Description of biotope or habitat type
Fucus spiralis on sheltered variable salinity upper eulittoral rock
Habitat (physical) description
|Salinity||Variable (18-35 ppt)|
|Wave exposure||Sheltered, Very sheltered, Extremely sheltered|
|Substratum||Bedrock; stable boulders; cobbles|
|Zone||Eulittoral - upper|
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.
Sheltered to extremely sheltered upper eulittoral bedrock or mixed substrata (boulders, large cobbles or shells on mud) in variable salinity conditions characterised by a band of the spiral wrack Fucus spiralis. The ephemeral green seaweed Enteromorpha intestinalis is usually found in this species poor biotope. The barnacles Semibalanus balanoides and Elminius modestus can be found where suitable substrata are available, while gammarids can be found underneath the fronds of F. spiralis and/or underneath the boulders and cobbles. Also found underneath the fronds and among the boulders are the winkles Littorina saxatilis and Littorina littorea and the crab Carcinus maenas.
This zone usually lies below a zone dominated by the wrack Pelvetia canaliculata (Pel) and occasional clumps of P. canaliculata may be present (usually less than common) amongst the F. spiralis. In areas of extreme shelter and variable salinity conditions (e.g. in Scottish sea lochs), the P. canaliculata and F. spiralis zones often merge together forming a very narrow band. Fspi.VS occurs above the wracks Ascophyllum nodosum (Asc.VS) and/or Fucus vesiculosus (Fves.VS) zones and these two fucoids may also occur, although F. spiralis always dominates. It can also be found above a zone dominated by the wrack Fucus ceranoides (Fcer).
During the summer months ephemeral green seaweeds such as E. intestinalis can be common.
|Taxon||Relative importance of taxon for defining this community (%)||Typical abundance - SACFOR scale||% of core records where taxon was recorded|
|Elminius modestus||3||Occasional||21-40 %|
|Semibalanus balanoides||5||Occasional||61-80 %|
|Carcinus maenas||4||Occasional||41-60 %|
|Littorina littorea||2||Occasional||41-60 %|
|Littorina saxatilis||3||Occasional||61-80 %|
|Fucus spiralis||62||Common||81-100 %|
|Enteromorpha intestinalis||10||Occasional||41-60 %|
|97.06||SLR.Fspi in part|