Description of biotope or habitat type
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Laminaria hyperborea on tide-swept, infralittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Extremely exposed, Very exposed, Exposed, Moderately exposed |
| Tidal streams | Strong (3-6 kn), Moderately strong (1-3 kn) |
| Substratum | Bedrock & boulders |
| 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.
- 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
Wave exposed to moderately wave exposed, tide-swept bedrock and boulders with Laminaria hyperborea, characterised by a rich under-storey and stipe flora of foliose seaweeds including the brown seaweed Dictyota dichotoma. The kelp stipes support epiphytes such as Cryptopleura ramosa and Phycodrys rubens. At some sites, instead of being covered by red seaweeds, the kelp stipes are heavily encrusted by the ascidian Botryllus schlosseri. Epilithic seaweeds Delesseria sanguinea, Plocamium cartilagineum Heterosiphonia plumosa, Hypoglossum hypoglossoides, Metacallophyllis laciniata, Kallymenia reniformis, Vertebrata byssoides 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. On the rock surface, a rich fauna comprising the bryozoan Electra pilosa, the sponge Pachymatisma johnstonia, anthozoans such as Alcyonium digitatum, Cylista elegans and Urticina felina, colonial ascidians such as Clavelina lepadiformis, the calcareous tubeworm Spirobranchus triqueter and the barnacle Balanus crenatus occur. More mobile species include the gastropod Calliostoma zizyphinum, the crab Cancer pagurus and the echinoderms Asterias rubens and Echinus esculentus. Two variants have been described: Tide-swept kelp forest (LhypT.Ft) and tide-swept kelp park (LhypT.Pk).
Situation
This biotope occurs below Alaria esculenta (Ala) at exposed sites or L. digitata (Ldig.Ldig) at moderately exposed locations. With increasing depth the kelp density diminishes to become tide-swept kelp park (LhypT.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 |
|---|---|---|---|
| Laminaria hyperborea | 13 | Common | 81-100% |
| Delesseria sanguinea | 6 | Frequent | 61-80% |
| Plocamium cartilagineum | 6 | Frequent | 61-80% |
| Corallinaceae | 5 | Frequent | 61-80% |
| Asterias rubens | 3 | Occasional | 61-80% |
| Cryptopleura ramosa | 3 | Frequent | 61-80% |
| Dictyota dichotoma | 3 | Frequent | 61-80% |
| Phycodrys rubens | 3 | Frequent | 41-60% |
| Membranipora membranacea | 2 | Frequent | 41-60% |
| Alcyonium digitatum | 2 | Occasional | 41-60% |
| Balanus crenatus | 2 | Frequent | 41-60% |
| Vertebrata byssoides | 2 | Occasional | 41-60% |
| Metacallophyllis laciniata | 2 | Occasional | 41-60% |
| Clavelina lepadiformis | 2 | Occasional | 41-60% |
| Heterosiphonia plumosa | 2 | Frequent | 41-60% |
| Hypoglossum hypoglossoides | 2 | Occasional | 41-60% |
| Echinus esculentus | 2 | Occasional | 41-60% |
| Electra pilosa | 1 | Frequent | 21-40% |
| Botryllus schlosseri | 1 | Occasional | 41-60% |
| Calliostoma zizyphinum | 1 | Occasional | 41-60% |
| Cancer pagurus | 1 | Occasional | 41-60% |
| Kallymenia reniformis | 1 | Occasional | 41-60% |
| Obelia geniculata | 1 | Frequent | 21-40% |
| Pachymatisma johnstonia | 1 | Occasional | 41-60% |
| Spirobranchus triqueter | 1 | Occasional | 21-40% |
| Cylista elegans | 1 | Occasional | 21-40% |
| Urticina felina | 1 | Occasional | 41-60% |
Similar biotopes or habitat types
IR.HIR.KFaR.LhypFa
On very exposed coasts subject to weaker tidal currents. The fauna turf is characterised by a higher abundance of anthozoans such as Corynactis viridis and Sargartia elegans, but topshells such Calliostoma zizyphinum and Steromphala cineraria are also common. Red seaweeds are present but less dense than IR.MIR.KR.LhypT.Ft.
