Description of biotope or habitat type
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Fucus serratus with sponges, ascidians and red seaweeds on tide-swept lower eulittoral mixed substrata
Physical habitat description
| Salinity | Full (30-35 ppt) |
|---|---|
| Wave exposure | Sheltered, Very sheltered |
| Tidal streams | Moderately strong (1-3 kn) |
| Substratum | Boulders, cobbles and pebbles on muddy sediments |
| Zone | Eulittoral - lower |
| Depth Band | Lower shore |
| Other Features |
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
Sheltered lower shore boulders, cobbles and pebbles on muddy sediments that are subject to enhanced tidal water movement and characterised by a species rich community. Dominant species include the sponges Halichondria panicea and Hymeniacidon perlevis, the sea squirts Ascidiella aspera, Ascidiella scabra, Styela clava and Botryllus schlosseri. A number of filamentous red seaweeds including Halurus flosculosus, Ceramium spp., Gracilaria gracilis, Vertebrata fucoides and foliose seaweeds Mastocarpus stellatus and Chondrus crispus are usually present. The brown seaweed Dictyota dichotoma and the wrack Fucus serratus with colonies of the hydroid Dynamena pumila, and Ectocarpus sp. may be found on more stable substrata. Boulders and large cobbles provide substrata for the top shell Steromphala cineraria, the whelk Nucella lapillus and barnacles such as Semibalanus balanoides, Balanus crenatus, or in areas with variable salinity Austrominius modestus, and the tube-forming polychaete Spirobranchus triqueter. Patches of sand or mud are often characterised by the polychaete Lanice conchilega and the polychaete Sabella pavonina. Aggregations of the mussel Mytilus edulis and, in southern and eastern England the limpet Crepidula fornicata, may be found attached to cobbles and pebbles. Sites in Scottish sea lochs may support maerl Lithothamnion spp. and bivalves Venerupis corrugata (see also VsenMtru).
Situation
This biotope is found above a community dominated by kelp such as Laminaria digitata (Ldig) or seagrass beds dominated by Zostera subg. Zostera marina (Zmar) depending on the substrata found below. It is found below biotopes dominated by wrack Fucus vesiculosus (Fves) or M. edulis beds (MytFab; Myt.Myt).
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 |
|---|---|---|---|
| Chondrus crispus | 6 | Frequent | 41-60% |
| Steromphala cineraria | 6 | Frequent | 61-80% |
| Littorina littorea | 5 | Occasional | 61-80% |
| Spirobranchus triqueter | 5 | Occasional | 41-60% |
| Ulva intestinalis | 4 | Occasional | 61-80% |
| Fucus serratus | 4 | Frequent | 61-80% |
| Halichondria panicea | 4 | Occasional | 41-60% |
| Mytilus edulis | 4 | Occasional | 41-60% |
| Ulva lactuca | 4 | Frequent | 61-80% |
| Semibalanus balanoides | 3 | Occasional | 41-60% |
| Corallinaceae | 3 | Occasional | 61-80% |
| Carcinus maenas | 3 | Occasional | 41-60% |
| Ceramium | 3 | Occasional | 41-60% |
| Austrominius modestus | 3 | Occasional | 41-60% |
| Gracilaria gracilis | 3 | Occasional | 41-60% |
| Lanice conchilega | 3 | Occasional | 41-60% |
| Mastocarpus stellatus | 3 | Occasional | 41-60% |
| Hymeniacidon perlevis | 2 | Occasional | 41-60% |
| Nucella lapillus | 2 | Occasional | 41-60% |
| Ascidiella scabra | 1 | Occasional | 21-40% |
| Balanus crenatus | 1 | Occasional | 21-40% |
| Botryllus schlosseri | 1 | Rare | 21-40% |
| Crepidula fornicata | 1 | Occasional | 21-40% |
| Lithothamnion | 1 | Occasional | 1-20% |
| Vertebrata fucoides | 1 | Rare | 41-60% |
| Sabella pavonina | 1 | Occasional | 21-40% |
| Styela clava | 1 | Rare | 21-40% |
Similar biotopes or habitat types
LR.HLR.FT.FserT
Occurs on bedrock and large boulders in areas with moderately strong tidal streams. It has a lower species richness and it lacks species associated with the mixed substrata such as L. conchilega, while filterfeeders such as spirorbid polychaetes are usually present.
LR.LLR.F.Fserr.X
Occurs on similar substrata, but is not tide-swept. It lacks the filter-feeding community associated with tide-swept conditions. Species not found include sponges such as H. perleve and bryozoans such as Electra pilosa.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 1997 (97.06) | SLR.FserX.T |
| 1995 | LMXD.SAR |