Laminaria saccharina forest on very sheltered upper infralittoral rock

English name: Laminaria saccharina forest on very sheltered upper infralittoral rock

Quick facts

EUNIS habitat type code A3.3132
Bern Convention Included in a Resolution 4 habitat type at a higher level (A3)

Description (English)

Sheltered to extremely sheltered sublittoral fringe and infralittoral bedrock, boulders and cobbles characterised by a dense canopy of the kelp Laminaria saccharina. In such sheltered conditions, a distinct sublittoral fringe is not always apparent and this biotope can therefore extend from below the Fucus serratus zone (A1 315) into the upper infralittoral zone, though there may be a mixed L. saccharina and Laminaria digitata zone (A3.3131) in between. There is a relatively low species diversity and species density due to a combination of heavy siltation of the habitat and the lack of light penetrating through the dense kelp canopy. Only a few species of red seaweeds are present compared with A3.3131 or A3.312. The most commonly occurring red seaweeds are Delesseria sanguinea, Phycodrys rubens, Bonnemaisonia hamifera and coralline crusts. Brown seaweeds are also sparse and generally comprise Chorda filum and ectocarpoids. At extremely sheltered sites, where there is a heavy silt cover on the rock and the kelp fronds, the sub-flora is reduced to a few specialised species able to tolerate these conditions, such as the cartilaginous seaweeds Polyides rotundus and Chondrus crispus. Ascidians such as Clavelina lepadiformis, Ascidiella aspersa and Ascidia mentula can remain prominent in such conditions, often occurring on steep or vertical rock which is subject to less siltation. The variety of red seaweeds is further reduced where grazers such as the urchin Echinus esculentus and the top shell Gibbula cineraria are present. The keelworm Pomatoceros triqueter, the crab Carcinus maenas and the hermit crab Pagurus bernhardus can be present. Geographical variations: Northern sites: in sheltered sealochs the most conspicuous fauna in these forests are the large solitary ascidians Ciona intestinalis, Ascidiella spp. and A. mentula which tend to occur in greater abundance than in the mixed kelp forests (A3.312). In common with mixed forests, echinoderms are consistently present in low abundance: the featherstar Antedon bifida, common starfish Asterias rubens, the brittlestar Ophiothrix fragilis and the urchin Echinus esculentus are typically present. Saddle oysters Pododesmus patelliformis and chitons Tonicella marmorea can occur in high abundance at some sites. The anthozoan Anemonia viridis is often more prevalent at the extremely sheltered sites. The communities of the sheltered voes and sounds of Shetland and Orkney are similar to those present in the mainland sealochs. Southern sites: Sheltered infralittoral rock is not commonly found outside of the fjordic sealochs. In south-west Britain, where sublittoral rock does occur in shallow marine inlets, the waters are more turbid than in the sealochs, generally limiting kelp to the sublittoral fringe zone. Echinoderms are rare or absent from the south-western L. saccharina forests. A far greater diversity of red seaweeds is associated with the south-western sites: Palmaria palmata, Gracilaria gracilis, Phyllophora pseudoceranoides, Cystoclonium purpureum, Rhodophyllis divaricata, Ceramium nodulosum and Polyneura bonnemaisonii typically occur.
Situation: Although this biotope may occur below a mixed kelp canopy that occupies the sublittoral fringe (units A3.3131 or A3.2111) at some sites it extends directly into the sublittoral fringe and abuts the F. serratus zone (A1 315 or A1.3152 on mixed substrata). Where suitable hard substrata are available, the L. saccharina diminishes in abundance (typically Frequent) with increasing depth to form kelp park (A3.3122).

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Anemonia viridis
Invertebrates Antedon bifida
Invertebrates Ascidia mentula
Invertebrates Ascidiella aspersa
Invertebrates Asterias rubens
Algae Bonnemaisonia hamifera
Invertebrates Carcinus maenas
Algae Chondrus crispus
Algae Chorda filum
Invertebrates Ciona intestinalis
Invertebrates Clavelina lepadiformis
Algae Cystoclonium purpureum
Algae Delesseria sanguinea
Invertebrates Echinus esculentus
Algae Fucus serratus
Invertebrates Gibbula cineraria
Algae Gracilaria gracilis
Algae Laminaria digitata
Algae Laminaria saccharina
Invertebrates Ophiothrix fragilis
Invertebrates Pagurus bernhardus
Algae Palmaria palmata
Algae Phycodrys rubens
Invertebrates Pododesmus patelliformis
Algae Polyides rotundus
Algae Polyneura bonnemaisonii
Invertebrates Pomatoceros triqueter
Algae Rhodophyllis divaricata
Invertebrates Tonicella marmorea
Species scientific name English common name Species group
Anemonia viridis Invertebrates
Antedon bifida Invertebrates
Ascidia mentula Invertebrates
Ascidiella aspersa Invertebrates
Asterias rubens Invertebrates
Bonnemaisonia hamifera Algae
Carcinus maenas Invertebrates
Chondrus crispus Algae
Chorda filum Algae
Ciona intestinalis Invertebrates
Clavelina lepadiformis Invertebrates
Cystoclonium purpureum Algae
Delesseria sanguinea Algae
Echinus esculentus Invertebrates
Fucus serratus Algae
Gibbula cineraria Invertebrates
Gracilaria gracilis Algae
Laminaria digitata Algae
Laminaria saccharina Algae
Ophiothrix fragilis Invertebrates
Pagurus bernhardus Invertebrates
Palmaria palmata Algae
Phycodrys rubens Algae
Pododesmus patelliformis Invertebrates
Polyides rotundus Algae
Polyneura bonnemaisonii Algae
Pomatoceros triqueter Invertebrates
Rhodophyllis divaricata Algae
Tonicella marmorea Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 IR.LIR.K.Lsac.Ft <I>Laminaria saccharina</I> forest on very sheltered upper infralittoral rock source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A3.3132 Laminaria saccharina forest on very sheltered upper infralittoral rock same
EUNIS Habitat Classification 200308 A3.3122 Laminaria saccharina forest on very sheltered upper infralittoral rock same
EUNIS Habitat Classification 200202 A3.3122 Laminaria saccharina forest on very sheltered upper infralittoral rock same
EUNIS Habitat Classification 199910 A3.3122 Laminaria saccharina forest on very sheltered upper infralittoral rock same
MNCR BioMar 97.06 (Britain & Ireland) SIR.K.Lsac.Ft Laminaria saccharina forest on very sheltered upper infralittoral rock same
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