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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 tide-swept upper infralittoral mixed substrata

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed, Sheltered
Tidal streams Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible)
Substratum Bedrock, boulders, cobbles, pebbles and gravel
Zone Infralittoral
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.LhypTX.Ft <I>Laminaria hyperborea</I> forest and foliose red seaweeds on tide-swept upper infralittoral mixed substrata

  • 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.


Moderately wave-exposed to wave sheltered, tide-swept mixed substrata, with dense Laminaria hyperborea forest and sparser Laminaria saccharina, characterised by an under-storey and stipe flora of foliose seaweeds. The kelp stipes support epiphytes such as Palmaria palmata Callophyllis laciniata, Cryptopleura ramosa, Membranoptera alata, and Phycodrys rubens. At some sites, instead of being covered by red seaweeds, the kelp stipes are heavily encrusted by the ascidians Botryllus schlosseri and in the south-west Distomus variolosus. Epilithic seaweeds (Delesseria sanguinea, Plocamium cartilagineum, Odonthalia dentata, Dictyota dichotoma and Desmarestia aculeata) and crustose seaweeds commonly occur beneath the kelp. The kelp fronds are often covered with growth of the hydroid Obelia geniculata or the bryozoan Membranipora membranacea. Although these species are also found in most kelp forests, in this biotope they are particularly dense. On the rock surface, a rich fauna comprising anthozoans such as Urticina felina, the barnacle Balanus crenatus, the calcareous tubeworm Pomatoceros triqueter, colonial ascidians such as Clavelina lepadiformis, the gastropods Calliostoma zizyphinum and Gibbula cineraria, and the bryozoans Electra pilosa and Alcyonidium diaphanum occur. Also found on the rock are the echinoderms Echinus esculentus, Asterias rubens and Ophiothrix fragilis, and the crabs Cancer pagurus, Pagurus bernhardus and Necora puber.


No situation data available.

Temporal variation

No temporal variation data available.

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 41-60 %
Urticina felina 2 41-60 %
Pomatoceros triqueter 2 41-60 %
Balanus crenatus 1 Occasional 21-40 %
Pagurus bernhardus 1 21-40 %
Cancer pagurus 3 41-60 %
Necora puber 2 41-60 %
Gibbula cineraria 3 61-80 %
Calliostoma zizyphinum 4 61-80 %
Alcyonidium diaphanum 1 41-60 %
Membranipora membranacea 2 41-60 %
Electra pilosa 2 41-60 %
Asterias rubens 5 61-80 %
Ophiothrix fragilis 1 21-40 %
Echinus esculentus 5 61-80 %
Clavelina lepadiformis 2 41-60 %
Botryllus schlosseri 2 41-60 %
Palmaria palmata 1 41-60 %
Lithophyllum 1 41-60 %
Callophyllis laciniata 2 41-60 %
Plocamium cartilagineum 3 61-80 %
Cryptopleura ramosa 2 41-60 %
Delesseria sanguinea 3 61-80 %
Membranoptera alata 2 41-60 %
Phycodrys rubens 3 61-80 %
Odonthalia dentata 3 41-60 %
Dictyota dichotoma 1 41-60 %
Desmarestia aculeata 3 41-60 %
Laminaria hyperborea 5 81-100 %
Laminaria saccharina 4 61-80 %

Similar biotopes or habitat types

Found in more tide-swept conditions, often forming a zone below the kelp forest (LhypTX.Ft) in deeper water where the kelp is less dense and more upper circalittoral species occurs.

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