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Biotope - Typologie Européenne EUNIS
A1.315 - Niveau 5 : Fucus serratus sur roche abritée du médiolittoral inférieur
Description
Sheltered to extremely sheltered lower eulittoral rock with Fucus serratus (for detailed description of the rich associated community please see unit A1.3151). Two variants of this biotope have been described; - Fully marine conditions (A1.3151) and mixed substrata (A1.3152). Please notice that three other biotopes with a F. serratus dominance have been described: Variable salinity (A1.326), tide-swept (A1.152) and tide-swept on mixed substrata (A1.153).
Situation: This biotope usually occurs immediately below a dense canopy of Fucus vesiculosus (A1.313) on sheltered shores or an Ascophyllum nodosum zone (A1.3141) on sheltered shores; consequently low densities of these species may occur in this biotope. The sublittoral fringe below is dominated by the kelps Laminaria saccharina and Laminaria digitata on sheltered shores (A3.3131; A3.3121).
Taxons (Liens actifs si espèces présentes)
A1.3151 - Niveau 6 : Fucus serratus sur roche abritée du médiolittoral inférieur en milieu marin
Description
Sheltered lower eulittoral rock subject to fully marine conditions characterised by a dense canopy of the wrack Fucus serratus. There is a wide range of associated species found on the surface of the rock underneath the canopy, including the barnacle Semibalanus balanoides, limpets Patella vulgata, winkles Littorina littorea, and even mussels Mytilus edulis can be present in cracks and crevices. These species are usually found in higher abundance further up on the shore. There may also be a number of other seaweeds present, including the red Corallina officinalis and Mastocarpus stellatus, the wrack Fucus vesiculosus and the green Enteromorpha intestinalis, Ulva lactuca or Cladophora rupestris, though these usually are present in low numbers if present at all. The sponge Halichondria panicea can be present underneath the F. serratus canopy in moist cracks or minor overhangs. Polychaetes such as Pomatoceros triqueter and Spirorbis spp. are present in their white calcareous tubes on the rock.
Situation: This biotope usually occurs immediately below a Fucus vesiculosus-barnacle mosaic (unit A1.213) on moderately exposed shores or a dense canopy of F. vesiculosus (A1.313) or Ascophyllum nodosum (A1.3141) on sheltered shores; consequently low densities of these species (typically less than Frequent) may also occur in this biotope. The sub littoral fringe below on moderately exposed shores is dominated by the kelp Laminaria digitata (A3.211; A3.2112), while the kelp Laminaria saccharina may co-dominate on sheltered shores (A3.3131; A3.3121).
Temporal variation: Fluctuations from year to year in the abundance of the F. serratus and the red seaweeds due to e.g. severe storms may convert this biotope into either A1.2141 or into a red seaweed dominated biotope on moderately exposed shores.
Taxons (Liens actifs si espèces présentes)
Cladophora rupestris (L.) Kütz., 1843 ( Esp. caract. )
Corallina officinalis L., 1758 ( Esp. caract. )
Enteromorpha intestinalis (L.) Nees, 1820 ( Esp. caract. )
Mastocarpus stellatus (Stackh.) Guiry, 1984 ( Esp. caract. )
Spirorbis sp. ( Esp. caract. )
Ulva lactuca L., 1753 ( Esp. caract. )
Corallina officinalis L., 1758 ( Esp. caract. )
Enteromorpha intestinalis (L.) Nees, 1820 ( Esp. caract. )
Mastocarpus stellatus (Stackh.) Guiry, 1984 ( Esp. caract. )
Spirorbis sp. ( Esp. caract. )
Ulva lactuca L., 1753 ( Esp. caract. )
Analyse Ecologie du milieu (En fonction des espèces présentes)