MB1-21E - Laminaria digitata, ascidies et bryozoaires sur roche de la frange infralittorale inférieure soumise aux courants de marée en Atlantique (EUNIS 2022)

MB1-21E - Laminaria digitata, ascidies et bryozoaires sur roche de la frange infralittorale inférieure soumise aux courants de marée en Atlantique

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

MB1-21D - Hiatella arctica et algues sur paroi verticale de calcaire/ ou de craie de l'infralittoral en Atlantique

MB1-21F - Laminaires mixtes avec algues rouges foliacées, éponges et ascidies sur roche de l'infralittoral abritée et soumise aux courants de marée en Atlantique

Classification des habitats EUNIS 2022

Descriptif de l'habitat

Sheltered bedrock, boulders and cobbles that are subject to moderate to strong tidal water movement characterised by dense Laminaria digitata, coralline crusts and sponges such as Halichondria panicea. Other seaweeds present include the foliose red seaweeds Chondrus crispus, Palmaria palmata, Cryptopleura ramosa and Mastocarpus stellatus as well as the calcareous Corallina officinalis. Green seaweeds present include Ulva lactuca, Enteromorpha intestinalis and Cladophora rupestris. The increased water movement encourages several filter-feeding faunal groups to occur. The sponges Leucosolenia spp., Scypha ciliata and Hymeniacidon perleve frequently occur on steep and overhanging rock faces. The bryozoans Electra pilosa, Membranoptera membranipora and Alcyonidium hirsutum encrust the kelp and other foliose seaweeds. In addition, ascidians such as Ascidiella scabra, Dendrodoa grossularia and colonial ascidians Botryllus byssoides and Botryllus leachi often thrive in this environment encrusting both the rock and the seaweeds. The tube-building polychaete Pomatoceros triqueter can be found on the rock and on the kelp holdfasts along with the barnacle Balanus crenatus. More mobile species such as the gastropods Gibbula cineraria and Calliostoma zizyphinum, the crab Carcinus maenas and the starfish Asterias rubens are also common. Areas where increased tidal movement influences this community can be found in the narrows and/or intertidal sills of sealochs.
Situation: This biotope often occurs immediately below the tide-swept Fucus serratus biotope (unit MA1-239) consequently, some F. serratus may occur in this biotope (typically only Occasional). The sublittoral fringe of similarly sheltered shores that are not tide-swept are generally characterised by mixed Laminaria saccharina and L. digitata (unit MB1-23A1) or L. saccharina (MB1-23A). Below MB1-21E, at these sheltered, tide-swept sites, a canopy of mixed kelp species often occurs (see units MB1-21F and MB1-21G).

Bibliography

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