Description of biotope or habitat type
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Laminaria hyperborea forest and foliose red seaweeds on moderately exposed upper infralittoral rock
Physical habitat 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.
- 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 Metacallophyllis 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 Spirobranchus triqueter and gastropods including Calliostoma zizyphinum and Steromphala cineraria. Many grazers are found in the kelp forest, the most commonly occurring being the gastropods Steromphala 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 |
|---|---|---|---|
| Laminaria hyperborea | 22 | Abundant | 81-100% |
| Corallinaceae | 6 | Common | 61-80% |
| Delesseria sanguinea | 5 | Frequent | 61-80% |
| Plocamium cartilagineum | 5 | Frequent | 61-80% |
| Steromphala cineraria | 4 | Frequent | 61-80% |
| Phycodrys rubens | 4 | Frequent | 61-80% |
| Asterias rubens | 3 | Occasional | 61-80% |
| Botryllus schlosseri | 3 | Occasional | 41-60% |
| Cryptopleura ramosa | 3 | Frequent | 41-60% |
| Spirobranchus triqueter | 3 | Frequent | 41-60% |
| Echinus esculentus | 3 | Occasional | 41-60% |
| Membranipora membranacea | 2 | Frequent | 41-60% |
| Metacallophyllis laciniata | 2 | Occasional | 41-60% |
| Dictyota dichotoma | 2 | Frequent | 41-60% |
| Membranoptera alata | 2 | Occasional | 41-60% |
| Obelia geniculata | 2 | Frequent | 21-40% |
| Urticina felina | 2 | Occasional | 41-60% |
| Electra pilosa | 1 | Frequent | 21-40% |
| Calliostoma zizyphinum | 1 | Occasional | 41-60% |
| Palmaria palmata | 1 | Frequent | 21-40% |
Similar biotopes or habitat types
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 Metacallophyllis 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
