Communities of Mediterranean upper circalittoral coastal detritic bottoms

This habitat occurs in big bays and opens seas, on a substratum whose nature varies widely and depends largely on the typology of the nearby coast and of nearby infralittoral rock formations. It occurs on terrigenous and organogenous sediment: gravel with a sandy-muddy filling originating from predominant local rocks, sometimes shell debris from various molluscs, debris from big calcified bryozoans, tests of echinoderms or of some dead melobesies (coralline red algae Melobesiae spp). The interstices between these various components of coarse sands and gravel are partially filled by a greater or lesser proportion of sand and mud. The muddy portion is usually less than 20%, but various more or less muddy types exist.

It develops at depths of between 30 and 100 metres, usually as an extension at depth of the biocenosis of well sorted fine sands. Some facies with epiflora and epifauna may present, depending on certain currents. These may be characterised  by brittlestars, colonial ascidians and by big colonies of arborescent bryozoans, unattached or fixed to small substrata.

Indicators of quality:

Some species are indicators of more particular environmental conditions such as the echinoderms (Echinocyamus pusillus, Spatangus purpureus, Astarte fusca), the bivalves (Cardium minimum, Venus ovata, Dentalium inaequicostatum), the  opisthobranch mollusc Philine aperta, or species with a wide ecological distribution in loose substrata.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats