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  4. MC1-2342 - Novocrania anomala, Dendrodoa grossularia et Sarcodictyon roseum sur roche du circalittoral en milieu à salinité variable
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MC1-2342 - Novocrania anomala, Dendrodoa grossularia et Sarcodictyon roseum sur roche du circalittoral en milieu à salinité variable

Neocrania anomala, Dendrodoa grossularia and Sarcodictyon roseum on variable salinity circalittoral rock
MC1-2341 - Novocrania anomala et Protanthea simplex sur roche du circalittoral très abritée

Classification des habitats EUNIS 2022

Descriptif de l'habitat

This variant typically occurs on lower circalittoral silty, bedrock or boulder cliffs and ridges in very wave-sheltered fjordic sealochs subjected to variable salinity regimes (such as Loch Etive, Scotland). In these sheltered conditions, there are frequently dense populations of the ascidian Dendrodoa grossularia, the brachiopod Neocrania anomala and to a lesser extent, the brachiopod Terebratulina retusa, which are able to tolerate the variable salinity. Other solitary ascidians that may be present include Ciona intestinalis, Corella parallelogramma, Ascidiella scabra, Ascidia mentula, Ascidia virginea and Polycarpa pomaria. The anemone Protanthea simplex is occasionally seen, although to a lesser extent than in unit MC1-234, possibly due to the variable salinity. The hydroids Bougainvillia ramosa and Lafoea dumosa, the cup-coral Caryophilia smithii and Sarcodictyon roseum are occasionally present. The tubes formed by the polychaete Sabella pavonina may be observed standing erect from the rock surface. The rest of the rock surface is usually covered by encrusting red algae and the polychaete Pomatoceros triqueter and Protula tubularia. The sea cucumber Psolus phantapus may be found on the underside of boulders. Other species such as the hermit crab Pagurus bernhardus and the spider crab Hyas araneus may be found amongst the rock/boulders. The starfish Asterias rubens, Crossaster papposus, and Henricia spp. and the sea urchin Psammechinus miliaris are also recorded within this variant. The relatively bare, silty rock supports low numbers of a relatively few species. Although barren rock grazed by the sea urchin Echinus esculentus is found in other sea loch biotopes (see units MC1-2245 and MC1-2246), E. esculentus is virtually absent within MC1-2342.
Situation: Due to the variable or reduced salinity conditions present where this biotope is found, you tend to find reduced salinity kelp biotopes above MC1-2342, such as MB1-242 and MB1-243. The very sheltered conditions give rise to muddy sediment slopes or plains beneath MC1-234 where species such as the seapen Funiculina quadrangularis, the anemone Cerianthus lloydii and the Norway lobster Nephrops norvegicus are typically abundant.

Bibliography

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