MB1-2391 - Forêt mixte de Laminaria hyperborea et Saccharina latissima (anciennement Laminaria saccharina) sur roche abritée de l'infralittoral supérieur en Atlantique (EUNIS 2022)

MB1-2391 - Forêt mixte de Laminaria hyperborea et Saccharina latissima (anciennement Laminaria saccharina) sur roche abritée de l'infralittoral supérieur en Atlantique

Mixed Laminaria hyperborea and Laminaria saccharina forest on sheltered Atlantic upper infralittoral rock

MB1-2392 - Zone clairsemée mixte de Laminaria hyperborea et Saccharina latissima (anciennement Laminaria saccharina) sur roche abritée de l'infralittoral inférieur en Atlantique

Classification des habitats EUNIS 2022

Descriptif de l'habitat

Sheltered, often silted, upper infralittoral bedrock and boulder slopes with mixed kelps Laminaria hyperborea and Laminaria saccharina and red seaweeds beneath. The kelp at these sheltered sites often has large `cape-form' fronds, which form a dense canopy over the seabed and are often epiphytised by the hydroid Obelia geniculata and the bryozoan Membranipora membranacea. Beneath the kelp, red seaweeds such as Delesseria sanguinea and Cryptopleura ramosa occur on top of encrusting coralline algae. Often, a dense algal turf of Bonnemaisonia hamifera (tetrasporophyte) carpets the rock. The stipes of L. hyperborea may be densely covered with seaweeds such as Phycodrys rubens, Plocamium cartilagineum and Porphyropsis coccinea. There can also be a prominent faunal component on the stipes including the solitary ascidian Clavelina lepadiformis and the colonial ascidian Botryllus schlosseri. Brown seaweeds, occurring here in low abundance, include Dictyota dichotoma. The kelp Saccorhiza polyschides may also occur but rarely in equal abundance to L. hyperborea or L. saccharina. Beneath the kelp canopy, the faunal component is generally less diverse than the more exposed kelp forests (unit MB1-21A). The silted rock supports a sparse fauna of gastropods Gibbula cineraria and Calliostoma zizyphinum, the tube-building polychaete Pomatoceros triqueter and occasional starfish Asterias rubens and the urchin Echinus esculentus. Steeper, less silted rock, may have the anthozoans Caryophyllia smithii and Alcyonium digitatum.Sheltered, often silted, upper infralittoral bedrock and boulder slopes with mixed kelps Laminaria hyperborea and Laminaria saccharina and red seaweeds beneath. The kelp at these sheltered sites often has large `cape-form' fronds, which form a dense canopy over the seabed and are often epiphytised by the hydroid Obelia geniculata and the bryozoan Membranipora membranacea. Beneath the kelp, red seaweeds such as Delesseria sanguinea and Cryptopleura ramosa occur on top of encrusting coralline algae. Often, a dense algal turf of Bonnemaisonia hamifera (tetrasporophyte) carpets the rock. The stipes of L. hyperborea may be densely covered with seaweeds such as Phycodrys rubens, Plocamium cartilagineum and Porphyropsis coccinea. There can also be a prominent faunal component on the stipes including the solitary ascidian Clavelina lepadiformis and the colonial ascidian Botryllus schlosseri. Brown seaweeds, occurring here in low abundance, include Dictyota dichotoma. The kelp Saccorhiza polyschides may also occur but rarely in equal abundance to L. hyperborea or L. saccharina. Beneath the kelp canopy, the faunal component is generally less diverse than the more exposed kelp forests (MB1-21A). The silted rock supports a sparse fauna of gastropods Gibbula cineraria and Calliostoma zizyphinum, the tube-building polychaete Pomatoceros triqueter and occasional starfish Asterias rubens and the urchin Echinus esculentus. Steeper, less silted rock, may have the anthozoans Caryophyllia smithii and Alcyonium digitatum.
Situation: This biotope occurs below Laminaria digitata on the sheltered sublittoral fringe (MB1-2171) or a mix of L. saccharina and L. digitata in very sheltered conditions (MB1-23A1). It can also be found on isolated rock exposures amid a sediment seabed (MC6-2141 or MB6-249). Where suitable substrata allow, the kelp thins out with increased depth to form a park below the forest (MB1-2392).

Bibliographie

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