Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on wave-exposed circalittoral rock

English name: Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on wave-exposed circalittoral rock

Description (English)

This variant is typically found on the vertical, steep and upper faces of wave-exposed circalittoral bedrock or boulders subject to varying amounts of current. The variant has a very grazed, sparse appearance, dominated only by the presence of Alcyonium digitatum and large expanses of encrusting red alage and bryozoan crusts particularly (Parasmittina trispinosa). The sparse appearance can be attributed to the frequently observed sea urchin Echinus esculentus. The polychaete Pomatoceros triqueter can be locally abundant, and may in some cases cover far more rock surface than A. digitatum, especially on vertical faces. Clumps of robust hydroids such as Abietinaria abietina occur occasionally. Other species present include the echinoderms Asterias rubens, Henricia sanguinolenta, Ophiothrix fragilis, the anemone Urticina felina, Calliostoma zizyphinum and Cancer pagurus.
Situation: Shallower than this biotope, dense kelp forest is typically found, containing species such as Laminaria hyperborea and Alaria esculentus. Occasionally, this biotope may be found on rocky outcrops surrounding by coarse sand. With this increased scour, A4.213 may develop at the rock/sand interface. Below this biotope, coarse sediments, muddy gravel and sand are typically recorded.

Source: EUNIS habitat classification

Quick facts

EUNIS habitat type code A4.2142
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Abietinaria abietina
Invertebrates Alcyonium digitatum
Invertebrates Asterias rubens
Invertebrates Calliostoma zizyphinum
Invertebrates Cancer pagurus
Invertebrates Echinus esculentus
Invertebrates Henricia sanguinolenta
Algae Laminaria hyperborea
Invertebrates Ophiothrix fragilis
Invertebrates Parasmittina trispinosa
Invertebrates Pomatoceros triqueter
Invertebrates Urticina felina
Species scientific name English common name Species group
Abietinaria abietina Invertebrates
Alcyonium digitatum Invertebrates
Asterias rubens Invertebrates
Calliostoma zizyphinum Invertebrates
Cancer pagurus Invertebrates
Echinus esculentus Invertebrates
Henricia sanguinolenta Invertebrates
Laminaria hyperborea Algae
Ophiothrix fragilis Invertebrates
Parasmittina trispinosa Invertebrates
Pomatoceros triqueter Invertebrates
Urticina felina Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.MCR.EcCr.FaAlCr.Adig <I>Alcyonium digitatum</I>, <I>Pomatoceros triqueter</I>, algal and bryozoan crusts on wave-exposed circalittoral rock source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A4.2142 Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on wave-exposed circalittoral rock same
EUNIS Habitat Classification 200308 A3.524 Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on vertical exposed circalittoral rock narrower
EUNIS Habitat Classification 200308 A3.241 Alcyonium digitatum and a bryozoan, hydroid and ascidian turf on vertical moderately exposed infralittoral rock overlap
EUNIS Habitat Classification 200202 A3.524 Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on vertical exposed circalittoral rock narrower
EUNIS Habitat Classification 200202 A3.241 Alcyonium digitatum and a bryozoan, hydroid and ascidian turf on vertical moderately exposed infralittoral rock narrower
EUNIS Habitat Classification 199910 A3.241 Alcyonium digitatum and a bryozoan, hydroid and ascidian turf on vertical moderately exposed infralittoral rock narrower
EUNIS Habitat Classification 199910 A3.524 Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on vertical exposed circalittoral rock narrower
MNCR BioMar 97.06 (Britain & Ireland) IR.FaSwV.AlcByH Alcyonium digitatum and a bryozoan, hydroid and ascidian turf on vertical moderately exposed vertical infralittoral rock narrower
MNCR BioMar 97.06 (Britain & Ireland) ECR.Alc.AlcC Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on vertical exposed circalittoral rock narrower
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