to A5.441 may develop with frequent [Cerianthus lloydii] and other burrowing anemones. However, the pebbles and cobbles embedded in the sediment are colonised by hydroids and in particular [Nemertesia antennina] and [N. ramosa]. Other hydroids may include [Kirchenpaueria pinnata] and [Halecium halecinum] whilst ascidians such as [Ascidiella aspersa] or [Corella parallelogramma] may also be present locally. [Pecten maximus] and [Pomatoceros triqueter] may also be frequent in certain areas.


HabitatName:
Sparse [Modiolus modiolus], dense [Cerianthus lloydii] and burrowing holothurians on sheltered circalittoral stones and mixed sediment

HabitatDescription:
Pebbles and cobbles on mud or muddy gravel in sealochs with frequent [Cerianthus lloydii] and occasional [Modiolus modiolus]. Large burrowing holothurians may include [Psolus phantapus], [Paracucumaria hyndmani], [Thyonidium commune], [Thyone fusus] and [Leptopentacta elongate]. Many of these species only extend their tentacles above the sediment surface seasonally and are likely to be under recorded by epifaunal surveys. Other more conspicuous characterising taxa include [Pagurus bernhardus], [Asterias rubens], and [Buccinum undatum]. This biotope is well developed in the Clyde sealochs, although many examples are rather species-poor. Some examples in south-west Scottish sealochs have greater quantities of boulders and cobbles and therefore have a richer associated biota (compared with other sheltered [Modiolus] bed biotopes such as A5.623). Examples in Shetland are somewhat different in having the cucumber [Cucumaria frondosa] amongst sparse [Modiolus] beds and a slightly different balance in abundance of other species; for example the brittlestar [Ophiopholis aculeata] is more abundant in these far northern examples in the voes and narrows


HabitatName:
[Mysella bidentata] and [Thyasira] spp. in circalittoral muddy mixed sediment

HabitatDescription:
In moderately exposed or sheltered, circalittoral muddy sands and gravels a community characterised by the bivalves [Thyasira] spp. (often [Thyasira flexuosa]), [Mysella bidentata] and [Prionospio fallax] may develop. Infaunal polychaetes such as [Lumbrineris gracilis], [Chaetozone setosa] and [Scoloplos armiger] are also common in this community whilst amphipods such as [Ampelisca] spp. and the cumacean [Eudorella truncatula] may also be found in some areas. The brittlestar [Amphiura filiformis] may also be abundant at some sites. Conspicuous epifauna may include encrusting bryozoans [Escharella] spp. particularly [Escharella immersa] and, in shallower waters, maerl ([Phymatolithon calcareum]), although at very low abundances and not forming maerl beds.


HabitatName:
[Flustra foliacea] and [Hydrallmania falcata] on tide-swept circalittoral mixed sediment

HabitatDescription:
This biotope represents part of a transition between sand-scoured circalittoral rock where the epifauna is conspicuous enough to be considered as a biotope and a sediment biotope where an infaunal sample is required to characterise it and is possibly best considered an epibiotic overlay. [Flustra foliacea] and the hydroid [Hydrallmania falcata] characterise this biotope; lesser amounts of other hydroids such as [Sertularia argentea], [Nemertesia antennina] and occasionally [Nemertesia ramose], occur where suitably stable hard substrata is found. The anemone [Urticina feline] and the soft coral [Alcyonium digitatum] may also characterise this biotope. Barnacles [Balanus crenatus] and tube worms [Pomatoceros triqueter] may be present and the robust bryozoans [Alcyonidium diaphanum] and [Vesicularia spinosa] appear amongst the hydroids at a few sites. [Sabella pavonina] and [Lanice conchilega] may be occasionally found in the coarse sediment around the stones. In shallower (i.e. upper circalittoral) examples of this biotope scour-tolerant robust red algae such as [Polysiphonia nigrescens], [Calliblepharis] spp. and [Gracilaria gracilis] are found.
Situation: This biotope is found around most coasts, although regional differences are seen where one or two similarly scour-tolerant species such as [Styela clava] and [Crepidula fornicata] (Solent) occupy the hard substrata


HabitatName:
[Ophiothrix fragilis] and/or [Ophiocomina nigra] brittlestar beds on sublittoral mixed sediment

HabitatDescription:
Circalittoral sediment dominated by brittlestars (hundreds or thousands m-2) forming dense beds, living epifaunally on boulder, gravel or sedimentary substrata. [Ophiothrix fragilis] and [Ophiocomina nigra] are the main bed-forming species, with rare examples formed by [Ophiopholis aculeate]. Brittlestar beds vary in size, with the largest extending over hundreds of square metres of sea floor and containing millions of individuals. They usually have a patchy internal structure, with localized concentrations of higher animal density. [Ophiothrix fragilis] or [Ophiocomina nigra] may dominate separately or there may be mixed populations of the two species. [Ophiothrix] beds may consist of large adults and tiny, newly-settled juveniles, with animals of intermediate size living in nearby rock habitats or among sessile epifauna. Unlike brittlestar beds on rock, the sediment based beds may contain a rich associated epifauna (Warner, 1971; Allain, 1974; Davoult & Gounin, 1995). Large suspension feeders such as the octocoral [Alcyonium digitatum], the anemone [Metridium senile] and the hydroid [Nemertesia antennina] are present mainly on rock outcrops or boulders protruding above the brittlestar-covered substratum. The large anemone [Urticina feline] may be quite common. This species lives half-buried in the substratum but is not smothered by the brittlestars, usually being surrounded by a 'halo' of clear space (Brun, 1969; Warner, 1971). Large mobile animals commonly found on Ophiothrix beds include the starfish [Asterias rubens], [Crossaster papposus] and [Luidia ciliaris], the urchins [Echinus esculentus] and [Psammechinus miliaris], edible crabs [Cancer pagurus], swimming crabs [Necora puber], [Liocarcinus] spp., and hermit crabs [Pagurus bernhardus]. The underlying sediments also contain a diverse infauna including the bivalve [Abra alba]. Warner (1971) found that numbers and biomass of sediment dwelling animals were not significantly reduced under dense brittlestar patches.


HabitatName:
Sandy mixed sediment with [Alcyonidium diaphanum]


HabitatDescription:
Offshore (deep) circalittoral habitats with slightly muddy mixed gravelly sand and stones or shell. This habitat may cover large areas of the offshore continental shelf although there is relatively little data available. Such habitats are often highly diverse with a high number of infaunal polychaete and bivalve species. Animal communities in this habitat are closely related to offshore gravels and coarse sands and in some areas populations of the horse mussel Modiolus modiolus may develop in these habitats (see A5.622).


HabitatName:
Polychaete-rich deep [Venus] community in offshore mixed sediments

HabitatDescription:
In offshore circalittoral slightly muddy mixed sediments, a diverse community particularly rich in polychaetes with a significant venerid bivalve component may be found. Typical species include the polychaetes [Glycera lapidum], [Aonides paucibranchiata], [Laonice bahusiensis], [Mediomastus fragilis], [Lumbrineris gracilis], [Pseudomystides limbata], [Protomystides bidentata] and syllid species and bivalves such as [Timoclea ovata], [Glycymeris glycymeris], [Spisula elliptica] and [Goodallia triangularis]. This biotope has been recorded on surveys of the Lambay and Codling Deeps and other areas of the Irish Sea and collectively with A5.142 comprise the 'Deep [Venus] Community' and the 'Boreal Off-Shore Gravel Association' as defined by other workers (Ford 1923; Jones 1950). Some examples of this biotope may have abundant juvenile [Modiolus modiolus]


HabitatName:
Mediterranean animal communities of coastal detritic bottoms

HabitatDescription:
These communities occur on a substratum whose nature varies widely and depends largely on the typology of the nearby coast and of nearby infralittoral formations. This implies that substrata can sometimes be gravels and sands originating from predominant local rocks, sometimes shell debris from various molluscs, sometimes debris from branched bryozoans or debris of dead and more or less corroded [Melobesiae] spp. The interstices between these various components are partially filled by a greater or lesser proportion of sand and mud.


HabitatDescription:
This facies is characterised by the high abundance of the Echinoderm [Ophiura texturata].


HabitatDescription:
This facies is characterised by the frequent presence of tunicate colonial ascidians or "Synascidies".


HabitatDescription:
This facies is characterised by the frequent presence of big colonies of arborescent bryozoans, unattached or fixed to small substrata.


HabitatName:
Mediterranean communities of shelf-edge detritic bottoms

HabitatDescription:
These communities are present in detritic bottoms with abundance of dead shells, bryozoans and coral skeletons.


HabitatDescription:
This facies is characterised by the high abundance of the sea urchin [Neolampas rostellata].


HabitatDescription:
This facies is characterised by the high abundance of the crynoid [Leptometra phalangium].


HabitatDescription:
This habitat type includes maerl beds, seaweed dominated mixed sediments (including kelps such as [Laminaria saccharina] and filamentous/foliose red and green algae), seagrass beds, and lagoonal angiosperm communities. These communities develop in a range of habitats from exposed open coasts to lagoons and are found in a variety of sediment types and salinity regimes.


HabitatDescription:
Beds of maerl in coarse clean sediments of gravels and clean sands, which occur either on the open coast or in tide-swept channels of marine inlets (the latter often stony). In fully marine conditions the dominant maerl is typically [Phymatolithon calcareum] (A5.511), whilst under variable salinity conditions in some sealochs beds of [Lithothamnion glaciale] (A5.512) may develop.


HabitatName:
[Phymatolithon calcareum] maerl beds in infralittoral clean gravel or coarse sand

HabitatDescription:
Maerl beds characterised by [Phymatolithon calcareum] in gravels and sands. Associated epiphytes may include red algae such as [Dictyota dichotoma, Halarachnion ligulatum], [Callophyllis laciniata], [Cryptopleura ramosa], [Brongniartella byssoides] and [Plocamium cartilagineum]. Algal species may be anchored to the maerl or to dead bivalve shells amongst the maerl. Polychaetes, such as [Chaetopterus variopedatus], [Lanice conchilega], [Kefersteinia cirrata], [Mediomastus fragilis, Chone duneri, Parametaphoxus fultoni] and [Grania] may be present. Gastropods such as [Gibbula cineraria], [Gibbula magus], [Calyptraea chinensis] [Dikoleps pusilla] and [Onoba aculeus] may also be present. [Liocarcinus depurator] and [Liocarcinus corrugatus] are often present, although they may be under-recorded; it would seem likely that robust infaunal bivalves such as [Circomphalus casina], [Mya truncata], [Dosinia exoleta] and other venerid bivalves are more widespread than available data currently suggests. It seems likely that stable wave-sheltered maerl beds with low currents may be separable from A5.511; having a generally thinner layer of maerl overlying a sandy /muddy substratum with a diverse cover of epiphytes (e.g. Bosence 1976; Blunden [et al]. 1977; 1981; Davies & Hall-Spencer 1996) but insufficient data currently exists on a national scale. Wave and current-exposed maerl beds, where thicker depths of maerl accumulate, frequently occur as waves and ridge / furrows arrangements (see Bosence 1976; Blunden [et al]. 1977; 1981; Irvine & Chamberlain 1994; Hall-Spencer 1995). At some sites where A5.511occurs, there may be significant patches of maerl gravel containing the rare burrowing anemone [Halcampoides elongatus]; this may be a separate biotope, but insufficient data exists at present. Northern maerl beds in the UK do not appear to contain [L. corallioides] but in south-west England and Ireland [L. corallioides] may occur to some extent in A5.511 as well as A5.513, where it dominates.


HabitatName:
[Phymatolithon calcareum] maerl beds with red seaweeds in shallow infralittoral clean gravel or coarse sand

HabitatDescription:
Upper infralittoral maerl beds characterised by [Phymatolithon calcareum] in gravels and sand with a wide variety of associated red seaweeds. These algae typically include [Dictyota dichotoma], [Plocamium cartilagineum], [Phycodrys rubens], [Chondrus crispus], [Halarachnion ligulatum], [Chylocladia verticillata], [Hypoglossum hypoglossoides] and [Nitophyllum punctum]. These species are not restricted to maerl beds but their abundance on maerl beds differentiates this biotope from A5.5112. Anthozoans and echinoderms are much less common in this biotope than in A5.5112, which typically occurs deeper than A5.5111.


HabitatName:
[Phymatolithon calcareum] maerl beds with [Neopentadactyla mixta] and other echinoderms in deeper infralittoral clean gravel or coarse sand

HabitatDescription:
Lower infralittoral maerl beds characterised by [Phymatolithon calcareum] in gravels and sand with a variety of associated echinoderms. The echinoderm [Neopentadactyla mixta] is frequently observed in this biotope. Other echinoderms such as [Echinus esculentus], [Ophiura albida] and rarely [Luidia ciliaris] may also be present. Red seaweed such as [Plocamium cartilagineum] may be present but at a much lower abundance than in A5.5111 and with fewer species present. Other, more ubiquitous echinoderms such as [Asterias rubens] may also be found in low numbers throughout A5.511 subunits.


HabitatName:
[Lithothamnion glaciale] maerl beds in tide-swept variable salinity infralittoral gravel

HabitatDescription:
Upper infralittoral tide-swept channels of coarse sediment in full or variable salinity conditions support distinctive beds of [Lithothamnion glaciale] maerl 'rhodoliths'. [Phymatolithon calcareum] may also be present as a more minor maerl component. Associated fauna and flora may include species found in other types of maerl beds (and elsewhere), e.g. [Pomatoceros triqueter], [Cerianthus lloydii], [Sabella pavonina], [Chaetopterus variopedatus], [Lanice conchilega], [Mya truncata], [Plocamium cartilagineum] and [Phycodrys rubens]. Unit A5.512, however, also has a fauna that reflects the slightly reduced salinity conditions, e.g. [Psammechinus miliaris] is often present in high numbers along with other grazers such as chitons and [Tectura] spp. [Hyas araneus], [Ophiothrix fragilis], [Ophiocomina nigra] and the brown seaweed [Dictyota dichotoma] are also typically present at sites. In Scottish lagoons this biotope may show considerable variation but the community falls within the broad description defined here.
Situation: This biotope can often be found at the upper end of Scottish sealochs where the variable salinity of the habitat may not be immediately obvious.


HabitatName:
[Lithothamnion corallioides] maerl beds on infralittoral muddy gravel

HabitatDescription:
Live maerl beds in sheltered, silty conditions which are dominated by [Lithothamnion corallioides] with a variety of foliose and filamentous seaweeds. Live maerl is at least common but there may be noticeable amounts of dead maerl gravel and pebbles. Other species of maerl, such as [Phymatolithon calcareum] and [Phymatolithon purpureum], may also occur as a less abundant component. Species of seaweed such as [Dictyota dichotoma], [Halarachnion ligulatum]. and [Ulva] spp. are often present, although are not restricted to this biotope, whereas [Dudresnaya verticillata] tends not to occur on other types of maerl beds. The anemones [Anemonia viridis] and [Cerianthus lloydii], the polychaetes [Notomastus latericeus] and [Caulleriella alata], the isopod [Janira maculosa] and the bivalve [Hiatella arctica] are typically found in A5.513 where as [Echinus esculentus] tends to occur more in other types of maerl. The seaweeds [Laminaria saccharina] and [Chorda filum] may also be present in some habitats. A5.513 has a south-western distribution in Britain and Ireland. Sheltered, stable, fully saline maerl beds in the north of Great Britain (where [L. corallioides] has not been confirmed to occur) may need to be described as an analogous biotope to A5.513 (see A5.511).


HabitatName:
[Lithophyllum fasciculatum] maerl beds on infralittoral mud

HabitatDescription:
Shallow, sheltered infralittoral muddy plains with [Lithophyllum fasciculatum] maerl. This rarely recorded maerl species forms flattened masses or balls several centimetres in diameter (Irvine & Chamberlain 1994). Unit A5.514 may be found on mud and muddy gravel mixed with shell. Species of anemone typical of sheltered conditions may be found in association, for example, [Anthopleura ballii], [Cereus pedunculatus] and [Sagartiogeton undatus]. Polychaetes such as [Myxicola infundibulum] and terebellids, also characteristic of sheltered conditions, may be present as may hydroids such as [Kirchenpaueria pinnata]. Occasional [Chlamys varia] and [Thyone fuscus] are present in all records of this biotope and red seaweeds such as [Plocamium cartilagineum], [Calliblepharis jubata] and [Chylocladia verticillata] are often present.


HabitatName:
Association with rhodolithes in coarse sands and fine gravels under the influence of bottom currents

HabitatDescription:
This facies is characterised by the presence of small calcareous algae species exposed to strong bottom currents.


HabitatName:
Association with rhodolithes on coastal detritic bottoms

HabitatDescription:
This association characterised by "balls" of calcareous encrusting algae occurs on coastal detritic bottoms.


HabitatDescription:
Shallow sublittoral sediments which support seaweed communities, typically including the kelp [Laminaria saccharina], the bootlace weed [Chorda filum] and various red and brown seaweeds, particularly filamentous types. The generally sheltered nature of these habitats enables the seaweeds to grow on shells and small stones which lie on the sediment surface; some communities develop as loose-lying mats on the sediment surface.


HabitatName:
[Laminaria saccharina] and red seaweeds on infralittoral sediments

HabitatDescription:
On infralittoral mixed muddy substrata communities characterised by the kelp [Laminaria saccharina] and mixed filamentous and foliose red algae can be found. This biotope contains a number of sub-biotopes distinguished by the degree of either wave or tidal exposure. In moderately strong tidal streams in exposed areas [Laminaria] is sparse and dense stands of red seaweeds are found attached to the boulders and cobbles that make up a large proportion of the sediment (A5.5211). As the degree of wave and/or tidal exposure decreases there is a change in community structure, with the density of [Laminaria] and the diversity of red algal species increasing (A5.5212). As the environment becomes more stable a number of brown algal species are able to inhabit this environment and a rich infauna develops (A5.5213). In the most sheltered examples of this biotope a diverse muddy sediment infauna can be found and the ['Trailliella'] phase of [Bonnemaisonia hamifera] may develop (A5.5214).


HabitatDescription:
Shallow mixed substrata of cobbles and pebbles swept by moderately strong tidal streams in exposed areas, and characterised by dense stands of red seaweeds. Tide-swept infralittoral cobbles and pebbles which may be highly mobile, create an environment that is difficult for many algae to survive in. Foliose and filamentous seaweeds with an encrusting phase in their life history, or those that are able to withstand rolling of the substratum and scouring, can form dense turfs of seaweed in the more settled summer months. Characteristic red seaweeds include [Halarachnion ligulatum] which is able to survive attached to the pebbles and cobbles. Ephemeral algae grow rapidly in periods of relative stability. Other characteristic red seaweeds include [Plocamium cartilagineum], [Hypoglossum hypoglossoides], [Bonnemaisonia asparagoides] and [Brongniartella byssoides]. Coralline encrusting algae cover many of the cobbles and pebbles; some areas of cobbles may be quite barren, dominated only by encrusting coralline algae and brittlestars. Of the brown seaweeds scattered [Laminaria] spp. and [Desmarestia] spp. may be present on more stable large boulders or bedrock outcrops. [Chorda filum] and [Halidrys siliquosa] may be present in low abundance but where these seaweeds occur in greater abundance (typically >Frequent) refer to A3.123 and A3.126 respectively. Although the faunal component of this biotope is usually relatively sparse it can include a wide variety of species. Turfs of hydroids ([Nemertesia] spp., [Aglaophenia tubulifera]) and bryozoans ([Crisia] spp. and [Bugula] spp.) are the major components but sponges and anemones may also occur. Brittlestars, sea-urchins, hydroids and solitary ascidians are more prominent in the Scottish examples of this biotope, which tend to occur in deeper water, due in part to clearer waters.

Situation: Although not common, this biotope is widely distributed from Sussex to the shallow areas of the Sarns in Cardigan Bay, the west coast of Scotland and the north-east coast of Ireland. Despite the wide distribution, the red seaweed composition remains remarkably constant. In areas such as the Sarns, in Wales, where mixed substrata continue into the shallows, dense swathes of A3.123 can be found. More stable but highly scoured areas adjacent to A5.5211 can support the [Halidrys] biotope A3.126. Where bedrock or large boulders occur above the mixed substrata of A5.5211 it may support a kelp forest or park (A3.115 or A3.214). At many sites the mixed substrata supporting the dense seaweed turf gives way to sediment of varying composition.

Temporal variation: This biotope will take on a much more depauperate appearance during the winter months, once the ephemeral seaweeds have died back in late summer/autumn. Storms can mobilise the loose pebbles and cobbles, removing all but the most resilient of seaweeds and animals. By summer, under more stable conditions, new growth will flourish and dense stands of seaweeds dominate the seabed.


HabitatName:
[Laminaria saccharina] and robust red algae on infralittoral gravel and pebble

HabitatDescription:
Shallow kelp community found on gravel and gravelly sand in slightly less exposed areas than A5.5211 but in moderately strong tidal currents, and characterised by occasional [Laminaria saccharina] with an undergrowth of robust red seaweeds. Characteristic red seaweeds, as with A5.5211, include [Plocamium cartilagineum], [Halarachnion ligulatum] and [Brongniartella byssoides]; however the greater stability of this biotope allows a slightly more diverse range of red seaweeds to become established including [Polyides rotundus], [Rhodophyllis divaricata], [Delesseria sanguinea] and [Nitophyllum punctatum]. Coralline encrusting algae may be found covering the larger pebbles. [Laminaria hyperborea] may also be present within this biotope, although at low densities. Other brown algal species present include [Desmarestia] spp., [Dictyota dichotoma] and [Chorda filum], all at low abundance. The ubiquitous green seaweed [Ulva] sp. may be found attached to larger pebbles.


HabitatName:
[Laminaria saccharina] and filamentous red algae on infralittoral sand

HabitatDescription:
Shallow kelp community found on sand and slightly gravelly sand, in moderately exposed and sheltered conditions, with weak tidal currents. The community is characterised by occasional [Laminaria saccharina] with an undergrowth of red algae. Characteristic red seaweeds, as with A5.5212, include [Plocamium cartilagineum], [Polyides rotundus], [Polysiphonia elongate] and [Lomentaria clavellosa]. Coralline encrusting algae is much less important in this biotope as a result of a lack of suitable substrate. Brown algal species present, as with other subunits of A5.521, include [Desmarestia] spp., [Dictyota dichotoma] and [Chorda filum], all at low abundance. The ubiquitous green seaweed [Ulva] sp. may also be present. The sandy substrate is home to a variety of typical sand dwelling infauna including polychaetes ([Scoloplos armiger], [Exogone hebes], and [Aricidea minuta]), amphipods ([Ampelisca brevicornis]), and bivalves ([Lucinoma borealis] and [Abra alba]). [Arenicola] worm casts and [Lanice] worm tubes may be visible at the sediment surface.


HabitatName:
[Laminaria saccharina] with red and brown seaweeds on lower infralittoral muddy mixed sediment

HabitatDescription:
Slightly deeper kelp community in the lower infralittoral, found on sandy gravelly mud, in sheltered and very sheltered conditions, with very weak tidal currents. The community is characterised by occasional [Laminaria saccharina] with an undergrowth of red and brown algae. Characteristic red seaweeds, as with other A5.521 subunits include [Plocamium cartilagineum] and [Phycodrys rubens]. However, the sheltered conditions of this biotope allow the '[Trailliella]' phase of [Bonnemaisonia hamifera] to develop (although not to the extent of forming distinct mats as in A5.526), and the related species [Bonnemaisonia asparagoides]. Brown algal species present, as with other A5.521 subunits, include [Desmarestia] spp at low abundance. The ubiquitous green seaweed [Ulva] sp. may also be present. The muddy substrate is home to a variety of typical mud dwelling fauna including the burrowing anemone [Cerianthus lloydii]. The gravelly component of this biotope provides a substrate for encrusting species such as the polychaete [Pomatoceros triqueter] and coralline encrusting algae.


HabitatName:
[Laminaria saccharina] and [Chorda filum] on sheltered upper infralittoral muddy sediment

HabitatDescription:
Shallow kelp community found on sandy mud and gravelly sandy mud, in sheltered or extremely sheltered conditions, with very weak tidal currents. The community is characterised by a reasonable covering of [Laminaria saccharina] and [Chorda filum]. Beneath the kelp canopy, [Ulva lactuca] is often frequent and some filamentous and foliose red algae may be present, along with filamentous brown ectocarpoid algae although in much lower abundance than in the A5.521 subunits. At the sediment surface ubiquitous fauna such as [Asterias rubens], crabs such as [Pagurus bernhardus], [Carcinus maenas], and the gastropod [Gibbula cineraria] may be visable and in some areas [Sabella pavonina] may be present. Given the nature of the sediment it is likely that a wide range of infaunal bivalves and polychaetes are present including [Arenicola marina], [Mediomastus fragilis] and [Anaitides mucosa]. In more tideswept areas with coarser and generally less muddy sediments A5.522 may be replaced by one of the sub units of A5.521.


HabitatName:
[Laminaria saccharina] with [Psammechinus miliaris] and/or [Modiolus modiolus] on variable salinity infralittoral sediment

HabitatDescription:
Shallow kelp community found on stoney mixed sediment, in full or variable salinity, in sheltered or moderately exposed conditions, with weak or very weak tidal currents. The community is characterised by a dense covering of [Laminaria saccharina]. Beneath the kelp canopy, frequent [Psammechinus miliaris] may be found grazing the algal turf and scattered [Modiolus modiolus] are characteristic of this biotope. Encrusting the suface of stones and pebbles are [Pomatoceros triqueter] and in the sediment between the stones, the burrowing anemone [Cerianthus lloydii] may also be present. Small patches of [Lithothamnion glaciale] may be found in this biotope, although these patches do not form distinct beds as in A5.512. In addition, a more ubiquitous fauna such as [Asterias rubens] and [Pagurus bernhardus] are also present. This biotope is generally found in sealochs.


HabitatName:
[Laminaria saccharina], [Gracilaria gracilis] and brown seaweeds on full salinity infralittoral sediment

HabitatDescription:
Shallow kelp community found on muddy sand, in moderately exposed or sheltered, fully marine conditions, with weak tidal currents. The community is characterised by a reasonable covering of [Laminaria saccharina]. Frequent [Chorda filum] may also form part of the canopy although not at the abundance in A5.522. Beneath the canopy the community is characterised by the red algae [Gracilaria gracilis], and various brown algal species particularly [Dictyota dichotoma]. Other members of the understory may include a variety of other filamentous and foliose red algae in particular [Ceramium nodulosum] and the green alga [Ulva]. The muddy sand substrate supports a variety of faunal species including polychaetes ([Lanice conchilega]) and gastropods ([Hinia reticulata]).


HabitatName:
[Laminaria saccharina] and [Gracilaria gracilis] with sponges and ascidians on variable salinity infralittoral sediment

HabitatDescription:
Shallow kelp community found on stony sediment, in extremely sheltered, variable salinity conditions, with moderately strong tidal currents. The community is characterised by a more sparse covering of [Laminaria saccharina], particularly when compared to the fully marine version of this sub biotope (A5.524). Beneath the canopy the community is characterised by the red algae [Gracilaria gracilis], and a variety of faunal species in particular sponges ([Suberites ficus] and [Halichondria panacea]) and ascidians ([Ascidiella aspersa] and [Dendrodoa grossularia]). The stony substrate provides a surface for attachment for these and many other filter and suspension feeding species, particularly barnacles ([Balanus crenatus]), hydroids ([Urticina feline] and [Hydractinia echinata]) and anemones. Other members of the understory may include a variety of filamentous and foliose red algae in particular [Pterothamnion plumula], and the green alga [Ulva].


HabitatName:
Mats of [Trailliella] on infralittoral muddy gravel

HabitatDescription:
Dense loose-lying beds of the '[Trailliella]' phase of [Bonnemaisonia hamifera] may occur in extremely sheltered shallow muddy environments. Beds of this alga are often 10 cm thick but may reach 100 cm at some sites. Other loose-lying algae may also occur such as [Audouinella floridula, Phyllophora crispa] and species of [Derbesia]. Often the mud is gravelly or with some cobbles and may be black and anoxic close to the sediment surface. This biotope is widely distributed in lagoons, sealochs and voes but should only be described as A5.526 when a continuous mat is found. It is likely that the infaunal component of this biotope may be considerably modified by the overwhelming quantity of loose-lying algae.


HabitatName:
Loose-lying mats of [Phyllophora crispa] on infralittoral muddy sediment

HabitatDescription:
Infralittoral muddy sand and sandy mud, sometimes with some shells or pebbles, and a dense, loose-lying cover of [Phyllophora crispa]. This biotope occurs in very sheltered conditions such as those found in sealochs and voes. A5.527 is similar to other biotopes described with dense, loose-lying algae but has been less frequently recorded, and from the few records available, appears to occur in slightly deeper infralittoral waters primarily between 10m to 30m and typically in fully saline waters. The seaweeds in this biotope may be epiphytised by ascidians such as [Ascidiella aspera]. Kelp such as [Laminaria saccharina] and red seaweeds including [Plocamium cartilagineum] may be present in some areas. The scallops [Pecten maximus] and [Aequipecten opercularis] may also be found occasionally in this biotope and [Trailliella]/[Bonnemaisonia hamifera] may also be present but not at the levels found in A5.526.


HabitatDescription:
Shallow muddy sediments, often with boulders, cobbles and pebbles around the edges of lagoons, or other areas that are exposed to wide salinity variations are unsuitable for colonisation by many species. Such areas may be colonised by a dense blanket of ephemeral green algae such as [Enteromorpha] spp., [Chaetomorpha linum], [Cladophora liniformis] or [Rhizoclonium riparium]. This biotope may also contain some red seaweeds, such as [Furcellaria lumbricalis], but always at low abundance (compare with A3.343). Amongst the filamentous green algae, grazing molluscs and solitary ascidians may be present. Infauna may typically include [Corophium volutator], [Heterochaeta costata], [Tubificoides benedeni] and other taxa suited for low/variable salinity environments.


HabitatDescription:
The characteristic species of this association is the Annelid [Ficopomatus enigmaticus].


HabitatDescription:
This association is characterised by the red algae belonging to the genus [Gracilaria].


HabitatName:
Association with [Chaetomorpha linum] and [Valonia aegagropila]

HabitatDescription:
This association is characterised by the green algae [Chaetomorpha linum] and [Valonia aegagropila].


HabitatDescription:
This association is characterised by the red alga [Halopitys incurvus].


HabitatName:
Association with [Ulva laetevirens] and [Enteromorpha linza]

HabitatDescription:
This association is characterised by the green algae [Ulva laetevirens] and [Enteromorpha linza].


HabitatDescription:
This association is characterised by the brown alga [Cystoseira barbata].


HabitatDescription:
This association is characterised by the foxtail stonewort (charophyte) [Lamprothamnium papulosum]. [Lamprothamnium papulosum] is a rare, brackish water stonewort growing to a height of up to 40 cm with regular whorls of slender cylindrical branches each with several spine-like bracts which give the plant a furry appearance. The foxtail stonewort has a sporadic distribution around the coast of Europe from Norway to the Iberian Peninsula. In the Mediterranean it extends eastwards to Tunisia and Sicily with isolated records from Cyprus and the Black Sea.


HabitatName:
Association with [Cladophora echinus] and [Rytiphloea tinctoria]

HabitatDescription:
The characteristic species of this association are the green alga [Cladophora echinus] and the red alga [Rytiphloea tinctoria].


HabitatDescription:
This association on coastal detritic bottoms is characterised by the abundance of the red alga [Peyssonnelia rosa-marina].


HabitatDescription:
This association on coastal detritic bottoms is characterised by the abundance of the brown alga [Arthrocladia villosa].


HabitatDescription:
This association on coastal detritic bottoms is characterised by the abundance of the brown alga [Osmundaria volubilis].


HabitatDescription:
This association on coastal detritic bottoms is characterised by the abundance of the red alga [Kallymenia patens].


HabitatDescription:
This association on coastal detritic bottoms is characterised by the abundance of the brown alga [Laminaria rodriguezii].


HabitatName:
Pontic [Phyllophora nervosa] biocenosis on shell gravel

HabitatDescription:
The dominant species is the alga [Phyllophora nervosa]. In addition to the dominant species there are three other species of Phyllophora: [Phyllophora brodiaei], [Phyllophora pseudoceranoides], [Phyllophora trallii]. There are 118 species of invertebrates in the Phyllophora field the most characteristic of which are: [Bittium reticulatum], [Harmothoe imbricata], [Balanus improvisus], [Synisoma capito] (Zaitsev and Alexandrov 1998). Studies conducted in the NW shelf area (Zernov's Phyllophora field) indicated tht the mass macrozoobenthos species are: the bivalve mollusc [Mytilus galloprovincialis], [Mytilaster lineatus], the gastropod [Rissoa parva], the barnacle [Balanus improvisus] and the polychaete [Nereis succinea]. In Egorlitsky Bay the mass species are [Mytilaster lineatus], [Nereis zonata] and [Platynereis dumerilii]. Studies conducted along the Romanian coast (Vailiu and Bodeanu, 1972) indicate that [Phyllophora nervosa] and [Phyllophora brodiae] are present between 10-56 m with highest biomass recorded in the northernmost part of the Romanian coasts, at 43-46 m depth where the presence of [Phyllophora brodiae] is favoured by the presence of a particular substrate given by the massive development of calcareous algal concretions of the red alga [Lithothamnion] present on bivalve shells (Vasiliu and Bodeanu, 1972). In Romanian waters, in the area known as Zernov's Phyllophora field, the fauna is composed mostly of [Mytilus galloprovincialis] up to 20-30 meters depth, and [Modiolus phaseolinus] at depths exceeding 30 meters (Tiganus, 1991-1992).


HabitatName:
Pontic degraded facies of the [Phyllophora] biocenosis

HabitatDescription:
This facies represents a degraded form of the [Phyllophora nervosa] biocenosis in which [Phyllophora nervosa] is substituted by [Phyllophora brodiaei] and [Mytilus galloprovincialis] is dominant.


HabitatDescription:
Beds of submerged marine angiosperms in the genera [Cymodocea], [Halophila], [Posidonia], [Ruppia], [Thalassia], [Zostera].


HabitatDescription:
Formations of [Cymodocea nodosa] of the Atlantic shores of southern Iberia, northwestern Africa and the Macaronesian Islands.


HabitatDescription:
Formations of [Cymodocea nodosa] or [Cymodocea] and [Caulerpa] spp., in particular [Caulerpa prolifera], occupying large surfaces, on sandy substrates at depths of 1-15 metres, around the Macaronesian Islands.


HabitatDescription:
Formations of [Cymodocea nodosa] of the southernmost Atlantic coasts of the Iberian peninsula.


HabitatDescription:
[Cymodocea nodosa] formations of the Mediterranean, permanently submerged in waters down to 10 metres deep, often in sheltered areas behind [Posidonia] reefs, monospecific or associated with either the alga [Caulerpa prolifera] or the phanerogam [Halophila stipulacea].


HabitatName:
Association with [Cymodocea nodosa] on well sorted fine sands

HabitatDescription:
This association, characterised by the seagrass [Cymodocea nodosa], lives on soft bottoms formed by well sorted fine sands and can constitute a local facies with epiflora.


HabitatName:
Association with [Cymodocea nodosa] on superficial muddy sands in sheltered waters

HabitatDescription:
This association is characterised by the seagrass [Cymodocea nodosa] and is present when the water is actively renewed and there is no trace of desalination.


HabitatDescription:
Deep water colonies of [Halophila] spp. or [Thalassia] spp. of the Mediterranean and the Macaronesian Atlantic.


HabitatDescription:
[Halophila decipiens] colonies of Tenerife, at depths between 10 and 14 metres.


HabitatDescription:
The facies characterised by the seagrass [Halophila stipulacea] lives on soft bottoms with fine sands that are fairly enriched by fine particles. Colonies of [Halophila stipulacea] have invaded the Mediterranean as a result of the opening of the Suez Canal; they have been reported from continental Greece, the Cyclades, Crete, Rhodes, Samos, the Maltese Islands.


HabitatName:
[Zostera] beds in full salinity infralittoral sediments

HabitatDescription:
Beds of seagrass ([Zostera marina] or [Ruppia] spp.) in shallow sublittoral sediments. These communities are generally found in extremely sheltered embayments, marine inlets, estuaries and lagoons, with very weak tidal currents. They may inhabit low, variable and full salinity marine habitats. Whilst generally found on muds and muddy sands they may also occur in coarser sediments, particularly marine examples of [Zostera] communities.


HabitatName:
[Zostera marina]/[angustifolia] beds on lower shore or infralittoral clean or muddy sand

HabitatDescription:
Expanses of clean or muddy fine sand and sandy mud in shallow water and on the lower shore (typically to about 5 m depth) can have dense stands of [Zostera marina/angustifolia] [Note: the taxonomic status of [Z. angustifolia] is currently under consideration]. In A5.5331 the community composition may be dominated by these [Zostera] species and therefore characterised by the associated biota. Other biota present can be closely related to that of areas of sediment not containing [Zostera marina], for example, [Laminaria saccharina], [Chorda filum] and infaunal species such as [Ensis] spp. and [Echinocardium cordatum] (e.g. Bamber 1993). From the available data it would appear that a number of sub-biotopes may be found within this biotope dependant on the nature of the substratum and it should be noted that sparse beds of [Zostera marina] may be more readily characterised by their infaunal community. For example, coarse marine sands with seagrass have associated communities similar to A5.133, A5.137 or A5.135 whilst muddy sands may have infaunal populations related to A5.241, A5.243 and A5.242. Muddy examples of this biotope may show similarities to A5.332, A5.343, A5.342 or A5.351. At present the data does not permit a detailed description of these sub-biotopes but it is likely that with further study the relationships between these assemblages will be clarified. Furthermore, whilst the [Zostera] biotope may be considered an epibiotic overlay of established sedimentary communities it is likely that the presence of [Zostera] will modify the underlying community to some extent. For example, beds of this biotope in the south-west of Britain may contain conspicuous and distinctive assemblages of Lusitanian fauna such as [Laomedea angulata], [Hippocampus] spp. and Stauromedusae. In addition, it is known that seagrass beds play an important role in the trophic status of marine and estuarine waters, acting as an important conduit or sink for nutrients and consequently some examples of [Zostera marina] beds have markedly anoxic sediments associated with them.


HabitatName:
Mediterranean and Pontic [Zostera noltii] beds

HabitatDescription:
Sparse meadows formed on muddy sands of the upper part of the infralittoral zone of Mediterranean coasts. This association is found in euryhaline and eurythermal waters and is characterised by the dwarf eel-grass [Zostera noltii] and the alga [Giraudya sphacelarioides].


HabitatName:
Association with [Zostera noltii] in euryhaline and eurythermal environment

HabitatDescription:
The association with [Zostera noltii] develops in lagoons that are subject to wide ranges of salinity, on varied loose substrata, from sand to mud, either at the entrances to the lagoons (graus) or even within the lagoons, where it develops monospecific phanerogam populations. It withstands a certain amount of hydrodynamics but is very sensitive to eutrophication, turbidity and pollution of the water. Given its wide potential, it constitutes the epiflora of various habitats. In the case of this association of the euryhaline and eurythermal lagoon biocenosis, the fauna is rich and is made up of brackish water species of the biocenosis to which it belongs with some addition of marine water species.


HabitatName:
Association with [Zostera noltii] on superficial muddy sands in sheltered waters

HabitatDescription:
Association with the [Zostera noltii] on muddy sands in sheltered waters. The [Zostera noltii] constitutes a bed in areas where there is an active deposit of fine matter. The epifauna of the vascular plants is poor. The population can tolerate a slight local lack of salt.


HabitatName:
Association with [Zostera marina] in euryhaline and eurythermal environment

HabitatDescription:
This association is found in euryhaline and eurythermal waters and it is characterised by the eel-grass [Zostera marina].


HabitatDescription:
Formations of the Mediterranean endemic [Zostera hornemanniana], vicariant of [Zostera marina], often confined to coastal lagoons, recorded also from the Istrio-Dalmatian archipelago.


HabitatName:
Middle European [Ruppia] and [Zannichellia] communities

HabitatDescription:
Submerged beds of [Ruppia maritima], [Ruppia cirrhosa], [Zannichellia pedicellata], [Chara] spp., [Tolypella nidifica] of brackish seas, sea inlets, estuaries, permanent pools of mud or sand flats, and coastal lagoons of Atlantic, North Sea and Baltic coasts of boreal and temperate Europe.


HabitatDescription:
Submerged beds of [Ruppia maritima] or [Ruppia cirrhosa] and of [Chara] spp. of sea inlets, estuaries, permanent pools of mud or sand flats, and coastal lagoons of the Mediterranean, the Black Sea and the subtropical Atlantic, north to southwestern Iberia, south to 27°N.


HabitatName:
[Ruppia maritima] in reduced salinity infralittoral muddy sand

HabitatDescription:
In sheltered brackish muddy sand and mud, beds of [Ruppia maritima] and more rarely [Ruppia spiralis] may occur. These beds may be populated by fish such as [Gasterosteus aculeatus] which is less common on filamentous algal-dominated sediments. Seaweeds such as [Chaetomorpha] spp., [Enteromorpha] spp., [Cladophora] spp., and [Chorda filum] are also often present in addition to occasional fucoids. In some cases the stoneworts [Lamprothamnium papulosum] and [Chara aspera] occur. Infaunal and epifaunal species may include mysid crustacea, the polychaete [Arenicola marina], the gastropod [Hydrobia ulvae], the amphipod [Corophium volutator] and oligochaetes such as [Heterochaeta costata]. In some areas [Zostera marina] may also be interspersed with the [Ruppia] beds.


HabitatDescription:
This assemblage is characterised by the presence of the marine seagrass (phanerogam) [Posidonia oceanica]. This species is endemic to the Mediterranean and constitutes characteristic formations called Posidonia meadows, located between the surface and up to 50 metres depth.


HabitatName:
Ecomorphosis of striped [Posidonia oceanica] meadows

HabitatDescription:
The striped [Posidonia oceanica] meadows facies is found at depth 0 - 5 metres. It appears as fairly narrow ribbons that can be several dozen metres long. These ribbons are separated by stretches of dead mat colonised by [Cymodocea nodosa] and/or [Caulerpa] spp.


HabitatName:
Ecomorphosis of "barrier-reef" [Posidonia oceanica] meadows

HabitatDescription:
This ecomorphosis can be found in [Posidonia oceanica] beds present in sheltered bays. The vertical growth of the rhizomes leads to the raising of the mat, thus enabling the meadow to reach the surface.


HabitatName:
Facies of dead "mattes" of [Posidonia oceanica] without much epiflora

HabitatDescription:
This facies is characterised by a dead mat of [Posidonia oceanica] without macro-epiflora.


HabitatName:
Association with [Caulerpa prolifera] on [Posidonia] beds

HabitatDescription:
This facies is characterised by the presence of the green alga [Caulerpa prolifera] in association with the [Posidonia oceanica] bed.


HabitatDescription:
Beds of submerged or slightly emergent vascular vegetation of brackish seas, sea inlets, estuaries, permanent pools of mud or sand flats, and coastal lagoons.


HabitatName:
Vegetation of brackish waters dominated by [Phragmites australis]

HabitatDescription:
Permanently low salinity muds or peaty muddy sands with some gravel which supports [Phragmites australis] reed beds. These reed beds are often found in enclosed water bodies influenced by freshwater inflow and may have notable quantities of decaying reed material. The substratum may be mixtures of mud, peaty mud, sand and some gravel. Filamentous green algae and charaphytes such as [Lamprothamnium papulosum] and [Chara aspera] may also be found in association with this biotope as well as a the freshwater quillwort [Myriophyllum] spp. The infaunal component of this biotope is poorly known. This biotope is further described as NVC type S4 (Rodwell 1995).


HabitatDescription:
Low and variable salinity infralittoral mud with beds of [Potamogeton pectinatus]. Other associated species are broadly similar to that of unit A5.5343, with blankets of filamentous green algae such as [Enteromorpha intestinalis], [Cladophora liniformis] and [Rhizoclonium riparium]. The grazing gastropod [Potamopyrgus antipodarum] is found in this biotope and juvenile [Mytilus edulis] have been observed settled on [Potamogeton] leaves and amongst the algae. The nationally scarce charaphyte [Lamprothamnium papulosum] may be found to some extent in this biotope but more often in neighbouring habitats (see Plaza & Sanderson 1997). Mysids, trout ([Salmo trutta]), and sticklebacks [Gasterosteus aculeatus] can be found swimming amongst the vegetation. [Mya arenaria] may be found in some examples of this biotope, but the infaunal component of this biotope requires further investigation but is likely to contain oligochaetes, [Arenicola marina], [Corophium volutator] and [Gammarus] spp.


HabitatName:
Vegetation of brackish waters dominated by [Ranunculus baudotii]

HabitatDescription:
[Ranunculus] spp.-dominated communities developed in shallow-waters of very low salinity of coastal lagoons, coastal basins and coastal waters of the Palaearctic region, including the Atlantic, North Sea, Baltic Sea, Mediterranean Sea and Black Sea. The most widespread characteristic species is [Ranunculus baudotii]. Locally, other crowfoots may be typical, as, in particular, in the Gulf of Bothnia, [Ranunculus trichophyllus] ([Ranunculus confervoides]).


HabitatName:
Vegetation of brackish waters dominated by [Scirpus lacustris] or [Scirpus tabernaemontani]


HabitatName:
[Zostera] beds in reduced salinity infralittoral sediments


HabitatDescription:
This habitat type includes polychaete reefs, bivalve reefs (e.g. mussel beds) and cold water coral reefs. These communities develop in a range of habitats from exposed open coasts to estuaries, marine inlets and deeper offshore habitats and may be found in a variety of sediment types and salinity regimes.


HabitatName:
Sublittoral polychaete worm reefs on sediment


HabitatName:
[Sabellaria spinulosa] on stable circalittoral mixed sediment

HabitatDescription:
The tube-building polychaete [Sabellaria spinulosa] at high abundances on mixed sediment. These species typically forms loose agglomerations of tubes forming a low lying matrix of sand, gravel, mud and tubes on the seabed. The infauna comprises typical sublittoral polychaete species such as [Protodorvillea kefersteini], [Pholoe synophthalmica], [Harmothoe] spp, [Scoloplos armiger], [Mediomastus fragilis], [Lanice conchilega] and cirratulids, together with the bivalve [Abra alba], and tube building amphipods such as [Ampelisca] spp. The epifauna comprise a variety of bryozoans including [Flustra foliacea], [Alcyonidium diaphanum] and [Cellepora pumicosa], in addition to calcareous tubeworms, pycnogonids, hermit crabs and amphipods. The reefs formed by [Sabellaria] consolidate the sediment and allow the settlement of other species not found in adjacent habitats leading to a diverse community of epifaunal and infauna species. The development of such reefs is assisted by the settlement behaviour of larval [Sabellaria] which are known to selectively settle in areas of suitable sediment and particularly on existing [Sabellaria] tubes (Tait and Dipper, 1997; Wilson 1929). These reefs are particularly affected by dredging or trawling and in heavily dredged or disturbed areas an impoverished community may be left (e.g. A5.143) particularly if the activity or disturbance is prolonged. However, it is likely that reefs of [S. spinulosa] can recover quite quickly from short term or intermediate levels of disturbance as found by Vorberg (2000) in the case of disturbance from shrimp fisheries and recovery will be accelerated if some of the reef is left intact following disturbance as this will assist larval settlement of the species.

Situation: [S. spinulosa] reefs are often found in areas with quite high levels of natural sediment disturbance.

Temporal variation: In some areas the reefs are periodically destroyed by storm events leading to a cyclical shift in biotopes from A5.611 to other biotopes e.g. A5.143 or A5.261 with re-establishment of the [Sabellaria] colonies in the following year.


HabitatName:
[Sabellaria alveolata] on variable salinity sublittoral mixed sediment

HabitatDescription:
Tide-swept sandy mixed sediments with cobbles and pebbles, in variable salinity or fully marine conditions, may be characterised by surface accumulations of the reef building polychaete [Sabellaria alveolata]. The presence of [Sabellaria] sp. has a strong influence on the associated infauna as the tubes bind the surface sediments together and provide increased stability. Such reefs may form large structures up to a metre in height although they are considerably less extensive than the intertidal reefs formed by this species (unit A2.711). Other associated species may include the polychaete [Melinna cristata], itself often as dense aggregations, mobile surface feeding polychaetes including [Typosyllis armillary] and [Eulalia tripunctata]. Other polychaetes may include [Mediomastus fragilis] and [Pygospio elegans] whilst amphipods such as [Harpinia pectinata] and tubificid oligochaetes may also be found.


HabitatName:
[Serpula vermicularis] reefs on very sheltered circalittoral muddy sand

HabitatDescription:
Large clumps (mini 'reefs') of the calcareous tubes of [Serpula vermicularis], typically attached to stones on muddy sediment in very sheltered conditions in sealochs and other marine inlets. A rich associated biota attached to the calcareous tube may include [Esperiopsis fucorum], thin encrusting sponges, and the ascidians [Ascidiella aspersa], [Ascidia mentula], [Dendrodoa grossularia] and [Diplosoma listerianum]. The echinoderms [Ophiothrix fragilis] and [Psammechinus miliaris] and the queen scallop ([Aequipecten opercularis]) are also found throughout this biotope. In shallow water dense [Phycodrys rubens] may grow on the 'reefs'. This biotope has been recorded in the U.K. from Loch Creran, where these reefs have been well studied (Moore 1996), and Loch Sween, where they are reported to have deteriorated. The only other known sites for this biotope are Salt Lake, Cliffden and Killary Harbour, Co. Galway.


HabitatDescription:
Sublittoral mussel beds comprised of either the horse mussel [Modiolus modiolus] or the common mussel [Mytilus edulis]. These communities may be sublittoral extensions of littoral reefs or exist independently. Found in a variety of habitats ranging from sheltered estuaries and marine inlets to open coasts and offshore areas they may occupy a range of substrata, although due to the stabilising effect such communities have on the substratum muddy mixed sediments are typical. A diverse range of epibiota and infauna often exists in these communities.


HabitatName:
[Modiolus modiolus] beds with hydroids and red seaweeds on tide-swept circalittoral mixed substrata

HabitatDescription:
[Modiolus] beds on mixed substrata (cobbles, pebbles and coarse muddy sediments) in moderately strong currents or wave exposed areas, typically on the open coast but also in tide-swept channels of marine inlets. [Ophiothrix fragilis] are often common in this biotope along with the calcareous tubes of [Pomatoceros triqueter], anemones such as [Alcyonium digitatum] and [Urticina felina] and hydroids such as [Abietinaria abietina] and [Sertularia argentea]. [Buccinum undatum] may also be important and in some areas the clam [Chlamys varia] may be frequent but not in the same abundances as in unit A5.624. Little information on the infaunal component is given here although it is likely that it is very rich and may highlight more subtle differences in the [Modiolus] biotopes. This biotope is typified by examples off the north-west Lleyn Peninsula in N Wales and off Co. Down, Northern Ireland.


HabitatName:
[Modiolus modiolus] beds on open coast circalittoral mixed sediment

HabitatDescription:
Muddy gravels and coarse sands in deeper water of continental seas may contain venerid bivalves with beds of [Modiolus modiolus]. The clumping of the byssus threads of the [M. modiolus] creates a stable habitat that attracts a very rich infaunal community with a high density of polychaete species including [Glycera lapidum], [Paradoneis lyra], [Aonides paucibranchiata], [Laonice bahusiensis], [Protomystides bidentata], [Lumbrineris] spp., [Mediomastus fragilis] and syllids such as [Exogone] spp. and [Sphaerosyllis] spp. Bivalves such as [Spisula elliptica], [Timoclea ovata] and other venerid species are also common. Brittlestars such as [Amphipholis squamata] may also occur with this community. This biotope is very similar to A5.451 and the 'boreal off-shore gravel association' and the 'deep Venus community' described by previous workers (Ford 1923; Jones 1951). Similar [Modiolus] beds (though with a less diverse infauna) on open coast stable boulders, cobbles and sediment are described under A5.621.


HabitatName:
[Modiolus modiolus] beds with fine hydroids and large solitary ascidians on very sheltered circalittoral mixed substrata

HabitatDescription:
Beds or scattered clumps of [Modiolus modiolus] in generally sheltered conditions with only slight tidal movement. Typically occurs in sealochs and the Shetland voes. Brittlestars [Ophiothrix fragilis] and [Ophiocomina nigra], as well as [Ophiopholis aculeata] are often frequent, sometimes forming a dense bed as described in A5.445. The queen scallop [Aequipecten opercularis] is often present in moderate abundances. Large solitary ascidians ([Ascidiella aspersa], [Corella parallelogramma, Dendrodoa grossularia]) and fine hydroids ([Kirchenpaueria pinnata]) are present attached to the mussel shells. Decapods such as hermit crabs ([Pagurus bernhardus]) and spider crabs ([Hyas araneus]) are typically present. Coralline algal crusts may be found on the mussel shells, with some red seaweeds in shallower water such as [Phycodrys rubens]. Little information on the infaunal component is given here although it is likely that it is very rich and may highlight more subtle differences in the [Modiolus] biotopes.


HabitatName:
[Modiolus modiolus] beds with [Chlamys varia], sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata

HabitatDescription:
Dense [Modiolus modiolus] beds, covered by hydroids and bryozoans, on soft gravelly, shelly mud with pebbles in areas of slight or moderate tidal currents. The variable scallop ([Chlamys varia]) is frequently found in large numbers amongst the [Modiolus] shells. Hydroids such as [Halecium] spp. and [Kirchenpaueria pinnata] and ascidians such as [Ascidiella aspersa], [Corella parallelogramma] and [Ciona intestinalis] may be found attached to pebbles or mussel shells. The echinoderms [Ophiothrix fragilis] and [Antedon bifida] are often frequent in this biotope as is the encrusting polychaete [Pomatoceros triqueter]. Similar communities have been found on cobble and pebble plains in stable, undisturbed conditions in some sealochs, although not all these examples have [Modiolus] beds.


HabitatName:
[Mytilus edulis] beds on sublittoral sediment

HabitatDescription:
Shallow sublittoral mixed sediment, in fully marine coastal habitats or sometimes in variable salinity conditions in the outer regions of estuaries, are characterised by beds of the common mussel [Mytilus edulis]. Other characterising infaunal species may include the amphipod [Gammarus salinus] and oligochaetes of the genus [Tubificoides]. The polychaetes [Harmothoe] spp., [Kefersteinia cirrata] and [Heteromastus filiformis] are also important. Epifaunal species in addition to the [M. edulis] include the whelks [Nucella lapillus] and [Buccinum undatum], the common starfish [Asterias rubens] the spider crab [Maja squinado] and the anemone [Urticina felina]. Relatively few records are available for this biotope and it is possible that as more data is accumulated separate estuarine and fully marine sub-biotopes may be described. Further clarification may also be required with regard to the overlap between littoral and sublittoral mussel beds and with regard to mussel beds biotopes on hard substratum.


HabitatName:
[Hiatella arctica] beds on silty clay with small pebbles and shells


HabitatName:
Baltic mussel beds in the infralittoral photic zone

HabitatDescription:
Communities of Atlantic, Baltic and Mediterranean mussel beds.


HabitatName:
Baltic mussel beds in the infralittoral photic zone with little or no macrophyte vegetation


HabitatName:
Baltic mussel beds of the infralittoral photic zone dominated by macrophyte vegetation


HabitatName:
Pontic [Mytilus galloprovincialis] beds on sublittoral sediment


HabitatName:
Pontic [Mytilus galloprovincialis] beds on infralittoral shelly gravel


HabitatName:
Pontic [Mytilus galloprovincialis] beds on infralittoral sand


HabitatName:
Pontic [Mytilus galloprovincialis] beds on circalittoral mud

HabitatDescription:
Found especially in muddy sediments forming seabed features as elongated patches perpendicular to predominant currents. These are destroyed by disturbance such as that generated by trawling activities and extreme siltation processes.


HabitatDescription:
The coral reef structures in UK waters are found in cold, largely aphotic waters, generally along the shelf edge and in offshore waters down to 2000 m. In the north east Atlantic, [Lophelia pertusa] is the dominant colonial coral and is the characterising species of the biotope described under this habitat type. [Lophelia] and its deep-water allies lack the symbiotic algae of their tropical relatives, so can live in the permanent darkness of the deep sea. These corals form colonies and can aggregate into patches and banks which may be described as reefs. These deep-sea corals can support and shelter hundreds of other species, including sponges, polychaete worms, echinoderms (starfish, sea urchins, brittle stars) and bryozoans (sea mats). Some 200-300 species can be found in one of these coral habitats, a number comparable to that found in other important deep-water habitats. Unlike tropical coral reef systems, they are dominated by only a few hard-coral species, and there are far fewer fish species.


HabitatDescription:
Reefs of the coral [Lophelia pertusa], typically supporting a range of other biota. [Lophelia] reefs are generally found in areas of elevated current. The coral provides a 3 dimensional structure and a variety of microhabitats that provide shelter and a surface of attachment for other species. Boring sponges, anemones, bryozoans, gorgonians including [Paragorgia arborea], [Paramuricea placomus], [Primnoa resedaeformis], polychaetes, barnacles, squat lobsters ([Munida sarsi]) and bivalves have all been recorded within and among the corals (Wilson, 1979; Mortensen et al., 1995) Other hard corals such as [Madrepora oculata] and [Solenosmilia variabilis] may also be present. Mobile species present include the redfish ([Sebastes viviparous] and [Sebastes marinus]), Ling ([Molva molva]) and tusk ([Brosme brosme]) (Husebo et al., 2002).
Situation: In British waters [Lophelia] reefs have been found on fine silt sediment and rock on the continental slope, on rock on the continental shelf, and on other hard structures such as the legs of oil platforms.


HabitatName:
Pontic [Ostrea edulis] biogenic reefs on mobile seabottom


HabitatName:
Deep massive [Ostrea edulis] reefs on bottoms of shelly gravel and boulders

HabitatDescription:
This habitat is composed of [Ostrea edulis] biogenic reefs of three dimensional structure on soft bottoms. The massive reefs can reach dimensions of up to 7m in height and are composed of dead [Ostrea edulis] shells and cemented tubes of serpulid are overgrown by blue mussels, sponges, the red algae [Delesseria ruscifolia], the brown algae [Xanardinia prototypus], crabs such as [Eriphia verrucosa] and also constitute essential habitat for the bivalve [Petricola lithophaga]. It is unknown whether live [Ostrea edulis] reefs can still be found in the Black Sea.


HabitatDescription:
New habitat created by the introduction of allochthonous species used for for cultivation such as [Crassostrea gigas] and [Ostrea virginica].


HabitatDescription:
Features of sublittoral sediments include sublittoral habitats characterised by the presence of gases or liquids bubbling or seeping through sediments (A5.71) and sublittoral sediments which are organically-enriched or permanently or periodically anoxic (A5.72).


HabitatName:
Seeps and vents in sublittoral sediments


HabitatName:
Bubbling reefs in the sublittoral euphotic zone


HabitatName:
Bubbling reefs in the sublittoral euphotic zone with little or no macrophyte vegetation


HabitatName:
Bubbling reefs in the sublittoral euphotic zone dominated by macrophyte vegetation


HabitatName:
Freshwater seeps in sublittoral sediments


HabitatName:
Pontic sulphide vents in infralittoral sediments


HabitatName:
Organically-enriched or anoxic sublittoral habitats


HabitatName:
Periodically and permanently anoxic sublittoral muds


HabitatName:
[Beggiatoa] spp. on anoxic sublittoral mud

HabitatDescription:
Sublittoral soft anoxic mud, often in areas with poor water exchange with the open sea, can have a conspicuous bacterial mat covering of [Beggiatoa] spp. The anoxia may be a result of natural conditions of poor water exchange in some sealochs (and many Scandinavian fjords) or artificially under fish farm cages from nutrient enrichment. The fauna is normally impoverished at such sites, with few elements of the infaunal communities present in other muddy biotopes. Scavenging species such as [Asterias rubens] and [Carcinus maenas] are typically present where the habitat is not too anoxic along with occasional [Arenicola marina] but in extreme conditions of anoxia little survives other than the [Beggiatoa]. The polychaete [Ophiodromus flexuosus] occurs in high densities at the interface between oxygenated and deoxygenated sediments (in Norwegian fjords).


HabitatDescription:
The sea bed beyond the continental shelf break. The shelf break occurs at variable depth, but is generally over 200 m. The upper limit of the deep-sea zone is marked by the edge of the shelf. Includes areas of the Mediterranean Sea which are deeper than 200 m but not of the Baltic Sea which is a shelf sea. Excludes caves in the deep sea which are classified in A4.71 irrespective of depth.


HabitatName:
Deep-sea rock and artificial hard substrata

HabitatDescription:
Deep-sea benthic habitats with substrates predominantly of bedrock, immobile boulders or artificial hard substrates.


HabitatDescription:
Deep-sea benthic habitats with substrates predominantly of mixed particle size or gravel. Includes habitats with mobile substrates of biogenic origin but no longer living, and of allochthonous material such as macrophyte debris. Deep-sea habitats with living biogenic substrates are included in A6.6.


HabitatName:
Deep-sea biogenic gravels (shells, coral debris)


HabitatDescription:
Deep-sea benthic habitats with substrates predominantly of sand.


HabitatName:
Communities of bathyal detritic sands with [Grypheus vitreus]

HabitatDescription:
These communities are characterised by detritic sand substrata and by the abundant presence of the brachiopod [Grypheus vitreus].


HabitatDescription:
Deep-sea benthic habitats with substrates predominantly of muddy sand.


HabitatDescription:
Bathyal and abyssal benthic habitats with substrates predominantly of yellowwish or blue-grey mud, relatively consistent, whose population is extremely sparse. This biocoenosis is characterised by constant homothermy and an almost total absence of light.


HabitatName:
Mediterranean communities of bathyal muds

HabitatDescription:
This biocenosis is characterised by a constant homothermy of around 13° C and an almost total absence of light. The granulometry and thickness of the sediment is not homogeneous. It is present, generally, at depths of 150 - 250 metres. The faunal composition is characterised by foraminifera, sponges, polychaetes, echinoderms and crustaceans.


HabitatName:
Facies of sandy muds with [Thenea muricata]

HabitatDescription:
This facies is characterised by sandy muds populated by the mollusc [Thenea muricata].


HabitatName:
Facies of fluid muds with [Brissopsis lyrifera]

HabitatDescription:
This facies is characterised by sandy muds populated by the echinoderm [Brissopsis lyrifera].


HabitatName:
Facies of soft muds with [Funiculina quadrangularis] and [Apporhais seressianus]

HabitatDescription:
This facies, present on the upper part of the continental slope, is characterised by sandy muds in which the cnidarian [Funiculina quadrangularis] and the gastropod [Apporhais serresianus] are present.


HabitatName:
Facies of compact muds with [Isidella elongata]

HabitatDescription:
This facies is present at the base of the continental slope and bathyal plain and is characterised by compact muds in which the cnidarian [Isidella elongata] is present.


HabitatDescription:
These are the communities populating the muddy seabottoms of the abyssal zone.


HabitatDescription:
A bioherm is a mound, dome, or reef-like mass of rock that is composed almost exclusively of the remains of sedentary marine organisms and is embedded in rock of different physical character. This habitat type includes deep-sea coral reefs (A6.61) and sponge beds (A6.62).


HabitatDescription:
The only community described is [Lophelia pertusa], a cold water, reef-forming coral, which has a wide geographic distribution ranging from 55°S to 70°N, where water temperatures typically remain between 4-8°C. These reefs are generally subject to moderate current velocities (0.5 knots). The majority of records occur in the north-east Atlantic. The extent of [L. pertusa] reefs varies, with examples off Norway several km long and more than 20 m high. These reefs occur within a depth range of 200 - &gt;2000 m on the continental slope, and in shallower waters in Norwegian fjords and Swedish west coast. In Norwegian waters, [L. pertusa] reefs occur on the shelf and shelf break off the western and northern parts on local elevations of the sea floor and on the edges of escarpments. The biological diversity of the reef community is approximately three times as high as the surrounding soft sediment (ICES, 2003), suggesting that these cold-water coral reefs may be biodiversity hotspots. Characteristic species include other hard corals, such as [Madrepora oculata] and [Solenosmilia variabilis], the redfish [Sebastes viviparous] and the squat lobster [Munida sarsi]. [L. pertusa] reefs occur on hard substrata; this may be [Lophelia] rubble from an old colony or on glacial deposits. For this reason, [L. pertusa] reefs can be associated with iceberg plough-mark zones.


HabitatDescription:
Lophelia pertusa, a cold water, reef-forming coral, has a wide geographic distribution ranging from 55°S to 70°N, where water temperatures typically remain between 4-8°C. These reefs are generally subject to moderate current velocities (0.5 knots). The majority of records occur in the north-east Atlantic. The extent of L. pertusa reefs vary, with examples off Norway several km long and more than 20m high. These reefs occur within a depth range of 200-&gt;2000m on the continental slope, and in shallower waters in Norwegian fjords and Swedish west coast. In Norwegian waters, L. pertusa reefs occur on the shelf and shelf break off the western and northern parts on local elevations of the sea floor and on the edges of escarpments. The biological diversity of the reef community is approximately three times as high as the surrounding soft sediment (ICES, 2003), suggesting that these cold-water coral reefs may be biodiversity hotspots. Characteristic species include other hard corals, such as Madrepora oculata and Solenosmilia variabilis, the redfish Sebastes viviparous and the squat lobster Munida sarsi. L. pertusa reefs occur on hard substrata; this may be Lophelia rubble from an old colony or on glacial deposits. For this reason, L. pertusa reefs can be associated with iceberg plough-mark zones.


HabitatDescription:
Deep sea sponge aggregations are principally composed of sponges from two classes: [Hexactinellida] and [Desmospongia]. They are known to occur between water depths of 250 m to 1300 m (Bett & Rice, 1992), where the water temperature ranges from 4-10°C and there is moderate current velocity (0.5 knots). Deep sea sponge aggregations may be found on soft substrata or hard substrata, such as boulders and cobbles which may lie on sediment. Iceberg plough-mark zones provide an ideal habitat for sponges because stable boulders and cobbles, exposed on the seabed, provide numerous attachment/settlement points (B. Bett, pers comm.). However, with 3.5 kg of pure siliceous spicule material per m2 reported from some sites (Gubbay, 2002), the occurrence of sponge fields can alter the characteristics of surrounding muddy sediments. Densities of occurrence are hard to quantify, but sponges in the class [Hexactinellida] have been reported at densities of 4-5 per m2, whilst ‘massive’ growth forms of sponges from the class [Desmospongia] have been reported at densities of 0.5 to 1 per m2 (B. Bett, pers comm.). Deep sea sponges have similar habitat preferences to cold-water corals, and hence are often found at the same location. Research has shown that the dense mats of spicules present around sponge fields may inhibit colonisation by infaunal animals, resulting in a dominance of epifaunal elements (Gubbay, 2002). Sponge fields also support ophiuroids, which use the sponges as elevated perches.


HabitatDescription:
This facies is characterised by the presence of the sponge [Pheronema grayi].


HabitatDescription:
Habitats on the deep-sea bed with significant elevation (typically &gt;200m) in relation to their surroundings. Includes permanently submerged flanks of oceanic islands (A6.71), seamounts, knolls and banks (A6.72), oceanic ridges (A6.73), abyssal hills (A6.74) and carbonate mounds (A6.75).


HabitatName:
Permanently submerged flanks of oceanic islands


HabitatDescription:
Seamounts are defined as undersea mountains, with a crest that rises more than 1,000 m above the surrounding sea floor (Menard, 1964 in Rogers, 1994). Seamounts can be a variety of shapes, but are generally conical with a circular, elliptical or more elongate base. Seamounts are volcanic in origin, and are often associated with seafloor ‘hot-spots’; thinner areas of the earth’s crust where magma can escape. Seamounts, often with a slope inclination of up to 60°, provide a striking contrast to the surrounding ‘flat’ abyssal plain. Their relief has profound effects on the surrounding oceanic circulation, with the formation of trapped waves, jets, eddies and closed circulations known as Taylor columns (Taylor, 1917 in Rogers, 1994). Seamounts occur frequently within the OSPAR Maritime Area. Analysis of narrow beam bathymetric data by the US Naval Oceanographic office from 1967-1989 identified more than 810 seamounts within the North Atlantic. The majority occur along the Mid-Atlantic ridge between Iceland and the Hayes fracture zone (Gubbay, 2002).
The enhanced currents that occur around seamounts provide ideal conditions for suspension feeders. Gorgonian, scleratinian and antipatharian corals may be particularly abundant, and other suspension feeders such as sponges, hydroids and ascidians are also present. Concentrations of commercially important fish species, such as [Hoplostethus atlanticus] (orange roughy), aggregate around seamounts and live in close association with the benthic communities (Gubbay, 2002).


HabitatName:
Summit communities of seamount, knoll or bank within euphotic zone


HabitatName:
Summit communities of seamount, knoll or bank within the mesopelagic zone, i.e. interacting with diurnally migrating plankton


HabitatName:
Deep summit communities of seamount, knoll or bank (i.e. below mesopelagic zone)


HabitatName:
Moat around base of seamount, knoll or bank


HabitatName:
Communities of ridge axial trough (i.e. non-vent fauna)


HabitatName:
Oceanic ridge without hydrothermal effects

HabitatDescription:
Benthic communities occupying raised features of the deep sea-floor; they include assemblages colonizing active or nonactive constructive midocean ridges, as well as those developed on asismic ridges, but with the exception of hydrothermal communities.


HabitatDescription:
Carbonate mounds are very steep-sided mounds of variety of shapes, which may be up to 350 m high and 2 km wide at their base (Weering et al, 2003). They occur offshore in water depths of 500 m-1100 m with examples present in the Porcupine Seabight and Rockall Trough (Kenyon et al, 2003). Carbonate mounds may have a sediment veneer, typically composed of carbonate sands, muds and silts. The cold-water reef-building corals [Lophelia pertusa] and [Madrepora oculata], as well as echiuran worms are characteristic fauna of carbonate mounds. Where cold-water corals (such as [Lophelia]) are present on the mound summit, coral debris may form a significant component of the overlying substratum.
There is currently speculation on the origin of carbonate mounds, with possible associations with fault-controlled methane seepage from deep hydrocarbon reservoirs, or gas-hydrate dissociation (Henriet et al, 1998) through to the debris from ‘cold-water’ coral colonies such as [Lophelia].


HabitatName:
Deep-sea trenches and canyons, channels, slope failures and slumps on the continental slope

HabitatDescription:
Habitats on the deep-sea bed significantly below the deep-sea bed, including deep ocean trenches, often greater than 6000 m depth with an active margin reduction zone (A6.82), and downslope or along-slope channels on the deep-sea bed (A6.81).


HabitatName:
Canyons, channels, slope failures and slumps on the continental slope


HabitatDescription:
Benthic communities of the oceanic trenches, deep elongated subduction troughs of the ocean floor.


HabitatName:
Vents, seeps, hypoxic and anoxic habitats of the deep sea

HabitatDescription:
Deep-sea habitats characterised by chemical conditions. Includes interface habitats on the deep-sea bed where reducing conditions exist (A6.91), not generally associated with drastically elevated temperatures, including the carcasses of large cetaceans (A6.913). These habitats are often indicated by the presence of seeping or bubbling gases or liquids, hypoxic and/or anoxic conditions in the water column above. Also includes vents in the deep-sea bed (A6.94).


HabitatName:
Cold seep benthic communities of hadal zone

HabitatDescription:
Highly distinctive benthic communities of large bivalves, sponges and bryozoans, inhabiting the vicinity of oceanic methane-laden seeps, mostly localized in subduction trenches.


HabitatName:
Cetacean and other carcasses on the deep-sea bed


HabitatName:
Deep-sea bed influenced by hypoxic water column


HabitatName:
Isolated ‘oceanic’ features influenced by hypoxic water column


HabitatDescription:
Hydrothermal vents occur along spreading ridges (such as the mid-Atlantic ridge), subduction zones, fracture zones and back-arc basins (Gage & Tyler, 1991), and are caused by seawater penetrating the upper levels of the Earth’s crust through channels formed in cooling lava flows, reacting chemically with hot basalt in the Earth’s crust and then rising back to the sea-bed to vent as superheated water containing compounds such as sulphides, metals, CO2 and methane (Tunnicliffe et al, 1998 in Gubbay, 2002). The water may trickle out from cracks and crevices on the seabed as hot springs (5-250°C), or as very concentrated jets of superheated water (270-380°C). As these concentrated jets of water cool, minerals dissolved in the water precipitate out in black clouds, giving them their common name of ‘black smokers’. At lower temperatures, sulphides are mostly precipitated within the rocks, making the venting fluids appear cloudier. These are known as ‘white smokers’ (Gage & Tyler, 1991). Hydrothermal vent fields cover relatively small areas of the seabed in water depths of 850 - 4000 m. The biological communities associated with hydrothermal vents are unusual as they are able to derive energy under conditions where photosynthesis is not possible. These habitats contain a huge diversity of chemoautotrophic bacteria, which form the core of the trophic structure around the vent. Characteristic species include the giant vent clam [Calyptogena magnifica], the mussel [Bathymodiolus thermophilus], the tube worm [Riftia pachyptila], the crabs [Cyanograea praedator] and [Bythograea thermydron] and the shrimp [Charocaris fortunate].


HabitatName:
Pontic anoxic H2S black muds of the slope and abyssal plain, with anaerobic sulphate reducing bacteria and nematodes


HabitatDescription:
The water column of shallow or deep sea, or enclosed coastal waters. Note that because of the strong temporal nature of the pelagic environment, the water column at a given location will be classified differently at different times of the year.


HabitatDescription:
The interface between air and sea water, inhabited by communities of minute or microscopic organisms.


HabitatName:
Completely mixed water column with reduced salinity

HabitatDescription:
A water column which is completely and actively mixed, and influenced by freshwater so that the salinity is reduced relative to the adjacent fully marine seawater. This habitat type is usually found in relatively shallow, coastal situations, and is the result of river inflow or ice melt. Note that some discretion should be used in the interpretation of “adjacent”, for example in the Baltic Sea, “adjacent” fully marine seawater is reached only in the Kattegat.


HabitatName:
Completely mixed water column with reduced salinity and short residence time


HabitatName:
Baltic outer unenclosed seasonally stratified coastal water


HabitatName:
Completely mixed water column with reduced salinity and medium residence time


HabitatName:
Baltic inner unenclosed seasonally stratified coastal water


HabitatName:
Completely mixed water column with reduced salinity and long residence time


HabitatName:
Water body of Baltic eutrophic coastal lakes


HabitatName:
Water body of Baltic mesotrophic coastal lakes


HabitatName:
Water body of Baltic eutrophic glo-lakes


HabitatName:
Water body of Baltic mesotrophic glo-lakes


HabitatName:
Completely mixed water column with full salinity

HabitatDescription:
A water column which is completely and actively mixed, not influenced by freshwater, so that the salinity is the same as that in adjacent seawater. This habitat type is usually found in relatively shallow, coastal situations, without river inflow or ice melt.


HabitatName:
Completely mixed water column with full salinity and short residence time


HabitatName:
Completely mixed water column with full salinity and medium residence time


HabitatName:
Completely mixed water column with full salinity and long residence time


HabitatName:
Partially mixed water column with reduced salinity and medium or long residence time

HabitatDescription:
A water column which is unmixed or only partially mixed because the depth of the water body is greater than the depth of mixing. Salinity is reduced relative to the adjacent fully marine seawater. This habitat type is usually found in deeper coastal water situations and is the result of river inflow or ice melt. Note that some discretion should be used in the interpretation of “adjacent”, for example in the Baltic Sea, “adjacent” fully marine seawater is reached only in the Kattegat. Medium residence time is defined as changing over time preiods greater than daily and up to about 14 days (based on the time required for the phytoplankton population to double) and long residence time lasting longer than 14 days.


HabitatName:
Partially mixed water column with reduced salinity and medium residence time


HabitatName:
Partially mixed water column with reduced salinity and long residence time


HabitatName:
Unstratified water column with reduced salinity

HabitatDescription:
A water column which is unmixed or only partially mixed because the depth of the water body is greater than the depth of mixing, and with short residence time, defined as changing diurnally. Salinity is reduced relative to the adjacent fully marine seawater. This habitat type is usually found in deeper coastal water situations and is the result of river inflow or ice melt. Note that some discretion should be used in the interpretation of “adjacent”, for example in the Baltic Sea, “adjacent” fully marine seawater is reached only in the Kattegat. Unstratified water columns have very weak or no horizontal or vertical gradients.


HabitatName:
Euphotic (epipelagic) zone in unstratified reduced salinity water


HabitatName:
Mesopelagic zone in unstratified reduced salinity water


HabitatName:
Bathypelagic zone in unstratified reduced salinity water


HabitatName:
Abyssopelagic zone in unstratified reduced salinity water


HabitatName:
Vertically stratified water column with reduced salinity

HabitatDescription:
A water column which is unmixed or only partially mixed because the depth of the water body is greater than the depth of mixing, and with short residence time, defined as changing diurnally. Salinity is reduced relative to the adjacent fully marine seawater. This habitat type is usually found in deeper coastal water situations and is the result of river inflow or ice melt. Note that some discretion should be used in the interpretation of “adjacent”, for example in the Baltic Sea, “adjacent” fully marine seawater is reached only in the Kattegat. This habitat type shows pronounced vertical stratification (e.g. caused by seasonal temperature changes, river discharge influence or ice-melt). The subtypes are separated at level 4 by the cause and degree of persistence of the gradient – e.g. seasonal temperature gradients or persistent salinity gradients.


HabitatName:
Water column with ephemeral thermal stratification and reduced salinity


HabitatName:
Water column with seasonal thermal stratification and reduced salinity


HabitatName:
Water column with permanent thermal stratification and reduced salinity


HabitatName:
Water column with ephemeral halocline and reduced salinity


HabitatName:
Water column with seasonal halocline and reduced salinity


HabitatName:
Water column with permanent halocline and reduced salinity


HabitatName:
Baltic offshore deep water above the halocline


HabitatName:
Baltic offshore deep water below the halocline


HabitatName:
Water column with ephemeral oxygen stratification and reduced salinity


HabitatName:
Water column with seasonal oxygen stratification and reduced salinity


HabitatName:
Water column with permanent oxygen stratification and reduced salinity


HabitatDescription:
A water column which is unmixed or only partially mixed because the depth of the water body is greater than the depth of mixing, and with short residence time, defined as changing diurnally. Salinity is reduced relative to the adjacent fully marine seawater. This habitat type is usually found in deeper coastal water situations and is the result of river inflow or ice melt. Note that some discretion should be used in the interpretation of “adjacent”, for example in the Baltic Sea, “adjacent” fully marine seawater is reached only in the Kattegat. Horizontal gradients give rise to fronts, which are separated at level 4 by the degree of persistence of the stratification.


HabitatName:
Ephemeral fronts in reduced salinity water column


HabitatName:
Seasonal fronts in reduced salinity water column


HabitatName:
Persistent fronts in reduced salinity water column


HabitatName:
Unstratified water column with full salinity

HabitatDescription:
A water column which is unmixed or only partially mixed because the depth of the water body is greater than the depth of mixing. Salinity is the same as that in adjacent seawater. Unstratified water columns have very weak or no horizontal or vertical gradients.


HabitatName:
Euphotic (epipelagic) zone in unstratified full salinity water


HabitatName:
Mesopelagic zone in unstratified full salinity water

HabitatDescription:
Waters situated over the continental slope, the steep descent from the continental shelf to the ocean bottom, an area where upwellings, water mixing or shearing and other anomalies often develop.


HabitatName:
Bathypelagic zone in unstratified full salinity water


HabitatName:
Abyssopelagic zone in unstratified full salinity water

HabitatDescription:
Waters beyond the continental shelf. They occupy the greatest part of the Arctic and Atlantic oceans, the Mediterranean Sea, the Ligurian Sea, the Tyrrhenian Sea, the Ionian Sea, as well as the central part of the Aegean Sea, the Black Sea, the southern Adriatic Sea, the eastern part of the northern North Sea. They are absent from the Baltic Sea.


HabitatName:
Vertically stratified water column with full salinity

HabitatDescription:
A water column which is unmixed or only partially mixed because the depth of the water body is greater than the depth of mixing. Salinity is the same as that in adjacent seawater. This habitat type shows pronounced vertical stratification (e.g. caused by atmospheric temperature). The subtypes are separated at level 4 by the cause and degree of persistence of the gradient – e.g. seasonal temperature gradients or persistent salinity gradients.


HabitatName:
Water column with ephemeral thermal stratification and full salinity


HabitatName:
Water column with seasonal thermal stratification and full salinity


HabitatName:
Water column with permanent thermal stratification and full salinity


HabitatName:
Water column with ephemeral halocline and full salinity


HabitatName:
Water column with seasonal halocline and full salinity


HabitatName:
Water column with permanent halocline and full salinity


HabitatName:
Water column with ephemeral oxygen stratification and full salinity


HabitatName:
Water column with seasonal oxygen stratification and full salinity


HabitatName:
Water column with permanent oxygen stratification and full salinity


HabitatName:
Anoxic water column in water with permanent oxygen stratification and full salinity


HabitatDescription:
A water column which is unmixed or only partially mixed because the depth of the water body is greater than the depth of mixing. Salinity is the same as that in adjacent seawater. Horizontal gradients give rise to fronts, which are separated at level 4 by the degree of persistence of the stratification – ephemeral such as eddies, gyres and upwellings; seasonal upwellings; or persistent water mass interfaces.


HabitatName:
Ephemeral fronts in full salinity water column


HabitatName:
Seasonal fronts in full salinity water column


HabitatName:
Persistent fronts in full salinity water column


HabitatDescription:
Sea ice, icebergs and other ice-associated marine habitats.


HabitatDescription:
Ice formations floating on sea water, usually constituting an incomplete cover, variable in form and structure, unstable and dynamic under the influence of surface air and water currents.


HabitatDescription:
Semi-continuous ice sheets forming on the sea for part of the year, characteristic of the Arctic Ocean, the Norwegian Sea, Bothnia Bay, the Bothnia Sea, and coastal areas of the Åland Sea, the Gulf of Finland and the Gulf of Riga, exceptional in other areas.


HabitatDescription:
Semicontinuous ice sheets covering the sea throughout the year, limited to the Arctic Ocean.


HabitatDescription:
Discontinuous formations of floating ice blocks, rafts and hummocks detached from the sea pack, remaining after the break-up of seasonal ice packs or drifting to more southern regions.


HabitatDescription:
Floating and drifting blocks of ice detached from coastal glaciers (H4.2). These are separated by size at level 4.


HabitatDescription:
Proposed new habitat type (CEH, May 2001), qualifying previous unspecified 'icebergs'.


HabitatDescription:
During freezing of seawater, salt is rejected from the ice crystals. The remaining brine solution forms a three-dimensional network of tubes and channels with typical diameters of 200 µm within the ice matrix. Despite the harsh environmental conditions (low light intensities, low temperature, high salinity), a specialised community has developed and adapted to live within the brine channel system. Minute unicellular algae like diatoms are the dominant primary producers.


HabitatDescription:
The boundary layer between sea ice and the water column with special abiotic (e.g. temperature, salinity) and biotic (e.g. food resources) factors, which also vary with season and region. This habitat is colonized by autochthonous under-ice amphipods ([Apherusa glacialis], [Onisimus] spp., [Gammarus wilkitzkii]), which live directly at the ice underside and complete their entire life-cycle here, and allochthonous sub-ice fauna, organisms originating either from the ice interior or the pelagic realm, which are found in this boundary layer temporarily, e.g. for feeding or during certain life stages. There is some evidence that the first metres below the ice are strongly stratified, particularly during the melt period in summer. Source: http://www.awi-bremerhaven.de/Climate/WorkingGroups/ofis/ARK-19-1/sea-ice-biology.htm.


HabitatDescription:
Coastal habitats are those above spring high tide limit (or above mean water level in non-tidal waters) occupying coastal features and characterised by their proximity to the sea, including coastal dunes and wooded coastal dunes, beaches and cliffs. Includes free-draining supralittoral habitats adjacent to marine habitats which are normally only affected by spray or splash, strandlines characterised by terrestrial invertebrates and moist and wet coastal dune slacks and dune-slack pools. Excludes supralittoral rock pools and habitats adjacent to the sea which are not characterised by salt spray, wave or sea-ice erosion.


HabitatDescription:
Sand-covered shorelines of the oceans, their connected seas and associated coastal lagoons, fashioned by the action of wind or waves. They include gently sloping beaches and beach-ridges, formed by sands brought by waves, longshore drift and storm waves, as well as dunes, formed by aeolian deposits, though sometimes re-fashioned by waves.


HabitatDescription:
The lowest level of the supralittoral, just above the normal tide limit, where drift material accumulates and the sand may be rich in nitrogenous organic matter. Vegetation, if present at all, is very open and composed of annuals, e.g. [Atriplex] spp., [Cakile] spp., [Salsola kali], [Polygonum] spp.


HabitatName:
Boreo-Arctic sand beach annual communities

HabitatDescription:
Annual communities of sand beaches of the low Arctic and high Arctic oceanic zones of the Palaearctic Atlantic, Pacific and Arctic oceans, with [Cakile edentula ssp. islandica] ([Cakile arctica]), [Atriplex lapponica].


HabitatName:
Middle European sand beach annual communities

HabitatDescription:
Annual halo-nitrophilous communities of the sand beaches of the temperate North Atlantic, the North Sea, the English Channel, the Irish Sea and the Baltic, with [Suaeda maritima], [Bassia hirsuta], [Cakile maritima], [Salsola kali], [Beta maritima], [Atriplex] spp., [Glaucium flavum], [Polygonum] spp., [Mertensia maritima].


HabitatDescription:
Annual driftline communities of central and southern Baltic sand beaches, with [Cakile maritima ssp. baltica], [Atriplex littoralis], [Atriplex calotheca], [Atriplex hastata], [Salsola kali], [Polygonum aviculare], [Polygonum oxyspermum], [Senecio vulgaris], [Matricaria perforata], [Matricaria maritima].


HabitatName:
Tethyan sand beach driftline communities

HabitatDescription:
Annual communities of sand beaches of the Mediterranean, Black Sea and Mediterraneo-Atlantic coasts. [Zosterion marinae] and [Cymodoceion nodosae] communities with e.g. [Caulerpa prolifera], [Zostera noltii], [Cymodocea nodosa].


HabitatName:
Western Tethyan sand beach annual communities

HabitatDescription:
Annual communities of sand beaches of the Mediterranean and the subtropical Atlantic, between Portugal and the southern limit of the Mediterraneo-Saharan transition zone at 27 degrees N.


HabitatDescription:
Annual halo-nitrophilous communities of sand beaches of the Black Sea, with [Cakile maritima ssp. euxina], [Salsola kali ssp. ruthenica], [Salsola kali ssp. tragus], [Atriplex hastata], [Polygonum maritimum], [Euphorbia peplis], [Euphorbia paralias], [Glaucium flavum], [Xanthium strumarium ssp. italicum], [Convolvulus lineatus], [Convolvulus persicus].


HabitatDescription:
Halo-nitrophilous communities of Black Sea sand beaches dominated by perennial herbs, including [Crambe maritima ssp. pontica], [Argusia sibirica], [Lactuca tatarica], [Petasites spurius] or [Trachomitum venetum].


HabitatDescription:
Gently sloping sand-covered shorelines fashioned by wind action along coasts and beside associated coastal lagoons.


HabitatName:
Unvegetated sand beaches above the driftline

HabitatDescription:
Sandy beaches of oceans, their connected seas and associated coastal lagoons, devoid of phanerogamic vegetation.


HabitatName:
Baltic unvegetated spits and bars above the driftline


HabitatName:
Baltic unvegetated sandy beaches above the driftline


HabitatDescription:
Area corresponding to the upper beach which is only humected by the sea during storms; however, certain areas do escape being totally submerged and receive a large amount of spray coming from the surge of the waves further down. 2 sets of phenomena are responsible for the dampness: at surface level, the dampness is caused by the salty spray from the breaking of the waves on the coast which is the main cause of the saltiness of the sand and the dampness of the night air. This humification only affects the top 2 or 3 centimetres and disappears quickly under the action of the sun; at depth, the sand is damp because of the proximity of the fairly unsalty ground water.


HabitatName:
Facies of depressions with residual humidity


HabitatName:
Facies of tree trunks which have been washed ashore


HabitatName:
Facies of phanerogams which have been washed ashore (upper part)

HabitatDescription:
On sandy beaches, in the supralittoral stage, at a higher level, rarely submerged, in the whole of the Mediterranean. Present on the upper beach, only humectated by the sea during storms. The temperature is highly variable and the daily differences in temperature may be more than 20°C. These temperatures may be extremely high, reaching 50°C in the summer, and are then lethal for individuals living in the sand. This facies is a relatively particular aspect of ‘wracks’ and corresponds to the washing up of almost exclusively marine phanerogam debris from nearby meadows and beds. These wracks always include a fairly sizeable part of other additional elements of anthropic or natural origin. The sediment of the upper beach ranges from shifting sand on compact sand to the presence of more or less damp saline plaques on coarse sand. The sedimentary granulometry varies according to the addition of fine elements.


HabitatName:
Boreo-arctic sand beach perennial communities

HabitatDescription:
Perennial halo-nitrophilous communities of sand, gravelly sand and gravel cordons of upper beaches of the arctic and boreal sea coasts of Eurasia formed by [Leymus arenarius] ([Elymus arenarius]), [Ammophila arenaria], [Honkenya peploides], [Elymus farctus], [Elymus repens], [Mertensia maritima], accompanied by [Atriplex] spp. ([Atriplex prostrata], [Atriplex longipes ssp. praecox], [Atriplex glabriuscula]), [Polygonum aviculare], [Cakile maritima], [Cakile arctica], [Petasites spurius], [Potentilla anserina]. Representatives of these communities occur very locally within the nemoral zone.


HabitatName:
North Sea sand beach perennial communities

HabitatDescription:
[Leymus arenarius]-dominated perennial halo-nitrophilous communities of upper beaches of North Sea coasts of southern Norway, Jutland, Schleswig-Holstein, Lower Saxony, the Netherlands, England, Scotland and Orkney, and of the Danish coast of the Kattegat.


HabitatDescription:
[Leymus arenarius]-dominated perennial halo-nitrophilous communities of southern and central Baltic upper beaches, often with [Petasites spurius].


HabitatName:
Boreo-Bothnian sand beach perennial communities

HabitatDescription:
Perennial halo-nitrophilous communities of the upper beaches of the Gulf of Bothnia dominated by [Leymus arenarius] and [Festuca rubra ssp. arenaria].


HabitatName:
Icelandic sand beach perennial communities

HabitatDescription:
Perennial halo-nitrophilous communities of upper beaches of Iceland dominated by [Leymus arenarius] or [Mertensia maritima].


HabitatName:
Beach ridges consisting of algal or other plant material


HabitatName:
Sandy beach ridges with no or low vegetation

HabitatDescription:
Sandy beach ridges may be bare or may host pioneer communities of the class [Ammophiletea] consisting mainly of geophytes and hemicryptophytes, e.g. the association [Agropyrion juncei]-[Sporoboletum pungentis]. They may sporadically be inundated by sea water during storms.
The vegetation may be ammonitrophilous, of the class [Cakiletea maritimae], enriched by many [Ammophiletea] species like [Echinophora spinosa], [Elymus farctus], [Eryngium maritimum].


HabitatName:
Sandy beach ridges dominated by shrubs or trees


HabitatDescription:
Mobile sands of the coasts of the boreal, nemoral, steppe, Mediterranean and warm-temperate humid zones, unvegetated or occupied by open grasslands; they may form tall dune ridges or, particularly along the Mediterranean and the Black Sea, be limited to a fairly flat upper beach, still subject in part to inundation.


HabitatDescription:
Formations of the coasts of nemoral, steppe, Mediterranean and warm-temperate humid zones, representing the first stages of dune construction, constituted by ripples or raised sand surfaces of the upper beach or by a seaward fringe at the foot of the tall dunes. Typically [Elymus farctus], [Otanthus maritimus], [Sporobolus pungens], [Pancratium maritimum], [Medicago marina] or [Anthemis tomentosa] may be present.
The vegetation may belong to the class [Ammophiletea] with communities of [Otanthus maritimus], [Agropyro juncei-Sporoboletum pungentis], [Cypero mucronati-Agropyretum juncei], [Elymetum sabulosi], [Medicagini marinae-Ammophiletum australis] and species [Elytrigia bessarabica], [Glycyrrhiza glabra], [Limonium graecum], [Limonium sinuatum], [Zygophyllum album], [Inula crithmoides], [Scirpus holoschoenus], [Paronychia argentea] and [Centaurea spinosa].


HabitatDescription:
Embryonic dunes of the Atlantic, south to southern Iberia, of the North Sea and of the Baltic coasts of Denmark, Germany, southern Sweden, Poland, the Baltic States, Russia and southwestern Finland, with [Elymus farctus] ([Agropyron junceum]) accompanied by [Leymus arenarius] in the north, by [Euphorbia paralias] on middle and southern Atlantic shores.


HabitatDescription:
Embryonic dunes of the Mediterranean coasts, on which [Elymus farctus] is accompanied by [Sporobolus pungens], [Euphorbia peplis], [Otanthus maritimus], [Medicago marina], [Anthemis maritima], [Anthemis tomentosa], [Eryngium maritimum], [Pancratium maritimum].


HabitatDescription:
Formations of Black Sea coasts, transitional between Pontic white dune and driftline communities, characterized by the adjunction to [Elymion gigantei] species assemblies of [Cakile maritima ssp. euxina], [Salsola kali ssp. ruthenica], [Euphorbia peplis] and other sand beach annual species.


HabitatName:
Large migrating dunes with no or low vegetation


HabitatDescription:
Mobile dunes forming the seaward cordon or cordons of dune systems of the coasts of nemoral, steppe, Mediterranean and warm-temperate humid zones. Communities of [Ammophilion arenariae], [Ammophilion borealis], [Zygophyllion fontanesii] and several indicator species: [Ammophila arenaria], [Eryngium maritimum], [Euphorbia paralias], [Otanthus maritimus]. White dunes are further subdivided by region: Atlantic, Western Tethyan, Canario-Saharan and Pontic.


HabitatDescription:
White dunes of the Atlantic, south to Aquitaine, of the North Sea and of the Baltic coasts of Denmark, southern Sweden, Germany, Poland, the Baltic States and Russia, dominated, when vegetated, by marram grass ([Ammophila arenaria]) accompanied by, among others, [Eryngium maritimum], [Euphorbia paralias], [Calystegia soldanella].


HabitatName:
Coastal dunes: white dunes (sensu strictu)


HabitatDescription:
White dunes of the Mediterranean coasts and of the subtropical Atlantic coasts of Iberia and mediterranean North Africa, south to Safi at 32° N, dominated, when vegetated, by the marram grass [Ammophila arenaria ssp. arundinacea] ([Ammophila australis]), accompanied by, among others, [Otanthus maritimus], [Echinophora spinosa], [Eryngium maritimum], [Euphorbia paralias], [Cutandia maritima], [Medicago marina], [Anthemis maritima].


HabitatDescription:
Mobile dunes of the Canary Islands and of the mediterraneo-Saharan coasts of Atlantic North Africa, with [Traganum moquini], [Euphorbia paralias], [Polycarpaea nivea], [Cyperus capitatus], [Ononis natrix], [Convolvulus caput-medusae], [Polygonum maritimum], [Lotus] spp. and the threatened Lanzarote endemic lily [Androcymbium psammophilum].


HabitatDescription:
Mobile dunes of the Black Sea coasts, with [Leymus racemosus ssp. sabulosus] ([Elymus giganteus]), [Elymus farctus ssp. bessarabicus], [Elymus pycnanthus], [Artemisia tschernieviana], [Eryngium maritimum], [Convolvulus persicus], [Petasites spurius], [Corispermum marschallii], [Lactuca tatarica], [Crambe maritima var. pontica], [Cynanchum acutum], [Centaurea arenaria ssp. odessana], [Argusia sibirica] ([Tournefortia arguzia]) and, in western formations, [Ammophila arenaria ssp. arundinacea], [Euphorbia paralias], [Calystegia soldanella].


HabitatDescription:
Young dunes of arctic and boreal latitudes colonised by halo-nitrophilous perennial vegetation similar to that of unit B1.23, including [Leymus arenarius] ([Elymus arenarius]), [Ammophila arenaria], [Honkenya peploides], [Elymus farctus] ([Elytrigia juncea]), [Elymus repens], [Mertensia maritima].


HabitatName:
Coastal stable dune grassland (grey dunes)

HabitatDescription:
Fixed or semifixed dunes of the coasts of the boreal, nemoral, steppe, mediterranean and warm-temperate humid zones, with the perennial grasslands, chamaephyte-dotted grasslands, forblands, subshrub or succulent communities that stabilise them and the therophyte communities that may occupy the grassland clearings.


HabitatDescription:
Grasslands of Baltic, North Sea, English Channel and northern Atlantic fixed dunes, including those of the British Isles, the Faeroes, southern Norway, the North Sea and Baltic coasts, the Channel coasts of France.


HabitatDescription:
Calciphile communities of fixed dunes of the North Sea, the English Channel, the north Atlantic and, locally, of the southwestern Baltic, with [Koeleria albescens], ([Koeleria glauca], [Koeleria arenaria]), [Galium verum var. maritimum], [Viola curtisii], [Ononis repens], [Festuca rubra], [Festuca polesica], [Anthyllis vulneraria ssp. maritima] and moss (e.g. [Tortula ruraliformis]) and lichen carpets.


HabitatDescription:
Communities of less calcareous or decalcified dunes of the North Atlantic, the English Channel, the North Sea and the Baltic north to southern Norway, northern Jutland, southern Sweden, the Kalinin district and the Gulf of Riga, often rich in [Corynephorus canescens] and [Viola canina].


HabitatDescription:
Short-lived, warmth-loving communities of the dunes of the North Atlantic and its connected seas north to extreme southern Sweden, with [Cerastium diffusum ssp. diffusum], [Cerastium diffusum ssp. subtetrandrum], [Cerastium semidecandrum], [Erodium lebelii], [Phleum arenarium], [Silene conica].


HabitatDescription:
Fixed dune grasslands infiltrated by dwarf bushes of French Brittany and the coasts of the Bay of Biscay, with [Helichrysum stoechas], [Artemisia campestris], [Ephedra distachya].


HabitatDescription:
Fixed dunes of the western and central Mediterranean and of the thermo-Atlantic coasts of Portugal, southwestern Spain and North Africa, colonised by communities mostly composed of fruticose species, with [Crucianella maritima], [Artemisia crithmifolia], [Armeria pungens], [Armeria welwitschi], [Helichrysum decumbens], [Helichrysum italicum], [Teucrium] spp., [Ephedra distachya], [Pancratium maritimum] and [Ononis natrix ssp. ramosissima]. Communities of [Crucianellion maritimae] and [Ononidion ramosissimae].


HabitatDescription:
Coastal dune communities of the Adriatic, the Ionian, the Aegean and the eastern Mediterranean, dominated by dwarf shrubs and subshrubs of genera [Ephedra], [Ononis], [Artemisia], and, very locally, [Crucianella] or others, by tall canes or by succulents; they may be rich in species of genus [Silene], together with [Euphorbia terracina] among others. Vegetation of the alliances [Crucianellion maritimae], [Medicagini marinae-Triplachnion nitensis], [Ammophilion arenariae].


HabitatDescription:
Dunal grasslands, in particular of northern Brittany, rich in species characteristic of dry calcareous grasslands (c.f. unit E1.26).


HabitatDescription:
[Geranium sanguineum]-rich forb and grass communities, related to hem formations of unit E5.2, developed within grey dune systems of western Ireland, southwestern England, Wales, Brittany and southwestern Norway.


HabitatDescription:
Sparse pioneer formations of fine grasses rich in spring-blooming therophytes characteristic of oligotrophic, superficial soils in grey dune systems of the Atlantic and the Mediterranean. They are closely related to grasslands of units E1.8 and E1.9.


HabitatName:
Tethyan dune deep sand therophyte communities

HabitatDescription:
Therophyte communities of the coasts of the Mediterranean basin and the subtropical Atlantic colonizing deep sands in clearings of perennial communities of fixed or semi-fixed dune systems, and sometimes deflation depressions of white dunes with e.g. several [Malcolmia] spp.


HabitatDescription:
Therophyte communities of shallow, calcareous fixed sands of the coastal dune systems of the Mediterranean basin. These are coastal dune representatives of unit E1.3.


HabitatName:
Thermo-Atlantic succulent and semi-fixed dunes

HabitatDescription:
Fixed or semi-fixed dunes of the Canary Islands and of the Saharo-mediterranean zone of the Atlantic coasts of North Africa, between Essaouira and Tan-Tan, dominated by the tall shrubby chenopod [Traganum moquinii] or by dwarf shrubs or subshrubs.


HabitatDescription:
Fixed dunes of the coasts of the Black Sea.


HabitatDescription:
Fixed dunes of the western coasts of the Black Sea, north of the Bosphorus and west of the Dniester.


HabitatDescription:
Fixed dunes of the southwestern coasts of the Black Sea, between the Bosphorus and Cape Caliacra, harbouring the psammophytes [Cionura erecta], [Peucedanum arenarium], [Jurinea albicaulis ssp. kilaea], [Silene thymifolia], [Medicago marina], [Secale sylvestre], [Pancratium maritimum], [Convolvulus persicus], [Scabiosa argentea] ([Scabiosa ucranica]), [Euphorbia seguierana] and the Balkan endemic [Lepidotrichum uechtritzianum].


HabitatDescription:
Dunes of the northwestern Black Sea coast, in particular, those associated with the mouth of the Danube.


HabitatDescription:
Fixed dunes of the northern and eastern Black Sea coasts, east of the Dniester, southeastwards to the Kuban basin.


HabitatDescription:
Fixed dunes of the southern and southeastern coasts of the Black Sea.


HabitatDescription:
Communities of fixed dunes of the boreal and arctic coasts of Atlantic Eurasia, characterized by the dominance of species of the [Honkenyo-Elymetea] and the presence of arcto-alpine species.


HabitatDescription:
Stable dunes with a leached surface and vegetation dominated by [Calluna vulgaris], [Empetrum nigrum] or [Erica] spp.


HabitatDescription:
[Empetrum nigrum] or [Empetrum hermaphroditum] colonizing dunes of the Arctic Ocean, the North Atlantic, the North Sea and the southern Baltic.


HabitatDescription:
[Erica], [Calluna] and [Ulex] heaths colonizing decalcified dunes of France, Iberia, Britain, the Baltic coast, and Scandinavia.


HabitatDescription:
[Calluna vulgaris]-[Carex arenaria] heaths of inner coastal dunes of East Anglia.


HabitatDescription:
[Calluna vulgaris]-[Carex trinervis] heaths of northern French inner coastal dunes.


HabitatName:
British bell heather coastal dune heaths

HabitatDescription:
[Erica cinerea]-[Carex arenaria] heaths of decalcified coastal dunes of the western British Isles, mostly dominated by [Erica cinerea], sometimes by [Calluna vulgaris].


HabitatDescription:
[Erica cinerea]-[Festuca vasconcensis] heaths of dry coastal dunes of southwestern France.


HabitatDescription:
[Erica ciliaris]-[Pseudarrhenatherum longifolium] ([Arrhenatherum thorei]) heaths of more humid coastal dunes of southwestern France.


HabitatName:
Iberian green heather coastal dune heaths

HabitatDescription:
[Erica scoparia]-[Ulex parviflorus ssp. eriocladus] ([Ulex australis]) heaths of southwestern Iberian coastal dunes, dunal fraction of the thermo-Mediterranean heaths of unit F5.5C1.


HabitatName:
Iberian Dorset heath coastal dune heaths

HabitatDescription:
[Erica ciliaris]-[Ulex parviflorus ssp. eriocladus] heaths of more humid southwestern Iberian coastal dunes.


HabitatDescription:
Open heathlands of inner coastal dunes of Denmark, of the southern and southeastern Baltic coast, of southern Scania, the Kattegat coast of Sweden, Åland, Gotland and the Öland-Archipelago Sea dominated by [Calluna vulgaris], with [Empetrum nigrum], [Carex arenaria], [Deschampsia flexuosa], [Hieracium umbellatum], [Lotus corniculatus], [Polypodium vulgare], [Salix repens], and a ground layer constituted mostly by [Dicranum scoparium] and [Pleurozium schreberi].


HabitatDescription:
Stable dunes with scrub, e.g. [Hippophae rhamnoides], [Salix repens] in the north, or [Juniperus] spp. or sclerophyllous shrubs in the south.


HabitatDescription:
Dense formations of large, mostly deciduous, shrubs of nemoral affinities of the coastal dunes and dune-slacks of the boreal, nemoral, steppe, mediterranean and warm-temperate humid zones of the Palaearctic region; they include sea-buckthorn, privet, elder, willow, gorse or broom, often festooned with creepers such as honeysuckle or white bryony ([Bryonia cretica]).


HabitatDescription:
Thickets dominated by [Hippophae rhamnoides ssp. rhamnoides] colonizing dry or humid dune depressions of the coasts of the North Sea, the eastern English Channel and the southern Baltic, mostly in Denmark, Germany, Poland, the Kalinin district, the Netherlands, Belgium, Northern France and southeastern and eastern England and southeastern Scotland.


HabitatDescription:
Dunal pre-forest thickets of nemoral affinities of the coastal dunes of the western Palaearctic region formed of species of genera [Ulex], [Sarothamnus], [Rubus], [Ligustrum], [Daphne], [Sambucus]. Codes of subdivisions of unit F3.2 can be used, in addition to unit B1.612, to specify the habitat. Listed elsewhere are dunal formations of heaths (units B1.51, B1.52), sea-buckthorn ([Hippophae rhamnoides], unit B1.611) or creeping willow ([Salix arenaria], unit B1.62).


HabitatDescription:
Mats of [Salix arenaria] colonizing dry or humid dune depressions of Atlantic, North Sea, English Channel, Irish Sea and Baltic coasts of western and northwestern Europe.


HabitatDescription:
Juniper heaths and thickets formed by [Juniperus phoenicea], [Juniperus lycia] s.l., [Juniperus macrocarpa], [Juniperus transtagana], [Juniperus communis] in dune slacks and on dune slopes of the coasts of the boreal, nemoral, steppe, mediterranean or warm-temperate humid zones of the Palaearctic region.


HabitatDescription:
[Juniperus oxycedrus ssp. macrocarpa] thickets and low woods of the outer belt of the juniper woods of fixed Mediterranean and Mediterraneo-Atlantic dunes. Well-developed woods and forests are placed in unit B1.7, with the habitat specified by unit G3.99 (B1.7 x G3.99).


HabitatDescription:
[Juniperus phoenicea ssp. lycia] thickets of the inner belt of the juniper woods of fixed Mediterranean and Mediterraneo-Atlantic dunes. Well-developed woods and forests are placed in unit B1.7, with the habitat specified by unit G3.9A (B1.7 x G3.9A).


HabitatDescription:
[Juniperus oxycedrus ssp. transtagana] scrub of the dunes of southwestern Portugal.


HabitatDescription:
[Juniperus communis] scrubs of the calcareous dunes of northwest Jutland.


HabitatDescription:
Sclerophyllous, lauriphyllous or drought-deciduous scrub and thickets established on dunes of mediterranean or warm-temperate humid regions. They are partially represented by classes of [Ononido-Rosmarinetea], [Quercetea ilicis], [Cisto-Lavanduletea], [Retametea raetami], [Cisto-Micromerietea] and [Ammophiletea].


HabitatDescription:
Naturalized planted [Rosa rugosa] thickets planted for stabilization of shifting sandy soils. Shrubs low (0.3–0.8 m height) and dense. Sparser thickets include species of the [Ammophiletea] class.


HabitatDescription:
Coastal dunes colonised by woodland which are directly influenced by proximity to the sea.


HabitatName:
Coastal dunes: (brown) dunes covered with natural or almost natural coniferous forest, e.g. pines


HabitatName:
Coastal dunes: (brown) dunes covered with deciduous forest (beech, birch, oak)


HabitatName:
Coastal dunes covered with planted dwarf mountain pine woodland

HabitatDescription:
Very dense [Pinus mugo] scrubland planted for stabilization of shifting sand dunes, particularly in the Curonian Spit (SE coast of the Baltic Sea).


HabitatName:
Coastal brown dunes covered with natural or almost natural thermophilous pines

HabitatDescription:
Coastal dunes colonised by Mediterranean and Atlantic thermophilous pines, corresponding to substitution facies or in some stations climax formations of evergreen oak of artificial origin ([Quercetalia ilicis] or [Ceratonio-Rhamnetalia]). Typical species are [Pinus pinea], [Pinus pinaster], [Pinus halepensis], [Juniperus macrocarpa], [Juniperus turbinata ssp. turbinata], [Scaligeria napiformis], [Rhamnus alaternus], [Arbutus unedo], [Erica arborea], [Pistacia lentiscus]. This is the coastal equivalent of unit G3.7.


HabitatDescription:
Moist or wet depressions in coastal dune systems, sometimes with permanent water but more often only seasonally moist or flooded by fresh water. Dune-slacks are extremely rich and specialised habitats, very threatened by the lowering of water tables.


HabitatDescription:
Freshwater aquatic communities (cf. units C1.22-C1.26, C1.32-C1.34, C1.42-C1.45, C1.69) of permanent dune-slack water bodies.


HabitatDescription:
Pioneer formations of humid sands and dune pool fringes on soils with low salinity. Component habitats may be found in unit C3, in particular unit C3.4132 and unit C3.512.


HabitatDescription:
Calcareous and, occasionally, acidic fen formations of coastal dune-slacks (cf. units D2.2, D4.1, in particular units D2.29, D4.11, D4.1H), often invaded by creeping willow, occupying the wettest parts of dune-slacks.


HabitatDescription:
Humid grasslands and rushbeds (units E3.1, E3.411F, E3.418, E3.51 i.a., wet heaths and swamp-heaths (unit F4.11 i.a.) of dune-slacks, also often with creeping willows ([Salix rosmarinifolia], [Salix arenaria]).


HabitatName:
Dune-slack reedbeds, sedgebeds and canebeds

HabitatDescription:
Reedbeds, tall-sedge communities and canebeds (cf. units C3.2, C3.3, D5.2) of dune-slacks. Communities of [Phragmition], [Magnocaricion], [Potamogetonion], [Juncetalia].


HabitatName:
Coastal dunes: wet dune slacks: dominated by shrubs or trees


HabitatDescription:
Short-turf grasslands formed on dry and seasonally waterlogged, relatively flat and low-lying sand plains, where windblown calcareous sand overlies peat or impermeable bedrock. Machair grasslands are machair in the strict sense, and form part of the machair complex (X27), characteristic of the Outer Hebrides and western Ireland, with dunes (B1.3, B1.4), shallow lochs (C1) and land cultivated on a strip rotation (I1). They support a flower-rich, and correspondingly insect-rich, dune grassland studded with shallow lochs and cultivated on a strip rotation. The grassland is dominated by [Poa pratensis] and [Festuca rubra], accompanied by [Thalictrum minus ssp. arenarium], [Thymus praecox ssp. arcticus] ([Thymus drucei]), [Bellis perennis], [Prunella vulgaris], [Erodium cicutarium], [Trifolium] spp., [Euphrasia] spp. and many orchids, among which [Dactylorhiza fuchsii ssp. hebridensis], [Dactylorhiza purpurella], [Gymnadenia conopsea], [Coeloglossum viride], [Platanthera chlorantha] and [Orchis mascula] are the most prominent. This grassland harbours a plant community of very restricted distribution comprising vulnerable species; [Cochlearia scotica], [Euphrasia marshallii] and [Dactylorhiza fuchsii ssp. hebridensis] are endemic. As a whole, machair is an essential habitat for breeding waders such as [Haematopus ostralegus], [Vanellus vanellus], [Charadrius hiaticula], [Calidris alpina], [Tringa totanus] and [Gallinago gallinago]; it supports the healthiest western European population of the threatened corncrake [Crex crex].


HabitatDescription:
Beaches of the oceans, of their connected seas and of their associated coastal lagoons, covered by pebbles, or sometimes boulders, usually formed by wave action.


HabitatDescription:
The lowest level of the supralittoral, just above the normal tide limit, where drift material accumulates and the shingle may be rich in nitrogenous organic matter. Vegetation, if present at all, is very open and composed of annuals or, particularly by the Mediterranean, especially the east Mediterranean, of annuals and perennials, occupying accumulations of drift material and gravels rich in nitrogenous organic matter; characteristic are [Cakile maritima], [Salsola kali], [Atriplex] spp., [Polygonum] spp., [Euphorbia peplis], [Mertensia maritima], and, particularly in Mediterranean formations, [Glaucium flavum], [Matthiola sinuata], [Matthiola tricuspidata], [Euphorbia paralias], [Eryngium maritimum].


HabitatName:
Boreo-arctic gravel beach annual communities

HabitatDescription:
Beach and upper beach formations, mostly of annuals of the low Arctic and high Arctic oceanic zones of the Palaearctic Atlantic, Pacific and Arctic oceans, occupying accumulations of drift material and gravels rich in nitrogenous organic matter; characteristic are [Cakile edentula], [Polygonum norvegicum] ([Polygonum oxyspermum ssp. raii]), [Atriplex longipes] s.l., [Atriplex glabriuscula], [Mertensia maritima].


HabitatName:
Atlantic and Baltic shingle beach drift lines

HabitatDescription:
Formations, predominantly of annuals, occupying accumulations of drift material and gravels rich in nitrogenous organic matter on nemoral and boreonemoral beaches of the Atlantic, the North Sea and the Baltic; characteristic are [Cakile maritima ssp. maritima], [Cakile maritima ssp. baltica], [Salsola kali], [Atriplex] spp. (particularly [Atriplex glabriuscula]), [Polygonum] spp., [Euphorbia peplis], [Mertensia maritima], [Glaucium flavum].


HabitatName:
Gravel beach communities of the mediterranean region

HabitatDescription:
Very open, low formations of annuals and perennials of Mediterranean, thermo-Atlantic and Black Sea gravel and shingle beaches, occupying accumulations of drift material, sandy gravels and gravels rich in nitrogenous organic matter; characteristic are [Cakile maritima ssp. aegyptiaca], [Cakile maritima ssp. euxina], [Enarthrocarpus arcuatus], [Matthiola sinuata], [Matthiola tricuspidata], [Salsola kali], [Atriplex] spp., [Polygonum] spp., [Euphorbia peplis], [Euphorbia paralias], [Glaucium flavum], [Eryngium maritimum].


HabitatName:
Unvegetated mobile shingle beaches above the driftline


HabitatName:
Upper shingle beaches with open vegetation

HabitatDescription:
The upper beach of large shingle bars, with open pioneer communities or perennial vegetation mostly formed by [Crambe maritima], [Honkenya peploides], [Lathyrus japonicus] and a few other specialised species. Mainly in northwest Europe, from the Atlantic to the Baltic.


HabitatDescription:
Perennial communities of the shingle beaches and bars of the southern Baltic, east to Mecklenburg, where they are represented by fragmentary, endangered formations, of the Swedish, Finnish and Estonian coasts and islands of the Öland-Gotland basin, of the coasts of the Kattegat, the Oresund and the Baelts, dominated by [Crambe maritima], with [Leymus arenarius] ([Elymus arenarius]), [Euphorbia palustris], [Honkenya peploides], [Angelica archangelica ssp. litoralis], [Atriplex] spp., [Beta vulgaris ssp. maritima], [Elymus repens], [Geranium robertiana ssp. rubricaule], [Glaucium flavum], [Isatis tinctoria], [Ligusticum scoticum], [Mertensia maritima], [Silene vulgaris ssp. maritima] ([Silene uniflora]), [Tripleurospermum maritimum], [Valeriana salina].


HabitatDescription:
Perennial communities of the shingle beaches and bars of the southern North Sea and Channel coasts of southeastern England and, very locally, the Channel coast of France, dominated by [Crambe maritima], with [Lathyrus japonicus] and [Honkenya peploides].


HabitatDescription:
Perennial communities of the shingle beaches and bars of Brittany, the Cotentin peninsula and Anglesey, dominated by [Crambe maritima], with [Crithmum maritimum] and a sparse representation of other nitrophiles, in particular, [Beta vulgaris ssp. maritima], [Matricaria maritima], [Rumex crispus], [Glaucium flavum], [Solanum dulcamara var. maritima], [Sonchus oleraceus], [Galium aparine].


HabitatName:
Gravelly beach and shingle pioneer communities

HabitatDescription:
Gravelly beaches can host pioneer communities of the class [Ammophiletea] consisting mainly of geophytes and hemicryptophytes, e.g. the association [Agropyro juncei-Sporoboletum pungentis] and the alliance [Medicagini marinae-Triplachnion nitensis]. They may sporadically be inundated by sea water during storms.


HabitatName:
Fixed shingle beaches, with herbaceous vegetation

HabitatDescription:
Vegetated landward expanses of large coastal shingle banks, dominated by grasses or with other herbaceous vegetation.


HabitatDescription:
Dense perennial grasslands of boreal and nemoral coastal gravel banks of the Palaearctic region, in particular, swards of [Arrhenatherum elatius] of large Channel gravel banks.


HabitatDescription:
Coastal gravel banks with scrub. Included are dense thermo-mediterranean scrub on gravel banks beside the Mediterranean and heaths on shingle in the nemoral zone.


HabitatDescription:
Low heaths of boreal and nemoral coastal gravel banks of the Palaearctic region, in particular, prostrate [Cytisus scoparius] formations of large Channel gravel banks.


HabitatDescription:
Coastal gravel banks, colonised by woodland or riparian thickets, in particular, Mediterranean gravel banks colonized by [Quercus ilex] low woods, by [Tamarix africana] or [Vitex agnus-castus].


HabitatName:
Rock cliffs, ledges and shores, including the supralittoral

HabitatDescription:
Rock exposures adjacent to the oceans, their connected seas and associated coastal lagoons, or separated from them by a narrow shoreline. The faces, ledges and caves of sea-cliffs and the expanses of rocky shore are important as reproduction, resting and feeding sites for seabirds, sea-mammals and a few groups of terrestrial birds. Sea-cliffs may also harbour highly distinctive, specialised salt-tolerant vegetation with associated terrestrial fauna.


HabitatName:
Supralittoral rock (lichen or splash zone)

HabitatDescription:
Cliffs and rocks of the supralittoral spray zone, mostly occupied by lichens such as [Caloplaca] spp. and [Verrucaria] spp.


HabitatDescription:
Lichen communities typically form a distinct zone or band in a 'splash' zone on most rocky shores. This splash zone occurs above the main intertidal zone (i.e. that subject to regular covering by the tide) and blends into angiosperm-dominated communities of coastal (terrestrial) habitats at its upper limits. The width of the splash zone varies considerably, depending on the degree of exposure of the shore to wave action. On very exposed coasts the zone is very wide, extending 10s of meters up cliffs, whilst in very sheltered sites it may be only a metre or so high. Several biotopes have been identified. Yellow and grey lichens such as [Xanthoria parietina], [Caloplaca marina], [Caloplaca thallincola] or [Ramalina] sp. dominate the supralittoral rock (B3.111) with the distinctive black band of [Verrucaria maura] occurring below in the littoral fringe (B3.1131, B3.1132). Small green seaweeds can sometimes be found in this splash zone, where localised conditions allow growth in what would otherwise be inhospitable conditions for seaweeds. Such an example is the green seaweed [Prasiola stipitata] which occurs in areas of nitrate enrichment from nearby roosting seabirds (B3.112). The littoral fringe on soft rock can be characterised by the green seaweed [Blidingia minima] (B3.114) while steep and vertical rock influenced by freshwater in the littoral fringe can be dominated by the green seaweeds [Ulothrix flacca], [Urospora penicilliformis] and [Urospora wormskioldii] (B3.115). The winkle [Littorina saxatilis] is one of the few 'marine' species found in this environment.
Situation: This habitat type is found in the littoral fringe and the supralittoral zone on all rocky shores if there is sufficient seawater spray to maintain a viable community.


HabitatDescription:
Vertical to gently sloping bedrock and stable boulders in the supralittoral (or splash zone) of the majority of rocky shores are typically characterised by a diverse maritime community of yellow and grey lichens, such as [Xanthoria parietina], [Caloplaca marina], [Lecanora atra] and [Ramalina] spp. The black lichen [Verrucaria maura] is also present, but usually in lower abundance than in the littoral fringe zone. In wave exposed conditions, where the effects of sea-spray extend further up the shore, the lichens generally form a wide and distinct band. This band then becomes less distinct as wave exposure decreases, and in sheltered locations, cobbles and pebbles may also support the biotope. Pools, damp pits and crevices in the rock are occasionally occupied by winkles such as [Littorina saxatilis] and halacarid mites may also be present.
Situation: This biotope is usually found at the top of the shore, immediately above a zone of the black lichen [V. maura] (B3.1131, B3.1132). Above the band of B3.111, and occasionally in crevices in the rock alongside the lichens, terrestrial plants such as the thrift [Armeria maritima] and other angiosperms often occur. In sheltered areas the transition from B3.111 to B3.1132 is often indistinct and a mixed zone of B3.111 and B3.1132 may occur. In estuaries, this biotope is often restricted to artificial substrata such as sea defences.


HabitatName:
[Prasiola stipitata] on nitrate-enriched supralittoral or littoral fringe rock

HabitatDescription:
Exposed to moderately exposed bedrock and large boulders in the supralittoral and littoral fringe that receives nitrate enrichment from nearby roosting sea birds and is characterised by a band or patches of the ephemeral tufty green seaweed [Prasiola stipitata] or [Prasiola] spp. This typically grows over the black lichen [Verrucaria maura] in the littoral fringe or yellow and grey lichens in the supralittoral zone. In damp pits and crevices, species such as the winkle [Littorina saxatilis], amphipods and halacarid mites are occasionally found. B3.112 often covers a smaller area than 5m x 5m and care should be taken to notice/record this biotope. The biotope can be associated with artificial substrata such as septic tanks, and in supralittoral areas influenced by sewage seeps or agricultural run-off.

Situation: This biotope is found at the top of rocky shores in the splash zone below colonies of nesting or roosting birds growing. B3.112 may also be found at the entrances to and on the ceilings of littoral caves or in patches on large boulders, where birds may be roosting. It can be found in the B3.111 or B3.1132 zones.

Temporal variation: [P. stipitata] reaches its maximum abundance during the winter months. It generally dies out during the summer in southern Britain, when the biotope reverts to either B3.111 or B3.1132. In the cooler northern areas it may be present all year round.


HabitatName:
[Verrucaria maura] on littoral fringe rock

HabitatDescription:
Bedrock or stable boulders and cobbles in the littoral fringe which is covered by the black lichen [Verrucaria maura]. This lichen typically covers the entire rock surface giving a distinct black band in the upper littoral fringe. The winkle [Littorina saxatilis] is usually present. Two variants are defined which both occur in a wide range of wave exposures. On exposed shores [V. maura] may occur with sparse barnacles such as [Chthamalus] spp. or [Semibalanus balanoides] and may be covered by a band of ephemeral seaweeds such as [Porphyra umbilicalis] or [Enteromorpha] spp. (B3.1131). Above B3.1131 or on more sheltered shores is a species poor community consisting mainly of [V. maura] and [L. saxatilis] (B3.1132).

Situation: This biotope occurs below the yellow and grey lichen zone (B3.111) and above eulittoral communities of barnacles and fuciod algae.

Temporal variation: Distinct band of red or green ephemeral algae may obscure the black lichen band at certain times of the year.


HabitatName:
[Verrucaria maura] and sparse barnacles on exposed littoral fringe rock

HabitatDescription:
The littoral fringe of very exposed to moderately exposed rocky shores with a sparse covering of the barnacles [Semibalanus balanoides] and/or [Chthamalus montagui] over the black lichen [Verrucaria maura]. Winkles [Littorina saxatilis] and [Melarhaphe neritoides] are usually present although [M. neritoides] tends to be found on more exposed shores. The limpet [Patella vulgata] is often present though at a low abundance (Occasional). This biotope can be dominated by ephemeral seaweeds including the red seaweed [Porphyra umbilicalis], the green seaweeds [Enteromorpha] spp. or, particulary in the north, microscopic blue-green algae (Cyanophyceae), which overgrow [V. maura]. The wrack [Pelvetia canaliculata] (Rare) may also be present, becoming increasingly more common with greater shelter (see A1.211). Geographical variation: On northern and eastern shores the barnacle is usually [S. balanoides], which is normally restricted to the lower littoral fringe, with a band of [V. maura] only in the upper littoral fringe. On south-west and western shores the barnacle is usually [C. montagui] which may extend over the whole of the littoral fringe zone.

Situation: B3.1131 is usually found on more exposed coasts below the [V. maura] biotope B3.1132. It is found above the mussel [Mytilus edulis] and barnacles biotope (A1.111) or above the barnacle and [Patella] spp. zone (A1.1121; A1.113). B3.1131 also occurs on vertical faces of moderately exposed shores where the [P]. [canaliculata] biotope (A1.211) usually dominates on non-vertical faces.

Temporal variation: The abundance of [P. umbilicalis] shows considerable seasonal and geographical variation. During warm weather [P. umbilicalis] is often bleached light brown and sticks to the rock as it dries out. On southern shores it may be absent during the summer on all but the most exposed shores, as it dies back leaving a barnacle and lichen dominated community. In the cooler north the [P]. [umbilicalis] covering persists throughout the year. [Porphyra linearis] can also be found in the among the [P. umbilicalis] during the late winter and spring.


HabitatName:
[Verrucaria maura] on very exposed to very sheltered upper littoral fringe rock

HabitatDescription:
Upper littoral fringe bedrock, boulders and stable cobbles on very exposed to very sheltered shores which have a blanket covering of the black lichen [Verrucaria maura]. The winkle [Littorina saxatilis] is often present. Due to the nature of this biotope it is species poor, but occasionally a range of species may be present in low abundance. These species include the yellow lichen [Caloplaca marina] and the winkle [Melarhaphe neritoides], the barnacles [Chthamalus montagui] and [Semibalanus balanoides] or the ephemeral seaweeds [Porphyra umbilicalis] and [Enteromorpha] spp. can be present in low abundance (see B3.1131). If one or more of these species is present compare with B3.1131. On northern shores [Littorina saxatilis var. rudis] can dominate along with the occasional presence of the lichens [Verrucaria mucosa] and [Xanthoria parietina]. V. maura can be found overlying stable mud in N. Ireland sea loughs.

Situation: The black lichen zone is normally found below the yellow and grey lichen zone (B3.111). In very sheltered areas there is not always a clear transition from one zone to the next and a mixed zone of B3.111 and B3.1132 is common. The wrack [Pelvetia canaliculata] can occur on these more sheltered shores. With increasing wave exposure the two lichen zones become wider and more distinct, and B3.1132 gives way to a lichen and barnacle dominated community (B3.1131) in the lower littoral fringe.

Temporal variation: In areas with nitrate enrichment [V. maura] can be overgrown by the small green seaweed [Prasiola stipitata] (B3.112) which reaches its maximum abundance during the winter months. It generally dies out during the summer in southern Britain, reverting the biotope to B3.1132.


HabitatName:
[Blidingia] spp. on vertical littoral fringe chalk

HabitatDescription:
Vertical soft rock in the littoral fringe may be characterised by a band of the green seaweeds [Blidingia minima] and [Blidingia marginata]. Unbranched filamentous green seaweeds, including [Ulothrix flacca] and [Urospora wormskioldii], are found amongst the [Blidingia] spp. The siphonous Xanthophyceae [Vaucheria] spp. can also occur in high abundance in this biotope, where they can form dense mats. During low tide terrestrial fauna such as red mites, insects and centipedes migrate into this zone. More information is needed to improve this description.
Situation: B3.114 is found below the [Verrucaria maura] zone (B3.1132) and above a band of the similar looking green algae [Enteromorpha] spp. (A1.451 and A1.452), where these occur in habitats not influenced by freshwater.


HabitatName:
[Ulothrix flacca] and [Urospora] spp. on freshwater-influenced vertical littoral fringe soft rock

HabitatDescription:
An assemblage of the small un-branched filamentous green seaweeds [Ulothrix flacca], [Urospora penicilliformis] and [Urospora wormskioldii] at High Water Spring Tide level on steep and vertical rock often influenced by freshwater. The community is also present in areas with freshwater seepage. It is visually recognised as a closely adherent, often shiny, green mat of filamentous growth. Associated species include the green seaweeds [Blidingia minima] and [Enteromorpha prolifera], the barnacle [Semibalanus balanoides] and the limpet [Patella vulgata], but these species are not common. Although this biotope does occur on rock other than chalk, this description has been derived from chalk coast sites. More information is needed to improve this description.

Situation: On chalk coasts this community can include [Enteromorpha] spp. and the transition from B3.115 to A1.451 is often indistinct and a mixed zone of B3.115 and A1.451 can occur.

Temporal variation: This biotope is more easily identifiable from autumn to spring as both [Urospora] spp. and [Bangia atropurpurea] may dry out and disappear during the summer. In late winter the red seaweed [B. atropurpurea] may be predominant and the community then appears as shiny blackish mats of filamentous growth.


HabitatName:
Association with [Entophysalis deusta] and [Verrucaria amphibia]


HabitatName:
Rock stacks and islets above high tide level in splash zone


HabitatName:
Unvegetated rock cliffs, ledges, shores and islets

HabitatDescription:
Hard-rock sea-cliffs, their faces, ledges and associated caves, rocky shores and isolated seaside rocks, their associated seabird, sea mammal, wader and, in a few cases, terrestrial passerine, communities. Vascular plant cover is by definition very low or absent, but lichens are normally present.


HabitatDescription:
Sea-cliffs and their associated features, rocky shores and isolated seaside rocks of the High Arctic seas bordering middle and northern Greenland, Spitzbergen, Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, the New Siberian Islands, Wrangel Island and the northern Siberian mainland from the north coast of the Yamal peninsula eastwards. Together with floating ice (unit A8.1), they constitute the main hauling-out places for [Odobenus rosmarus]. [Fulmarus glacialis], [Larus glaucoides], [Larus hyperboreus], [Cepphus grylle], [Plautus alle], [Uria lomvia], [Branta bernicla] are among characteristic bird species.


HabitatName:
Atlantic low Arctic sea-cliffs and rocky shores

HabitatDescription:
Sea-cliffs, cliff-faces, ledges and caves, rocky shores and isolated seaside rocks of the Low Arctic region of the North Atlantic and the Arctic Ocean, in southern Greenland, Iceland, Jan Mayen, Bear Island, northern Scandinavia, northwestern mainland Russia, southern and middle Novaya Zemlya. They constitute the principal breeding, resting or feeding areas of multitudes of seabirds and sea-mammals during at least part of the year.


HabitatName:
Temperate Atlantic sea-cliffs and rocky shores

HabitatDescription:
Sea-cliffs, their faces, ledges and associated caves, rocky shores and isolated seaside rocks of the Atlantic temperate region, including the North Sea, the English Channel, the Irish Sea and the Bay of Biscay, along the coasts of Scandinavia south of the Arctic Circle, of the Faeroes, of the British Isles and their outlying archipelagoes, of mainland Europe south to Galicia. They are the breeding, resting or feeding places of great numbers of seabirds and sea-mammals, of which [Halichoerus grypus], [Sula bassana], [Uria aalge], [Alca torda], [Rissa tridactyla], [Phalacrocorax aristotelis aristotelis] are characteristic.


HabitatName:
Unvegetated Baltic rocky shores and cliffs

HabitatDescription:
Sea-cliffs, their faces and ledges, rocky shores and isolated seaside rocks of the Baltic Sea.


HabitatName:
Baltic unvegetated gently sloping limestone rocky shores


HabitatName:
Baltic unvegetated gently sloping sandstone rocky shores


HabitatName:
Baltic unvegetated gently sloping crystalline bedrock shores


HabitatName:
Baltic unvegetated coastal limestone cliffs and caves


HabitatName:
Baltic unvegetated coastal sandstone cliffs and caves


HabitatName:
Baltic unvegetated coastal crystalline bedrock cliffs and caves


HabitatName:
Subtropical Atlantic sea-cliffs and rocky shores

HabitatDescription:
Sea-cliffs, their faces, ledges and associated caves, rocky shores and isolated seaside rocks of the subtropical zone of the Atlantic, including the Canary Islands, Madeira, the Azores, the Mediterraneo-Atlantic coasts of Iberia, the Mediterraneo-Atlantic and Saharo-Atlantic coasts of Africa, south to Cap Blanc. A major zone of upwelling developed along the north African coast and the Canary Islands enhances their value as important breeding and resting places for marine birds and mammals. Their caves harbour the two remaining Atlantic subpopulations of the gravely endangered Monk Seal [Monachus monachus], endemic to this region and the next, those of Madeira and of the Cap Blanc coasts. [Calonectris diomedea borealis], [Larus cachinnans atlantis], [Phalacrocorax carbo maroccanus], [Phalacrocorax aristotelis riggenbachi] are seabirds endemic to the region for which cliffs and rocky shores provide an important breeding habitat.


HabitatName:
Mediterraneo-Pontic sea-cliffs and rocky shores

HabitatDescription:
Sea-cliffs, their associated faces, ledges and caves, rocky shores and isolated rocks of the Mediterranean Sea and the Black Sea. The endangered [Monachus monachus] depends on their caves for reproduction. [Calonectris diomedea diomedea], [Puffinus yelkouan mauretanicus], [Puffinus yelkouan yelkouan], [Phalacrocorax aristotelis desmarestii], [Falco eleonorae], [Larus audouinii] are characteristic breeders. Their vascular aerohaline communities, as well as the rock communities of unit H3 that colonize their less salt-influenced reaches, are particularly diverse and rich in endemics.


HabitatName:
Rock stacks and islets above splash zone


HabitatName:
Rock cliffs, ledges and shores, with angiosperms

HabitatDescription:
Sea-cliffs, or parts of sea-cliffs, and rocky shores colonized by disjunct assemblages of salt-tolerant crevice plants (chasmophytes) or by more or less closed salt-tolerant grasslands with associated terrestrial invertebrate and vertebrate faunal communities.


HabitatDescription:
Vegetated cliffs of the northern Atlantic, the English Channel, the Irish Sea, the North Sea, the Baltic Sea, the Arctic Ocean and its seas, the northwest Pacific and its seas.


HabitatName:
Vegetated Baltic gently sloping rocky shores and cliffs

HabitatDescription:
Vegetated cliffs of the Baltic Sea, with [Silene vulgaris ssp. maritima], [Silene uniflora], [Ligusticum scoticum], [Armeria maritima], [Odontites litoralis ssp. litoralis], [Odontites litoralis ssp. fennica], [Matricaria maritima], [Senecio viscosus].


HabitatName:
Baltic gently sloping limestone rocky shores with low vegetation


HabitatName:
Baltic gently sloping limestone rocky shores dominated by shrubs or trees


HabitatName:
Baltic gently sloping sandstone rocky shores with low vegetation


HabitatName:
Baltic gently sloping sandstone rocky shores dominated by shrubs or trees


HabitatName:
Baltic gently sloping crystalline bedrock shores with low vegetation


HabitatName:
Baltic gently sloping crystalline bedrock shores dominated by shrubs or trees


HabitatName:
Baltic coastal limestone cliffs and caves with low vegetation


HabitatName:
Baltic coastal limestone cliffs and caves dominated by shrubs or trees


HabitatName:
Baltic coastal sandstone cliffs and caves with low vegetation


HabitatName:
Baltic coastal sandstone cliffs and caves dominated by shrubs or trees


HabitatName:
Baltic coastal crystalline bedrock cliffs and caves with low vegetation


HabitatName:
Baltic coastal crystalline bedrock cliffs and caves dominated by shrubs or trees


HabitatDescription:
Vegetated cliffs and rocky shores of the Mediterranean, of the Black Sea and of the subtropical eastern Atlantic with endemic [Limonium] spp. and e.g. [Silene sedoides], [Frankenia hirsuta], [Frankenia pulverulenta], [Crithmum maritimum], [Lotus cytisoides] of the [Crithmo-Staticetea] and the species of the [Saginetea]: [Anthemis rigida], [Bellium minutum], [Catapodium marinum], [Mesembryanthemum nodiflorum], [Parapholis incurva], [Phleum crypsoides], [Phleum exaratum], [Plantago weldenii], [Psilurus incurvus], [Sagina maritima], [Sedum litoreum], [Valantia muralis].


HabitatDescription:
Aerohaline communities of the cliffs and rocky shores of the Mediterranean, as well as of the southwestern Iberian and northwestern African Atlantic, with [Crithmum maritimum], [Plantago subulata], [Silene sedoides], [Sedum litoreum], [Limonium] spp., [Armeria] spp., [Euphorbia] spp., [Daucus] spp., [Asteriscus maritimus]. Mediterranean sea-cliffs harbour numerous endemics of of extremely local occurrence, in particular, of genus [Limonium], which comprises at least 43 and probably closer to 120-150 Mediterranean cliff species species, many of them restricted to a few stations, and several threatened, such as, for instance, [Limonium remotispiculum] of southern Italy and [Limonium strictissimum] of Corsica and Caprera.


HabitatDescription:
Communities of the cliffs of the Black Sea, the Sea of Azov and the Sea of Marmara.


HabitatName:
Western Pontic herbaceous sea-cliff communities

HabitatDescription:
Herbaceous aerohaline communities of the sea-cliffs of the maritime façade of the Stranja and of the Cape Kaliakra area of Bulgaria, with [Limonium gmelinii], [Goniolimon collinum], [Crithmum maritimum], [Elymus pycnanthus], [Cichorium intybus], [Atriplex hastata], [Kochia prostrata], [Melilotus officinalis], [Convolvulus lineatus] and the local endemic [Silene caliacrae].


HabitatName:
Western Pontic sea-cliff [Ficus] thickets

HabitatDescription:
Thickets of [Ficus carica] and [Ulmus minor] of the cliffs of the western Black Sea coast.


HabitatDescription:
Low cliffs and neighbouring sands of the southern Romanian Black Sea coast (between Constanta and Vama Veche), harbouring communities dominated by [Scolymus hispanicus] and [Ecbalium elaterium], with [Atriplex tatarica], [Xanthium spinosum], [Lactuca saligna], [Lolium perenne] and [Polygonum aviculare].


HabitatDescription:
Aerohaline communities of the cliffs of the northern Black Sea and the Sea of Azov, with [Crithmum maritimum], [Kochia prostrata], [Elymus farctus ssp. bessarabicus], [Holosteum umbellatum], [Puccinellia distans], [Limonium meyeri].


HabitatDescription:
Aerohaline communities of the cliffs of the southern coasts of the Black Sea.


HabitatName:
Canary Island and Madeiran sea-cliff communities

HabitatDescription:
Aerohaline communities of the sea-cliffs of the Canaries and Madeira, with [Crithmum maritimum], [Astydamia latifolia], [Schizogyne sericea], [Andryala glutinosa], [Plantago coronopus], [Tolpis fruticosa], [Aizoon canariense], [Campylanthus salsoloides], [Limonium pectinatum], [Frankenia ericifolia], [Reichardia ligulata], [Argyranthemum frutescens], [Lotus] spp., [Asplenium marinum].


HabitatDescription:
Communities of the sea-cliffs of the Azores dominated by the endemic [Festuca petraea].


HabitatDescription:
Communities of vascular chasmophytes and animals colonizing the cliffs of coastal saline or hypersaline bodies of water, which differ very significantly from the cliff communities of units B3.31-B3.35.


HabitatDescription:
Endemic [Limonium secundirameum]-dominated formations of the cliffs overlooking Bagno dell' Acqua on the island of Pantelleria, southwest of Sicily.


HabitatDescription:
Halocalcareous cliff communities of coastal lagoons of the Black Sea at Cape Dolosman (Romania), dominated by [Artemisia santonicum], [Limonium gmelinii], [Halimione verrucifera] ([Obione verrucifera]) and [Lepidium cartilagineum], with Irano-Turanian species such as [Camphorosma annua], [Halocnemum strobilaceum], [Leuzea salina] and [Taraxacum bessarabicum].


HabitatDescription:
Sea-cliffs composed of relatively soft, unconsolidated or uncompacted mineral particle deposits, carved by wind and wave action. They may support scrub similar to that on dunes (B1.6), with [Hippophae rhamnoides], [Salix repens], [Sorbus aucuparia].


HabitatName:
Baltic unvegetated coastal chalk cliffs and caves


HabitatName:
Baltic coastal chalk cliffs and caves with low vegetation


HabitatName:
Baltic coastal chalk cliffs and caves dominated by shrubs or trees


HabitatName:
Baltic unvegetated coastal moraine cliffs and caves


HabitatName:
Baltic unvegetated coastal moraine cliffs and caves with low vegetation


HabitatName:
Baltic unvegetated coastal moraine cliffs and caves dominated by shrubs or trees


HabitatName:
Dwarf spike-rush ([Eleocharis]) beds of inland saline and brackish waters

HabitatDescription:
Emergent [Eleocharis parvula] or [Eleocharis acicularis] formations of brackish lakes and inland seas, their inlets, estuaries, lagoons, mud or sand flats, and other inland brackish waterbodies.


HabitatDescription:
Formations of annuals or representatives of annuals and perennials, occupying accumulations of drift material and gravel rich in nitrogenous organic matter. 


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Atlantic salt meadows (Glauco-Puccinellietalia maritimae)

HabitatDescription:
Salt meadows of Baltic, North Sea, English Channel and Atlantic shores. Aster tripolium can be present or abundant in most subdivisions.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Mediterranean and thermo-Atlantic halophilous scrubs (Sarcocornetea fruticosi)

HabitatDescription:
Perennial vegetation of marine saline muds (schorre) mainly composed of scrub, essentially with a Mediterranean-Atlantic distribution (Salicornia, Limonium vulgare, Suaeda and Atriplex communities) and belonging to the Sarcocornetea fruticosi class.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Mediterranean salt meadows (Juncetalia maritimi)

HabitatDescription:
Various Mediterranean and western Pontic (Black Sea) communities of the Juncetalia maritimi with their characteristic plant species.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Mudflats and sandflats not covered by seawater at low tide

HabitatDescription:
Sands and muds of the coasts of the oceans, their connected seas and associated lagoons, not covered by sea water at low tide, devoid of vascular plants, usually coated by blue algae and diatoms. They are of particular importance as feeding grounds for wildfowl and waders.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatDescription:
Reefs can be either biogenic concretions or of geogenic origin. They are hard compact substrata on solid and soft bottoms, which arise from the sea floor in the sublittoral and littoral zone. Reefs may support a zonation of benthic communities of algae and animal species as well as concretions and corallogenic concretions.


 


Clarifications:


- “Hard compact substrata” are: rocks (including soft rock, e.g. chalk), boulders and cobbles (generally >64 mm in diameter).


- “Biogenic concretions” are defined as: concretions, encrustations, corallogenic concretions and bivalve mussel beds originating from dead or living animals, i.e. biogenic hard bottoms which supply habitats for epibiotic species.


- “Geogenic origin” means: reefs formed by non biogenic substrata.


- “Arise from the sea floor" means: the reef is topographically distinct from the surrounding seafloor.


- “Sublittoral and littoral zone” means: the reefs may extend from the sublittoral uninterrupted into the intertidal (littoral) zone or may only occur in the sublittoral zone, including deep water areas such as the bathyal.


- Such hard substrata that are covered by a thin and mobile veneer of sediment are classed as reefs if the associated biota are dependent on the hard substratum rather than the overlying sediment.


- Where an uninterrupted zonation of sublittoral and littoral communities exist, the integrity of the ecological unit should be respected in the selection of sites.


- A variety of subtidal topographic features are included in this habitat complex such as: Hydrothermal vent habitats, sea mounts, vertical rock walls, horizontal ledges, overhangs, pinnacles, gullies, ridges, sloping or flat bed rock, broken rock and boulder and cobble fields. 


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Salicornia and other annuals colonising mud and sand

HabitatDescription:
Formations composed mostly or predominantly of annuals, in particular Chenopodiaceae of the genus Salicornia or grasses, colonising periodically inundated muds and sands of marine or interior salt marshes. Thero-Salicornietea, Frankenietea pulverulentae, Saginetea maritimae.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Sandbanks which are slightly covered by seawater all the time

HabitatDescription:
Sandbanks are elevated, elongated, rounded or irregular topographic features, permanently submerged and predominantly surrounded by deeper water. They consist mainly of sandy sediments, but larger grain sizes, including boulders and cobbles, or smaller grain sizes including mud may also be present on a sandbank. Banks where sandy sediments occur in a layer over hard substrata are classed as sandbanks if the associated biota are dependent on the sand rather than on the underlying hard substrata.


 


“Slightly covered by sea water all the time” means that above a sandbank the water depth is seldom more than 20 m below chart datum. Sandbanks can, however, extend beneath 20 m below chart datum. It can, therefore, be appropriate to include in designations such areas where they are part of the feature and host its biological assemblages.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatDescription:
Perennial pioneer grasslands of coastal salt muds, formed by Spartina or similar grasses. When selecting sites, preference should be given to those areas supporting rare or local Spartina. 


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Submarine structures made by leaking gases

HabitatDescription:
Submarine structures consist of sandstone slabs, pavements, and pillars up to 4 m high, formed by aggregation of carbonate cement resulting from microbial oxidation of gas emissions, mainly methane. The formations are interspersed with gas vents that intermittently release gas. The methane most likely originates from the microbial decomposition of fossil plant materials.


 


The first type of submarine structures is known as “bubbling reefs”. These formations support a zonation of diverse benthic communities consisting of algae and/or invertebrate specialists of hard marine substrates different to that of the surrounding habitat. Animals seeking shelter in the numerous caves further enhance the biodiversity. A variety of sublittoral topographic features are included in this habitat such as: overhangs, vertical pillars and stratified leaf-like structures with numerous caves. The second type are carbonate structures within “pockmarks”. “Pockmarks” are depressions in soft sediment seabed areas, up to 45 m deep and a few hundred meters wide. Not all pockmarks are formed by leaking gases and of those formed by leaking gases, many do not contain substantial carbonate structures and are therefore not included in this habitat. Benthic communities consist of invertebrate specialists of hard marine substrata and are different from the surrounding (usually) muddy habitat. The diversity of the infauna community in the muddy slope surrounding the “pockmark” may also be high. 


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatName:
Submerged or partially submerged sea caves

HabitatDescription:
Caves situated under the sea or opened to it, at least at high tide, including partially submerged sea caves. Their bottom and sides harbour communities of marine invertebrates and algae.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatDescription:
Downstream part of a river valley, subject to the tide and extending from the limit of brackish waters. River estuaries are coastal inlets where, unlike 'large shallow inlets and bays' there is generally a substantial freshwater influence. The mixing of freshwater and sea water and the reduced current flows in the shelter of the estuary lead to deposition of fine sediments, often forming extensive intertidal sand and mud flats. Where the tidal currents are faster than flood tides, most sediments deposit to form a delta at the mouth of the estuary.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatDescription:
Large indentations of the coast where, in contrast to estuaries, the influence of freshwater is generally limited. These shallow indentations are generally sheltered from wave action and contain a great diversity of sediments and substrates with a well developed zonation of benthic communities. These communities have generally a high biodiversity. The limit of shallow water is sometimes defined by the distribution of the Zosteretea and Potametea associations.


 


 Several physiographic types may be included under this category providing the water is shallow over a major part of the area: embayments, fjards, rias and voes.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatDescription:
Lagoons are expanses of shallow coastal salt water, of varying salinity and water volume, wholly or partially separated from the sea by sand banks or shingle, or, less frequently, by rocks. Salinity may vary from brackish water to hypersalinity depending on rainfall, evaporation and through the addition of fresh seawater from storms, temporary flooding of the sea in winter or tidal exchange. With or without vegetation from Ruppietea maritimae, Potametea, Zosteretea or Charetea.


 


Description from EU Habitats Committee document "Interpretation Manual of European Union Habitats - EUR28" (http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/Int_Manual_EU28.pdf)


HabitatDescription:
A drowned river valley in an area of high relief; most have resulted from the post-glacial rise in relative sea level. In Scotland this sub-type is called a voe.


HabitatDescription:
A series of shallow basins connected to the sea via shallow, sometimes intertidal, sills. Fjards are found in areas of low-lying ground which have been subject to glacial scouring. They have a highly irregular outline, no main channel and lack the high relief and U-shaped cross-section of fjordic sea lochs.


HabitatDescription:
A type of marine inlet where the line of the coast typically follows a concave sweep between rocky headlands, sometimes with only a narrow entrance to the embayment.


HabitatDescription:
Carbonate mounds are distinct elevations of various shapes, which may be up to 350m high and 2km wide at their base (Weering et al, 2003).  They occur offshore in water depths of 500-1100m with examples present in the Porcupine Seabight and Rockall Trough (Kenyon et al, 2003).  Carbonate mounds may have a sediment veneer, typically composed of carbonate sands, muds and silts.  The cold-water reef-building corals Lophelia pertusa and Madrepora oculata, as well as echiuran worms are characteristic fauna of carbonate mounds.  Where cold-water corals (such as Lophelia) are present on the mound summit, coral debris may form a significant component of the overlying substratum.

There is currently speculation on the origin of carbonate mounds, with possible associations with fault-controlled methane seepage from deep hydrocarbon reservoirs, or gas-hydrate dissociation (Henriet et al, 1998) through to the debris from ‘cold-water’ coral colonies such as Lophelia.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Deep sea sponge aggregations are principally composed of sponges from two classes: Hexactinellida and Demospongia.  They are known to occur between water depths of 250-1300m (Bett & Rice, 1992), where the water temperature ranges from 4-10°C and there is moderate current velocity (0.5 knots).  Deep-sea sponge aggregations may be found on soft substrata or hard substrata, such as boulders and cobbles which may lie on sediment.  Iceberg plough-mark zones provide an ideal habitat for sponges because stable boulders and cobbles, exposed on the seabed, provide numerous attachment/settlement points (B. Bett, pers comm.).  However, with 3.5kg of pure siliceous spicule material per m2 reported from some sites (Gubbay, 2002), the occurrence of sponge fields can alter the characteristics of surrounding muddy sediments.  Densities of occurrence are hard to quantify, but sponges in the class Hexactinellida have been reported at densities of 4-5 per m2, whilst ‘massive’ growth forms of sponges from the class Demospongia have been reported at densities of 0.5-1 per m2 (B. Bett, pers comm.).  Deep-sea sponges have similar habitat preferences to cold-water corals, and hence are often found at the same location.  Research has shown that the dense mats of spicules present around sponge fields may inhibit colonisation by infaunal animals, resulting in a dominance of epifaunal elements (Gubbay, 2002).  Sponge fields also support ophiuroids, which use the sponges as elevated perches.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatName:
Ocean ridges with hydrothermal vents/fields

HabitatDescription:
Hydrothermal vents occur along spreading ridges (such as the mid-Atlantic ridge), subduction zones, fracture zones and back-arc basins (Gage & Tyler, 1991), and are caused by seawater penetrating the upper levels of the Earth’s crust through channels formed in cooling lava flows, reacting chemically with hot basalt in the Earth’s crust and then rising back to the sea-bed to vent as superheated water containing compounds such as sulphides, metals, CO2 and methane (Tunnicliffe et al, 1998 in Gubbay, 2002).  The water may trickle out from cracks and crevices on the seabed as hot springs (5-250°C), or as very concentrated jets of superheated water (270-380°C).  As these concentrated jets of water cool, minerals dissolved in the water precipitate out in black clouds, giving them their common name of ‘black smokers’.  At lower temperatures, sulphides are mostly precipitated within the rocks, making the venting fluids appear cloudier.  These are known as ‘white smokers’ (Gage & Tyler, 1991).  Hydrothermal vent fields cover relatively small areas of the seabed in water depths of 850-4,000m.  The biological communities associated with hydrothermal vents are unusual as they are able to derive energy under conditions where photosynthesis is not possible.  These habitats contain a huge diversity of chemoautotrophic bacteria, which form the core of the trophic structure around the vent.  Characteristic species include the mussel Bathymodiolus azoricus and its commensal worm Branchipolynoe seepensis, the shrimps Mirocaris fortunata, Chorocaris chacei  and Rimicaris exoculata (this last one is dominant on the southern vent fields of Lucky Strike), the crab Segonzacia mesatlantic, the polychaete Amathys lutzi, the amphipod Luckia strike and the limpet Lepetodrilus atlanticus.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Lophelia pertusa, a cold water, reef-forming coral, has a wide geographic distribution ranging from 55°S to 70°N, where water temperatures typically remain between 4-8°C.  These reefs are generally subject to moderate current velocities (0.5 knots).  The majority of records occur in the north-east Atlantic.  The extent of L. pertusa reefs vary, with examples off Norway several km long and more than 20m high.  These reefs occur within a depth range of 200->2000m on the continental slope, and in shallower waters in Norwegian fjords and Swedish west coast.  In Norwegian waters, L. pertusa reefs occur on the shelf and shelf break off the western and northern parts on local elevations of the sea floor and on the edges of escarpments.  The biological diversity of the reef community can be three times as high as the surrounding soft sediment (ICES, 2003), suggesting that these cold-water coral reefs may be biodiversity hotspots.  Characteristic species include other hard corals, such as Madrepora oculata and Solenosmilia variabilis, the redfish Sebastes viviparous and the squat lobster Munida sarsi.  L. pertusa reefs occur on hard substrata; this may be Lophelia rubble from an old colony or on glacial deposits.  For this reason, L. pertusa reefs can be associated with iceberg plough-mark zones. Areas of dead coral reef indicate the site supported coral reef habitat in the past and should be reported as this habitat type.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Beds of the oyster Ostrea edulis occurring at densities of 5 or more per m² on shallow mostly sheltered sediments (typically 0-10m depth, but occasionally down to 30m).  There may be considerable quantities of dead oyster shell making up a substantial portion of the substratum. The clumps of dead shells and oysters can support large numbers of the ascidians Ascidiella aspersa and Ascidiella scabra. Several conspicuously large polychaetes, such as Chaetopterus variopedatus and terebellids, may be present as well as additional suspension-feeding polychaetes such as Myxicola infundibulum, Sabella pavonina and Lanice conchilega. A turf of seaweeds such as Plocamium cartilagineum, Nitophyllum punctatum and Spyridia filamentosa may also be present (Connor et al, 2004).

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Seamounts are defined as undersea mountains, with a crest that rises more than 1,000 metres above the surrounding sea floor (Menard, 1964 in Rogers, 1994).  Seamounts can be a variety of shapes, but are generally conical with a circular, elliptical or more elongate base.  Seamounts are volcanic in origin, and are often associated with seafloor ‘hot-spots’ (thinner areas of the earth’s crust where magma can escape).  Seamounts, often with a slope inclination of up to 60°, provide a striking contrast to the surrounding ‘flat’ abyssal plain.  Their relief has profound effects on the surrounding oceanic circulation, with the formation of trapped waves, jets, eddies and closed circulations known as Taylor columns (Taylor, 1917 in Rogers, 1994).  Seamounts occur frequently within the OSPAR Maritime Area.  Analysis of narrow beam bathymetric data by the US Naval Oceanographic office from 1967-1989 identified more than 810 seamounts within the North Atlantic.  The majority occur along the Mid-Atlantic ridge between Iceland and the Hayes fracture zone (Gubbay, 2002).

The enhanced currents that occur around seamounts provide ideal conditions for suspension feeders.  Gorgonian, scleratinian and antipatharian corals may be particularly abundant, and other suspension feeders such as sponges, hydroids and ascidians are also present.  Concentrations of commercially important fish species, such as orange roughy, aggregate around seamounts and live in close association with the benthic communities (Gubbay, 2002).

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatName:
Seapen and burrowing megafauna communities

HabitatDescription:
Plains of fine mud, at water depths ranging from 15-200m or more, which are heavily bioturbated by burrowing megafauna with burrows and mounds typically forming a prominent feature of the sediment surface. The habitat may include conspicuous populations of seapens, typically Virgularia mirabilis and Pennatula phosphorea.  The burrowing crustaceans present may include Nephrops norvegicus, Calocaris macandreae or Callianassa subterranea.  In the deeper fiordic lochs which are protected by an entrance sill, the tall seapen Funiculina quadrangularis may also be present.  The burrowing activity of megafauna creates a complex habitat, providing deep oxygen penetration.  This habitat occurs extensively in sheltered basins of fjords, sea lochs, voes and in deeper offshore waters such as the North Sea and Irish Sea basins.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Two sub-types :

  8.1 Zostera marina beds

  8.2 Zostera noltii beds

To qualify as a Zostera ‘bed’, plant densities should provide at least 5% cover (although when Zostera densities are this low, expert judgement should be sought to define the bed).  More typically, however, Zostera plant densities provide greater than 30% cover.  Seagrass beds stabilise the substratum as well as providing a habitat for many other species.  As well as an important source of organic matter, seagrass beds may also provide an important nursery habitat for juvenile fish (ICES, 2003).

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Zostera marina forms dense beds, with trailing leaves up to 1m long, in sheltered bays and lagoons from the lower shore to about 4m depth, typically on sand and sandy mud (occasionally with an admixture of gravel).  Where their geographical range overlaps, such as the Solent in the UK, Z. marina passes upshore to Z. noltii.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Z. noltii forms dense beds, with leaves up to 20cm long, typically in the intertidal region (although it can occur in the very shallow subtidal), on mud/sand mixtures of varying consistency.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Intertidal mud typically forms extensive mudflats in calm coastal environments (particularly estuaries and other sheltered areas), although dry compacted mud can form steep and even vertical faces, particularly at the top of the shore adjacent to salt marshes.  The upper limit of intertidal mudflats is often marked by saltmarsh, and the lower limit by Chart Datum.  Sediments consist mainly of fine particles, mostly in the silt and clay fraction (particle size less than 0.063 mm in diameter), though sandy mud may contain up to 80% sand (mostly very fine and fine sand), often with a high organic content.  Little oxygen penetrates these cohesive sediments, and an anoxic layer is often present within millimetres of the sediment surface. Intertidal mudflats support communities characterised by polychaetes, bivalves and oligochaetes.  This priority habitat has been divided into two sub-types, based on the predominant salinity regime.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
The erosion of chalk exposures on the coast has resulted in the formation of vertical cliffs and gently-sloping intertidal platforms with a range of micro-habitats of biological importance.  Supralittoral and littoral fringe chalk cliffs and sea caves support various algal communities unique to this soft rock type.  Orange, brownish or blackish gelatinous bands of algae, composed of an assemblage of Haptophyceae species such as Apistonema spp., Pleurochrysis carterae and the orange Chrysotila lamellosa, but other genera and species of Chrysophyceae, Haptophyceae and Prasinophyceae are likely to be present as well.  The lower littoral fringe may be characterised by a dense mat of green algae Enteromorpha spp. and Ulva lactuca.  Lower down the shore in the eulittoral the generally soft nature of the chalk results in the presence of a characteristic flora and fauna, notably ‘rock-boring’ invertebrates such as piddocks, overlain by mostly algal-dominated communities (fucoids and red algal turfs) (Gubbay, 2002).  Such coastal exposures of chalk are rare in Europe, with those occurring on the southern and eastern coasts of England accounting for the greatest proportion (57%) (ICES, 2003).  Elsewhere, this habitat occurs in France, Denmark and Germany.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
“Maerl” is a collective term for several species of calcified red seaweed (e.g. Phymatolithon calcareum, Lithothamnion glaciale, Lithothamnion corallioides and Lithophyllum fasciculatum) which live unattached on sediments.  In favourable conditions, these species can form extensive beds, typically 30% cover or more, mostly in coarse clean sediments of gravels and clean sands or muddy mixed sediments, which occur either on the open coast or in tide-swept channels of marine inlets, where it grows as unattached nodules or ‘rhodoliths’.  Maerl beds have been recorded from a variety of depths, ranging from the lower shore to 30m depth.  As maerl requires light to photosynthesize, depth is determined by water turbidity.  In fully marine conditions the dominant species is typically P. calcareum, whilst under variable salinity conditions such as sealochs, beds of L. glaciale may develop.  Maerl beds have been recorded off the southern and western coasts of the British Isles, north to Shetland, in France and other western European waters.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
The horse mussel Modiolus modiolus forms dense beds, at depths up to 70m (but may extend onto the lower shore), mostly in fully saline conditions and often in tide-swept areas.  Although M. modiolus is a widespread and common species, horse mussel beds (with typically 30% cover or more) are more limited in their distribution.  Modiolus beds are found on a range of substrata, from cobbles through to muddy gravels and sands, where they tend to have a stabilising effect, due to the production of byssal threads.  Communities associated with Modiolus beds are diverse, with a wide range of epibiota and infauna being recorded, including hydroids, red seaweeds, solitary ascidians and bivalves such as Aequipecten opercularis and Chlamys varia.  As M. modiolus is an Arctic-Boreal species, its distribution ranges from the seas around Scandinavia (including Skagerrak & Kattegat) and Iceland south to the Bay of Biscay.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Two sub-types: 


Sabellaria spinulosa reefs on rock


   Sabellaria spinulosa reefs on mixed (sediment) substrata


 


The tube-building polychaete Sabellaria spinulosa can form dense aggregations on mixed substrata and on rocky habitats. In mixed substrata habitats, comprised variously of sand, gravel, pebble and cobble, the Sabellaria covers 30% or more of the substrata and needs to be sufficiently thick and persistent to support an associated epibiota community which is distinct from surrounding habitats. On rocky habitats of bedrock, boulder and cobble, the Sabellaria covers 50% or more of the rock and may form a crust or be thicker in structure. In some areas, these two variations of reef type may grade into each other. Sabellaria reefs have been recorded in depths between 10-50m BCD or more. The reef infauna typically comprises polychaete species such as Protodorvillea kefersteini, Scoloplos armiger, Harmothoe spp., Mediomastus fragilis, Lanice conchilega and cirratulids together with the bivalves Abra alba and Nucula spp. and tube-building amphipods such as Ampelisca spp. Epifauna comprise calcareous tubeworms, pycnogonids, hermit crabs, amphipods, hydroids, bryozoans, sponges and ascidians.  S. spinulosa reefs are often found in areas with quite high levels of natural sediment disturbance; in some areas of reef, individual clumps of Sabellaria may periodically break down and rebuild following storm events.  S. spinulosa reefs have been recorded from all European coasts except the Baltic Sea, Skagerrak and Kattegat. Areas of dead Sabellaria reef indicate the site supported reef habitat in the past and should be reported as this habitat type.


Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Sediment shores characterised by beds of the mussel Mytilus edulis occur principally on mid and lower shore mixed substrata (mainly cobbles and pebbles on muddy sediments) but also on sands and muds. In high densities (at least 30% cover) the mussels bind the substratum and provide a habitat for many infaunal and epibiota species. This habitat is also found in lower shore tide-swept areas, such as in the tidal narrows of sealochs.  A fauna of dense juvenile mussels may be found in sheltered firths, attached to algae on shores of pebbles, gravel, sand, mud and shell debris with a strandline of fucoids.  Mussel beds on intertidal sediments have been reported all along the coast of Europe, particularly in UK, France, Netherlands and Germany.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
The main characteristic of a coral garden is a relatively dense aggregation of colonies or individuals of one or more coral species. Coral gardens can occur on a wide range of soft and hard seabed substrata. For example, soft-bottom coral gardens may be dominated by solitary scleractinians, sea pens or certain types of bamboo corals, whereas hard-bottom coral gardens are often found to be dominated by gorgonians, stylasterids, and/or black corals (ICES 2007).

The biological diversity of coral garden communities is typically high and often contains several species of coral belonging to different taxonomic groups, such as leather corals (Alcyonacea), gorgonians (Gorgonacea), sea pens (Pennatulacea), black corals (Antipatharia), hard corals (Scleractinia) and, in some places, stony hydroids (lace or hydrocorals: Stylasteridae). However, reef-forming hard corals (e.g. Lophelia, Madrepora and Solenosmilia), if present, occur only as small or scattered colonies and not as a dominating habitat component. The habitat can also include relatively large numbers of sponge species, although they are not a dominant component of the community. Other commonly associated fauna include basket stars (Gorgonocephalus), brittle stars, crinoids, molluscs, crustaceans and deep-water fish (Krieger and Wing 2002). Krieger and Wing (2002) conclude that the gorgonian coral Primnoa is both habitat and prey for fish and invertebrates and that its removal or damage may affect the populations of associated species.

Densities of coral species in the habitat vary depending on taxa and abiotic conditions, e.g. depth, current exposure, substrate). The few scientific investigations available indicate that smaller species (e.g. the gorgonians Acanthogorgia and Primnoa, and stylasterids) can occur in higher densities, e.g. 50 – 200 colonies per•100m2, compared to larger species, such as Paragorgia, which may not reach densities of 1 or 2 per 100 m2. Depending on biogeographic area and depth, coral gardens containing several coral species may in some places reach densities between 100 and 700 colonies per•100m2. These densities merely indicate the biodiversity richness potential of coral gardens. In areas where the habitat has been disturbed, by for example, fishing activities, densities may be significantly reduced. Currently, it is not possible  to determine threshold values for the presence of a coral garden as knowledge of the in situ growth forms and densities of coral gardens (or abundance of coral by-catch in fishing gear) is very limited, due to technical or operational restrictions. Visual survey techniques will hopefully add to our knowledge in the coming years. 

Non-reef-forming cold-water corals occur in most regions of the North Atlantic, most commonly in water with temperatures between 3 and 8ºC (Madsen, 1944; Mortensen et al., 2006) in the north, but also in much warmer water in the south, e.g. around the Azores. Their bathymetric distribution varies between regions according to different hydrographic conditions, but also locally as an effect of topographic features and substrate composition. They can be found as shallow as 30 m depth (in Norwegian fjords) and down to several thousand meters on open ocean seamounts. The habitat is often subject to strong or moderate currents, which prevents silt deposition on the hard substrata that most coral species need for attachment. The hard substrata may be composed of bedrock or gravel/boulder, the latter often derived from glacial moraine deposition, whilst soft sandy/clayey sediments can also support cold-water corals (mostly seapens and some gorgonians within the Isididae).

Notes on practical identification and mapping of the habitat: Given the diversity of possible appearances of the habitat across the North East Atlantic, a more precise description of the habitat as it occurs in relation to different substrates, depths and regions will need to be developed. For individual locations, expert judgement is required to distinguish this habitat from surrounding habitats, including an assessment of the appropriate densities of octocoral species to constitute this habitat. As a first step to further clarification a site-by-site description of coral gardens is required that will lead to further refinement of this habitat definition and its inclusion in national and European habitat classifications. The habitat definition above does not encompass shelf and coastal water habitats with seapen and octocoral communities (for example Alcyonium spp. Caryopyllia spp.), including the OSPAR habitat ‘seapens and burrowing megafauna’ or deeper-water habitats where colonial scleractinian corals (Lophelia pertusa reefs) or sponges (Deep-sea sponge aggregations) dominate.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatDescription:
Cymodocea nodosa forms large and dense patches with green leaves that can reach 100 cm long and 8 mm wide in well sorted fine sands or on superficial muddy sands in sheltered waters at depths of 1-30 meters. Frequently is mixed with other habitat forming phanerogams (Zostera noltii and Zostera marina) at muddy sands rich in organic nutrients. Shallow meadows of Cymodocea and Zostera are usually found in sheltered bays close to harbours, e.g. Cadiz Bay, or in areas subject to human impact. 

C. nodosa has a tropical origin, nowadays restricted to the Mediterranean and scattered locations in the North Atlantic from southern Portugal and Spain to Senegal, including Canary Island and Madeira. Southern Portugal constitutes the current northern geographic limit of its distribution.

Description from OSPAR document "08-07e Priority habitat definitions" (http://www.ospar.org/documents/DBASE/DECRECS/Agreements/08-07e_Priority%20habitat%20definitions.doc).


HabitatName:
Sabellaria spinulosa reefs on mixed (sediment) substrata


HabitatDescription:
This habitat includes intertidal and subtidal beds of the blue mussel Mytilus edulis on a variety of sediment types and in a range of conditions from open coasts to estuaries, marine inlets and deeper offshore habitats. Blue mussel beds plays an important part of a healthy functioning marine ecosystem, having a role in coastal sediment dynamics, acting as a food source for over-wintering waders, and providing an enhanced area of biodiversity in an otherwise sediment-dominated environment.



Intertidal mussel beds occur on a variety of sediment substrata such as sand, cobbles and pebbles, muddy sand and mud. Mussel aggregations in this habitat are dense, and can support various age classes. The wrack Fucus vesiculosus is often present, attached to the cobbles or mussel shells, and the shells themselves are often encrusted with various barnacles and bryozoans. The spaces between the mussels can provide refuges for a diverse community of organisms, prominent amongst which are the winkles Littorina littorea and L. saxatilis and small shore crabs, Carcinus maenas. The infauna of the underlying sediment (except where this is anoxic mud) may feature the gastropod Hydrobia ulvae, the bivalves Macoma balthica and Cerastoderma edule, the isopods Corophium volutator, Crangon crangon and Jaera forsmani and polychaetes such as the sandmason Lanice conchilega, the lugworm Arenicola marina and ragworm Hediste diversicolor. Further infaunal sampling has indicated a diverse range of nematodes, oligochates and polychaetes.



In the subtidal, dense mussel beds can form on the upper faces of tide-swept sediment dominated substrates, almost to the exclusion of almost all other species. The common starfish Asterias rubens is often locally abundant as it feeds on mussels, along with other predators such as the crabs Necora puber, Carcinus maenas, Maja squinado and Cancer pagurus. Anemones such as Sagartiogeton undatus, the dahlia anemone Urticina equina and the daisy anemone Cereus pedunculatus can be found on gravel patches and amongst the mussels themselves. The hydroid Kirchenpaueria pinnata and others characteristic of strong tides and a little scour, such as Sertularia argentea and Tubularia

indivisa, may also be present. Ascidians such as Molgula manhattensis and Polycarpa spp. can also feature on subtidal mussel beds, particularly in silty conditions. Infaunal species include the amphipod Gammarus salinus and oligochaetes of the genus Tubificoides. The polychaetes Harmothoe spp. Kefersteinia cirrata and Heteromastus filiformis are also characteristic of this habitat.



Note that the habitat only covers ‘natural’ beds on a variety of sediment types, and excludes artificially created mussel beds, and mussel beds which occur on rock and boulders.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Carbonate mounds are very steep-sided mounds of variety of shapes, which may be up to 350m high and 2 km wide at their base (Weering et al, 2003). They occur offshore in water depths of 500-1100m with examples present in the Porcupine Seabight and Rockall Trough (Kenyon et al, 2003). Carbonate mounds may have a sediment veneer, typically composed of carbonate sands, muds and silts. The cold-water reef-building corals Lophelia pertusa and Madrepora oculata which form colonies up to 30cm high, as well as echiuran worms are characteristic fauna of carbonate mounds. The solitary coral Desmophyllum cristagalli and the octocoral Stylaster sp. Were also occasionally present and nearby areas of cobbles and small boulders provided a surface for settlement of individual coral colonies (Wilson & Vina Herbon, 1998). Where cold-water corals (such as Lophelia) can also be (occasionally) present on the mound summit, coral debris may form a significant component of the overlying substratum. The branching structure underlying dead coral cam provide a surface for settlement which was also elevated from the seabed and was extensively colonised by sponges, bryozoans, hydroids, soft corals, ascidians, calcareous tube worms, zoanthids, crinoids and bivalves. Other species that can be present include; large eunicid wormsnd sipunculids, Ophiactis balli (ophiuroid), Astarte sp (bivalve), cerianthid anemones and caridean shrimps (Wilson & Vina Herbon, 1998).



There is currently speculation on the origin of carbonate mounds, with possible associations with fault-controlled methane seepage from deep hydrocarbon reservoirs, or gas-hydrate dissociation (Henriet et al, 1998) through to the debris from ‘cold-water’ coral colonies such as Lophelia.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Lophelia pertusa, a cold water, reef-forming coral, has a wide geographic distribution ranging from 55°S to 70°N, where water temperatures typically remain between 4-8°C. These reefs are generally subject to moderate current velocities (0.5 knots). The majority of records occur in the north-east Atlantic. The extent of L. pertusa reefs vary and occur within a depth range of 200->2000 m. The species that associate with L. pertusa reefs change from one biogeographic province to another with an overall reduction in diversity from south to north coupled with a shift towards a more northern fauna (Hall-Spencer et al. 2002, 2007; Roberts et al. 2008).

The biological diversity of the reef community can be three times as high as the surrounding soft sediment (ICES, 2003), suggesting that these cold-water coral reefs may be biodiversity hotspots. Characteristic species include other hard corals, such as Madrepora oculata and Solenosmilia variabilis, the redfish Sebastes viviparous and the squat lobster Munida sarsi.

The reef-forming coral Madrepora oculata often occurs amongst L. pertusa reefs which trap sediment and create carbonate-rich deposits to form isolated habitats of high benthic biomass. The reefs commonly harbour abundant sessile suspension feeders and a multitude of grazing, scavenging and predatory invertebrates such as echiurans (e.g. Bonellia sp.), molluscs (e.g. Acesta oxcavate), crustaceans (Pandalus spp. Munida spp.) and echinoderms (e.g. Cidaris spp. Gorgonocephalus sp.) (Freiwald et al. 2004; Hovland, 2008; Roberts et al. 2006, 2008). L. pertusa reefs occur on hard substrata; this may be Lophelia rubble from an old colony or on glacial deposits. For this reason, L. pertusa reefs can be associated with iceberg plough-mark zones.

The conservation importance of L. pertusa reefs is increasingly recognised, not only because of their longevity and high biodiversity, but also due to potential benefits for commercial fisheries. Although functional relationships have not been demonstrated so far, the reefs are presumed to act as breeding grounds for commercial species such as redfish (Sebastes spp.), which hide amongst the complex 3-dimensional structure, and provide hunting territory for demersal predators such as monkfish, cod, ling, saithe and tusk (Husebo et al. 2002; Costello et al. 2005).

Lophelia pertusa larvae require hard substrata to settle and its reefs mainly occur at depths where temperature varies less than in surface waters, in areas with strong currents and sloping bathymetry which enhance the supply of organic material for reef growth (Frederiksen et al. 1992; Duineveld et al. 2004; Thiem et al. 2006). Lophelia pertusa requires temperatures between 4-13°C and salinities of around 35-38 psu, with oxygen concentrations >3 ml l-1 in waters saturated with aragonite (Freiwald et al. 2004; Taviani et al. 2005; Dodds et al. 2007; Davies et al. 2008).



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Deep sea sponge aggregations are principally composed of sponges from two classes: Hexactinellida and Demospongia. Glass sponges (Hexactinellidae) tend to be the dominant group of sponges in the deep sea although demospongids such as Cladorhiza and Asbestopluma are also present. The massive sponges that dominate some areas include Geodia barretti, G. macandrewi, and Isops phlegraei. They can occur at very high densities, particularly on the slope in areas where substrate and hydrographic conditions are favourable. Survey material from a sponge field in the northern North Sea and other locations had a comparable diversity and density of sponges with tropical reefs (Konnecker, 2002). The sponges also influence the density and occurrence of other species by providing shelter to small epifauna, within the oscula and canal system, and an elevated perch, e.g. for brittlestars (Konnecker, 2002). Deep-sea sponges have similar habitat preferences to cold-water corals, and hence are often found at the same location. Research has shown that the dense mats of spicules present around sponge fields may inhibit colonisation by infaunal animals, resulting in a dominance of epifaunal elements (Gubbay, 2002). Information indicates that dominant species are slow growing taking several decades to reach large size (Klitgaard & Tendal, 2001). The habitat and the rich diverse associated fauna is therefore likely to take many years to recover if adversely affected (Konnecker, 2002).

They occur between water depths of 250-1300m (Bett & Rice, 1992), where the water temperature ranges from 4-10°C and there is moderate current velocity (0.5 knots). Deep-sea sponge aggregations may be found on soft substrata or hard substrata, such as boulders and cobbles which may lie on sediment. Iceberg plough-mark zones provide an ideal habitat for sponges because stable boulders and cobbles, exposed on the seabed, provide numerous attachment/settlement points (B. Bett, pers comm.). However, with 3.5kg of pure siliceous spicule material per m2 reported from some sites (Gubbay, 2002), the occurrence of sponge fields can alter the characteristics of surrounding muddy sediments. Densities of occurrence are hard to quantify, but sponges in the class Hexactinellida have been reported at densities of 4-5 per m², whilst ‘massive’ growth forms of sponges from class Demospongia have been reported at densities of 0.5-1 per m2 (B. Bett, pers. Comm.).



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
The horse mussel Modiolus modiolus forms dense beds at depths of 5-70 m in fully saline, often moderately tide-swept areas off northern and western parts of the British Isles. Although it is a widespread and common species, true beds forming a distinctive biotope are much more limited and are not known south of the Humber and Severn estuaries. Beds are known from Shetland, Orkney, the Hebrides and other parts of western Scotland, the Ards Peninsula, Strangford Lough, off both ends of the Isle of Man, off north-west Anglesey and north of the Lleyn Peninsula. Dense beds of young Modiolus modiolus also occur in the Bristol Channel but often seem not to survive to adulthood. Off North Sea coasts occasional beds occur between Berwickshire and the Humber, and probably elsewhere.

M. modiolus can occur as relatively small, dense beds of epifaunal mussels carpeting steep rocky surfaces, as in some Scottish sealochs, but is more frequently recessed at least partly into mixed or muddy sediments in a variety of tidal regimes. In some sea lochs and open sea areas, extensive expanses of seabed are covered in scattered clumps of semi-recessed M. modiolus on muddy gravels. In a few places in the UK, beds are more or less continuous and may be raised up to several metres above the surrounding seabed by an accumulation of shell, faeces, pseudofaeces and sand. 

In some areas of very strong currents extensive areas of stony and gravelly sediment are bound together by more or less completely recessed M. modiolus, creating waves or mounds with steep faces up to one metre high and many metres long. These areas of semi-recessed and recessed beds may in some cases extend over hundreds of hectares, and in many cases may be considered as `biogenic reefs`, though they are all referred to here as beds. The JNCC Marine Nature Conservation Review (MNCR) has identified four major biotopes dominated by dense M. modiolus.

M. modiolus is a long-lived species and individuals within beds are frequently 25 years old or more. Juvenile M. modiolus are heavily preyed upon, especially by crabs and starfish, until they are about 3-6 years old, but predation is low thereafter. Recruitment is slow and may be very sporadic; there may be poor recruitment over a number of years in some populations.

There have been no studies of the recovery of damaged beds but full recovery after severe damage would undoubtedly take many years at best and may not occur at all. Some beds may be self maintaining relict features.

The byssus threads secreted by M. modiolus have an important stabilising effect on the seabed, binding together living M. modiolus, dead shell, and sediments. As M. modiolus is a filter feeder, the accumulation of faeces and pseudofaeces probably represents an important flux of organic material from the plankton to the benthos. This rich food source, together with the varied habitat, means that extremely rich associated faunas, sometimes with hundreds of species, may occur on dense beds.

The composition of the biotopes is variable, and is influenced by the depth, degree of water movement, substrate, and density of M. modiolus. Sponges, ascidians, soft corals, anemones, hydroids, bryozoans, tubeworms, brittlestars, urchins, starfish, barnacles, crabs, spider crabs and other decapods, whelks and other gastropods, scallops and fish all tend to be abundant as epifauna, while there may also be coralline algae and other red seaweeds in shallower areas. Infauna often includes the purple heart urchin Spatangus purpureus and numerous bivalves. The possible role of M. Modiolus beds as nursery areas for other species has not been investigated.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
The erosion of chalk exposures on the coast has resulted in the formation of vertical cliffs and gently sloping intertidal platforms with a range of micro-habitats of biological importance. Supralittoral and littoral fringe chalk cliffs and sea caves support various algal communities unique to this soft rock type. Orange, brownish or blackish gelatinous bands of algae, composed of an assemblage of Haptophyceae species such as Apistonema spp. Pleurochrysis carterae and the orange Chrysotila lamellosa, but other genera and species of Chrysophyceae, Haptophyceae and Prasinophyceae are likely to be present as well. The lower littoral fringe may be characterised by a dense mat of green algae Enteromorpha spp. and Ulva lactuca. Lower down the shore in the eulittoral the generally soft nature of the chalk results in the presence of a characteristic flora and fauna, notably ‘rock-boring’ invertebrates such as piddocks, overlain by mostly algal-dominated communities (fucoids and red algal turfs) (Gubbay, 2002). Such coastal exposures of chalk are rare in Europe, with those occurring on the southern and eastern coasts of England accounting for the greatest proportion (57%) (ICES,2003).



A recent survey of chalk cliffs throughout England revealed that 56% of coastal chalk in Kent, and 33% in Sussex has been modified by coastal defence and other works. On the Isle of Thanet (Kent) this increases to 74%. There has been less alteration of chalk at lower shore levels except at some large port and harbour developments (e.g. Dover & Folkestone) (Doody et al. 1991; Fowler & Tittley, 1993). Elsewhere in England, coastal chalk remains in a largely natural state.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Mudflats are sedimentary intertidal habitats created by deposition in low energy coastal environments,particularly estuaries and other sheltered areas. Their sediment consists mostly of silts and clays with a high organic content. Towards the mouths of estuaries where salinity and wave energy are higher the proportion of sand increases. Mudflats are intimately linked by physical processes to, and may be dependent on, other coastal habitats such as soft cliffs and saltmarshes. They commonly appear in the natural sequence of habitats between subtidal channels and vegetated saltmarshes. In large estuaries they may be several kilometres wide and commonly form the largest part of the intertidal area of estuaries. However, in many places they have been much reduced by land claim.



Mudflats, like other intertidal areas, dissipate wave energy, thus reducing the risk of eroding saltmarshes, damaging coastal defences and flooding low-lying land. The mud surface also plays an important role in nutrient chemistry. In areas receiving pollution, organic sediments sequester contaminants and may contain high concentrations of heavy metals.



Mudflats are characterised by high biological productivity and abundance of organisms, but low diversity with few rare species. The mudflat biota reflects the prevailing physical conditions. The JNCC Marine Nature Conservation Review (MNCR) biotope codes for mudflats are LMU.SMu (Sandy mud shores), LMU.Mu (Soft mud shores) and LMS.MS (Muddy sand shores). In areas of lowered salinity, the macroinvertebrate fauna is predominantly of the Petersen Macoma community, characteristic species being: common cockle Cerastoderma edule, sand-hopper Corophium volutator, laver spire shell Hydrobia ulvae, ragworm Hediste diversicolor and, when salinity is low, large numbers of oligochaete annelids (principally Tubificoides spp). With a slight increase in the proportion of sand, the polychaetes catworm Nephtys hombergi and lugworm Arenicola marina occur. In slightly coarser areas, seagrass (Zostera spp) beds may develop. Where stones and shells provide an initial attachment for byssus threads, beds of the common mussel Mytilus edulis occur and accrete material through faecal deposition. Occasional stones or shells may also provide suitable attachment for stands of fucoid macroalgae such as Fucus vesiculosus or F. spiralis.



The surface of the sediment is often apparently devoid of vegetation, although mats of benthic microalgae (diatoms and euglenoids) are common. These produce mucilage (mucopolysaccharides) that binds the sediment. Under nutrient-rich conditions, there may be mats of the macroalgae Enteromorpha spp. or Ulva spp.



The total UK estuarine resource has been estimated as c588,000 ha of which 55% is intertidal area, mostly mud and sandflats with a lesser amount of saltmarsh. Intertidal flats cover about 270,000 ha. The UK has approximately 15% of the north-west European estuarine habitat.



Mudflats are highly productive areas which, together with other intertidal habitats, support large numbers of predatory birds and fish. They provide feeding and resting areas for internationally important populations of migrant and wintering waterfowl, and are also important nursery areas for flatfish. They are widespread in the UK with significant examples in the Wash, the Solway Firth, Mersey Estuary, Bridgwater Bay and Strangford Lough.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Maerl is a collective term for several species of calcified red seaweed. It grows as unattached nodules on the seabed, and can form extensive beds in favourable conditions. Maerl is slow-growing, but over long periods its dead calcareous skeleton can accumulate into deep deposits (an important habitat in its own right), overlain by a thin layer of pink, living maerl.



Maerl beds typically develop where there is some tidal flow, such as in the narrows and rapids of sea lochs, or the straits and sounds between islands. Beds may also develop in more open areas where wave action is sufficient to remove fine sediments, but not strong enough to break the brittle maerl branches. Live maerl has been found at depths of 40 m, but beds are typically much shallower, above 20 m and extending up to the low tide level.



Maerl beds are found off the southern and western coasts of the British Isles, north to Shetland, but are particularly well developed around the Scottish islands and in sea loch narrows, around Orkney, and in the south in the Fal Estuary. Maerl beds also occur in other western European waters, from the Mediterranean to Scandinavia.



The distributions of the three main maerl bed-forming species in the UK are not entirely clear because of problems with identification in the field. Phymatolithon calcareum occurs throughout British waters, while Lithothamnion glaciale is a northern species with its southern limits at Lundy in the Bristol Channel and in the North Sea, off Yorkshire. Lithothamnion corallioides has caused the most problems with identification, but appears to be a south-western species with Scottish records as yet unconfirmed. Currently, it is known to occur in less than 15 of the ten km squares for the UK as defined by JNCC.



Maerl beds are an important habitat for a wide variety of marine animals and plants which live amongst or are attached to its branches, or burrow in the coarse gravel of dead maerl beneath the top living layer. Maerl beds, because of the wide geographical range over which they occur, have a wide range of associated animals and plants, with species diversity tending to be greater in the south and west. Due to the fragility of maerl, the beds are easily damaged and have probably declined substantially in some areas.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Mud habitats in deep water (circalittoral muds) occur below 20-30 m in many areas of the UK's marine environment, including marine inlets such as sea lochs. The relatively stable conditions associated with deep mud habitats often lead to the establishment of communities of burrowing megafaunal species where bathyal species may occur with coastal species. The burrowing megafaunal species include burrowing crustaceans such as Nephrops norvegicus and Callianassa subterranea. The mud

habitats in deep water can also support seapen populations and communities with Amphiura spp.



Burrows and mounds produced by megafauna are prominent features on the surface of plains of fine mud, amongst conspicuous populations of seapens, typically Virgularia mirabilis and Pennatula phosphorea. These soft mud communities occur extensively throughout the more sheltered basins of sea lochs and voes. As these sites are typically sheltered from wave action, these communities may occur in quite shallow depths (15 m). These communities also occur in deep offshore waters of the North Sea, where densities of N. norvegicus can reach 68 per 100 m2, and in the Irish Sea. Other burrowing crustaceans include Calocaris macandreae, C. subterranea and Goneplax rhomboides. The echiuran Maxmuelleria lankesteri forms large mounds in some sea loch sites. Epibenthic scavengers include Asterias rubens, Pagurus bernhardus and Liocarcinus depurator. Brittlestars may

be present and the infauna can contain populations of polychaetes and bivalves.



Within deep fjordic sea lochs, 'forests' of the nationally scarce tall seapen Funiculina quadrangularis can occur, together with the other two species of seapens. However, as F. quadrangularis is considered to be a bathyal species which 'intrudes' into sea lochs and fjords, it may only be nationally scarce in inshore waters. The mud is also extensively burrowed by crustaceans, mainly N. norvegicus, and the goby Lesueurigobius friesii may be present in burrow entrances. 



Areas of soft anoxic mud can have extensive bacterial mats of Beggiatoa spp. The anoxia may be the result of natural conditions of poor water exchange in some Scottish sea lochs or of nutrient enrichment under fish farm cages. The associated fauna is usually impoverished but scavenging species such as Asterias rubens and Carcinus maenas are typically present. In extreme conditions of anoxia, little survives except the Beggiatoa.



Offshore mud habitats can be characterised by the burrowing urchin Brissopsis lyrifera and the brittlestar Amphiura chiajei and in certain areas around the UK, such as the northern Irish Sea, this community may also include N. norvegicus.



In boreal and Arctic areas of water deeper than 100 m, the soft muds are dominated by a community of foraminiferans and hatchett shells Thyasira spp. with polychaete worms. There can be thousands of dead foraminiferan tests per square metre.



The most rare deep mud biotope is notable for the very high density of the rare sea squirt Styela gelatinosa and is known from only one site in the UK: Loch Goil, a Clyde sea loch. Within Loch Goil, the fine mud at 65 m has large numbers of solitary ascidicans, including S. gelatinosa, Ascidia conchilega, Corella parallelogramma and Ascidiella spp along with terebellid worms and the bivalve Pseudamussium septemradiatum. This biotope is considered to be an ice age relic.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Sabellaria spinulosa reefs comprise of dense subtidal aggregations of this small, tube-building polychaete worm. Sabellaria spinulosa can act to stabilise cobble, pebble and gravel habitats, providing a consolidated habitat for epibenthic species. They are solid (albeit fragile), massive structures at least several centimetres thick, raised above the surrounding seabed, and persisting for many years. As such, they provide a biogenic habitat that allows many other associated species to become established. The S. spinulosa reef habitats of greatest nature conservation significance are those which occur on predominantly sediment or mixed sediment areas. These enable a range of epibenthic species with their associated fauna and a specialised 'crevice` infauna, which would not otherwise be found in the area, to become established. Studies have compared an area of S. spinulosa with other macrofaunal communities in the Bristol Channel and found that the former had a higher faunal diversity (more than 88 species) and higher annual production (dominated by suspension-feeders) than other benthic communities in the area.



S. spinulosa requires only a few key environmental factors for survival in UK waters. Most important seems to be a good supply of sand grains for tube building, put into suspension by strong water movement (either tidal currents or wave action). S. spinulosa also appears to be very tolerant of polluted conditions. The worms need some form of hard substratum to which their tubes will initially be attached, whether bedrock, boulders, artificial substrata, pebbles or shell fragments. However, the presence of extensive reefs in predominantly sediment areas indicates that, once an initial concretion of tubes has formed, additional worms may settle onto the colony enabling it to grow to considerable size without the need for additional 'anchorage` points. Published work has noted that the planktonic larvae are strongly stimulated to settle onto living or old colonies of S. spinulosa, although they will eventually (after two or three months in the plankton) settle onto any suitable substratum in the absence of other individuals.



Given its few key requirements, and its tolerance of poor water quality, S. spinulosa is naturally common around the British Isles. It is found in the subtidal and lower intertidal/sublittoral fringe with a wide distribution throughout the north-east Atlantic, especially in areas of turbid seawater with a high sediment load. Recent research in the Wash using remote video, identified very extensive areas of reef rising up to 60 cm above the seabed and almost continuously covering a linear extent of 300 m. However, in most parts of its geographical range S. spinulosa does not form reefs, but is solitary or in small groups encrusting pebbles, shell, kelp holdfasts and bedrock. It is often cryptic and easily overlooked in these habitats. Where conditions are favourable, much more extensive thin crusts can be formed, sometimes covering extensive areas of seabed. However, these crusts may be only seasonal features, being broken up during winter storms and quickly reforming through new settlement the following spring. There are extensive examples of this form of colony on the west Wales coast, particularly off the Lleyn Peninsula and Sarnau candidate Special Area of Conservation (cSAC) and the Berwickshire and North Northumberland Coast cSAC. These crusts are not considered to constitute true S. spinulosa reef habitats because of their ephemeral nature, which does not provide a stable biogenic habitat enabling associated species to become established in areas where they are otherwise absent.



The closely related Sabellaria alveolata has been recorded as living for up to nine years. It is possible that S. spinulosa is similarly long-lived. The examination of reefs in the Bristol Channel revealed that they possessed only a small number of young, derived from sources outside of the study area. The adults in the colony were not gravid during the study and grew very little. The age of a colony may greatly exceed the age of the oldest individuals present, as empty concretions of S. spinulosa sand tubes are frequently found and must be able to persist for some time in the marine environment. However, there have been no studies of the longevity of individual worms, or the longevity and stability of colonies or reefs.



Consideration of the present and historical status of this habitat in the Wadden Sea area is useful because it has been much better studied than in the UK. Large subtidal S. spinulosa reefs in the German Wadden Sea, which provided an important habitat for a wide range of associated species, have been completely lost since the 1920s. S. spinulosa now appears in the Red List of Macrofaunal Benthic Invertebrates of the Wadden Sea.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Seagrass beds develop in intertidal and shallow subtidal areas on sands and muds. They may be found in marine inlets and bays but also in other areas, such as lagoons and channels, which are sheltered from significant wave action.



Three species of Zostera occur in the UK, and all are considered to be scarce (present in 16-100 ten km squares). Dwarf eelgrass Zostera noltii is found highest on the shore, often adjacent to lower saltmarsh communities, narrow-leaved eelgrass Zostera angustifolia on the mid to lower shore and eelgrass Zostera marina predominantly in the sublittoral. The plants stabilise the substratum, are an important source of organic matter, and provide shelter and a surface for attachment by other species. Eelgrass is an important source of food for wildfowl, particularly brent goose and widgeon which feed on intertidal beds. Where this habitat is well developed the leaves of eelgrass plants may be colonised by diatoms and algae such as Enteromorpha spp, Cladophora rectangularis, Rhodophysema georgii, Ceramium rubrum, stalked jellyfish and anemones. The soft sediment infauna may include amphipods, polychaete worms, bivalves and echinoderms. The shelter provided by seagrass beds makes them important nursery areas for flatfish and, in some areas, for cephalopods. Adult fish frequently seen in Zostera beds include pollack, two-spotted goby and various wrasse. Two species of pipefish, Entelurus aequoraeus and Syngnathus typhie are almost totally restricted to seagrass beds while the red algae Polysiphonia harveyi which has only recently been recorded from the British Isles is often associated with eelgrass beds.



Five different community types have been identified for seagrass beds from the southern North Sea and the Channel and 16 microhabitats including the seagrass itself, sessile epifauna, infauna and free swimming animals not confined to a special part of the community. The diversity of species will depend on environmental factors such as salinity and tidal exposure and the density of microhabitats, but it is potentially highest in the perennial fully marine subtidal communities and may be lowest in

intertidal, estuarine, annual beds.



The Cromarty Firth supports what is most probably the largest total area of dwarf eelgrass and narrow leaved eelgrass in Britain (approximately 1200 ha) while the Maplin Sands is estimated to be the largest surviving continuous population of dwarf eelgrass in Europe (covering around 325 ha). The Fleet has the most extensive population of all three Zostera species in Britain. Other important sites are the Exe Estuary, Maplin Sands, the Solents marshes and the Isles of Scilly, Morfa Nefyn, Milford Haven, the Moray Firth, Carlingford Lough, Dundrum Bay, Strangford Lough and Lough Foyle.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Seamounts are defined as undersea mountains, with a crest that rises more than 1,000 metres above the surrounding sea floor (Menard, 1964 in Rogers, 1994). Seamounts can be a variety of shapes, but are generally conical with a circular, elliptical or more elongate base. Seamounts are volcanic in origin, and are often associated with seafloor ‘hot-spots’ (thinner areas of the earth’s crust where magma can escape). Seamounts, often with a slope inclination of up to 60°, provide a striking contrast to the surrounding ‘flat’ abyssal plain. Their relief has profound effects on the surrounding oceanic circulation, with the formation of trapped waves, jets, eddies and closed circulations known as Taylor columns (Taylor, 1917 in Rogers, 1994). Seamounts occur frequently within the OSPAR Maritime Area. Analysis of narrow beam bathymetric data by the US Naval Oceanographic office from 1967-1989 identified more than 810 seamounts within the North Atlantic. The majority occur along the Mid-Atlantic ridge between Iceland and the Hayes fracture zone (Gubbay, 2002).



The enhanced currents that occur around seamounts provide ideal conditions for suspension feeders. Gorgonian, scleratinian and antipatharian corals may be particularly abundant, and other suspension feeders such as sponges, hydroids and ascidians are also present. Concentrations of commercially important fish species, such as orange roughy, aggregate around seamounts and live in close association with the benthic communities (Gubbay, 2002). 



Seamounts are a distinct and different environment from much of the deep sea. They act as ‘islands’ for epibenthic and pelagic faunas, have a high rate of endemic species, are used as ‘stepping stones’ for the transoceanic dispersion of shell species and as reproduction/feeding grounds for migratory species (eg. Richer de Forges, 2000).



Studies of the pelagic communities above seamounts reveal both qualitative and quantitative differences when compared to the surrounding water. The biomass of planktonic organisms over seamounts is often higher than surrounding areas, which, in turn, become an important component of the diet of fish and top predators such as sharks, rays, tuna and swordfish. The ecological importance of seamounts for top predators is emphasised by the fact that some far-ranging pelagic species concentrate their mating and spawning in such places. Two examples are the pelagic armorhead (Pentaceros wheeleri) and the scalloped hammerhead (Sphyrna lewini) (Boehlert & Sasaki, 1988). Some seamounts are belied to act as a feeding ground, fish spawning or possibly nursery areas for many species since groups of small cetaceans such as bottlenose dolphin, common dolphin, spotted dolphin and pilot whales as well as captures of loggerhead turtles have been recorded in the area.



The benthic fauna are dominated by suspension feeders some of which are typically restricted to the seamount environment. They are characterised by high levels of endemism, which suggests limited reproductive dispersal. Sampling of the benthic seamount fauna in the SW Pacific, for example, suggests that some of these species are notably localised. Somewhere between 29-34% of the species collected during 23 cruises to the region are believed to be new to science and potentially endemic to these seamounts (Richer de Forges et al. 2000). Less is known about the level of endemism on seamounts in the North East Atlantic.



The concentration of commercially valuable fish species around seamounts is well documented. Fishes such as the orange roughy and some deepwater oreos appear to be adapted to life in this environment, their substantial aggregations supported in the otherwise food-poor deep sea by the enhanced flow of prey organisms past the seamounts (Koslow & Gowlett-Holmes, 1998).



Apart from these general characteristics of seamounts that make them ecological significant there are also unique situations which make some even more significant. They may have an important role as a ‘stepping stone’ for species colonising islands.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Sheltered muddy gravel habitats occur principally in estuaries, rias and sea lochs, in areas protected from wave action and strong tidal streams. In fully marine conditions on the lower shore this habitat can be extremely species-rich because the complex nature of the substratum supports a high diversity of both infauna and epifauna. However, good quality examples of this habitat are very scarce. Polychaetes and bivalve molluscs are normally dominant and the most varied, but representatives of most marine phyla can be present. The fauna is often characterised by a large range in body size. As one moves into an estuary, with a consequent reduction in salinity, there is a marked reduction in species richness. Low salinity (mid to upper estuarine) muddy gravels have a lower, but distinctive, species diversity. This plan concentrates on the intertidal and shallow subtidal high salinity muddy gravel habitats.



The carpet shell mollusc Venerupis senegalensis is often, though not necessarily, present and can sometimes occur in large numbers. The blunt gaper Mya truncata is another characteristic species. There are considerable variations in the composition of these communities depending upon the sediment composition and salinity regime present. Members of the fully saline community can include the tube-dwelling polychaetes Sabella pavonina, Myxicola infundibulum and Amphitrite edwardsi, the sipunculan worm Golfingia sp, the anemones Sagartia troglodytes and Cereus pedunculatus and the holothurian Labidoplax digitata. Burrowing deposit-feeding polychaetes such as Notomastus latericeus, Aphelochaeta marioni and Melinna palmata may be abundant throughout the salinity range. The presence of coarse gravel and stones at the sediment surface often provides a substratum for the attachment of a variety of fauna and epiflora, for example fucoids, ephemeral green algae with associated littorinids and filamentous red algae.



Although the most diverse communities occur in fully saline conditions a number of different species can occur under reduced salinity (upper estuarine) conditions. Here, Mya arenaria may be present, with the polychaetes Neanthes virens and Cirriformia tentaculata, the cockle Cerastoderma edule and the native oyster Ostrea edulis. Oligochaetes and the rag worm Hediste diversicolor usually dominate the upper estuarine low salinity muddy gravels.



The prority habitat may be considered as an intertidal extension of a habitat more common in the sublittoral. The communities of interest to this plan are restricted to the intertidal and shallow sublittoral. Shallow subtidal muddy gravel (more than 3 m below Chart Datum) can contain communities of burrowing anemones such as Mesacmaea mitchelli, Aureliania heterocera, Cereus pedunculatus and Cerianthus lloydii. Deeper water muddy gravel associations are not considered here. However, there are similarities in the infaunal component of the offshore muddy-gravel (Venerupis) associations.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
This habitat encompasses rocky habitats in estuaries, extending from supralittoral lichens down to the subtidal circalittoral. Estuarine rocky habitats incorporate substrata types such as bedrock and stable boulders. Generally rias, fjords and fjards are the most relevant types of inlet for rocky estuarine habitats.



Rocky habitat is a comparatively uncommon feature in estuaries in the UK. Although generally forming small areas in comparison with the extent of sediment substrates in estuaries, estuarine rocky habitats contribute much to the overall biodiversity within estuaries. Estuarine rocky habitats, along with a complex of other estuarine habitats, are part of the ‘connectivity’ of land, estuary and open sea. For example, the rich and sheltered waters of estuaries provide nursery grounds for fish, and estuarine rocky habitats are an important component of these nursery grounds.



Conditions in estuaries are distinctly different to those on the open coast, where rocky habitats are generally more abundant. Rocky habitats in estuaries are typically located in low wave energy environments with reduced salinity, and experience accelerated tidal streams with increased turbidity and siltation. The communities present on rocky habitats are adapted to these conditions and consequently their composition and character is different to that found on similar substrata on the open coast e.g. the cape form of the sugar kelp Laminaria saccharina and the tasselled morphology of sponges such as Halichondria panicea.



Depending on the extent and heterogeneity of the substrate, there can be a wide variety of community types associated with estuarine rocky habitats. The extent of rocky habitat in estuaries can range from a narrow strip restricted to the top of the shore to littoral reef structures extending to the subtidal, particularly in rias. Similarly, the topography of estuarine rocky shores varies from flat and gently sloping to rugged reefs and large boulders with many microhabitats.



In general terms, the supralittoral of rocky habitat supports yellow and grey lichens, with a band of the black lichen Verrucaria maura below. These bands may be unusually narrow in areas of low wave exposure. The remainder of the shore can be dominated by fucoids and kelp with an understorey of barnacles, algae, grazing molluscs and gammarids, and occasionally sponges and seasquirts. Where the topography is varied, there is added community interest - for example entangled turfs of the red algae Gelidium pusillum and Catenella caespitosa on shaded surfaces, dense covers of the seasquirt Dendrodoa grossularia on overhangs, variable salinity hydroids on shaded verticals, and green algae dominated rockpools in depressions.



The communities on subtidal estuarine rocky habitats are equally variable, and at the most diverse end of the scale, may support a rich and exceptionally abundant sessile epibiota of anemones (e.g. Metridium senile and Diadumene sincta), filter feeding sponges (e.g. Halichondria panacea, Hymeniacidon perleve, Haliclona oculata, Raspalia spp., Suberties spp. and Stelligera spp.), bryozoa (e,g, Alcyonidium digitata), hydroids (e.g. Sertularella gaudichaudi, Bugula spp. and Tubularia spp.) and seasquirts (e.g. Ascidiella aspersa and Dendrodoa grossularia).



Estuarine rocky habitats often display a transition of community types down the length of an estuary, reflecting the different environmental conditions i.e. those at the upper ends of estuaries being specific to ultra sheltered and low salinity to communities similar to open coast rock communities towards the mouth of estuaries.



This habitat excludes rocky habitats in areas of permanent full salinity. Some occurrences of estuarine rocky habitats may also fall within the BAP habitat of ‘Tideswept Channels’ and may contain examples of the BAP ‘Intertidal Underboulder Community’ habitat. The fucoid alga Ascophyllum nodosum mackaii and the native oyster Ostrea edulis, both UK BAP priority species, can be associated with estuarine rocky habitats.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Limaria hians, commonly known as the ‘gaping file shell’, has been described as the most beautiful British bivalve (Yonge and Thompson, 1976). Individuals have a solid, but thin and delicately ribbed, shell up to 4 cm in length with a prominent gape running along the dorsal side. Even when the valves are closed, long vibrant orange tentacles (fringing the red mantle tissue) protrude (hence ‘gaping’). The Limaria form characteristic woven 'nests' or galleries constructed from byssal threads and the animals themselves are rarely seen above the seabed (Hall-Spencer and Moore, 2000).



Limaria hians beds in tide-swept sublittoral muddy mixed sediment (SS.SMX.IMX.Lim) have been recorded from 4-98 m on mixed muddy gravel or sand, coarse sands and muddy maerl in areas with weak to strong tidal streams and across the spectrum of wave exposure (although it is unlikely that dense beds can survive in shallow wave exposed locations) (Connor et al. 1997; JNCC, 1999; Hall-Spencer & Moore, 2000b; Tyler-Walters, H. 2003).



File shell beds are characterized by dense populations of Limaria hians where nests coalesce into a carpet over the sedimentary substratum. These nests can be built of shell, stones debris and maerl (when present) interlaced by several hundred byssus threads, and lined by mucus, mud and their faeces (Gilchrist, 1896; Hall-Spencer & Moore, 2000b). Nests may be constructed by expansion of smaller burrows, in gravel, shell sand or laminarian holdfasts, or may be simply composed of byssus threads (see Merrill & Turner (1963) and Gilmour (1967) for details). Nests are about the maximum gape of shell in diameter by about twice the length of the animal, with holes for the entrance and exit of water. Nests vary in size and complexity with individual Limaria hians being recorded from nests of 2-5 cm diameter, while larger nests of up to 25 cm diameter and 10 cm in length consisted of numerous ventilated holes and galleries (Gilmour, 1967; Tebble, 1976; Hall-Spencer & Moore, 2000). Hall-Spencer and Moore (2000) reported that six of these large nests contained 24-52 small and 25-40 large individuals of Limaria hians, with adult individuals occupying single galleries with two ventilation holes, while juveniles occupied complex galleries with multiple ventilation holes. Limaria hians can also occur individually or in small numbers, for example in kelp holdfasts, or under stones intertidally (Jason Hall-Spencer, pers comm.).



The biotope occurs at high densities in the Creag Gobhainn area of Loch Fyne (Hall-Spencer & Moore, 2000), is widespread in areas of accelerated tidal streams within Loch Sunart (Howson, 1996; Bates et al. 2004; Mercer et al. 2007) and a number of other sealochs on the west coast of Scotland (Loch Carron, Loch Creran, Loch Alsh, Lochs Broom and lower Loch Linnhe) and within Moross Channel, Mulroy Bay, Ireland (Minchin, 1995).



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatName:
Fragile sponge and anthozoan communities

HabitatDescription:
These communities are found on bedrock which is locally sheltered but close to tide-swept or wave exposed areas. They are dominated by large, slow growing species such as branching sponges and sea fans. The branching sponges include species such as Axinella dissimilis, Axinella damicornis, Axinella infundibuliformis, Homaxinella subdola and to a lesser extent Raspailia and Stelligera species. Other sponge species which may be present include Dysidea fragilis, Pachymatisma johnstonia, Esperiopsis fucorum, Hemimycale columella, Cliona celata, Stelligera rigida, Polymastia boletiformis, Polymastia mamillaris, Stelligera stuposa, Raspailia ramosa and Tethya aurantium. A silty hydroid/bryozoan turf may develop in the understorey of this rich sponge assemblage, with species such as Aglaophenia pluma, Cellaria sinuosa, Bugula flabellata, Bugula plumosa and Bugula turbinata, and crisiids. Larger species of hydroids such as Nemertesia antennina and Nemertesia ramosa may be present prominent surfaces together with the bryozoans Pentapora foliacea and Alcyonidium diaphanum. Other fauna includes aggregations of the colonial ascidians Clavelina lepadiformis and Stolonica socialis, together with the yellow cluster anemone Parazoanthus axinellae.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Sabellaria alveolata reefs are formed by the honeycomb worm Sabellaria alveolata, a polychaete which constructs tubes in tightly packed masses with a distinctive honeycomb-like appearance. These reefs can be up to 30 or even 50 cm thick and take the form of hummocks, sheets or more massive formations. Reefs are mainly found on the bottom third of the shore, but may reach mean high water of neap tides and extend into the shallow subtidal in places. They do not seem to penetrate far into low salinity areas. Reefs form on a variety of hard substrata, from pebbles to bedrock, in areas with a good supply of suspended sand grains from which the animals form their tubes, and include areas of sediment when an attachment has been established. The larvae are strongly stimulated to settle by the presence of existing colonies or their dead remains. S. alveolata has a very variable recruitment and the cover in any one area may vary greatly over a number of years, although in the long term reefs tend mainly to be found on the same shores.



In Britain, S. alveolata reefs are found only on shores with strong to moderate wave action in the south and west, between Lyme Bay on the south coast of England and the Scottish coast of the Solway Firth. The reefs have also been found on parts of the Northern Ireland coast. The British Isles represent the northern extremity of the range in the north-east Atlantic, which extends south to Morocco. The reefs also occur in the Mediterranean.



Individual worms have a lifespan of typically three to five years, and possibly up to nine years, but reefs themselves may last longer as a result of further settlement of worms onto existing colonies. Typically in the first two years or so, after a heavy intertidal settlement, there are few associated species. Over time, seaweeds including fucoids, Palmaria palmata, Polysiphonia spp, Ceramium spp, Enteromorpha spp and Ulva lactuca, and animals including barnacles, dogwhelks, winkles, mussels and other bivalves such as Nucula nucleus, Sphenia binghami and Musculus discors, colonise the reef. Small polychaetes such as Fabricia stellaris, Golfingia spp and syllidae predators may occur within the colonies. Blennies, small crabs (Carcinus maenas) and other crustacea (such as Unicola crenatipalma) can be found within crevices. Older reefs may increase the biodiversity and stability of what would otherwise be sand abraded rocks and boulders. Sheet-like reefs may restrict drainage of the shore, creating rockpools where there would otherwise be none. Less is known about subtidal communities.



In Britain, S. alveolata forms well developed reefs over much of its range. The most numerous and extensive areas occur on the Cumbrian coast, particularly between the Morecambe Bay and the Solway Estuary and at Dubmill Point. Reefs are also found in Cardigan Bay and in the Bristol Channel, including the coasts of south Wales, north Devon, Somerset and Avon. Very extensive subtidal reefs occur in the Severn Estuary, and subtidal populations have also been reported in the Walney Channel (Morecambe Bay) and from Glassdrumman, Northern Ireland.



There is evidence of a significant contraction in range on the south coast of England over a period of at least 20 years until 1984. Declines have also been reported in the western part of the north Cornish coast, the upper parts of the Bristol Channel and in North Wales and the Dee Estuary. Causes have not been postulated and it is difficult to assess the true significance of these changes given the natural variability of the species. For example, S. alveolata reefs have recently developed off Heysham (in Morecambe Bay), dominating two hectares of boulder scar from where it had been absent for 30 years.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
This habitat is found from the mid-shore down to the extreme lower shore, and encompasses areas of boulders (greater than 256 mm diameter) that support a diverse underboulder community. The underboulder habitat, along with fissures, crevices and any interstitial spaces between adjacent boulders, form a series of microhabitats that add greatly to the biodiversity of a shore. The presence of boulders on a shore may also lead to local modification to wave exposure, current strength and levels of trapped organic matter in the area surrounding the boulders themselves. Altering the physical environment in this way results in an enhancement to the immediate biodiversity beyond the boulders themselves. This habitat can occur on a variety of substrata (including bedrock, mixed rock and sediment or mud), but there needs to be a sufficient gap on the underside of the boulder to support an under-boulder community. The richest underboulder communities are often found where there is running seawater (for instance, from pools or lagoons emptying after the tide has fallen). Boulders with a limited underboulder community are not included in this UK BAP habitat, as may occur for example where boulders are embedded in sediment, in low salinity conditions, and where boulders experience high levels of mobility and scour.



Underboulder habitat provides an environment of shade, moisture and shelter. The undersides of boulders can therefore sustain a diverse collection of animals needing these conditions to survive on an otherwise hostile shore. Underboulder communities are generally dominated by an encrusting fauna of sea mats (bryozoans), sponges (Porifera), sea squirts (ascidians), barnacles, coat-of-mail shells (chitons) and calcareous tube worms (polychaetes). Crustaceans such as the hairy porcelain crab Porcellana platycheles, the long-clawed porcelain crab Pisidia longicornis, other small crabs and squat lobsters shelter on the undersides of boulders together with scale worms and brittle stars. Herbivores include the top shells Gibbula spp. the winkle Littorina littorea, the cushion star Asterina gibbosa and the green sea urchin Psammechinus miliaris. Encrusting sponges can be predated upon by sea slugs such as the sea-lemon Archidoris pseudoargus, as are colonial seasquirts by the cowrie, Trivia monacha. Encrusting coralline algae are also found on the undersides of the boulders. The bulbous encrusting bryozoan Turbicellepora magnicostata is only recorded in the British Isles in the Isles of Scilly where it is largely restricted to underboulder habitat. Like other examples of hard substrata, the species composition of the upward face of boulders varies with a number of factors – geology, wave exposure, tidal strength and position on the shore etc.



Underboulder habitat plays an important role in the life cycle of marine animals, for example the undersurfaces are an important refuge for the eggs of fish, dog whelks and sea slugs. The sheltered gaps between and under the boulders provide security for mobile species such as larger crabs and fish, and also the juveniles of many more species.



Whilst boulders are widespread around the UK coast, only a component of these support a diverse underboulder community.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
This habitat includes littoral and sublittoral examples of peat and clay exposures, both of which are soft enough to allow them to be bored by a variety of piddocks, particularly Pholas dactylus, Barnea candida and Barnea parva. Peat and clay exposures with either existing or historical evidence of piddock activity are unusual communities of limited extent, adding to the biodiversity interest where they occur. These unique and fragile habitats are irreplaceable, arising from former lake bed sediments and ancient forested peatland (or ‘submerged forests’). Depending on erosion at the site, both clay and peat can occur together or independently of each other.



Where peat is present on the shore or in shallow waters, the surface may be characterised by algal mats consisting of the red seaweed Ceramium spp. and the green seaweeds Ulva lactuca and Ulva intestinalis. However, sand scour can limit the cover provided by these seaweeds. The crabs Carcinus maenas and Cancer pagurus often occur in crevices in the peat, with hydroids in any small pools. On clay, seaweed cover is generally sparse with species such as Mastocarpus stellatus and Ceramium spp. attached to loose-lying pebbles or shells. On the surface of the clay, there may be small clumps of the mussel Mytilus edulis, together with barnacles and the winkle Littorina littorea. The polychaete worms Polydora spp. and Hediste diversicolor can sometimes be present within the clay. When the piddocks have died, their holes provide a micro-habitat for species such as small crabs and anemones such as Cereus pedunculatus and Aulactinia verrucosa.



It is known that peat and clay beds exist sublittorally, but the extent and maximum depth of this habitat is not known. There is little information on the communities associated with subtidal examples of peat and clay exposures, but the flora and fauna is likely to be different to those found associated with intertidal examples. It is possible that subtidal exposures of this BAP habitat support communities, which may or may not include piddocks. Surveys of a subtidal peat and clay exposure in the Menai Strait recorded the piddock Zirfaea crispata, a sparse cover of hydroids, e.g. Sertularia cupressina, Hydrallmania falcata, Tubularia indivisa and Nemertesia antennina and crabs - Cancer pagurus, Necora puber and Carcinus meanas.



Depending on its location, this habitat can experience periodic inundation and emergence from sediments. This habitat encompasses examples of peat and clay exposures with either existing or historical piddock activity (i.e. dead shells in piddock holes). This BAP habitat also encompasses occurrences of peat and clay exposures with no evidence of either past or present piddock activity, but which have the potential for this community to develop on the basis of environmental conditions and presence of similar beds locally. This BAP habitat does not include examples of harder sedimentary rock (e.g. limestone) with the piddock Hiatella arctica. It also does not include piddocks in sandstone, chalk and soft mudstone.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatName:
Sea pen and burrowing megafauna communities


HabitatDescription:
A characteristic of chalk coasts, in contrast to many harder rocky coasts of western and northern Britain is the geomorphological structure in which, because of subaerial and marine erosion , a vertical cliff face abuts an extensive Foreshore (a wave eroded platform) often extending several hundreds of metres seawards. This is of significance in the formation of subtidal chalk sea caves and reefs habitats and the occurrence of the associated communities / biotopes (Tittley et al. 1998).



The most extensive areas of sublittoral chalk in Britain occur in Kent and Sussex. In south-east England shallow subtidal (up to 5 m) communities are limited or absent due to the unusual friable and easily eroded nature of chalk and the prevailing harsh environment, characterised by extreme water temperatures, high levels of turbidity, siltation and scouring (UK BAP). In these conditions it is difficult to undertake subtidal surveys and hence the extent of this habitat and its associated communities are not well documented (Tittley et al, 1998). However less robust species e.g. large seaweeds which are more prone to scouring are replaced by more opportunistic species. As a result the shallow subtidal is dominated by animals and communities that are low in species richness reflecting the hostile environment.



At Flamborough, the Isle of Wight and Studland, shallow subtidal (up to 5M) communities are more diverse and extend into deeper waters where harder rock occurs but there are less unique algal species present.



In Northern Ireland, Upper Cretaceous chalk deposits belong to the Ulster White Limestone Formation with exposures on the County Antrim coast. The Northern Ireland chalk forms extremely hard, low porosity deposits with subsequent erosion forming cobble and boulder spreads with subtidal reefs. Faults on the seabed offshore have also exposed Cretaceous deposits. (UK BAP) and off Rathlin there are spectacular, deep subtidal cliffs affected by strong tidal currents (NI BAP).



Little is known of the extent or nature of chalk in the sublittoral zone in the Republic of Ireland. Rathlin has extensive underwater exposures of chalk, and sublittoral caves are known to be present in chalk down to at least 75m depth. These caves support rich populations of rare species. During the Northern Ireland Sublittoral Survey (NISS) (Erwin et al. 1986) up to three species of rare sponge were found from chalk habitats, one of which was known from only one other locality, on the west coast of Sweden. It is reported that chalk and limestone have a far higher biodiversity than any other rock types in the sublittoral zone on the island (B. Picton, pers. comm.) (NI BAP).



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Sublittoral sand and gravel habitats occur in a wide variety of environments, from sheltered (sea lochs, enclosed bays and estuaries) to highly exposed conditions (open coast). The particle structure of these habitats ranges from mainly sand, through various combinations of sand and gravel, to mainly gravel. While very large areas of seabed are covered by sand and gravel in various mixes, much of this area is covered by only very thin deposits over bedrock, glacial drift or mud. The strength of tidal currents and exposure to wave action are important determinants of the topography and stability of sand and gravel habitats.



The diversity of flora and fauna living within the biotopes varies according to the level of environmental stress to which they are exposed. Sand and gravel habitats that are exposed to variable salinity in the mid- and upper regions of estuaries, and those exposed to strong tidal currents or wave action, have low diversity and are inhabited by robust, errant fauna specific to the habitat such as small polychaetes, small or rapidly burrowing bivalves and amphipods. The epifauna in these habitats tends to be dominated by mobile predatory species. Upper estuarine mobile sands, subject to very low fluctuating salinity, are species poor. This habitat is characterised by mysids (Neomysis integer) and amphipods (Gammarus spp).



Coarse sand sediment can occur in sand-wave formations in shallow water, wave exposed and tideswept coasts. The infauna in this type of habitat is highly impoverished and is typified by small opportunistic capitellid and spionid polychaetes and isopods (Pontocrates arenarius, Haustorius arenarius and Eurydice pulchra) that are adapted to living in a highly perturbed environment. The epifauna is characterised by mobile predators such as crabs (Carcinus maenas and Liocarcinus spp), hermit crabs (Pagurus bernhardus), whelks (Buccinum undatum), and occasionally sand eels (Ammodytes spp). Similar habitats also occur in estuaries where the marine fauna is replaced with a sparse low salinity tolerant fauna (Forth and Humber Estuaries, Solway Firth).



Well sorted medium and fine sands on exposed coasts subjected to frequent wave action and variable tidal currents are typified by errant polychaetes such as Nephtys cirrosa and isopods such as Bathyporeia spp (common in full salinity areas of many estuaries). A low salinity variant of this habitat occurs in the Humber and Severn Estuaries.



Loose, coarse sand habitats fully exposed to wave action and swept by strong tidal streams are comparative with the 'Shallow Venus Community', the 'Boreal Off-shore Sand Association' and the 'Goniadella-Spisula Association' defined in past studies. This habitat is dominated by small or highly mobile polychaetes, thick shelled and rapidly burrowing bivalves (Spisula elliptica and S. subtruncata) and mobile amphipods that are adapted to periodic disturbance. It is a common habitat with examples found from Shetland to the Scilly Isles.



A close variant of this community occurs in fine compacted sands with moderate exposure and weak tidal currents. This habitat is characterised by the thin-shelled bivalve Fabulina fabula, and is found in the Irish Sea, north-east coast of England and in numerous Scottish sea lochs.



Sand mixed with cobbles and pebbles that is exposed to strong tidal streams and sand scour is characterised by conspicuous hydroids (Sertularia cupressina and Hydrallmania falcata) and bryozoans (Flustra foliacea and Alcyonidium diaphanum). These fauna increase the structural complexity of this habitat and may provide an important microhabitat for smaller fauna such as amphipods and shrimps. Examples of the habitat are to be found in Shapinsay Sound, Cromarty Firth, Lowestoft, Thames, Thanet, Menai Strait, Lough Foyle and in numerous Scottish sea lochs.



In contrast, those biotopes found in full salinity in sheltered or deeper waters that are less perturbed by natural disturbance are among the most diverse marine habitats with a wide range of anemones, polychaetes, bivalves, amphipods and both mobile and sessile epifauna. Clean stone gravel habitats are characterised by the sea anemones Halcampa chrysanthellum and Edwardsia timida, associated with hydroid/bryozoan turfs and red seaweeds. This habitat type has limited recorded distribution: Loch Creran, Loch Eynort (Skye), Church Bay (Rathlin Island) and Strangford Narrows.



Shallow areas with coarse sand swept by tidal currents but sheltered from wave exposure may develop dense beds of the polychaete Lanice conchilega. Dense beds of polychaete tubes reduce near-bed currents and significantly increase sediment stability. Examples are to be found in Outer Hebrides lagoons, Skye and sea lochs.



Circalittoral gravels, sands and shell gravel are split into three different biotopes and have communities of high diversity. These habitats are dominated by thick-shelled bivalve and echinoderms species, (e.g. Pecten maximus, Circomphalus casina, Ensis arcuatus and Clausinella fasciata), sessile sea cucumbers (Neopentadactyla mixta), and sea urchins (Psammechinus miliaris and Spatangus purpureus). These biotopes have been described by previous workers as the 'Boreal Off-Shore Gravel Association' and the 'Deep Venus Community' and can be found in Shetland, the western coasts, Irish Sea and English Channel.



Many of the inshore habitats are important nursery grounds for juvenile commercial species such as flatfishes and bass. Offshore, sand and gravel habitats support internationally important fish and shellfish fisheries while SE have recently carried out a comprehensive survey of benthic communities in the Greater Minch. Broad scale habitat mapping has also been carried out on behalf of the nature conservation agencies to support their work on marine SACs and by other organisations responsible for carrying out environmental assessments, for example for dredging and cable laying



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
In this habitat action plan, the term 'tidal rapids' is used to cover a broad range of high energy environments including deep tidal streams and tide-swept habitats. The JNCC`s Marine Nature Conservation Review (MNCR) defined rapids as 'strong tidal streams resulting from a constriction in the coastline at the entrance to, or within the length of, an enclosed body of water such as a sea loch. Depth is usually shallower than five metres.' In deeper situations, defined in this plan as being more than five metres, tidal streams may generate favourable conditions for diverse marine habitats (eg the entrances to fjordic sea lochs, between islands, or between islands and the mainland, particularly where tidal flow is funnelled by the shape of the coastline). Wherever they occur, strong tidal streams result in characteristic marine communities rich in diversity, nourished by a constantly renewed food source brought in on each tide.



The marine life associated with these habitats is abundant in animals fixed on or in the seabed, and typically include soft corals, hydroids (sea firs), bryozoans (sea mats), large sponges, anemones, mussels and brittlestars in dense beds. In shallow water, bedrock and boulders often support kelp and sea oak plants, which grow very long in the tidal currents, and have a variety of animals growing on them. Other smaller red and brown seaweeds grow on cobbles and pebbles, many of these being characteristic of tide-swept situations. Both the Menai Strait in North Wales and the Scilly Isles provide good examples of tide-swept communities considered to be of national importance. Also, the Dorn in Strangford Lough MNR is remarkable for its diversity of flora and fauna and for displaying a marked emergence phenomenon. Coarse gravel is a more difficult habitat for animals to colonise, as it is constantly moving, yet even here there are typical animals, such as sea cucumbers, worms and burrowing anemones. Maerl beds are also closely identified with the conditions found in tidal narrows and rapids in the south-west (the Fal estuary) and the north of the British Isles (Orkney).



In deeper water, such as between islands, strong tidal streams may be felt down to 30 m. For example, between the Pembrokeshire islands strong tidal currents in the centre of Ramsey Sound provide conditions for a distinctive community, unrecorded elsewhere in south-west Britain.



An important range of tidal rapid habitats are found in Scottish and Irish fjordic and fjardic sea lochs. Fjordic sea lochs occur in the more mountainous areas of the Scottish west coast and islands and were formed by the scouring action of glaciers and ice sheets. The result was an over-deepened basin (with some examples recording a charted depth of 200 m) or a series of basins connected to each other and the open sea by narrow and shallow 'sills' at depths of less than 30 m, with many less than 20 m. It is this high energy sill habitat, over which the tide flows, that produces the diverse communities that inhabit this environment. A considerable volume of water may move over the sill during the tidal cycle, with a tidal range in some Scottish sea lochs of up to 5 m on spring tides, generating a tidal flows of up to 10 knots. For example, Strangford Lough in Northern Ireland also has a long rapids system with very strong tidal streams up to 8 knots.



The variability of sea lochs in size, shape, number of basins and length and depth of sills, produces a wide range of marine communities. The seabed may be of bedrock and boulders, or a range of mixed material down to coarse shell gravel. The species composition of tidal rapids in some sea lochs may also be influenced by marked variations in salinity.



Fjardic sea lochs are much shallower often with a maze of islands and shallow basins connected by rapids, which are usually less than five metres deep and often intertidal. Fjardic sea lochs are found mainly in the Western Isles.



The morphology of fjords and fjards is therefore very different to lowland marine inlets and the estuaries of the south and east of the British Isles. However, in south-west England, eustatic change has created rias by drowning coastal river valleys such as the Dart, Tamar and Fal. At the narrow entrances of these rias, strong tidal currents have generated diverse habitats of biological significance.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatName:
Peat and clay exposures [N. Ireland, England, Wales]


HabitatDescription:
Coastal saltmarshes in the UK (also known as 'merse' in Scotland) comprise the upper, vegetated portions of intertidal mudflats, lying approximately between mean high water neap tides and mean high water spring tides. For the purposes of this action plan, however, the lower limit of saltmarsh is defined as the lower limit of pioneer saltmarsh vegetation (but excluding seagrass Zostera beds) and the upper limit as one metre above the level of highest astronomical tides to take in transitional zones. Saltmarshes are usually restricted to comparatively sheltered locations in five main physiographic situations: in estuaries, in saline lagoons, behind barrier islands, at the heads of sea lochs, and on beach plains. The development of saltmarsh vegetation is dependent on the presence of intertidal mudflats.



Saltmarsh vegetation consists of a limited number of halophytic (salt tolerant) species adapted to regular immersion by the tides. A natural saltmarsh system shows a clear zonation according to the frequency of inundation. At the lowest level the pioneer glassworts Salicornia spp can withstand immersion by as many as 600 tides per year, while transitional species of the upper marsh can only withstand occasional inundation.



The communities of stabilised saltmarsh can be divided into species-poor low-mid marsh, and the more diverse communities of the mid-upper marsh. On traditionally grazed sites, saltmarsh vegetation is shorter and dominated by grasses. At the upper tidal limits, true saltmarsh communities are replaced by driftline, swamp or transitional communities which can only withstand occasional inundation. Saltmarsh communities are additionally affected by differences in climate, the particle size of the sediment and, within estuaries, by decreasing salinity in the upper reaches. Saltmarshes on fine sediments, which are predominant on the east coasts of Britain, tend to differ in species and community composition from those on the more sandy sediments typical of the west. The northern limits of some saltmarsh species also influence plant community variation between the north and south of Britain.



Saltmarshes are an important resource for wading birds and wildfowl. They act as high tide refuges for birds feeding on adjacent mudflats, as breeding sites for waders, gulls and terns and as a source of food for passerine birds particularly in autumn and winter. In winter, grazed saltmarshes are used as feeding grounds by large flocks of wild ducks and geese. Areas with high structural and plant diversity, particularly where freshwater seepages provide a transition from fresh to brackish conditions, are particularly important for invertebrates. Saltmarshes also provide sheltered nursery sites for several species of fish.



Since medieval times, many saltmarshes have been reduced in extent by land claim. This practice continued until very recently; for instance, in the Wash 858 ha of saltmarsh were converted to agricultural use between 1970 and 1980. The land enclosed by sea walls was originally converted to grazing marsh with brackish ditches, but since the 1940s large areas of grazing marsh have been agriculturally improved to grow arable crops. As a consequence, many saltmarshes now adjoin arable land, and the upper and transitional zones of saltmarshes have become comparatively scarce in England. Sites still displaying a full range of zonation are particularly valuable for nature conservation. In Scotland and Wales, transitions (e.g. to freshwater, grassland and dune communities) are still comparatively common. In Northern Ireland most saltmarsh is composed of mid- and upper saltmarsh vegetation with transitions to freshwater or grassland.



The most recent saltmarsh surveys of the UK estimate the total extent of saltmarsh (including transitional communities) to be approximately 45,500 ha (England 32,500 ha, Scotland 6747 ha, Wales 6089 ha, and Northern Ireland 215 ha).This resource is concentrated in the major estuaries of low-lying land in eastern and north-west England and in Wales, with smaller areas in the estuaries of southern England, the firths of eastern and south-west Scotland and the sea loughs of Northern Ireland; north-west Scotland is characterised by a large number of very small saltmarsh sites at the heads of sea lochs, embayments and beaches. It is estimated that, at the mean high water line, 24% of the English coastline, 11% of the Welsh coastline and 3% of the Scottish coastline consists of saltmarsh vegetation.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Lagoons in the UK are essentially bodies, natural or artificial, of salinewater partially separated from the adjacent sea. They retain a proportion of their seawater at low tide and may develop as brackish, full saline or hyper-saline water bodies.The largest lagoon in the UK is in excess of 800 ha (Loch of Stenness) although the rest are much smaller and some may be less than 1 ha. Lagoons can contain a variety of substrata, often soft sediments which in turn may support tasselweeds and stoneworts as well as filamentous green and brown algae. In addition lagoons contain invertebrates rarely found elsewhere. They also provide important habitat for waterfowl, marshland birdsand seabirds. The flora and invertebrate fauna present can be divided into three main components: those that are essentially freshwater in origin, those that are marine/brackish species and those that are more specialist lagoonal species. The presence of certain indigenous and specialist plants and animals make this habitat important to the UK's overall biodiversity.



There are several different types of lagoons, ranging from those separated from the adjacent sea by a barrier of sand or shingle ('typical lagoons'), to those arising as ponded waters in depressions on soft sedimentary shores, to those separated by a rocky sill or artificial construction such as a sea wall. Sea water exchange in lagoons occurs through a natural or man-modified channel or by percolation through, or overtoppingof, the barrier. The salinity of the systems is determined by various levels of freshwater input from ground or surface waters. The degree of separation and the nature of the material separating the lagoon from the sea are the basis for distinguishing several different physiographic types of lagoon.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatName:
Fragile sponge and anthozoan communities on subtidal rocky habitats


HabitatDescription:
Machair is a distinctive type of coastal grassland found in the north and west of Scotland, and in western Ireland. It is associated with calcareous sand, blown inland by very strong prevailing winds from beaches and mobile dunes. The Gaelic word Machair is the only name for this major habitat type in Britain.



In its strict sense, 'machair' refers to a relatively flat and low lying sand plain formed by dry and wet (seasonally waterlogged) short-turf grasslands above impermeable bedrock, a habitat termed 'machair grassland'. However, machair can also cover the beach zone, mobile and semi-fixed foredunes, dune slacks, fens, swamps, lochs (some of them brackish), saltmarsh, and sand blanketing adjacent hillslopes, together forming the 'machair system'. It is also often associated with an inland transition to heath and mire termed 'blackland' which can include sand-affected peatland. Though this action plan principally addresses the machair grassland, this is an integral part of the wider machair system so the plan must consider the former in the context of the latter.



It is estimated that 'machair grassland is restricted to about 25,000 ha in world-wide extent, with 17,500 ha in Scotland and the remainder in western Ireland, so that world distribution is very restricted. The largest extents in Scotland are in the Western Isles (10,000 ha, mainly in the Uists), Tiree and Coll (4000 ha), Orkney (2300 ha) western Scottish mainland (1000 ha) and Shetland (180 ha). The full (global) geographical extent of the wider 'machair systems' is believed to be in the region of 40,000 ha, with some 30,000 ha in Scotland and 10,000 ha in Ireland.



Machair grassland plains are complex features in terms of origin, development, processes, local habitat types and management. They are formed from sand blown inland following the periodic breakdown of foredunes above the beach and contain a mosaic of wet and dry grassland communities. These are related to grazing and tillage history superimposed upon gradients of surface stabilisation, soil acidity, and salinity which are controlled by local sand blow, water-table fluctuation and micro-topography, giving rise to highly complex habitat mosaics. Some plant communities are largely restricted to western and northern Scotland.



Machair has a very long history of management by local communities over several millennia. In recent times this has involved a mix of seasonal extensive grazing (mainly by cattle, with pastures rested in the summer) and low-input low-output rotational cropping based on potatoes, oats and rye. A very small area of beer barley is also cultivated. This traditional mixed management sustains varied dune, fallow and arable weed communities which offer in some areas superb displays of flowering colour across wide expanses of unfenced land in summer. The periodic ground disturbance and seasonal absence of stock supports very important breeding wader populations. The wider machair system has a rich invertebrate fauna. This traditional agriculture is associated mainly with the Uists and Tiree; outside these areas there has been a marked decline in such land management with a corresponding decline in wildlife.



No plant sub-communities of the National Vegetation Classification are confined to machair, but the two most indicative are the Festuca rubra-Galium verum fixed dune grassland, Ranunculus acris-Bellis perennis sub-community of dry machair (SD8d) and the Festuca rubra-Galium verum grassland, Prunella vulgaris sub-community of wet machair (SD8e).



Few rare plant species are largely restricted to machair systems. Exceptions are the slender naiad Najas flexilis which is strongly associated with machair lochs, some pondweeds, Potamogeton spp (grass-wrack pondweed Potamogeton compressus, Shetland pondweed Potamogeton rutilus) and their hybrids, and the endemic orchid Dactylorhiza majalis scotica. This environment is more important as one of the last areas in Britain supporting old field successions, some of which are a century or more old. The great complexity and diversity of habitats and plant communities within machair systems is also a special feature. Two nationally scarce birds, corncrake Crex crex (which is globally threatened)and corn bunting Miliaria calandra, are noted birds of machair systems. The machair breeding wader populations of the Uists, Tiree and Coll are claimed as the most important in the north-west Palaearctic. Notable invertebrates include the belted beauty moth Lycia zonaria, and the northern colletes Colletes floralis.



There is a very strong association between traditional land use and crofting communities. Machair is a living, cultural landscape and much of its conservation value is dependent on the maintenance of viable crofting agriculture based on low-input shifting cultivation. Machair is highly susceptible to agricultural modification and is particularly sensitive to changes in grazing, sand and shingle extraction, and recreational impact.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Maritime cliffs and slopes comprise sloping to vertical faces on the coastline where a break in slope is formed by slippage and/or coastal erosion. There appears to be no generally accepted definition of the minimum height or angle of slope which constitutes a cliff, but the zone defined as cliff-top (also covered in this plan) should extend landward to at least the limit of maritime influence (i.e. limit of salt spray deposition), which in some exposed situations may continue for up to 500 m inland. This plan may therefore encompass entire islands or headlands, depending on their size. On the seaward side, the plan extends to the limit of the supralittoral zone and so includes the splash zone lichens and other species occupying this habitat. Approximately 4000 km of the UK coastline has been classified as cliff.



Cliff profiles vary with the nature of the rocks forming them and with the geomorphology of the adjoining land. While most maritime cliffs have been formed by coastal erosion, steep slopes falling to the sea in mountainous districts may have been formed long before the sea level reached its present position; in such cases only the lower part of the slope will have been steepened by the sea. Maritime cliffs can broadly be classified as 'hard cliffs' or 'soft cliffs', though in practice there are a number of intermediate types. Hard cliffs are vertical or steeply sloping; they are inclined to support few higher plants other than on ledges and in crevices or where a break in slope allows soil to accumulate. They tend to be formed of rocks resistant to weathering, such as granite, sandstone and limestone, but can be formed of softer rocks, such as chalk, which erode to a vertical profile. Soft cliffs are formed in less resistant rocks such as shales or in unconsolidated materials such as boulder clay; being unstable they often form less steep slopes and are therefore more easily colonised by vegetation. Soft cliffs are subject to frequent slumping and landslips, particularly where water percolates into the rock and reduces its effective shear strength.



The vegetation of maritime cliff and slopes varies according to several factors: the extent of exposure to wind and salt spray, the chemistry of the underlying rock, the water content and stability of the substrate and, on soft cliffs, the time elapsed since the last movement event. Cliff-top habitats can also be transformed by soil erosion processes.



Vegetation of a strictly maritime nature occurs where exposure to the waves and winds is at its greatest. In the UK, such conditions are found principally on the northern and south-western coasts. In extreme conditions, such as on the Isle of Lewis, saltmarsh vegetation can occur on cliff-tops. In other areas, where cliffs occur adjacent to sand dunes, sufficient wind blown sand can accumulate on the cliff-tops to allow cliff-top dune vegetation to develop (perched dunes). On exposed hard cliffs giving little foothold to higher plants, lichens are often the predominant vegetation. Ledges on such cliffs support a specialised flora with species such as rock samphire Crithmum maritimum and rock sea spurrey Spergularia rupicola in the south and Scots lovage Ligusticum scoticum and in the north. Seabird nesting ledges enriched by guano support a particular community characterised by oraches Atriplex spp and sea beet Beta vulgaris sap maritima. Maritime grasslands occur on cliffs and slopes in less severely exposed locations; a maritime form of red fescue Festuca rubra is a constant component, together with maritime species such as thrift Armeria maritima, sea plantain Plantago maritima, buck's-horn plantain P. coronopus and sea carrot Daucus carota sap gummifer. Species of inland grasslands which also commonly occur in maritime grasslands include ribwort plantain Plantago lanceolata, bird's-foot trefoil Lotus corniculatus, common restharrow Ononis repens and several species of grass.



On cliffs and slopes which are more sheltered from the prevailing winds and salt spray, the vegetation communities are more similar to those found inland, and are increasingly influenced by the chemistry of the substrate. Calcareous grassland communities with a few maritime specialist species occur on sheltered chalk or limestone cliffs. The upper sections and cliff-tops of hard cliffs on acidic rocks may support maritime heaths characterised by heather Calluna vulgaris. Mobile soft cliffs support a wide range of vegetation from pioneer communities on freshly exposed faces through ruderal and grassland communities to scrub and woodland. Wet flush vegetation commonly occurs on soft cliffs where groundwater issues as seepage.



Maritime cliffs are often significant for their populations of breeding seabirds, many of which are of international importance. Some 70% of the international population of gannet Morus bassanus and important proportions of the European populations of shag Phalacrocorax aristotelis, razorbill Alca torda and guillemot Uria aalge nest colonially on cliff ledges whilst significant populations of Manx shearwater Puffinus puffinus and puffins Fratercula arctica nest in burrows in turf on cliff-tops or slopes. Coastal cliffs are also important for crag nesting species, such as raven Corvus corax and peregine Falco peregrinus, and cliff-top vegetation may provide important feeding grounds for chough Pyrrhocorax pyrrhocorax.



Hard cliffs are widely distributed around the more exposed coasts of the UK, occurring principally in south-west and south-east England (the latter area having the bulk of the 'hard' chalk cliffs), in northwest and south-west Wales, in western and northern Scotland and on the north coast of Northern Ireland. Soft cliffs are more restricted, occurring mainly on the east and central south coasts of England and in Cardigan Bay and north-west Wales. There are also examples on the coasts of Fife and Skye in Scotland and Antrim in Northern Ireland.



Soft cliffs provide important breeding sites for sand martins Riparia riparia, which burrow into soft faces exposed by recent slippages, but they are particularly important for invertebrates as they provide a suite of conditions which are rarely found together in other habitats. The combination of friable soils, hot substrates and open conditions maintained by cliff slippages offer a continuity of otherwise very restricted microhabitats and these support many rare invertebrates which are confined to such sites. These include the ground beetle Cicindela germanica, the weevil Baris analis, the shore bug Saldula arenicola, and the Glanville fritillary Melitaea cinxia.



Seepages, springs and pools are a feature of many soft cliff sites and these provide the wet muds required by many species of solitary bees and wasps for nest building. They also support rich assemblages of other invertebrates including many rare species which are confined to this habitat. These include the craneflies Gonomyia bradleyi and Helius hispanicus, and the water beetle Sphaerius acaroides.



The hard coastal cliffs of west Britain support a western oceanic invertebrate assemblage of European significance. Important species include the snail Ponentina subvirescens, weevils such as the highly restricted Cathormiocerus attaphilus and moths such as Barrett’s marbled coronet Hadena luteago. Other species are confined to certain rock types. For example, the fiery clearwing Bembecia chrysidiformis is restricted to the chalk cliffs of Kent and Sussex and the water beetle Ochthebius poweri occurs predominantly in small seepages on red sandstone cliff faces in south-west England and south Wales.



The supralittoral zone represents the lowest belt of terrestrial vegetation on maritime cliffs and is usually exemplified by a zone of orange and grey maritime lichens. The zone tends to be dominated by species such as Caloplaca marina, Ramalina siliquosa and Verrucaria maura, but may also include uncommon species such as Roccella filiformis and R. phycopsis.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008. (Updated Dec 2011)" http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Serpula vermicularis is a marine worm which makes a hard, calcareous tube 4–5 mm in diameter and up to 150 mm long. In most places the worms are solitary with the base of the tube attached to stones or shells, and the feeding end growing up into the water. The worms can also aggregate into clumps or ‘reefs’ up to 1 m across. The species has a worldwide distribution (except for polar seas) in sheltered sites, but the reef form has been reported from very few locations. In the UK, reefs have only been found in Loch Creran, and the Linne Mhuirich arm of Loch Sween, both sea lochs on the west mainland coast of Scotland. The reefs in Loch Sween are now reported to be dead. Small Serpula vermicularis reefs have also been found in two loughs on the west coast of Ireland, but the best developed reefs in the world are in Loch Creran.



The serpulid reefs in Loch Creran begin as single tubes on stones or shells on a sandy mud seabed. As more worms settle and grow on already established ones the reef grows upwards and outwards to form a rounded clump of white tubes, similar to a coral head. The worms extend their feeding fans, which are about 2 cm across and a range of colours from white through orange to bright red, from the ends of the tubes. The larger reefs, over 1 m in diameter, tend to collapse outwards from the centre but the collapsed sections continue growing. The reefs are best developed in a relatively narrow vertical zone in the loch, at a depth between 6 m and 10 m.



The reefs are a haven for other marine wildlife on the muddy seabed where there is little other solid attachment, and become covered with orange sponges, colonial and solitary sea squirts, hydroids and seaweeds. Mobile animals live between the tubes in the centre of the reef; particularly common are brittlestars, terebellid worms, small spider crabs, squat lobsters, hermit crabs, starfish and a range of marine snails.



The reefs at Loch Creran, at least in the sublittoral fringe, have declined over the last 100 years (together with eelgrass Zostera marina beds), while those in Loch Sween apparently died between 1982 and the mid 1990s.



Description from "UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008." http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf


HabitatDescription:
Blue mussels, Mytilus edulis, are very common all around the coast of the British Isles. Although Scottish mussel beds only make up a small proportion of the British resource, they play a vital role in certain areas with extensive beds and significant wild mussel fisheries on the tidal flats of the Solway and Dornoch Firths.



Mussel beds are of considerable functional importance as they stabilise the sediment, have a major role in nutrient cycling, provide community structure, increase diversity and are food for other species. Subtidal mussel beds are highly vulnerable to damage from demersal fishing. Mussel beds are included in the UK Biodiversity Action Plan. The species Mytilus edulis did not pass the criteria assessment in its own right and so is not included.



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Undisturbed mud in both shallow and deep water is extensively burrowed by several species, particularly crustaceans such as Nephrops norvegicus and Maera loveni. Tall seapens and the burrowing fireworks anemone Pachycerianthus multiplicatus are characteristic epifauna of sheltered mud communities; these are large animals and recorded as uncommon although they may be numerous at particular sites. Scottish sea lochs and the northern North Sea have an estimated 95% of British records of inshore and deep burrowed mud. Elsewhere in Europe these habitats are recorded from the Norwegian North Sea and fjords, and from a few sites around the French and Irish coasts.



This group of biotopes and species are highly vulnerable to damage by seabed trawling activities, particularly for Nephrops. The Scottish inshore populations of Funiculina quadrangularis are globally important; there are few other places where this seapen occurs inshore in such large beds, although the species is more widespread offshore. Scotland also has a large proportion of the regional/global population of P. multiplicatus. 



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
The most extensive cold-water coral reefs known to date are from inshore sites in western Norway and in deep water beyond the shelf break around the North-East Atlantic. However, some areas of reef have been recorded from deep (ca. 50-100 m) inshore waters in Scotland and they are also known from the North Sea attached to oil industry structures. The best examples in Scottish territorial waters are found off the Island of Mingulay on the west coast. The Mingulay reef structures are known to be at least 4000 years old (14C-dating by Roberts et al., 2005) with new work showing they go back to 5000 years (14C and U/Th dating, Douarin unpublished data)



Cold-water coral reefs are structurally complex, species rich communities and are highly vulnerable to damage by demersal trawling and to localised effects of oil and gas drilling and scientific research sampling. It has been agreed by OSPAR that Lophelia pertusa reefs face grievous threat and are declining due to destructive fishing practices (Hall-Spencer & Stehfest 2009). Lophelia pertusa is also considered to be sensitive to potential effects of climate change such as ocean warming. The species is shown to be highly responsive to changes in local temperature, increasing metabolic rate with warming (Dodds et al., 2007). If food supplies fail to increase to match increased metabolic demand these coral reefs may not be able to sustain themselves. 



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
The flame shell Limaria hians is a bivalve that builds nests or galleries with its byssal threads in the sediment surface, consolidating loose material to form reefs that stand 10 to 20 cm above the sediment surface. By stabilizing the seabed in this way, they provide a structure for colonisation by other species and greatly increase the diversity of the area. Hall-Spencer and Moore (2000) observed that in the tidal narrows systems of sea lochs, L. hians nests can form continuous reefs covering several hectares in extent.



Beds of L. hians are known from the Scottish west coast with the most extensive and undisturbed examples found in Loch Sunart. They have been damaged historically by seabed trawling - there were once large beds in the Firth of Clyde for instance - and are highly vulnerable to damage by bottom gear. Large and pristine reefs are now only known and surveyed from a few west coast Scottish locations.



The species Limaria hians is not included, as its primary conservation importance is as part of the biotope. 



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Beds of the horse mussel Modiolus modiolus are highly diverse examples of biogenic reef structures. British horse mussel beds form a significant proportion of the European resource, with the only other beds recorded in this part of the North-East Atlantic found along the north and north-east coast of Norway (OSPAR map in NBN). There are no beds recorded in the Norwegian section of the North Sea. Scotland holds an estimated 85% of British horse mussel beds.



Horse mussel beds are highly vulnerable to demersal fishing, particularly scallop dredging which destroys the integrity of the beds. Recovery after significant damage would take many years, particularly as Modiolus modiolus is a very long lived species. They are of considerable functional importance.



Modiolus modiolus beds are included as a UK BAP Habitat. Service (1998) suggested limits of acceptable change for horse mussel populations in Strangford Lough, but noted that further research was required to derive ecological quality standards. Horse mussel reefs appear to be relatively stable communities in which any detectable changes over periods of a few years are likely to be regarded as unacceptable (Holt et al., 1998 cited by Scottish Environment Link review).



The species Modiolus modiolus is not included as its primary conservation importance is as part of the biotope. 



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatName:
Inshore deep mud with burrowing heart urchins

HabitatDescription:
There are scattered records of this biotope from Scottish sea lochs and one from Strangford Lough in Northern Ireland. The sea urchin Brissopsis lyrifera is frequent in North Sea sediments, particularly the northern North Sea, and occasional in the Irish Sea. The biotope may therefore be more widespread in Scottish waters than elsewhere in the UK. It is highly vulnerable to damage from bottom trawling.  



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Intertidal mudflats are extensive in the Solway and the other Firths. Some of the mudflats are considered of particular importance such as those in the Cromarty Firth, which support eelgrass beds, and those in the Solway. Mudflats are often important bird feeding grounds.



There are a large number of potential threats to this feature including sea level rise, shellfish extraction, land claim and coastal development, pollution and recreational activities.

 

Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Kelp and seaweed communities on sublittoral sediments are particularly common in Scotland, although they are recorded all around the British Isles. These habitats are generally very species rich (those sub-biotopes that are considered to be less diverse are specifically excluded from the feature description) and are vulnerable to damage by demersal fishing. 


 


Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Low or variable salinity habitats are an important and diverse feature of the Scottish marine environment and Scotland has a large proportion of the national and regional resource. The biotopes included in this group represent the range of low and variable salinity communities. The mollusc Hydrobia acuta neglecta has been included; a large proportion of the British records of this species are from Scotland.


 


This group includes three species of stonewort which are all UK BAP priority species. Tolypella nidifica is also included in the SNH Species Action Framework and is now known in the UK from only two sites, both in Scotland. All three species live in low or variable salinity habitats, including lagoons, and have declined in their distribution. Scottish saline lagoons provide probably the best stronghold for stoneworts outside the Baltic Sea. Lamprothamnion populations in Scotland are regarded as Globally Important with the Hebridean sites possibly representing the most secure global stronghold for the species; the other species are Nationally Important.


 


These brackish habitats and species are highly vulnerable to coastal development, pollution, changes in hydrodynamic regime and changing sea levels.


 


Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Maerl beds are found along the west coasts of the British Isles from Shetland to south-west England, but the vast majority of beds are in Scotland. OSPAR maps show that Scotland has approximately 30% of the maerl beds in north-west Europe, with others recorded from the Canaries, north-west France, west Ireland and north-west Iceland; they are rare in Sweden and Norway. Maerl beds, including dead maerl, have a complex structure which supports species rich communities, with many species which live preferentially on maerl. They are fragile and easily damaged by traditional and hydraulic scallop dredging, extraction and pollution (Hall-Spencer & Moore, 2000; Hall-Spencer et al., 2003). Hauton et al. (2003), in a study of the effects of hydraulic dredging, commented that undredged maerl grounds can be of long-term benefit to fisheries, acting as reproductive reservoirs for future generations of commercially important bivalve species.



All of the maerl bed sub-biotopes which occur in Scotland are included in this group and so are not listed separately. Maerl species are not included as their primary conservation value is as part of the habitat.



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatName:
Maerl or coarse shell gravel with burrowing sea cucumbers

HabitatDescription:
The sea cucumber Neopentadactyla mixta is recorded from northern Norway to the Bay of Biscay with the majority of records from British seas. The biotope which is included here is recorded only from the west coasts of the British Isles. It is likely to be more common than records suggest but most records are from west Scotland. This is a species rich community which often occurs on the edge of maerl beds and in areas of dead maerl and other coarse gravels. It is highly vulnerable to damage from scallop dredging.



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
There is historical documentation which shows that beds of the native oyster, Ostrea edulis, were once much more widespread in Scotland and Europe, but have been decimated by harvesting. Oysters are an important commercial species and have functional importance as they substantially increase the biodiversity of an area.


 


This feature includes both the biotope and the species, as individual oysters may occur in other biotopes and are threatened by harvesting in any habitat.


 


Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
The Northern sea fan communities are very diverse communities and highly characteristic of moderately exposed reefs on the Scottish west coast. All British records of the species Swiftia pallida and these sea fan biotopes are from Scotland. S. pallida also occurs on the west coasts of Norway and Sweden, in south-west Ireland and in deep water in the Bay of Biscay although this last record may be a different species; Swiftia rosea in Norway is probably a separate species.


 


Deep sponge communities are also very diverse and the majority of British records are from Scotland. In Scottish waters, these communities are found off the north-east coast of Shetland and to the west of the Hebrides. Closer inshore deep sponge communities are located off the coast of Mingulay, the Firth of Lorn and in the mouth of Loch Sunart. Deep sponge communities are also recorded from Northern Ireland, the west coast of Ireland and the Isles of Scilly.


 


Pressures on this group of biotopes include siltation from fishfarms and fishing activities and the risk of physical damage from mobile fishing gear. The species Swiftia pallida, which is the host for the nationally rare anemone Amphianthus dohrnii, is included in this group as it is considered to be of conservation importance in its own right.


 


Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Seagrass beds are found on the west coasts of the British Isles from Shetland southwards, and in the major inlets on the east coast. The Cromarty Firth has what may be the largest area of intertidal eelgrass in Britain, possibly in Europe, as well as significant beds of the tasselweed Ruppia maritima. OSPAR habitat maps suggest that Scotland has an estimated 20% of the seagrass beds in north-west Europe.


 


Seagrass beds are often associated with cockle beds and may be damaged by suction dredging for bivalves, such as cockles and Mercenaria sp. There was a major decline in seagrass beds in the 1920s and 1930s and, given their importance in coastal processes, there have been a number of scientific research and experimental management studies as a result. Seagrasses are considered to be of great ecological and economic importance and act as nutrient and sediment sinks. They promote the accumulation and binding of sediment and thus absorb a proportion of incident wave energy and may form a natural coastal defence. In the past seagrasses have been put to a number of uses world-wide such as sound-proofing, insulation, roofing thatch, binding soil, packaging, basket weaving and in the manufacture of 'coir' matting.


 


The seagrass beds feature includes both intertidal and subtidal beds. The individual species are excluded as their conservation importance is as part of the habitat.


 


Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Beds of the unattached form of the egg wrack Ascophyllum nodosum ecad mackaii are found in Britain and Ireland only, in sheltered embayments such as sea lochs. Scotland has most records worldwide of this growth form. The loose mats provide a sheltered and humid habitat for many mobile mid-shore animals which would otherwise be unable to live on open sediments or shingle, such as gammarid amphipods, shore crabs and littorinid snails. Fish such as young eels, Anguilla anguilla, and viviparous blennies, Zoarces viviparus, may also shelter in the weed.


 


The attached form of A. nodosum is still collected on a small scale in western Scotland for the extraction of alginates and as packing material for shellfish transport. The unattached A. nodosum ecad mackaii is particularly attractive to collectors as it is easy to harvest. The habitat is highly vulnerable to coastal developments such as shore armouring, road widening, land claim and causeway construction.


 


The sea loch egg wrack beds feature only contains the biotope LR.LLR.FVS.Ascmac. The individual species is not included, as its conservation importance is as part of the habitat.


 


Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Serpula vermicularis aggregations are oases of high epifaunal diversity on sediment plains and are only known from two sites in Britain; Loch Creran and Loch Teacuis. Living reefs are no longer found at a third known site in Loch Sween. Elsewhere, the aggregating form of Serpula vermicularis has only been reported from a few locations on the west coast of Ireland and in an Italian lagoon. Their fragile structure makes them highly vulnerable to damage from physical activities such as mooring, anchoring and fishing.



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
There are two types of structure included within this category: bubbling reefs; and submarine structures associated with pockmarks. At the moment there are eight British records of which six are in Scottish waters. This is currently an area of active research. These structures are vulnerable to damage by demersal fishing and by oil and gas development.



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
Tide-swept algal communities are a feature of much of the littoral and infralittoral around Scottish coasts and are frequently important in the tidal narrows of Scottish sea lochs. They are species rich, structurally complex habitats. The majority of British records are from Scotland and Northern Ireland although some of these biotopes are characteristic of other areas and most records of IR.HIR.KSed.XKHal are from the Sarns area in Wales. It is likely that this particular biotope is under recorded in Scotland. Mixed substrate habitats such as these are highly vulnerable to impacts from scallop dredging.



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatName:
Tide-swept coarse sands with burrowing bivalves

HabitatDescription:
This coarse mixed sand with Moerella and bivalves is uncommon in the British Isles. Many components of the biotope are moderately robust as it occupies a relatively dynamic habitat. However, the biotope is vulnerable to activities such as trawling, aggregate extraction and offshore construction and one of its important component bivalves Spisula solida is commercially fished in some areas. Long-lived venerid bivalves, which can be an important food source for birds, are thought to be particularly sensitive to disturbance and Spisula solida appears to have declined in some areas.



Description from "Howson, C. M., Steel. L., Carruthers, M. & Gillham, K. (2012). Identification of Priority Marine Features in Scottish territorial waters. Scottish Natural Heritage Commissioned Report No. 388."


HabitatDescription:
At high densities, blue mussels (Mytilus edulis) form beds or reefs in the intertidal or subtidal, composed of a single or multi-layered framework, held together by byssus threads. The bed stabilises sediment and creates a habitat for a diverse community of animals, living on, within, or under the bed, and within the underlying sediment. Includes several biotopes depending on the sediment on which in occurs (e.g. Myt.Sa on sand, Myt.Mu on mud and Myt.Mx on mixed), the abundance of fanworms (MytFab), and if it occurs in the subtidal (in MytSS) or on reduced salinity rock (MytRS).



Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Areas of finer sediments that are home to a range of burrowing crustaceans, including langoustine Nephrops norvegicus, the mud shrimps Calocaris macandreae, Callianassa subterranean, or Maera loveni and the crab Goneplax rhomboides. The burrowing action of these species makes burrows and mounds a prominent feature of this habitat. In some areas, burrowed mud may support conspicuous populations of seapens, so called due to their resemblance to feather quills. Typically the species Virgularia mirabilis and Pennatula phosphorea are present, although in deeper waters off the continental shelf, Kophobelemnon stelliferum and Umbellula encrinus may be recorded. This habitat can also support populations of the spectacular fireworks anemone (Pachycerianthus multiplicatus), and the scarce tall seapen (Funiculina quadrangularis) (SpnMeg.Fun). Large mounds of mud may also be found where the spoon worm (Maxmuelleria lankesteri) is present (MegMax).



Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Carbonate mounds are steep sided mounds of varying shape, which may be up to 350m high and 2km wide at their base. They often have a sediment veneer composed of carbonate sands, muds and silts and host diverse communities of deep-sea organisms, which include: cold water reef building corals (e.g. Lophelia pertusa); sponges; bryozoans; soft corals; sea squirts; tube worms; sea firs; feather stars; and bivalve molluscs.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Coral gardens are highly diverse habitats comprising dense aggregations of colonies or individuals of one or more coral species, which in some locations may reach densities of between 100 and 700 colonies per 100m². Where reef-forming corals do occur, they settle in scattered clumps or small colonies and do not dominate the habitat. Life typically harboured by coral garden communities includes basket stars, brittlestars, feather stars, molluscs, crustaceans and deep water fish species.


HabitatDescription:
Deep sea sponge aggregations are principally composed of sponges from two classes: the glass sponge (Hexactinellida) and the giant sponge (Demospongia). They support diverse biological communities, with the sponges increasing habitat complexity and influencing the occurrence of other species. They provide shelter for a huge range of tiny animals seeking protection and an elevated perch for filter feeding animals such as brittle stars. The dense spicule mats associated with sponge communities are thought to support a rich community of species.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
The flame or gaping file shell Limaria hians creates nests by weaving together tough threads (byssus) with surrounding material such as seaweed, maerl and shells. Adjoining nests coalesce to form larger structures with multiple flame shells which, in some locations where conditions allow, carpet the bed for several hectares. The carpets create a unique habitat that stabilises the sediment and provides an attachment surface for many organisms including hydroids, bryozoans, ascidians and seaweeds. These organisms in turn add to the habitat complexity and provide shelter for other species such as cod and saithe. A rich diversity of fauna is also found within and below the flame shell bed.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
The silty muddy basins of sea lochs and other stable deep waters support this community which is dominated by the heart urchin Brissopsis lyrifera, and the brittlestar Amphiura chiajei. The habitat supports several species of burrowing bivalves, polychaete worms and may also contain Nephrops and low numbers of sea pens.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Shallow sublittoral sediments which support seaweed communities typically include the sugar kelp Saccharina latissima, the bootlace weed Chorda filum and various red and brown seaweeds, particularly filamentous types. With increasing shelter from wave action, some communities develop as loose-lying mats on the sediment surface. A diverse array of animals are associated with these kelps and seaweeds e.g. burrowing polychaete worms and bivalves, scavenging hermit crabs, crabs, starfish, fish and grazing top shells.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Low or variable salinity habitats occur where seawater and fresh water meet and mix to varying degrees. The salinity may vary from full to low with the tide, with fresh water input from rivers or intermittent fresh water input from rainfall and runoff. In coastal saline lagoons, a proportion of the seawater is retained at low tide and the lagoon and may become brackish, fully saline or (rarely) hypersaline. Communities tend to be less diverse than either fully marine or fresh water habitats but are dominated by tolerant or specialist species. Specialist species include sea anemones, snails, bivalves and stoneworts; some of which are very rare and restricted to saline lagoons or variable salinity habitats.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
The horse mussel Modiolus modiolus forms scattered clumps, thin layers or dense raised beds several metres in height and length. Raised beds are formed of horse mussels, bound together by a matrix of byssus threads which accumulate a sediment of silt, organically rich faeces and shells, further increasing the bed height. They significantly modify sedimentary habitats and provide hard substratum, refuge and ecological niches for a wide variety of organisms.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
An unusual red seaweed with a hard chalky skeleton that grows as small rounded nodules or short branched twig-like shapes. In high abundance, maerl can form loosely interlocking beds through which water is able to circulate, providing the perfect conditions for the development of diverse communities of plants and animals (on, within or under the beds). Red seaweeds, sea firs, sea urchins, brittlestars, starfish, sea anemones and scallops may colonise the surface. Maerl needs light to grow, so living maerl is restricted to the surface of the beds overlying the chalky skeletons of dead maerl. Three maerl species exist in the British Isles and the relative composition of these within a bed, and the proportion of living / dead maerl within and between beds, varies with factors such as salinity and wave exposure. Maerls are extremely slow growing and extensive beds may be over 1000 years old.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Gravel, maerl gravel (dead maerl) or coarse sands with high densities of the gravel sea cucumber, Neopentadactyla mixta. Scallops, brittlestars, crabs and dragonets live on the surface of the sediment (some seaweeds may also be present) with widespread species such as tube dwelling sea anemones, sand mason worms and parchment worms living within the coarse substrates. This biotope may occur adjacent to maerl beds. During winter months, gravel sea cucumbers bury deep in the sediment and become dormant.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
This once widespread habitat is comprised of dense beds of the native oyster Ostrea edulis (at densities of 5 or more per m2). A diverse community or organisms live on, amongst, or in the sediment beneath the bed. Dead oyster shells, which may make up a large proportion of the substratum, support sea squirts, sponges, hydroids and a turf of algae. Large polychaete worms are often present, along with predatory fish, starfish and crabs.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Offshore deep sea muds support a wealth of biological diversity despite often appearing as featureless environments. The most common larger surface-dwelling animals are the echinoderms, including sea cucumbers, brittlestars and sea urchins. Other mobile species in or on the seabed include various types of „worms‟, sea spiders, amphipods, bivalves, molluscs, crustaceans and fish species. Bathymetry, current velocity, bottom water-mass distribution and particle size of the mud (clay, silty or sandy) all have a significant influence on the distribution and composition of the seabed communities present. This habitat also includes the Atlantic and Arctic bathyal and abyssal sediments which occur off the continental slope in Scotland and those on the continental slope.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Sand and gravel sediments are the most common subtidal habitat around the coast of the British Isles. Offshore sands and gravels are more stable than their shallower equivalents with diverse infaunal communities dominated by polychaetes; hatchet shells (OCS.GlapThyAmy) and small bivalves e.g. the little tellin (OCS.HeloPkef). Offshore fine to muddy sands support a diversity of tube building polychaetes, burrowing brittlestars, polychaetes and bivalves (OSa.OfusAfil and OSa.MalEdaf), while the pea urchin occurs in medium sands (CFiSaEpusOborApri) and amphipods and hooded shrimp in fine sands (CFiSa.ApriBatPo). Mobile predators include flatfish, starfish, crabs and hermit crabs. This habitat also includes the Atlantic and Arctic bathyal and abyssal sediments which occur off the continental slope in Scotland and those on the continental slope.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Seagrasses are marine flowering plants found in shallow coastal areas around the world, typically on sheltered sandy or muddy substrata. Seagrasses often grow in dense, extensive beds or meadows, stabilising the sediment and creating productive habitats that provide shelter and food for a wide variety of plants and animals (including other species of conservation importance and commercially important fish species). Three seagrass bed communities are encompassed by this broad habitat; two eelgrass biotopes (Zostera spp.) and one dominated by the tasselweed Ruppia maritima.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
A detached dwarf variety of the common egg wrack (Ascophyllum nodosum). Individual plants rarely exceed 60cm in diameter but they often grow together to form dense mats. Occurs as two forms - the „beach‟ form is olive green or yellow, very branched, and may appear bent and irregularly twisted; whereas the smaller „turf‟ form is found on the upper shore as individual plants where it forms small clumps or mats. The complex three dimensional structure provides a humid habitat for shrimp, crabs, snails, winkles, eels and small fish, while mussels, barnacles and worms often live among the pebbles and within the mud below.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
Seamounts have been described as 'hotspots' for marine life, offering a distinct environment from the characteristically flat, sediment covered abyssal plain from which they arise. The presence of an exposed hard substrate for marine life to settle on and the effect of their size and relief on oceanic currents create ideal conditions for a range of suspension feeders which form the basis of seamount communities. Typically these communities comprise cold-water corals (principally Lophelia pertusa), coral garden species (such as black corals, lace corals and bamboo corals) and deep water sponges. Concentrations of deep water fish species, such as orange roughy and blue ling, aggregate around seamounts and live in close association with the benthic communities they harbour. The biological richness of seamount communities is also attractive to spawning aggregations of fish which draw top predators including a range of shark species and cetaceans.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatName:
Shallow tideswept coarse sands with burrowing bivalves

HabitatDescription:
Tide-swept coarse and gravelly sands in the shallow subtidal support an abundance of burrowing bivalves, particularly Tellina spp. and polychaete worms. In some areas, this habitat supports surf clams (Spisula solida). Suspension feeding bivalves dominate and are abundant in the coarse sediment. Infaunal species also include tanaids (shrimp-like crustaceans) and sand hoppers. The bivalves may be preyed upon by starfish, snails and flatfish. Seaweeds including sugar kelp (Saccharina latissima) and Ulva spp. may be present on the sediment surface attached to small pebbles and larger shells.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
A diverse habitat characterised by aggregations of the sea fan Swiftia pallida and the cup coral Caryophyllia smithii (CarSwi) on upper and vertical surfaces of bedrock and boulders (10-50m). With increasing water depth (35-120m+), and in areas of low tidal flow, erect branching sponges replace sea fans as the most striking component of the habitat (DpSp). Rock is colonised by sea firs, soft corals (e.g. dead man‟s fingers) and large sea squirts, with crevices providing shelter for sea cucumbers, squat lobsters and wrasse. In silty conditions (CarSwi.Aglo) sea fans, cup corals, and red sea fingers abound. As water flow increases (CarSwi.LgAs) less sponges and sea firs are present but sea fans are still frequent and, as the current increases further (XFa.SwiLgAs), so does the biodiversity.


 


Description from "Tyler-Walters, H., James, B. (eds.), Wilding, C., Durkin, O., Lacey, C., Philpott, E., Adams, L., Chaniotis, P.D., Wilkes, P.T.V., Seeley, R., Neilly, M., Dargie, J. and Crawford-Avis, O.T. (2012). Descriptions of Marine Protected Area (MPA) search features. A report produced by MarLIN (Marine Life Information Network), SMRU Ltd., Scottish Natural Heritage and the Joint Nature Conservation Committee, for the Scottish Marine Protected Areas Project."


HabitatDescription:
The Littoral Biogenic Reefs habitat contains two biological subtypes, littoral Sabellaria reefs (A2.71) and mixed sediment shores with mussels (A2.72), encompassing the littoral biotope dominated by the honeycomb worm Sabellaria alveolata, and littoral Mytilus edulis- dominated communities. S. alveolata can form honeycomb reefs on mid to lower shore on exposed coasts, where there is a plentiful supply of sediment. The underlying substratum may consist primarily of rock or stable cobbles and boulders, or of cobbles and boulders on sand. Mixed sediment shores characterised by beds of adult mussels Mytilus edulis occur principally on mid and lower eulittoral mixed substrata (mainly cobbles and pebbles on muddy sediments) in a wide range of exposure conditions. In high densities the mussels bind the substratum and provide a habitat for many infaunal and epifaunal species.



Temporal variation: S. alveolata reefs may be susceptible to storm damage in the winter, although they can regenerate remarkably quickly in a season as long as some adults are left as they facilitate the larval settlement. S. alveolata is tolerant to burial under sand for several weeks. Changes in desiccation over a period of time can cause part of the population to die. One of the mussel-dominated subtypes, A2.7212, could change to A2.7213 over time as pseudofaeces build up forming a layer of mud. This cannot happen where wave action or tidal streams wash away pseudofaeces and prevent a build up. In areas where mussel spat ("mussel crumble") settles on the surface shell layer of cockle beds, the mussel cover may be ephemeral.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Extremely exposed to moderately exposed or tide-swept bedrock and boulder shores. Extremely exposed shores dominated by mussels and barnacles, occasionally with robust fucoids or turfs of red seaweed. Tide-swept shores support communities of fucoids, sponges and ascidians on the mid to lower shore. Three biological subtypes have been described: Communities on very exposed to moderately exposed upper and mid eulittoral bedrock and boulders dominated by the mussel Mytilus edulis, barnacles Chthamalus spp. and/or Semibalanus balanoides and the limpets Patella spp. (A1.11); red and brown seaweeds able to tolerate the extreme conditions of exposed rocky shores, primarily the physical stresses caused by wave action (A1.12), and tide-swept shores in more sheltered areas (such as narrow channels in sea loch) with canopy forming fucoids and a rich filter-feeding community (A1.15).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Moderately exposed shores (bedrock, boulders and cobbles) characterised by mosaics of barnacles and fucoids on the mid and upper shore; with fucoids and red seaweed mosaics on the lower shore. Where freshwater or sand-scour affects the shore ephemeral red or green seaweeds can dominate. Other shores support communities of mussels and fucoids in the mid to lower shore. Two biological subtypes have been described: barnacles and fucoids (A1.21) and mussels and fucoids (A1.22).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Sheltered to extremely sheltered rocky shores with very weak to weak tidal streams are typically characterised by a dense cover of fucoid seaweeds which form distinct zones (the wrack Pelvetia canaliculata on the upper shore through to the wrack Fucus serratus on the lower shore). Where salinity is reduced (such as at the head of a sea loch or where streams run across the shore) Fucus ceranoides may occur. Fucoids also occur on less stable, mixed substrata (cobbles and pebbles on sediment) although in lower abundance and with fewer associated epifaunal species; beds of mussels Mytilus edulis are also common. In summer months, dense blankets of ephemeral green and red seaweeds can dominate these mixed shores. Two biological subtypes have been described: Dense blankets of fucoid seaweeds dominating sheltered, fully marine littoral rocky shores (A1.31) and fucoids dominating variable salinity rocky shores (A1.32).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Shores comprising clean sands (coarse, medium or fine-grained) and muddy sands with up to 25% silt and clay fraction. Shells and stones may occasionally be present on the surface. The sand may be duned or rippled as a result of wave action or tidal currents. Littoral sands exhibit varying degrees of drying at low tide depending on the steepness of the shore, the sediment grade and the height on the shore. The more mobile sand shores are relatively impoverished (A2.22), with more species-rich communities of amphipods, polychaetes and, on the lower shore, bivalves developing with increasing stability in finer sand habitats (A2.23). Muddy sands (A2.24), the most stable within this habitat complex, contain the highest proportion of bivalves.



Situation: A strandline of talitrid amphipods (A2.211) typically develops at the top of the shore where decaying seaweed accumulates. Fully marine sandy shores occur along stretches of open coast, whilst muddy sands are often present in more sheltered lower estuarine conditions and may be subject to some freshwater influence.

Temporal variation: Littoral sandy shore environments can change markedly over seasonal cycles, with sediment being eroded during winter storms and accreted during calmer summer months. The particle size structure of the sediment may change from finer to coarser during winter months, as finer sediment gets resuspended in seasonal exposed conditions. This may affect the sediment infauna, with some species only present in summer when sediments are more stable. More sheltered muddy sand shores are likely to be more stable throughout the year, but may have a seasonal cover of green seaweeds during the summer period, particularly in nutrient enriched areas or where there is freshwater input.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Shores of mixed sediments ranging from muds with gravel and sand components to mixed sediments with pebbles, gravels, sands and mud in more even proportions. By definition, mixed sediments are poorly sorted. Stable large cobbles or boulders may be present which support epibiota such as fucoids and green seaweeds more commonly found on rocky and boulder shores. Mixed sediments which are predominantly muddy tend to support infaunal communities which are similar to those of mud and sandy mud shores.



Situation: It is probable that there are broad transition areas between areas of mudflat or sandy mudflat, and mixed sediment biotopes where the sediment consists principally of mud but has significant proportions of gravel and sand mixed in. Gravelly mud may occur in patches on mudflats. Similarly, there is unlikely to be an easily defined boundary between areas of mixed sediment with stable cobbles and boulders, and boulder fields which fall into the rocky shore category.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Littoral coarse sediments include shores of mobile pebbles, cobbles and gravel, sometimes with varying amounts of coarse sand. The sediment is highly mobile and subject to high degrees of drying between tides. As a result, few species are able to survive in this environment. Beaches of mobile cobbles and pebbles tend to be devoid of macroinfauna, while gravelly shores may support limited numbers of crustaceans, such as Pectenogammarus planicrurus.



Situation: Littoral coarse sediments are found along relatively exposed open shores, where wave action prevents finer sediments from settling. Coarse sediments may also be present on the upper parts of shores where there are more stable, sandy biotopes on the lower and mid shore.



Temporal variation: The sediment particle size structure may vary seasonally, with relatively finer sediments able to settle during calmer conditions in summer. Where the sediment grain size is very large (at the interface between sediment and boulder shores), cobbles may be mobile during exposed winter conditions, but stable enough during summer months to support limited juvenile rocky shore epifauna (e.g. juvenile barnacles).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Angiosperm-dominated stands of vegetation, occurring on the extreme upper shore of sheltered coasts and periodically covered by high tides. The vegetation develops on a variety of sandy and muddy sediment types and may have admixtures of coarser material. The character of the saltmarsh communities is affected by height up the shore, resulting in a zonation pattern related to the degree or frequency of immersion in seawater.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatName:
Intertidal sediments dominated by aquatic angiosperms

HabitatDescription:
Dominants are Eleocharis acicularis, Eleocharis parvula, Zostera spp.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Rocky habitats in the infralittoral zone subject to exposed to extremely exposed wave action or strong tidal streams. Typically the rock supports a community of kelp Laminaria hyperborea with foliose seaweeds and animals, the latter tending to become more prominent in areas of strongest water movement. The depth to which the kelp extends varies according to water clarity, exceptionally (e.g. St Kilda) reaching 45 m. The sublittoral fringe is characterised by dabberlocks Alaria esculenta.Dominants are Eleocharis acicularis, Eleocharis parvula, Zostera spp.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Predominantly moderately wave-exposed bedrock and boulders, subject to moderately strong to weak tidal streams. On the bedrock and stable boulders there is typically a narrow band of kelp Laminaria digitata in the sublittoral fringe which lies above a Laminaria hyperborea forest and park. Associated with the kelp are communities of seaweeds, predominantly reds and including a greater variety of more delicate filamentous types than found on more exposed coasts (cf. A3.11).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Infralittoral rock in wave and tide-sheltered conditions, supporting silty communities with Laminaria hyperborea and/or Laminaria saccharina (A3.31). Associated seaweeds are typically silt-tolerant and include a high proportion of delicate filamentous types. In turbid-water estuarine areas, the kelp and seaweeds (A3.32) may be replaced by animal-dominated communities (A3.36) whilst stable hard substrata in lagoons support distinctive communities (A3.34).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Occurs on extremely wave-exposed to exposed circalittoral bedrock and boulders subject to tidal streams ranging from strong to very strong. Typically found in tidal straits and narrows. The high energy levels found within this habitat complex are reflected in the fauna recorded. Sponges such as Pachymatisma johnstonia, Halichondria panicea, Esperiopsis fucorum and Myxilla incrustans may all be recorded. Characteristic of this habitat complex is the dense 'carpet' of the hydroid Tubularia indivisa. The barnacle Balanus crenatus is recorded in high abundance on the rocky substrata. On rocky outcrops, Alcyonium digitatum is often present.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Mainly occurs on exposed to moderately wave-exposed circalittoral bedrock and boulders, subject to moderately strong and weak tidal streams. This habitat type contains a broad range of biological subtypes, from echinoderms and crustose communties (A4.21) to Sabellaria reefs (A4.22) and circalittoral mussel beds (A4.24).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Occurs on wave-sheltered circalittoral bedrock and boulders subject to mainly weak/very weak tidal streams. The biotopes identified within this habitat type are often dominated by encrusting red algae, brachiopods (Neocrania anomala) and ascidians (Ciona intestinalis and Ascidia mentula).



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Sublittoral mixed (heterogeneous) sediments found from the extreme low water mark to deep offshore circalittoral habitats. These habitats incorporate a range of sediments including heterogeneous muddy gravelly sands and also mosaics of cobbles and pebbles embedded in or lying upon sand, gravel or mud. There is a degree of confusion with regard nomenclature within this complex as many habitats could be defined as containing mixed sediments, in part depending on the scale of the survey and the sampling method employed. The BGS trigon can be used to define truly mixed or heterogeneous sites with surficial sediments which are a mixture of mud, gravel and sand. However, another 'form' of mixed sediment includes mosaic habitats such as superficial waves or ribbons of sand on a gravel bed or areas of lag deposits with cobbles/pebbles embedded in sand or mud and these are less well defined and may overlap into other habitat or biological subtypes. These habitats may support a wide range of infauna and epibiota including polychaetes, bivalves, echinoderms, anemones, hydroids and Bryozoa. Mixed sediments with biogenic reefs or macrophyte dominated communities are classified separately in A5.6 and A5.5 respectively.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Coarse sediments including coarse sand, gravel, pebbles, shingle and cobbles which are often unstable due to tidal currents and/or wave action. These habitats are generally found on the open coast or in tide-swept channels of marine inlets. They typically have a low silt content and a lack of a significant seaweed component. They are characterised by a robust fauna including venerid bivalves.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Sublittoral mud and cohesive sandy mud extending from the extreme lower shore to offshore, circalittoral habitats. This biotope is predominantly found in sheltered harbours, sealochs, bays, marine inlets and estuaries and stable deeper/offshore areas where the reduced influence of wave action and/or tidal streams allow fine sediments to settle. Such habitats are often by dominated by polychaetes and echinoderms, in particular brittlestars such as Amphiura spp. Seapens such as Virgularia mirabilis and burrowing megafauna including Nephrops norvegicus are common in deeper muds. Estuarine muds tend to be characterised by infaunal polychaetes and oligochaetes.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
Clean medium to fine sands or non-cohesive slightly muddy sands on open coasts, offshore or in estuaries and marine inlets. Such habitats are often subject to a degree of wave action or tidal currents which restrict the silt and clay content to less than 15%. This habitat is characterised by a range of taxa including polychaetes, bivalve molluscs and amphipod crustacea.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
This habitat type includes maerl beds, seaweed dominated mixed sediments (including kelps such as Laminaria saccharina and filamentous/foliose red and green algae), seagrass beds, and lagoonal angiosperm communities. These communities develop in a range of habitats from exposed open coasts to lagoons and are found in a variety of sediment types and salinity regimes.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
This habitat type includes polychaete reefs, bivalve reefs (e.g. mussel beds) and cold water coral reefs. These communities develop in a range of habitats from exposed open coasts to estuaries, marine inlets and deeper offshore habitats and may be found in a variety of sediment types and salinity regimes.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatDescription:
The sea bed beyond the continental shelf break. The shelf break occurs at variable depth, but is generally over 200 m. The upper limit of the deep-sea zone is marked by the edge of the shelf. Includes areas of the Mediterranean Sea which are deeper than 200 m but not of the Baltic Sea which is a shelf sea. Excludes caves in the deep sea which are classified in A4.71 irrespective of depth.



Definition from the EUNIS habitat classification 2012 (http://eunis.eea.europa.eu/habitats/1)


HabitatName:
Shallow sublittoral rock & biogenic reef


HabitatName:
Bathyal (slope/upper) rock and biogenic reef


HabitatName:
Bathyal (mid/lower) rock and biogenic reef


HabitatDescription:
Atlantic waters are warm (typically >8°C within the UK) and Atlantic seabed habitats occur around most of the UK, excluding depths greater than 300 m in the Faroe-Shetland Channel. The upper bathyal is the shallowest deep-sea zone occuring below the deep-circalittoral. Where the Atlantic upper bathyal meets the Arctic, waters mix to form the Atlanto-Arctic upper bathyal zone; here the lower boundary of the Atlantic upper bathyal zone is appoximately 300 m at the seabed, while in other areas the lower boundary is approximately 600 m, where the Atlantic mid bathyal zone begins. Communities found in this zone are described in child habitats. 

Biological zones are three-dimensional biogeographical regions which represent changes in biological community both spatially around the UK and vertically in relation to depth. Biological zones have some overlap in the types of community which can occur. The boundaries relate to areas of greatest change in overall species composition. The boundaries of zones are based on water mass structure which drives differences in biology. Rough boundaries of the zones have been predicted using modelled environmental data; a GIS proxy biogeographic zone layer can be downloaded from the Marine Habitat Classification download page. The depths of upper and lower boundaries depend on several variables, so the given depth range should be treated as a guide only.


HabitatName:
Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
Rock and other hard substrate has a more diverse epifaunal community as species attach to the hard surface that in turn attract more fauna. Deep-sea rock is generally encrusted in a range of species including sponges and cold water water corals. Rock includes bedrock mixed substrate of pebbles, cobbles and boulders, and isolated drop stones. It can occur in a mosaic with sediment habitats. Hard artificial surfaces are considered 'other hard substrate' as is carbonate and hard clay. Rock does not have an infaunal community.


HabitatName:
Barnacle dominated community on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This broad community includes all biotopes where barnacle species are the dominant fauna. The species of barnacle will vary with depth and location. This community is found on rock and  associated fauna are sparse. Currently, barnacle dominated communities in both the upper bathyal and the mid bathyal have only one child biotope (Bathylasma hirsutum assemblage) but in the future new barnacle biotopes may be discovered which differ between zones. It is likely that, due to changes in depth, associated species differ in the upper and mid bathyal versions of this broad community, but further evidence is required to describe differences.


HabitatName:
Bathylasma hirsutum assemblage on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
Biotope dominated by the barnacle Bathylasma hirsutum. Observed on bedrock in high current areas. Barnacle coverage may not be dense. This assemblage was also identified in the mid bathyal, but the associated species are likely to differ. Characterising species listed refer to all Bathylasma hirsutum assemblages not just those found associated with the zone and substrate specified in this biotope.


HabitatName:
Brachiopod dominated community on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This broad community includes all biotopes where brachiopod species are the dominant fauna. The species of brachiopod will vary with depth and location. Associated fauna are sparse. Currently, brachiopod dominated communities in both the upper bathyal and the mid bathyal have only one child biotope (Dallina septigera assemblage), but in the future new brachiopod biotopes may be discovered which differ between zones. It is likely that, due to changes in depth, associated species differ in the upper and mid bathyal versions of this broad community, but further evidence is required to describe differences.


HabitatName:
Dallina septigera assemblage on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
Biotope dominated by the brachiopods Dallina septigera and Macandrevia cranium. Brachiopod dominated assemblages have been observed from multiple locations with the UK deep-sea occuring on bedrock, bedrock with a sand veneer and mixed substrates. Previous observations have been made in the high current areas on the Wyville-Thomson Ridge and summit of the Anton-Dohrn Seamount, but also on Hatton Bank, Rosemary Bank Seamount, Dangaard and Explorer Canyons and the warm shallow regions of the Wyville-Thomson Ridge and Faroe-Shetland Channel. This assemblage was also identified in the mid bathyal, but the associated species are likely to differ. Characterising species listed refer to all Dallina septigera and Macandrevia cranium assemblages not just those found associated with the zone and substrate specified in this biotope.


HabitatName:
Deep sponge aggregation on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This broad community contains assemblages where sponges dominate sediment habitats. Sponges can be of all morphotypes except encrusting. Aggregations of Axinellid sponges as well as lobose sponges have been recorded on Atlantic mid bathyal rock.


HabitatName:
Reteporella and Axinellid sponges on Atlantic upper bathyal  rock and other hard substrata

HabitatDescription:
This biotope occurs on cobbles and pebbles on sandy sea bed possibly associated with shallow iceberg ploughmarks, characterised by Axinellid and massive lobose sponges,  cup sponges and bryozoan Reteporella attached to the cobbles, with squat lobsters sheltering under the cobbles. It is similar to a deeper expression of the shallower biotope “deep sponge communities (circalittoral)".


HabitatName:
Lobose sponge and stylasterid assemblage on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This biotope has been found on bedrock and boulders on the shallow flanks of Rockall Bank and is characterised by large yellow lobose sponges and Stylasterid corals. It has only been observed on Rockall Bank most likely due to the shallow depth range over which it occurs; the summits of many of the features are too deep.


HabitatName:
Mixed cold water coral community on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This broad community contains those biotopes where corals dominate but do not form a living coral reef. A mixture of different coral types can be present. Associated species are similar to 'sparse encrusting community', including sponges and ophiuroids. Discrete colonies of Lophelia pertusa occur on Atlantic upper bathyal rock.


HabitatName:
Discrete Lophelia pertusa colonies on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This biotope occurs on bedrock, cobbles and boulders and isolated drop stones. Small growths of Lophelia pertusa and often Madrepora occulata are present. Lophelia pertusa reef framework may also be present adjacent to this biotope in areas where it occurs in an elevated position allowing dead coral framework to accumulate below. This biotope is often observed on the edge of escarpment features. The same assemblage is recorded on Atlantic mid bathyal coarse sediment. Characterising species listed refer to all discrete Lophelia pertusa assemblages not just those found associated with the zone and substrate specified in this biotope.


HabitatName:
Sparse encrusting community on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This broad community includes all biotopes that are characterised by encrusting species including deep-sea sponges, serpulid worms, cup corals and Anoniimid bivalves. This community is widespread and occurs on coarse sediment and rock where erect coral species are absent. When this broad community occurs on rock it is distinguished by the present of holuthurian Psolus squamatus.


HabitatName:
Psolus squamatus and encrusting sponge assemblage on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This assemblage occurs on cobble, boulder and bedrock areas with the holothurian Psolus being the most conspicuous faunal compenent and lamellate sponges also being present. A range of encrusting species are also present and are like to vary with depth and location. This assemblage also occurs in the mid bathyal. It is likely this biotope represents more than one assemblage but data are not sufficent to separate them. Characterising species listed refer to all Psolus squamatus and encrusting sponge assemblages not just those found associated with the zone and substrate specified in this biotope.


HabitatName:
Psolus squamatus, Anomiidae, serpulid polychaetes and Munida on Atlantic upper bathyal rock and other hard substrata

HabitatDescription:
This biotope consists of cobble, boulder and bedrock areas with the holothurian Psolus being the most conspicuous faunal compenent. A range of encrusting species are also present but there is no conspicuous presence of lamellate sponges as there is within "Psolus squamatus and encrusting sponge assemblage". This assemblage also occurs in the mid bathyal. This assemblage also occurs in the mid bathyal. Characterising species listed refer to all Psolus squamatus, Anomiidae, serpulid polychaetes and Munida assemblages not just those found associated with the zone and substrate specified in this biotope.


