Description of biotope or habitat type
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Green seaweeds (Ulva spp. and Cladophora spp.) in shallow upper shore rockpools
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Very exposed, Exposed, Moderately exposed, Sheltered |
| Tidal streams | |
| Substratum | Bedrock |
| Zone | Eulittoral - upper, Littoral fringe |
| Depth Band | Upper shore |
| Other Features | Rockpool |
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
Rockpools in the littoral fringe or upper eulittoral zone subject to widely fluctuating temperatures and salinity are characterised by ephemeral green alga of the genus Ulva, along with Cladophora spp. and Ulva lactuca. Due to the physical stress imposed on these upper shore pools, grazing molluscs such as the limpet Patella vulgata and the winkles Littorina littorea and Littorina saxatilis are generally in lower abundance than eulittoral pools, allowing the green seaweeds to proliferate under reduced grazing pressures. The bright orange copepod Tigriopus fulvus is tolerant of large salinity fluctuations and may occur in large numbers in these upper shore pools, along with gammarid amphipods.
Situation
Rockpools throughout the upper eulittoral and lower littoral fringe in bedrock.
Temporal variation
Fluctuations especially in the abundance of the green seaweeds will occur due to marked changes in salinity and temperature during the year. Enteromorpha intestinalis can often be bleached during the summer.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Ulva intestinalis | 77 | Abundant | 61-80% |
| Cladophora rupestris | 5 | Frequent | 21-40% |
| Littorina littorea | 4 | Frequent | 21-40% |
| Littorina saxatilis | 3 | Occasional | 21-40% |
| Patella vulgata | 2 | Occasional | 21-40% |
Similar biotopes or habitat types
LR.FLR.Eph.Ulv
Occurs on very exposed to very sheltered shores from the supralittoral to the upper eulittoral zone. This biotope does not includes rockpools. It has a similar species composition.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 2015 (15.03) | LR.FLR.Rkp.G |
| 1996 (6.95) | LRK.CHL |
| 1996 (6.95) | RKP.G |
