Description of biotope or habitat type
Fucus vesiculosus on moderately exposed to sheltered mid eulittoral rock
Habitat (physical) description
|Salinity||Full (30-35 ppt), Variable (18-35 ppt)|
|Wave exposure||Moderately exposed, Sheltered, Very sheltered|
|Zone||Eulittoral - mid|
|Depth Band||Mid shore|
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.
Moderately exposed to very sheltered mid eulittoral bedrock and large boulders characterised by a dense canopy of the wrack Fucus vesiculosus (Abundant to Superabundant). Beneath the seaweed canopy the rock surface has a sparse covering of the barnacle Semibalanus balanoides and the limpet Patella vulgata. The mussel Mytilus edulis is confined to pits and crevices. A variety of winkles including Littorina littorea and Littorina saxatilis can be found grazing on the fucoid fronds. The whelk Nucella lapillus is found beneath the seaweed canopy. In areas of localised shelter the wrack Ascophyllum nodosum may occur, though never at high abundance. The crab Carcinus maenas may be present in pools or among the boulders. Two variants have been described: Bedrock and large boulders (Fves.FS) and mixed substrata (Fves.X). Please notice that a F. vesioculosus biotope subject to variable salinity (FvesVS) has been identified.
This biotope usually occurs between the wrack Fucus spiralis (Fspi) and the Fucus serratus (Fserr) zones; both of these fucoids may be present in this biotope, though never at high abundance (typically less than Frequent). In some sheltered areas F. vesiculosus forms a narrow zone above the A. nodosum zone (Asc). Where freshwater runoff occurs on more gradually sloping shores F. vesiculosus may be replaced by the wrack Fucus ceranoides (Fcer).
On some shores, particularly those which are moderately exposed to wave action, temporal fluctuations in the abundance of limpets, barnacles and fucoid seaweeds may occur. As a result, over a number of years, a single shore may cycle between the barnacle-P. vulgata dominated biotope (Sem.FvesR), through this mosaic (FvesB) to a F. vesiculosus-dominated biotope (Fves).
|Taxon||Relative importance of taxon for defining this community (%)||Typical abundance - SACFOR scale||% of core records where taxon was recorded|
|Semibalanus balanoides||10||Frequent||61-80 %|
|Carcinus maenas||3||Occasional||41-60 %|
|Patella vulgata||6||Frequent||41-60 %|
|Littorina littorea||3||Frequent||61-80 %|
|Littorina saxatilis||11||Occasional||21-40 %|
|Nucella lapillus||4||Occasional||41-60 %|
|Mytilus edulis||2||Occasional||21-40 %|
|Ascophyllum nodosum||2||Occasional||21-40 %|
|Fucus vesiculosus||41||Abundant||81-100 %|
|Enteromorpha intestinalis||5||Frequent||41-60 %|