Description of biotope or habitat type
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Laminaria hyperborea forest, foliose red seaweeds and a diverse fauna on tide-swept upper 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 - 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.
- 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
Exposed to moderately exposed, tide-swept bedrock and boulders, with dense Laminaria hyperborea forest, characterised by a rich under-storey and stipe flora of foliose seaweeds. The kelp stipes support epiphytes such as Metacallophyllis laciniata, Corallina officinalis, 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 (Dilsea carnosa, Hypoglossum hypoglossoides, Delesseria sanguinea, Plocamium cartilagineum, Vertebrata byssoides, and Dictyota dichotoma ) 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 of the sponges Pachymatisma johnstonia, Halichondria panicea, Amphilectus fucorum and Dysidea fragilis, anthozoans such as Urticina felina, Alcyonium digitatum and Caryophilia smithii, the barnacle Balanus crenatus, colonial ascidians such as Clavelina lepadiformis, and the gastropods Calliostoma zizyphinum and Steromphala cineraria, occur. Also found on the rock is the echinoderm Asterias rubens and the crab Cancer pagurus.
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 | 10 | Abundant | 81-100% |
| Plocamium cartilagineum | 6 | Frequent | 61-80% |
| Delesseria sanguinea | 4 | Frequent | 61-80% |
| Corallinaceae | 3 | Frequent | 61-80% |
| Asterias rubens | 3 | 61-80% | |
| Botryllus schlosseri | 3 | Occasional | 41-60% |
| Cryptopleura ramosa | 3 | Frequent | 61-80% |
| Phycodrys rubens | 3 | Frequent | 61-80% |
| Membranipora membranacea | 2 | 41-60% | |
| Alcyonium digitatum | 2 | Occasional | 41-60% |
| Vertebrata byssoides | 2 | Occasional | 41-60% |
| Metacallophyllis laciniata | 2 | Occasional | 41-60% |
| Clavelina lepadiformis | 2 | Occasional | 41-60% |
| Dictyota dichotoma | 2 | Frequent | 41-60% |
| Dilsea carnosa | 2 | Occasional | 41-60% |
| Dysidea fragilis | 2 | Occasional | 21-40% |
| Pachymatisma johnstonia | 2 | Occasional | 41-60% |
| Balanus crenatus | 1 | Occasional | 21-40% |
| Cancer pagurus | 1 | 41-60% | |
| Caryophyllia smithii | 1 | Occasional | 21-40% |
| Corallina officinalis | 1 | Occasional | 21-40% |
| Amphilectus fucorum | 1 | Occasional | 21-40% |
| Halichondria panicea | 1 | Occasional | 21-40% |
| Hypoglossum hypoglossoides | 1 | Frequent | 21-40% |
| Membranoptera alata | 1 | Occasional | 41-60% |
| Obelia geniculata | 1 | Frequent | 41-60% |
| 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 C. zizyphinum and Steromphala cineraria are also common. Red seaweeds are present but less dense than IR.MIR.KR.LhypT.Ft.
IR.MIR.KR.LhypT.Pk
Found in similar tide-swept conditions, often forming a zone below the kelp forest (IR.MIR.KR.LhypT.Ft) in deeper water where the kelp is less dense and more upper circalittoral species occurs.
IR.MIR.KR.Lhyp.Ft
Found in areas similar wave exposure but not subject to accelerated tidal currents and lacks therefore a prominent filter feeder community. The large variety of sponges such as H. panicea and Amphilectus fucorum, the bryozoans A. diaphanum and Flustra foliacea and the barnacle Balanus balanus are not found in great abundance in the kelp forest.
