Description of biotope or habitat type
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Novocrania anomala and Protanthea simplex on sheltered circalittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Sheltered, Very sheltered, Extremely sheltered |
| Tidal streams | Weak (>1 kn), Very weak (negligible) |
| Substratum | Bedrock, boulders |
| Zone | Circalittoral |
| Depth Band | 5-10 m, 10-20 m, 20-30 m, 30-50 m |
| Other Features | Steep slopes |
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
This biotope typically occurs in full to variable salinity conditions on very wave-sheltered circalittoral bedrock and boulder slopes subject to negligible tidal streams (this tends to be in the landward, very sheltered basins of fjordic sealochs). This biotope is characterised by often dense populations of the anemone Protanthea simplex, growing on the silty bedrock. The underlying rock surfaces are usually covered by encrusting red algae, the polychaete Spirobranchus triqueter, the brachiopods Novocrania anomala and Terebratulina retusa, the saddle oyster Pododesmus patelliformis and the polychaete Sabella pavonina. Scattered colonies of Alcyonium digitatum and the hydroid Bougainvillia muscus may occasionally be recorded. A diverse range of ascidians including Ciona intestinalis, Ascidia mentula, Corella parallelogramma, Ascidia virginea, Polycarpa pomaria and Dendrodoa grossularia are also occasionally recorded. Echinoderms such as the common brittlestar Ophiothrix fragilis are frequently reported with their arms protruding from crevices in the rock, whilst the starfish Asterias rubens, Henricia oculata, and the sea urchin Echinus esculentus and Psammechinus miliaris are occasionally found on the boulder/rock surface. The whelk Buccinum undatum is often present but in very low numbers. The squat lobster Munida rugosa may be seen hiding in crevices. The hermit crab Pagurus bernhardus may also be recorded.
Situation
No situation data available.
Temporal variation
Not known.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Novocrania anomala | 10 | Frequent | 61-80% |
| Spirobranchus triqueter | 10 | Frequent | 61-80% |
| Protanthea simplex | 7 | Common | 61-80% |
| Corallinaceae | 6 | Common | 41-60% |
| Ciona intestinalis | 6 | Occasional | 61-80% |
| Ascidia mentula | 5 | Occasional | 61-80% |
| Corella parallelogramma | 4 | Occasional | 61-80% |
| Pododesmus patelliformis | 4 | Occasional | 41-60% |
| Sabella pavonina | 4 | Occasional | 61-80% |
| Ascidia virginea | 3 | Occasional | 41-60% |
| Asterias rubens | 3 | Occasional | 41-60% |
| Ophiothrix fragilis | 3 | Occasional | 41-60% |
| Psammechinus miliaris | 3 | Occasional | 41-60% |
| Bougainvillia muscus | 2 | Occasional | 21-40% |
| Buccinum undatum | 2 | Rare | 41-60% |
| Dendrodoa grossularia | 2 | Common | 21-40% |
| Munida rugosa | 2 | Occasional | 41-60% |
| Pagurus bernhardus | 2 | Occasional | 41-60% |
| Polycarpa pomaria | 2 | Occasional | 41-60% |
| Echinus esculentus | 2 | Rare | 41-60% |
| Alcyonium digitatum | 1 | Occasional | 21-40% |
| Henricia | 1 | Rare | 21-40% |
| Terebratulina retusa | 1 | Occasional | 21-40% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 2015 (15.03) | CR.LCR.BrAs.NeoPro |
