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  4. MC1-2242 - Alcyonium digitatum, Spirobranchus triqueter (anciennement Pomatoceros triqueter), algues et bryozoaires encroûtants sur roche du circalittoral exposée aux vagues
  5. Description
MC1-2242 - Alcyonium digitatum, Spirobranchus triqueter (anciennement Pomatoceros triqueter), algues et bryozoaires encroûtants sur roche du circalittoral exposée aux vagues

Alcyonium digitatum, Pomatoceros triqueter, algal and bryozoan crusts on wave-exposed circalittoral rock
MC1-2241 - Flustra foliacea sur roche du circalittoral envasée légèrement abrasée en Atlantique
MC1-2243 - Alcyonium digitatum avec Securiflustra securifrons sur roche du circalittoral soumise aux courants de marée et modérément exposée aux vagues en Atlantique

Classification des habitats EUNIS 2022

Descriptif de l'habitat

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, MC1-223 may develop at the rock/sand interface. Below this biotope, coarse sediments, muddy gravel and sand are typically recorded.

Bibliography

European Topic Centre on Biological Diversity 2022. EUNIS marine habitat classification 2022 including crosswalks. Table Excel. (Source)