Description of biotope or habitat type
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Ulva spp. on freshwater-influenced and/or unstable upper eulittoral rock
Physical habitat description
| Salinity | Full (30-35 ppt), Variable (18-35 ppt) |
|---|---|
| Wave exposure | Very exposed, Exposed, Moderately exposed, Sheltered |
| Tidal streams | |
| Substratum | Chalk, firm mud, bedrock, boulders |
| Zone | Eulittoral - upper, Littoral fringe - lower |
| Depth Band | Upper shore |
| Other Features | Physical disturbance |
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
Upper shore hard substratum that is relatively unstable (e.g. soft rock) or subject to considerable freshwater runoff is typically very species poor and characterised by a dense mat of Ulva spp., though Ulva lactuca can occur as well. It occurs in a wider zone spanning from the supralittoral down to the upper eulittoral, across a wide range of wave exposures range. This biotope is generally devoid of fauna, except for occasional limpets Patella vulgata, winkles Littorina littorea or Littorina saxatilis and barnacles Semibalanus balanoides.
Situation
This band of green seaweeds is usually found above a zone dominated by a mixture Ulva spp. and Porphyra spp. (EntPor) or a Fucus spiralis or Fucus ceranoides zone (Fspi; Fcer), and may replace the Pelvetia canaliculata zone (PelB). It can be found below a zone dominated by yellow and grey lichens. In very sheltered areas the seagrass Ruppia maritima can be found above this biotope while different wracks such as Fucus spp. can dominate the zone below (Rup; Asc; Fspi).
Temporal variation
Seasonal fluctuations in the abundance of the Enteromorpha spp. and the occurrence of the other green seaweeds species will occur.
Characterising species
| Taxon | Relative importance of taxon for defining this community (%) | Typical abundance - SACFOR scale | % of core records where taxon was recorded |
|---|---|---|---|
| Ulva | 74 | Common | 61-80% |
| Semibalanus balanoides | 4 | Rare | 21-40% |
| Patella vulgata | 3 | Occasional | 21-40% |
| Ulva intestinalis | 2 | 21-40% | |
| Ulva prolifera | 2 | 21-40% | |
| Littorina saxatilis | 2 | Occasional | 21-40% |
| Ulva lactuca | 1 | 1-20% |
Similar biotopes or habitat types
LR.FLR.Eph.UlvPor
Occurs in the lower to mid-eulitttoral zone in sand influenced habitats. It has a higher species richness, which include the red seaweed Porphyra purpurea and the occasional wracks such as F. spiralis or Fucus vesiculosus. The winkle L. littorea is usually present.
LR.FLR.Eph.EphX
Occurs in more estuarine conditions and on mixed substrata. The green seaweed Ulva lactuca may be present. A very similar biotope.Classification history of this biotope or habitat type
| Classification version | Code |
|---|---|
| 2015 (15.03) | LR.FLR.Eph.Ent |
| 1996 (6.95) | MLR.Eph.Ent |
| 1995 | LRK.ENT |
