The Marine Life Information Network

Habitats listed as 'habitats of principal importance'

Lists of 'species and habitats of principal importance' have been drawn up across the UK's devolved administrations. The lists are a requirement under the 'duty to conserve biodiversity' placed on public authorities under Section 41 in England and Section 42 in Wales of the Natural Environment and Rural Communities (NERC) Act 2006,  Section 2(4) of the Nature Conservation (Scotland) Act 2004, and Section 3(1) of the Wildlife and Natural Environment Act (Northern Ireland) 2011.  The resultant lists include species and habitats of 'principal importance' in England, Wales and Northern Ireland and the Scottish Biodiversity List.  Available MarLIN information on 'habitats of principal importance' is listed below, based on the JNCC rationalised list (JNCC, 2018). 

Habitat listings

Blue mussel beds

Littoral mussel beds on sediment

Mytilus edulis beds on littoral mixed substrata

Mytilus edulis beds on littoral mud

Mytilus edulis beds on littoral sand

Mytilus edulis beds on littoral sediments

Mytilus edulis beds on sublittoral sediment

Carbonate mounds Scotland

Bubbling reefs in the aphotic zone

Seeps and vents in sublittoral sediments

Carbonate reef Wales

Bubbling reefs in the aphotic zone

Seeps and vents in sublittoral sediments

Coastal saltmarsh

Saltmarsh (pioneer)

Puccinellia maritima salt-marsh community

Cold-water coral reefs Scotland

Atlantic lower bathyal live Solenosmilia variabilis reef (biogenic structure)

Atlantic upper bathyal live Lophelia pertusa reef (biogenic structure)

Mixed coral assemblage on Atlantic lower bathyal Solenosmilia reef framework (biogenic structure)

Mixed coral assemblage on Atlantic mid bathyal Lophelia pertusa reef framework (biogenic structure)

Mixed coral assemblage on Atlantic upper bathyal Lophelia pertusa reef framework (biogenic structure)

Lophelia reefs

Coral gardens

Mixed coral assemblage on Atlantic lower bathyal Solenosmilia reef framework (biogenic structure)

Deep-sea sponge communities Scotland

Lobose sponge and stylasterid assemblage on Atlantic upper bathyal rock and other hard substrata

Geodia and other massive sponges on Atlanto-Arctic upper bathyal coarse sediment

Geodia and other massive sponges on Atlanto-Arctic upper bathyal mixed sediment

Pheronema carpenteri field on Atlantic lower bathyal mud

Pheronema carpenteri field on Atlantic mid bathyal mud

Reteporella and Axinellid sponges on Atlantic upper bathyal rock and other hard substrata

Estuarine rocky habitats

Kelp in variable or reduced salinity

Ascophyllum nodosum and Fucus vesiculosus on variable salinity mid eulittoral rock

Ascophyllum nodosum ecad mackayi beds on extremely sheltered mid eulittoral mixed substrata

Codium spp. with red seaweeds and sparse Saccharina latissima on shallow, heavily-silted, very sheltered infralittoral rock

Cordylophora caspia and Einhornia crustulenta on reduced salinity infralittoral rock

Fucus ceranoides on reduced salinity eulittoral rock

Fucus serratus and large Mytilus edulis on variable salinity lower eulittoral rock

Fucus spiralis on sheltered variable salinity upper eulittoral rock

Fucus vesiculosus on variable salinity mid eulittoral boulders and stable mixed substrata

Hartlaubella gelatinosa and Conopeum reticulum on low salinity infralittoral mixed substrata

Mytilus edulis beds on reduced salinity tide-swept infralittoral rock

Pelvetia canaliculata on sheltered variable salinity littoral fringe rock

Saccharina latissima and Psammechinus miliaris on variable salinity grazed infralittoral rock

Saccharina latissima with Phyllophora spp. and filamentous green seaweeds on variable or reduced salinity infralittoral rock

File shell beds Scotland

Limaria hians beds in tide-swept sublittoral muddy mixed sediment

Fragile sponge and anthozoan communities on subtidal rocky habitats

Bryozoan turf and erect sponges on tide-swept circalittoral rock

Mixed turf of bryozoans and erect sponges with Dysidia fragilis and Actinothoe sphyrodeta on tide-swept wave-exposed circalittoral rock

Mixed turf of hydroids and large ascidians with Callistephanus pallida and Caryophyllia (Caryophyllia) smithii on weakly tide-swept circalittoral rock

Caryophyllia (Caryophyllia) smithii and Callistephanus pallida on circalittoral rock

Caryophyllia (Caryophyllia) smithii, Callistephanus pallida and large solitary ascidians on exposed or moderately exposed circalittoral rock

Caryophyllia (Caryophyllia) smithii, Callistephanus pallida and Alcyonium glomeratum on wave-sheltered circalittoral rock

Eunicella verrucosa and Pentapora foliacea on wave-exposed circalittoral rock

Phakellia ventilabrum and axinellid sponges on deep, wave-exposed circalittoral rock

Horse mussel beds

Modiolus modiolus beds on open coast circalittoral mixed sediment

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

Modiolus modiolus beds with hydroids and red seaweeds on tide-swept circalittoral mixed substrata

Modiolus modiolus beds with Mimachlamys varia, sponges, hydroids and bryozoans on slightly tide-swept very sheltered circalittoral mixed substrata

Intertidal chalk N. Ireland, England

Chrysophyceae and Haptophyceae on vertical upper littoral fringe soft rock

Fucus serratus and piddocks on lower eulittoral soft rock

Osmundea pinnatifida on moderately exposed mid eulittoral rock

Intertidal mudflats

Polychaete / bivalve dominated muddy sand shores

Bathyporeia pilosa and Corophium arenarium in littoral muddy sand

Cerastoderma edule and polychaetes in littoral muddy sand

Hediste diversicolor and oligochaetes in littoral mud

Hediste diversicolor and Corophium volutator in littoral mud

Hediste diversicolor and Macoma balthica in littoral sandy mud

Hediste diversicolor and Streblospio shrubsolii in littoral sandy mud

Hediste diversicolor in littoral mud

Hediste diversicolor, Macoma balthica and Eteone longa in littoral muddy sand

Hediste diversicolor, Macoma balthica and Scrobicularia plana in littoral sandy mud shores

Lanice conchilega in littoral sand

Nephtys hombergii and Streblospio shrubsolii in littoral mud

Nephtys hombergii, Macoma balthica and Streblospio shrubsolii in littoral sandy mud

Tubificoides benedii and other oligochaetes in littoral mud

Intertidal under boulder communities

Fucus serratus and under-boulder fauna on exposed to moderately exposed lower eulittoral boulders

Laminaria digitata and under-boulder fauna on sublittoral fringe boulders

Maerl beds

Maerl beds

Lithothamnion corallioides maerl beds on infralittoral muddy gravel

Lithothamnion glaciale maerl beds in tide-swept variable salinity infralittoral gravel

Phymatolithon calcareum maerl beds in infralittoral clean gravel or coarse sand

Phymatolithon calcareum maerl beds with red seaweeds in shallow infralittoral clean gravel or coarse sand

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

Maritime cliffs and slopes

Yellow and grey lichens on supralittoral rock

Prasiola stipitata on nitrate-enriched supralittoral or littoral fringe rock

Mud habitats in deep water

Burrowing megafauna and Maxmuelleria lankesteri in circalittoral mud

Cerianthid anemones and burrowing megafauna in Atlantic mid bathyal mud

Foraminiferans and Thyasira sp. in deep circalittoral fine mud

Seapens and burrowing megafauna in circalittoral fine mud

Seapens, including Funiculina quadrangularis, and burrowing megafauna in undisturbed circalittoral fine mud

Acanella arbuscula assemblage on Atlantic lower bathyal mud

Acanella arbuscula assemblage on Atlantic mid bathyal mud

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

Amphiura filiformis and Ennucula tenuis in circalittoral and offshore sandy mud

Amphiura filiformis, Kurtiella bidentata and Abra nitida in circalittoral sandy mud

Beggiatoa spp. on anoxic sublittoral mud

Brissopsis lyrifera and Amphiura chiajei in circalittoral mud

Capitella capitata and Thyasira spp. in organically-enriched offshore circalittoral mud and sandy mud

Gracilechinus acutus norvegicus assemblage on Atlantic lower bathyal mud

Gracilechinus acutus norvegicus assemblage on Atlantic mid bathyal mud

Kophobelemnon field on Atlantic mid bathyal mud

Kophobelemnon field on Atlantic upper bathyal mud

Lagis koreni and Phaxas pellucidus in circalittoral sandy mud

Levinsenia gracilis and Heteromastus filiformis in offshore circalittoral mud and sandy mud

Myrtea spinifera and polychaetes in offshore circalittoral sandy mud

Paramphinome jeffreysii, Thyasira spp. and Amphiura filiformis in offshore circalittoral sandy mud

Pheronema carpenteri field on Atlantic lower bathyal mud

Pheronema carpenteri field on Atlantic mid bathyal mud

Styela gelatinosa, Pseudamussium peslutrae and solitary ascidians on sheltered deep circalittoral muddy sediment

Syringammina fragilissima field on Atlantic lower bathyal mud

Syringammina fragilissima field on Atlantic mid bathyal mud

Thyasira spp. and Ennucula tenuis in circalittoral sandy mud

Virgularia mirabilis and Ophiura spp. with Pecten maximus on circalittoral sandy or shelly mud

Virgularia mirabilis and Ophiura spp. with Pecten maximus, hydroids and ascidians on circalittoral sandy or shelly mud with stones

Musculus discors Wales

Musculus discors beds on moderately exposed circalittoral rock

Peat and clay exposures N. Ireland, England, Wales

Piddocks with a sparse associated fauna in sublittoral very soft chalk or clay

Ceramium sp. and piddocks on eulittoral fossilised peat

Mytilus edulis and piddocks on eulittoral firm clay

Sabellaria alveolata reefs

Sabellaria alveolata on variable salinity sublittoral mixed sediment

Sabellaria alveolata reefs on sand-abraded eulittoral rock

Sabellaria spinulosa reefs England

Circalittoral Sabellaria reefs (on rock)

Sabellaria spinulosa on stable circalittoral mixed sediment

Sabellaria spinulosa, didemnids and other small ascidians on tide-swept moderately wave-exposed circalittoral rock

Saline lagoons

Mixed fucoids, Chorda filum and green seaweeds on reduced salinity infralittoral rock

Sublittoral mixed sediment in low or reduced salinity (lagoons)

Sublittoral mud in low or reduced salinity (lagoons)

Sublittoral sand in low or reduced salinity (lagoons)

Ascophyllum nodosum with epiphytic sponges and ascidians on variable salinity infralittoral rock

Fucus ceranoides and Ulva spp. on low salinity infralittoral rock

Phragmites australis swamp and reed beds

Polyides rotunda and/or Furcellaria lumbricalis on reduced salinity infralittoral rock

Stuckenia pectinata community

Seagrass beds

Ruppia maritima in reduced salinity infralittoral muddy sand

Zostera marina beds on lower shore or infralittoral clean or muddy sand

Zostera noltii beds in littoral muddy sand

Serpulid reefs Scotland

Serpula vermicularis reefs on very sheltered circalittoral muddy sand

Sheltered muddy gravels

Cirratulids and Cerastoderma edule in littoral mixed sediment

Crepidula fornicata with ascidians and anenomes on infralittoral coarse mixed sediment

Hediste diversicolor dominated gravelly sandy mud shores

Kurtiella bidentata and Thyasira spp. in circalittoral muddy mixed sediment

Ostrea edulis beds on shallow sublittoral muddy mixed sediment

Sabella pavonina with sponges and anemones on infralittoral mixed sediment

Synarachnactis lloydii and other burrowing anemones in circalittoral muddy mixed sediment

Synarachnactis lloydii with Nemertesia spp. and other hydroids in circalittoral muddy mixed sediment

Venerupis corrugata, Amphipholis squamata and Apseudes holthuisi in infralittoral mixed sediment

Subtidal chalk

Piddocks with a sparse associated fauna in sublittoral very soft chalk or clay

Subtidal chalk N. Ireland, England

Hiatella arctica with seaweeds on vertical limestone / chalk.

Hiatella-bored vertical sublittoral limestone rock

Laminaria digitata and piddocks on sublittoral fringe soft rock

Polydora sp. tubes on moderately exposed sublittoral soft rock

Subtidal mixed muddy sediments Wales

Polychaete-rich deep Venus community in offshore gravelly muddy sand

Kurtiella bidentata and Thyasira spp. in circalittoral muddy mixed sediment

Ophiothrix fragilis and/or Ophiocomina nigra brittlestar beds on sublittoral mixed sediment

Saccharina latissima and red seaweeds on infralittoral sediments

Saccharina latissima and Chorda filum on sheltered upper infralittoral muddy sediment

Synarachnactis lloydii and other burrowing anemones in circalittoral muddy mixed sediment

Synarachnactis lloydii with Nemertesia spp. and other hydroids in circalittoral muddy mixed sediment

Venerupis corrugata, Amphipholis squamata and Apseudes holthuisi in infralittoral mixed sediment

Subtidal sands and gravels

Cumaceans and Chaetozone setosa in infralittoral gravelly sand

Dense Lanice conchilega and other polychaetes in tide-swept infralittoral sand and mixed gravelly sand

Infralittoral mobile clean sand with sparse fauna

Infralittoral mobile sand in variable salinity (estuaries)

Semi-permanent tube-building amphipods and polychaetes in sublittoral sand

Sparse fauna on highly mobile sublittoral shingle (cobbles and pebbles)

Sublittoral coarse sediments in variable salinity (estuaries)

Sublittoral sand in variable salinity (estuaries)

Abra alba and Nucula nitidosa in circalittoral muddy sand or slightly mixed sediment

Abra prismatica, Bathyporeia elegans and polychaetes in circalittoral fine sand

Acrocnida brachiata with Astropecten irregularis and other echinoderms in circalittoral muddy sand

Arenicola marina in infralittoral fine sand or muddy sand

Branchiostoma lanceolatum in circalittoral coarse sand with shell gravel

Echinocardium cordatum and Ensis spp. in lower shore and shallow sublittoral slightly muddy fine sand

Echinocyamus pusillus, Ophelia borealis and Abra prismatica in circalittoral fine sand

Fabulina fabula and Magelona mirabilis with venerid bivalves and amphipods in infralittoral compacted fine muddy sand

Glycera lapidum in impoverished infralittoral mobile gravel and sand

Glycera lapidum, Thyasira spp. and Amythasides macroglossus in offshore gravelly sand

Halcampa chrysanthellum and Edwardsia timida on sublittoral clean stone gravel

Hesionura elongata and Microphthalmus similis with other interstitial polychaetes in infralittoral mobile coarse sand

Hesionura elongata and Protodorvillea kefersteini in offshore coarse sand

Maldanid polychaetes and Eudorellopsis deformis in offshore circalittoral sand or muddy sand

Mediomastus fragilis, Lumbrineris spp. and venerid bivalves in circalittoral coarse sand or gravel

Moerella spp. with venerid bivalves in infralittoral gravelly sand

Neomysis integer and Gammarus spp. in variable salinity infralittoral mobile sand

Neopentadactyla mixta in circalittoral shell gravel or coarse sand

Nephtys cirrosa and amphipods in variable salinity infralittoral mobile sand

Nephtys cirrosa and Bathyporeia spp. in infralittoral sand

Owenia fusiformis and Amphiura filiformis in offshore circalittoral sand or muddy sand

Protodorvillea kefersteini and other polychaetes in impoverished circalittoral mixed gravelly sand

Sertularia cupressina and Hydrallmania falcata on tide-swept sublittoral sand with cobbles or pebbles.

Spirobranchus triqueter with barnacles and bryozoan crusts on unstable circalittoral cobbles and pebbles

Spisula subtruncata and Nephtys hombergii in shallow muddy sand

Tide-swept channels

Circalittoral faunal communities in variable salinity

Cushion sponges and hydroids on turbid tide-swept sheltered circalittoral rock

Cushion sponges and hydroids on turbid tide-swept variable salinity sheltered circalittoral rock

Cushion sponges, hydroids and ascidians on turbid tide-swept sheltered circalittoral rock

Filamentous red seaweeds, sponges and Balanus crenatus on tide-swept variable-salinity infralittoral rock

Mixed kelp and red seaweeds on infralittoral boulders, cobbles and gravel in tidal rapids

Mixed kelp with foliose red seaweeds, sponges and ascidians on sheltered tide-swept infralittoral rock

Red seaweeds and kelps on tide-swept mobile infralittoral cobbles and pebbles

Alcyonium digitatum with dense Tubularia indivisa and anemones on strongly tide-swept circalittoral rock

Ascophyllum nodosum, sponges and ascidians on tide-swept mid eulittoral rock

Balanus crenatus and Tubularia indivisa on extremely tide-swept circalittoral rock

Fucus serratus with sponges, ascidians and red seaweeds on tide-swept lower eulittoral mixed substrata

Fucus serratus, sponges and ascidians on tide-swept lower eulittoral rock

Laminaria digitata, ascidians and bryozoans on tide-swept sublittoral fringe rock

Laminaria hyperborea forest, foliose red seaweeds and a diverse fauna on tide-swept upper infralittoral rock

Laminaria hyperborea on tide-swept, infralittoral mixed substrata.

Laminaria hyperborea on tide-swept, infralittoral rock

Laminaria hyperborea park with hydroids, bryozoans and sponges on tide-swept lower infralittoral rock

Saccharina latissima with foliose red seaweeds and ascidians on sheltered tide-swept infralittoral rock

Tubularia indivisa and cushion sponges on tide-swept turbid circalittoral bedrock

Tubularia indivisa on tide-swept circalittoral rock