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Marine Habitat Classification

Description of biotope or habitat type

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   Blidingia spp. on vertical littoral fringe soft rock

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Moderately exposed
Tidal streams
Substratum Bedrock
Zone Littoral fringe
Depth Band
Other Features Soft rock (chalk); vertical faces

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.FLR.Lic.Bli <I>Blidingia</I> spp. on vertical littoral fringe soft 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.


Vertical soft rock in the littoral fringe may be characterised by a band of the green seaweeds Blidingia minima and Blidingia marginata. Unbranched filamentous green seaweeds, including Ulothrix flacca and Urospora wormskioldii, are found amongst the Blidingia spp. The siphonous Xanthophyceae Vaucheria spp. can also occur in high abundance in this biotope, where they can form dense mats. During low tide terrestrial fauna such as red mites, insects and centipedes migrate into this zone. More information is needed to improve this description.


Bli is found below the Verrucaria maura zone (Ver.Ver) and above a band of the similar looking green algae Ulva spp. (Ent and EntPor), where these occur in habitats not influenced by freshwater.

Temporal variation


Characterising species

Taxon % of core records where taxon was recorded
Blidingia marginata
Blidingia minima
Ulva intestinalis
Urospora wormskioldii

Similar biotopes or habitat types

Occurs in similar physical conditions, but usually on freshwater influenced rock. Ulothrix flacca and Urospora spp. are the dominant species.

Occurs similar physical conditions at a wide exposure range. Also on freshwater-influenced rock, but below the LR.FLR.Lic.Bli. Ulva spp. dominate instead of Blidingia spp., but care should be taken in distinguishing and recording these as separate biotopes as the green seaweeds are superficially similar.

Classification history of this biotope or habitat type

Classification version Code

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