Description of biotope or habitat type
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Green algal films on upper and mid-shore cave walls and ceilings
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Moderately exposed, Sheltered |
| Tidal streams | |
| Substratum | Bedrock |
| Zone | Eulittoral - mid, Eulittoral - upper, Littoral fringe, Supralittoral |
| Depth Band | |
| Other Features | Moist, dark caves |
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'
Point data based on records in the UK Marine Recorder Snapshot.
Description
The upper walls and ceilings of upper and mid-shore hard and soft rock (chalk) dominated by a band of green algal films (or 'stains'). Other encrusting algae including the non-calcified Hildenbrandia rubra may be present. In chalk caves, on the east and south-east coasts of England, a distinctive assemblage of species occurs, including the brown alga Pleurocladia lacustris and the bright green algae Pseudendoclonium submarinum and Epicladia perforans that often covers the cave ceilings. Fauna is generally sparse and limited to limpets such as Patella vulgata and the winkle Littorina saxatilis. The species forming a green algal film that covers upper shore caves in Berwickshire were not identified. More information required to validate this biotope description.
Situation
This biotope is situated above the AudCla or VmucHil zone, extending to cover the upper walls and ceilings of caves. GCv can be found at the entrances to caves and through to the darkest areas at the back and is often found above a zone of AudPil. In hard rock caves however, the green and brown algae (AudPil) or Haptophyceae (ChrHap) occur as separate zones or GCv may occur on its own.
Temporal variation
Unknown.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Chlorophyta | 70 | Super abundant | 81-100% |
| Hildenbrandia rubra | 13 | Super abundant | 21-40% |
| Littorina saxatilis | 3 | Frequent | 21-40% |
| Patella vulgata | 3 | Frequent | 21-40% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1996 (6.95) | SUR.PilPse |
