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  4. MA1-252 - Fucus spiralis sur roche abritée du médiolittoral supérieur en milieu à salinité variable
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MA1-252 - Fucus spiralis sur roche abritée du médiolittoral supérieur en milieu à salinité variable

Fucus spiralis on sheltered variable salinity upper eulittoral rock
MA1-251 - Pelvetia canaliculata sur roche abritée de la frange littorale en milieu à salinité variable
MA1-253 - Fucus vesiculosus sur blocs et substrats hétérogènes stables du médiolittoral moyen en milieu à salinité variable

Classification des habitats EUNIS 2022

Descriptif de l'habitat

Sheltered to extremely sheltered upper eulittoral bedrock or mixed substrata (boulders, large cobbles or shells on mud) in variable salinity conditions characterised by a band of the spiral wrack Fucus spiralis. The ephemeral green seaweed Enteromorpha intestinalis is usually found in this species poor biotope. The barnacles Semibalanus balanoides and Elminius modestus can be found where suitable substrata are available, while gammarids can be found underneath the fronds of F. spiralis and/or underneath the boulders and cobbles. Also found underneath the fronds and among the boulders are the winkles Littorina saxatilis and Littorina littorea and the crab Carcinus maenas.
Situation: This zone usually lies below a zone dominated by the wrack Pelvetia canaliculata (unit MA1-23B) and occasional clumps of P. canaliculata may be present (usually less than common) amongst the F. spiralis. In areas of extreme shelter and variable salinity conditions (e.g. in Scottish sea lochs), the P. canaliculata and F. spiralis zones often merge together forming a very narrow band. This unit occurs above the wracks Ascophyllum nodosum (MA1-254) and/or Fucus vesiculosus (MA1-253) zones and these two fucoids may also occur, although F. spiralis always dominates. It can also be found above a zone dominated by the wrack Fucus ceranoides (MA1-257).
Temporal variation: During the summer months ephemeral green seaweeds such as E. intestinalis can be common.

Bibliography

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