Description of biotope or habitat type
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Novocrania anomala and Protanthea simplex on very wave-sheltered circalittoral rock
Physical habitat description
| Salinity | Full (30-35 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, often near vertical 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 variant typically occurs on deep, lower circalittoral bedrock or boulder slopes (often-vertical walls) in the landward, very sheltered basins of fjordic sealochs. In these very sheltered conditions, there are frequently dense populations of the anemone Protanthea simplex growing on the silty boulder or rock slope, and on the tubes of the parchment worm Chaetopterus variopedatus. The underlying rock surfaces are usually covered with encrusting red algae, the polychaete Spirobranchus triqueter, the brachiopod Novocrania anomala, the saddle oyster Pododesmus patelliformis and the conspicuous fan worm Sabella pavonina. Scattered colonies of Alcyonium digitatum are occasionally present along with the hydroid Bougainvillia muscus. The barnacle Balanus balanus and the hermit crab Pagurus bernhardus is occasionally seen on boulder or rock surface, whilst underneath in crevices, the squat lobster Munida rugosa may be present. A diverse range of solitary ascidians, typically found in sheltered conditions, are often present including Ciona intestinalis, Corella parallelogramma, Polycarpa pomaria, Ascidia mentula and Ascidia virginea. Echinoderms such as brittlestars Ophiothrix fragilis are frequently seen with their arms protruding from crevices in the rock, whilst the starfish Asterias rubens, the sea urchin Echinus esculentus and Psammechinus miliaris are occasionally found on the boulder or rock surface. The whelk Buccinum undatum is often present but in very low numbers.
Situation
Where this biotope occurs on vertical rock cliffs, you tend to find silted sugar kelp Saccharina latissima communities above NeoPro, in the infralittoral zone (Lsac). Where NeoPro occurs on a rock or boulder slope and due to the very sheltered nature of the habitat, it is common to find a mud plain community where slope ends (CMU). Species such as the seapen Funiculina quadrangularis, the anemone Cerianthus lloydii and the Norway lobster Nephrops norvegicus are typically abundant.
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 |
|---|---|---|---|
| Spirobranchus triqueter | 12 | Frequent | 81-100% |
| Novocrania anomala | 9 | Frequent | 61-80% |
| Protanthea simplex | 9 | Common | 61-80% |
| Corallinaceae | 7 | Common | 61-80% |
| Ascidia mentula | 6 | Occasional | 61-80% |
| Pododesmus patelliformis | 6 | Occasional | 61-80% |
| Ciona intestinalis | 5 | Occasional | 61-80% |
| Asterias rubens | 4 | Occasional | 61-80% |
| Ophiothrix fragilis | 4 | Frequent | 61-80% |
| Psammechinus miliaris | 4 | Occasional | 61-80% |
| Sabella pavonina | 4 | Occasional | 61-80% |
| Echinus esculentus | 3 | Rare | 61-80% |
| Ascidia virginea | 2 | Rare | 41-60% |
| Corella parallelogramma | 2 | Occasional | 41-60% |
| Munida rugosa | 2 | Occasional | 41-60% |
| Polycarpa pomaria | 2 | Occasional | 41-60% |
| Alcyonium digitatum | 1 | Occasional | 41-60% |
| Balanus balanus | 1 | Occasional | 21-40% |
| Bougainvillia muscus | 1 | Occasional | 21-40% |
| Buccinum undatum | 1 | Rare | 41-60% |
| Pagurus bernhardus | 1 | Occasional | 41-60% |
Similar biotopes or habitat types
CR.LCR.BrAs.AntAsH
This biotope is found under slightly more exposed conditons and tends to have a more diverse range of cnidarians and echinoderms than CR.LCR.BrAs.NovPro.FS. In CR.LCR.BrAs.AntAsH, Antedon spp. are occasionally recorded, but they are absent in CR.LCR.BrAs.NovPro.FS.
CR.LCR.BrAs.NovPro.VS
This sub-biotope is found under similar physical conditions as CR.LCR.BrAs.NovPro.FS, but is only found in stable, reduced salinity environments. The ascidian Dendrodoa grossularia is commonly recorded in this sub-biotope, but is absent in CR.LCR.BrAs.NovPro.FS. However, the anemone Protanthea simplex is recorded in higher abundances in CR.LCR.BrAs.NovPro.FS.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 2015 (15.03) | CR.LCR.BrAs.NeoPro.FS |
