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Marine Habitat Classification

Description of biotope or habitat type

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   Sparse Laminaria hyperborea and dense Paracentrotus lividus on exposed infralittoral limestone

Physical habitat description

Salinity Full (30-35 ppt)
Wave exposure Very exposed
Tidal streams Very weak (negligible)
Substratum Bedrock
Zone Infralittoral - upper
Depth Band 0-5 m, 5-10 m
Other Features Limestone platforms

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 IR.HIR.KFaR.LhypPar Sparse <I>Laminaria hyperborea</I> and dense <I>Paracentrotus lividus</I> on exposed infralittoral limestone

  • 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'
  • Predicted extent of the level 3 (for sublittoral rock & deep sea) or 4 (for sublittoral sediment) habitat

Point data based on records in the UK Marine Recorder Snapshot. Predicted habitat extent is from UKSeaMap.


This biotope is known from only one location, the Aran Islands, Co. Galway. Here, a limestone platform between 3 m and 6 m of depth is dominated by a dense population of the urchin Paracentrotus lividus, which heavily graze and burrow into the soft limestone. So intense is the grazing pressure that the rock appears completely bare, except for a coralline algal crust and occasional Laminaria hyperborea and Saccorhiza polyschides. The anthozoans Cylista elegans and Corynactis viridis are also present, though at low abundance. The grazed kelp also extends deeper to 20 to 25 m further offshore. (Only one CB record within this biotope).


This rare biotope has only been recorded from one location and the neighbouring biotopes were not fully surveyed. In deeper water (30-40m) there is PhaAxi.

Temporal variation


Characterising species

Taxon Typical abundance - SACFOR scale % of core records where taxon was recorded
Anemonia viridis Frequent 81-100%
Cliona celata Occasional 81-100%
Corynactis viridis Occasional 81-100%
Cylista elegans Frequent 81-100%
Laminaria hyperborea Occasional 81-100%
Paracentrotus lividus Super abundant 81-100%
Saccorhiza polyschides Occasional 81-100%
Urticina felina Rare 81-100%

Similar biotopes or habitat types

Not applicable or unknown.

Classification history of this biotope or habitat type

Classification version Code
1996 (6.95) EIR.LhypFa.Par

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