Description of biotope or habitat type
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Sparse Laminaria hyperborea and dense Paracentrotus lividus on exposed infralittoral limestone
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Very exposed |
| Tidal streams | Very weak (negligible) |
| Substratum | Bedrock |
| Zone | Infralittoral - upper |
| Depth Band | 0-5 m, 5-10 m |
| Other Features | Limestone platforms |
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 known from only one location, the Aran Islands, Co. Galway. Here, a limestone platform between 3 m and 6 m of depth is dominated by a dense population of the urchin Paracentrotus lividus, which heavily graze and burrow into the soft limestone. So intense is the grazing pressure that the rock appears completely bare, except for a coralline algal crust and occasional Laminaria hyperborea and Saccorhiza polyschides. The anthozoans Cylista elegans and Corynactis viridis are also present, though at low abundance. The grazed kelp also extends deeper to 20 to 25 m further offshore. (Only one CB record within this biotope).
Situation
This rare biotope has only been recorded from one location and the neighbouring biotopes were not fully surveyed. In deeper water (30-40m) there is PhaAxi.
Temporal variation
Unknown.
Characterising species
| Taxon | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|
| Anemonia viridis | Frequent | 81-100% |
| Cliona celata | Occasional | 81-100% |
| Corynactis viridis | Occasional | 81-100% |
| Cylista elegans | Frequent | 81-100% |
| Laminaria hyperborea | Occasional | 81-100% |
| Paracentrotus lividus | Super abundant | 81-100% |
| Saccorhiza polyschides | Occasional | 81-100% |
| Urticina felina | Rare | 81-100% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1996 (6.95) | EIR.LhypFa.Par |