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Marine Habitat Classification


Description of biotope or habitat type

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   Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock; large boulders
Zone Infralittoral - upper
Depth Band 0-5 m, 5-10 m, 10-20 m
Other Features

Download comparative physical and biological data. The comparative tables enable a rapid comparison of the species composition and principal physical characteristics between a given set of biotopes.

Distribution of habitat IR.MIR.KR.Lhyp.Ft <I>Laminaria hyperborea</I> forest and foliose red seaweeds on moderately exposed upper infralittoral rock

  • Records used to define the biotope (core records)
  • Other records assigned to this biotope, marked as 'certain'
  • Other records assigned to this biotope, marked as 'uncertain'
  • Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat

Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.

Description

Moderately exposed upper infralittoral bedrock and boulders characterised by a dense forest of Laminaria hyperborea with dense foliose red seaweeds beneath the canopy. These include Callophyllis laciniata, Plocamium cartilagineum, Cryptopleura ramosa and Delesseria sanguinea. Kelp stipes are usually covered in a rich mixture of red seaweeds of which Palmaria palmata, Phycodrys rubens and Membranoptera alata are often present. Small kelp plants can also be found on the larger kelp stipes. Kelp fronds may be covered with a hydroid growth of Obelia geniculata or the bryozoans Membranipora membranacea and Electra pilosa. The kelp holdfasts can be colonised by bryozoans Scrupocellaria spp. and/or crisiids and colonial ascidians such as Botryllus schlosseri. The rock surface between the kelp plants is generally covered by encrusting coralline algae, often with sponge crusts Halichondria panicea. Small vertical surfaces within the kelp forest generally lack kelp plants, instead being characterised by foliose red seaweeds such as Dictyota dichotoma, the anthozoans Alcyonium digitatum, Urticina felina and Caryophyllia smithii, the tube-building polychaete Pomatoceros triqueter and gastropods including Calliostoma zizyphinum and Gibbula cineraria. Many grazers are found in the kelp forest, the most commonly occurring being the gastropods Gibbula cineraria and Calliostoma zizyphinum and the echinoderm Echinus esculentus. Other echinoderms present include Asterias rubens and Antedon bifida which can be locally abundant, particularly in the north-west.

Situation

This biotope occurs over a wide geographic area and is generally found below the sublittoral fringe Laminaria digitata zone (Ldig) and above the L. hyperborea park (Lhyp.Pk). In the north, Shetland in particular, LsacSac can occur in the lower infralittoral; where grazing influence is present the abundance of red seaweeds may be much reduced (Lhyp.GzPk). In turbid water kelp park is often absent and dense foliose seaweed cover may occur instead (XFoR). In areas affected by scour, such as the rock-sediment interface at the base of bedrock slopes, a mixed kelp canopy can develop below the kelp forest (XKScrR).

Temporal variation

The under-storey of foliose and filamentous seaweeds will diminish towards the autumn and regrow in the spring. Otherwise this biotope is not known to vary markedly over time. Certain areas are prone to urchin grazing and this can substantially alter the community structure of the biotope, such that any site subject to intensive urchin grazing should be recorded as Lhyp.GzFt.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Obelia geniculata 2 Frequent 21-40 %
Urticina felina 2 Occasional 41-60 %
Pomatoceros triqueter 3 Frequent 41-60 %
Gibbula cineraria 4 Frequent 61-80 %
Calliostoma zizyphinum 1 Occasional 41-60 %
Membranipora membranacea 2 Frequent 41-60 %
Electra pilosa 1 Frequent 21-40 %
Asterias rubens 3 Occasional 61-80 %
Echinus esculentus 3 Occasional 41-60 %
Botryllus schlosseri 3 Occasional 41-60 %
Palmaria palmata 1 Frequent 21-40 %
Corallinaceae 6 Common 61-80 %
Callophyllis laciniata 2 Occasional 41-60 %
Plocamium cartilagineum 5 Frequent 61-80 %
Cryptopleura ramosa 3 Frequent 41-60 %
Delesseria sanguinea 5 Frequent 61-80 %
Membranoptera alata 2 Occasional 41-60 %
Phycodrys rubens 4 Frequent 61-80 %
Dictyota dichotoma 2 Frequent 41-60 %
Laminaria hyperborea 22 Abundant 81-100 %

Similar biotopes

IR.LIR.K.LhypCape
Occurs in very and extremely sheltered silted sites. Ascidians such as Ascidia mentula, Ascidiella aspersa, Ascidiella scabra and Clavelina lepadiformi are more common and foliose red seaweeds such as Callophyllis laciniata, Plocamium cartilagineum, Cryptopleura ramosa and Delesseria sanguinea form a silted understorey on the rock. The filamentous red seaweed Bonnemaisonia hamifera may carpet the seabed.

Photos

IR.MIR.KR.Lhyp.Ft Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock, SW of Northern Hares. Sue Hiscock © JNCC
IR.MIR.KR.Lhyp.Ft Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock, SW of Northern Hares. Sue Hiscock © JNCC
IR.MIR.KR.Lhyp.Ft Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock, NW Surf Point, Lundy. Keith Hiscock © JNCC
IR.MIR.KR.Lhyp.Ft Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock, NW Surf Point, Lundy. Keith Hiscock © JNCC
IR.MIR.KR.Lhyp.Ft Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock, Sron na H-Airde, Loch Gairloch. Rohan Holt © JNCC
IR.MIR.KR.Lhyp.Ft Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock, Sron na H-Airde, Loch Gairloch. Rohan Holt © JNCC

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