Description of biotope or habitat type
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Kelp and seaweed communities in tide-swept sheltered conditions
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | Strong (3-6 kn), Moderately strong (1-3 kn), Weak (>1 kn) |
| Substratum | Bedrock, boulders and cobbles |
| Zone | Infralittoral, Sublittoral fringe |
| Depth Band | 0-5 m, 5-10 m, 10-20 m, Lower shore |
| 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
Sheltered infralittoral rock exposed to strong tidal streams. In the sublittoral fringe dense Laminaria digitata is found together with erect seaweeds, sponges, ascidians and bryozoans (LdigT). Below this, on bedrock and stable boulders a canopy of mixed kelp (primarily Laminaria hyperborea and Saccharina latissima) occurs with foliose red seaweeds, sponges and ascidians (XKT). This biotope is typically found in the sheltered narrows and sills of Scottish sealochs. Mixed substrata of boulders, cobbles, pebbles and gravel, that also occurs in the tidal rapids of Scottish sealochs, supports a reduced kelp canopy (L. hyperborea and L. saccharina; typically Frequent), with a rich red seaweed component and maerl at some sites (XKTX). In south-west Britain, sheltered, tide-swept rock is restricted to estuarine conditions where variable salinity and increased turbidity of the water have a significant effect on the biota, limiting the infralittoral zone to very shallow depths. Unlike the tide-swept channels in sealochs, the rock in these estuaries is characterised by a relatively low abundance of L. saccharina (< Common) with foliose red seaweeds, sponges and ascidians (LsacT). L. hyperborea is rarely present.
Situation
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 |
|---|---|---|---|
| Saccharina latissima | 7 | Frequent | 61-80% |
| Halichondria panicea | 6 | Frequent | 41-60% |
| Corallinaceae | 4 | Frequent | 41-60% |
| Carcinus maenas | 4 | Occasional | 41-60% |
| Laminaria hyperborea | 4 | Common | 41-60% |
| Spirobranchus triqueter | 4 | Frequent | 41-60% |
| Asterias rubens | 3 | Occasional | 41-60% |
| Ulva lactuca | 3 | Occasional | 41-60% |
| Balanus crenatus | 2 | Frequent | 21-40% |
| Botryllus schlosseri | 2 | Occasional | 41-60% |
| Chondrus crispus | 2 | Occasional | 41-60% |
| Dictyota dichotoma | 2 | Occasional | 21-40% |
| Steromphala cineraria | 2 | Occasional | 41-60% |
| Halidrys siliquosa | 2 | Occasional | 41-60% |
| Laminaria digitata | 2 | Common | 21-40% |
| Echinus esculentus | 2 | Occasional | 21-40% |
| Anemonia viridis | 1 | Occasional | 21-40% |
| Clavelina lepadiformis | 1 | Occasional | 21-40% |
| Corallina officinalis | 1 | Occasional | 21-40% |
| Hypoglossum hypoglossoides | 1 | Frequent | 21-40% |
| Lithothamnion glaciale | 1 | Frequent | 21-40% |
| Ophiothrix fragilis | 1 | Occasional | 21-40% |
| Urticina felina | 1 | Occasional | 21-40% |
Similar biotopes or habitat types
Not applicable or unknown.