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Marine Habitat Classification

Description of biotope or habitat type

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   Fucus spiralis on sheltered upper eulittoral rock

Physical habitat description

Salinity Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure Moderately exposed, Sheltered, Very sheltered, Extremely sheltered
Tidal streams
Substratum Bedrock; stable boulders; cobbles
Zone Eulittoral - upper
Depth Band
Other Features

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.

Distribution of habitat LR.LLR.F.Fspi <I>Fucus spiralis</I> on sheltered upper eulittoral rock

  • 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 Ulva 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).

Temporal variation


Characterising species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Fucus spiralis 50 Common 81-100%
Littorina saxatilis 9 Occasional 61-80%
Ulva intestinalis 8 Frequent 41-60%
Semibalanus balanoides 6 Occasional 61-80%
Patella vulgata 4 Frequent 41-60%
Verrucaria maura 3 Frequent 21-40%
Littorina littorea 3 Occasional 41-60%
Pelvetia canaliculata 1 Occasional 21-40%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
1995 LRK.FSP


LR.LLR.F.Fspi Fucus spiralis on sheltered upper eulittoral rock, W. Side of Rerwick Head, Shapinsay Sound. Roger Covey© JNCC
LR.LLR.F.Fspi Fucus spiralis on sheltered upper eulittoral rock, W. Side of Rerwick Head, Shapinsay Sound. Roger Covey© JNCC

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