Description of biotope or habitat type
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Mastocarpus stellatus and Chondrus crispus on very exposed to moderately exposed lower eulittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Exposed, Moderately exposed |
| Tidal streams | |
| Substratum | Bedrock; boulders |
| Zone | Eulittoral - lower |
| Depth Band | |
| Other Features | Vertical faces on very exposed rock |
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
Exposed to moderately exposed lower eulittoral vertical to almost horizontal bedrock characterised by a dense turf of Mastocarpus stellatus and Chondrus crispus (either together or separately). Beneath these foliose seaweeds the rock surface is covered by encrusting coralline algae and the barnacle Semibalanus balanoides, the limpet Patella vulgata and spirorbid polychaetes. Other seaweeds including the red Lomentaria articulata and Osmundea pinnatifida, Palmaria palmata, Corallina officinalis and coralline crusts. The wrack Fucus serratus and the green seaweeds Ulva intestinalis and Ulva lactuca may also be present though usually at a low abundance. Although both M. stellatus and C. crispus are widespread in the lower eulittoral and the sublittoral fringe, they occur only infrequently in a distinct band, or in large enough patches, to justify separation from Fser.R. Consequently, where only small patches of these species occur within a larger area of mixed red algal turf, then records should be assigned to more general mixed red algal turf biotope (Coff; Him). M. stellatus can be present in high abundance in a number of biotopes (Coff: Him; Fser.R etc.) found on the shore. At least one other species normally co-dominates and records should be assigned to the appropriate biotope. Caution should be taken regarding the characterising species list due to the low number of records. More information needed to validate this description.
Situation
This biotope can form a band above the main kelp zone, above Alaria esculenta (Ala) or the mussel Mytilus edulis (MytB) or within a F. serratus-red algal mosaic (Fser.R).
Temporal variation
M. stellatus is more resistant to wave action than C. crispus and may therefore dominate more exposed shores; it can dominate vertical rock at very exposed sites (e.g. Mingulay, Outer Hebrides). On more sheltered shores, especially in the south-west, M. stellatus may give way to C. crispus which has a faster growth rate.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Mastocarpus stellatus | 21 | Abundant | 81-100% |
| Patella vulgata | 13 | Common | 81-100% |
| Ulva lactuca | 10 | Occasional | 81-100% |
| Semibalanus balanoides | 9 | Frequent | 81-100% |
| Corallina officinalis | 8 | Occasional | 81-100% |
| Osmundea pinnatifida | 7 | Occasional | 81-100% |
| Corallinaceae | 4 | Occasional | 61-80% |
| Ulva intestinalis | 4 | Occasional | 41-60% |
| Lomentaria articulata | 4 | Occasional | 61-80% |
| Palmaria palmata | 3 | Occasional | 61-80% |
| Fucus serratus | 2 | Rare | 61-80% |
| Spirorbinae | 2 | Frequent | 41-60% |
| Chondrus crispus | 1 | Occasional | 41-60% |
Similar biotopes or habitat types
Not applicable or unknown.
Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1996 (6.95) | MLR.R.Mas |
| 1995 | LRK.RED.MAS |
Photos
