Description of biotope or habitat type
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Crustose sponges on extremely wave-surged infralittoral cave or gully walls
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Very exposed, Exposed |
| Tidal streams | Weak (>1 kn), Very weak (negligible) |
| Substratum | Bedrock; massive boulders |
| Zone | Infralittoral - upper, Sublittoral fringe |
| Depth Band | 0-5 m, 5-10 m, 10-20 m |
| Other Features | Extreme wave surge and scour on |
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
Walls, or massive boulders, in caves or gullies that are subject to severe wave-surge and characterised by extensive thin crusts of the sponge Halichondria panicea with smaller patches of other sponges such as Amphilectus fucorum or Clathrina coriacea. Small turfs of robust hydroids, such as Diphasia rosacea and Ventromma halecioides, and patches of the barnacle Balanus crenatus, coralline crusts and tube-building spirorbid polychaetes may be present. The starfish Henricia spp., the brittlestar Ophiopholis aculeata and the crabs Cancer pagurus and Necora puber can be present. The anemones Cylista elegans, Urticina felina and Actinia equina can be found in cracks and crevices or under boulders. The mussel Mytilus edulis may be present in low densities.
Situation
This surge-tolerant biotope of low-growing fauna is typically confined to the mid or rear section of caves (or the narrowest part of gullies) where the wave-surge is intensified. It generally abuts the less surged ascidian-sponge communities (CrSpAsAn, DenCcor and CrSpAsDenB). A highly scoured zone of barnacles and calcareous tubeworms often form a zone below, abutting the cave/gully floor (CC.BalPom).
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 |
|---|---|---|---|
| Halichondria panicea | 20 | Abundant | 41-60% |
| Corallinaceae | 13 | Frequent | 41-60% |
| Spirorbinae | 8 | Common | 21-40% |
| Henricia | 7 | Occasional | 21-40% |
| Clathrina coriacea | 6 | Frequent | 41-60% |
| Pachymatisma johnstonia | 5 | Occasional | 41-60% |
| Balanus crenatus | 4 | Frequent | 21-40% |
| Leuconia nivea | 4 | Common | 21-40% |
| Porifera indet crusts | 4 | Occasional | 21-40% |
| Cancer pagurus | 3 | Occasional | 21-40% |
| Dendrodoa grossularia | 3 | Occasional | 21-40% |
| Necora puber | 3 | Occasional | 21-40% |
| Ophiopholis aculeata | 3 | Frequent | 21-40% |
| Urticina felina | 3 | Occasional | 21-40% |
| Actinia equina | 2 | Occasional | 21-40% |
| Cylista elegans | 2 | Frequent | 21-40% |
Similar biotopes or habitat types
IR.FIR.SG.CrSpAsAn
IR.FIR.SG.CrSpAsDenB
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | EIR.SC |