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Marine Habitat Classification


Description of biotope or habitat type

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


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Sheltered, Very sheltered, Extremely sheltered
Tidal streams Weak (>1 kn)
Substratum Bedrock; boulders
Zone Infralittoral - upper
Depth Band 0-5 m, 5-10 m
Other Features Siltation

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.LIR.K.LhypLsac.Ft Mixed <I>Laminaria hyperborea</I> and <I>Laminaria saccharina</I> forest on sheltered 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

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 (Lhyp). 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 (Lhyp). 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 (Ldig.Ldig) or a mix of L. saccharina and L. digitata in very sheltered conditions (Lsac.Ldig). It can also be found on isolated rock exposures amid a sediment seabed (VirOphPmax or PhiVir). Where suitable substrata allow, the kelp thins out with increased depth to form a park below the forest (LhypLsac.Pk).

Temporal variation

Unknown.

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 Occasional 41-60 %
Alcyonium digitatum 1 Occasional 21-40 %
Caryophyllia smithii 1 Occasional 21-40 %
Pomatoceros triqueter 5 Frequent 61-80 %
Necora puber 1 Occasional 41-60 %
Gibbula cineraria 5 Frequent 61-80 %
Calliostoma zizyphinum 1 Occasional 41-60 %
Membranipora membranacea 2 Occasional 41-60 %
Asterias rubens 3 Occasional 61-80 %
Echinus esculentus 3 Occasional 61-80 %
Clavelina lepadiformis 1 Occasional 41-60 %
Botryllus schlosseri 1 Occasional 41-60 %
Bonnemaisonia hamifera 1 Occasional 21-40 %
Corallinaceae 7 Common 61-80 %
Callophyllis laciniata 1 Occasional 41-60 %
Plocamium cartilagineum 4 Frequent 61-80 %
Cryptopleura ramosa 1 Occasional 41-60 %
Delesseria sanguinea 3 Occasional 61-80 %
Phycodrys rubens 3 Occasional 41-60 %
Rhodophycota indet.(non-calc.crusts) 1 Frequent 21-40 %
Dictyota dichotoma 2 Occasional 41-60 %
Laminaria hyperborea 15 Common 81-100 %
Laminaria saccharina 13 Common 81-100 %

Similar biotopes

IR.LIR.K.LhypLsac.Pk
Found in deeper water below the kelp forest and has a lower abundance of kelp and red seaweeds. The abundance of Laminaria spp. in the kelp park is typically only Frequent. The fauna remains much the same as the forest, unless there is a greater fraction of mixed substrata in the deeper park, in which case there may be an increase in infaunal species, brittlestars and starfish. The assemblage of red seaweeds does not differ greatly from that of the forest.

IR.LIR.K.Lsac.Ft
Generally occurs in more sheltered, siltier conditions and lacks L. hyperborea.

IR.LIR.K.LhypLsac.Gz
A greater number of grazing echinoderms reduce the abundance of foliose red seaweeds and kelp (Common-Frequent).

IR.LIR.K.LhypCape
Cape-form of L. hyperborea on very silted rock (particularly in extremely sheltered sealochs of western Scotland). L. saccharina can be present but does not co-dominant as in LhypLsac.


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