Description of biotope or habitat type
Fucus spiralis on sheltered upper eulittoral rock
Habitat (physical) description
|Salinity||Full (30-35 ppt), Variable (18-35 ppt)|
|Wave exposure||Moderately exposed, 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 upper eulittoral bedrock is typically characterised by a band of the spiral wrack Fucus spiralis overlying the black lichen Verrucaria maura. Underneath the fronds of F. spiralis and the occasional Pelvetia canaliculata is a community consisting of the limpet Patella vulgata, the winkles Littorina saxatilis and Littorina littorea and the barnacle Semibalanus balanoides. The rock surface can often be covered by the red crust Hildenbrandia rubra. During the summer months the ephemeral green seaweed Enteromorpha intestinalis can be common. Two variants have been described: Upper eulittoral bedrock characterised by F. spiralis, the black lichen Verrucaria maura and the olive green lichen Verrucaria mucosa (Fspi.FS). Upper eulittoral mixed substrata characterised by F. spiralis with occasional clumps of the wrack Pelvetia canaliculata (Fspi.X). Note that a F. spiralis biotope in variable salinity conditions (FspiVS) has also been descibed.
This zone usually lies below a zone dominated by the wrack Pelvetia canaliculata (PelB: Pel), but occasional clumps of P. canaliculata may be present (usually less than common) amongst the F. spiralis. In areas of extreme shelter, such as in Scottish sea lochs, the P. canaliculata and F. spiralis zones often merge together forming a very narrow band. Fspi occurs above the wracks Ascophyllum nodosum (Asc) and/or Fucus vesiculosus (Fves) zones and these two fucoids may also occur, although F. spiralis always dominates. Vertical surfaces in this zone, especially on moderately exposed shores, often lack the fucoids and are characterised by a barnacle-limpet dominated community (Sem).
|Taxon||Relative importance of taxon for defining this community (%)||Typical abundance - SACFOR scale||% of core records where taxon was recorded|
|Semibalanus balanoides||6||Occasional||61-80 %|
|Patella vulgata||4||Frequent||41-60 %|
|Littorina littorea||3||Occasional||41-60 %|
|Littorina saxatilis||9||Occasional||61-80 %|
|Fucus spiralis||50||Common||81-100 %|
|Pelvetia canaliculata||1||Occasional||21-40 %|
|Enteromorpha intestinalis||8||Frequent||41-60 %|
|Verrucaria maura||3||Frequent||21-40 %|
Not applicable or unknown.