Description of biotope or habitat type
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Hiatella arctica and seaweeds on vertical limestone / chalk.
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Very exposed, Exposed, Moderately exposed |
| Tidal streams | Moderately strong (1-3 kn), Weak (>1 kn), Very weak (negligible) |
| Substratum | Bedrock |
| Zone | Infralittoral |
| Depth Band | 0-5 m, 5-10 m, 10-20 m |
| Other Features | Vertical limestone. |
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 is found in the infralittoral zone on moderately exposed vertical limestone/chalk surfaces in weak tidal streams, and has been recorded most frequently between 0-10m. This biotope is characterised by abundant Hiatella arctica and a rich sponge community including Cliona celata, Dysidea fragilis and Pachymatisma johnstonia. Other species that may be frequent in this biotope are the crab Necora puber, the sea squirt Clavelina lepadiformis, and the top shell Calliostoma zizyphinum, although these species are found in other vertical rock biotopes, however in lesser abundance.
Situation
Shallow rocky coasts with vertical limestone faces.
Temporal variation
No temporal data available
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Alcyonium digitatum | 4 | Abundant | 81-100% |
| Clavelina lepadiformis | 4 | Frequent | 81-100% |
| Cliona celata | 4 | Common | 81-100% |
| Dysidea fragilis | 4 | Frequent | 81-100% |
| Calliostoma zizyphinum | 3 | Frequent | 81-100% |
| Cancer pagurus | 3 | Occasional | 81-100% |
| Hiatella arctica | 3 | Abundant | 61-80% |
| Necora puber | 3 | Frequent | 81-100% |
| Hydrozoa | 2 | Common | 41-60% |
| Polychaeta | 2 | Common | 61-80% |
| Aslia lefevrei | 2 | Frequent | 61-80% |
| Botryllus schlosseri | 2 | Frequent | 61-80% |
| Bryozoa indet crusts | 2 | Common | 61-80% |
| Bugula | 2 | Frequent | 61-80% |
| Caryophyllia smithii | 2 | Frequent | 61-80% |
| Cryptopleura ramosa | 2 | Common | 61-80% |
| Morchellium argus | 2 | Frequent | 61-80% |
| Pachymatisma johnstonia | 2 | Frequent | 61-80% |
| Phyllophora crispa | 2 | Abundant | 41-60% |
| Urticina felina | 2 | Frequent | 61-80% |
| Maja squinado | 2 | Occasional | 81-100% |
| Corallinaceae | 1 | Occasional | 61-80% |
| Membranipora membranacea | 1 | Frequent | 41-60% |
| Aplidium punctum | 1 | Occasional | 61-80% |
| Asterias rubens | 1 | Occasional | 61-80% |
| Balanus crenatus | 1 | Common | 41-60% |
| Vertebrata byssoides | 1 | Common | 41-60% |
| Corynactis viridis | 1 | Occasional | 61-80% |
| Dercitus bucklandi | 1 | Frequent | 61-80% |
| Didemnidae | 1 | Frequent | 61-80% |
| Amphilectus fucorum | 1 | Frequent | 41-60% |
| Halichondria panicea | 1 | Frequent | 41-60% |
| Laminaria hyperborea | 1 | Common | 41-60% |
| Mytilus edulis | 1 | Occasional | 41-60% |
| Polycarpa scuba | 1 | Abundant | 41-60% |
| Spirobranchus triqueter | 1 | Common | 41-60% |
| Cylista elegans | 1 | Frequent | 41-60% |
| Tethya aurantium | 1 | Frequent | 61-80% |
Similar biotopes or habitat types
CR.MCR.SfR.Hia
Similar vertical limestone/chalk habitat, but lacks seaweed component.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | IMX.VsenMtru |
| 1996 (6.95) | IMX.VenMya |
| 1995 | LMGR.VEN |