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Marine Habitat Classification


Description of biotope or habitat type

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   Chthamalus spp. and Lichina pygmaea on steep exposed upper eulittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Very exposed, Exposed, Moderately exposed
Tidal streams
Substratum Bedrock
Zone Eulittoral - upper, Littoral fringe - lower
Depth Band
Other Features Steep sunny rock

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.HLR.MusB.Cht.Lpyg <I>Chthamalus</I> spp. and <I>Lichina pygmaea</I> on steep exposed 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.

Description

Areas of steep and vertical rock in the upper eulittoral on very exposed to moderately exposed shores characterised by tufts of the dark brownish lichen Lichina pygmaea and the barnacles Chthamalus montagui and Chthamalus stellatus, although long-established patches of L. pygmaea ultimately exclude barnacles. The rigid branching thallus of L. pygmaea provides an ideal habitat for the bivalve Lasaea adasoni, the winkles Littorina saxatilis and Melarhaphe neritoides. The anemone Actinia equina and the mussel Mytilus edulis are confined to moist cracks and crevices, while the limpet Patella vulgata is found on the open bedrock. In the south-west the top shell Gibbula umbilicalis can be found on L. pygmaea. On the north-east coast this biotope does not have Chthamalus spp., L. pygmaea being the most important characterising species on these sites.

Situation

The band of L. pygmaea lies between the Verrucaria maura zone (Ver.B or Ver.Ver) above and the barnacle-P. vulgata zone (Sem) below. Other upper shore biotopes (Ver.B or Ver.Ver) may contain occasional patches of L. pygmaea, particularly on steep sunny faces, though not forming a distinct zone. L. pygmaea also occurs on less steeply-sloping shores if they are in a sunny aspect. In some areas, a high abundance of L. pygmaea results in a distinct zone, particularly in the south. On Chthamalus spp. dominated shores (south and west coasts) the band of L. pygmaea lies within the barnacle zone, whereas on Semibalanus balanoides dominated shores (north and east coasts) Cht.Lpyg lies astride the upper limit of the barnacles (Sem).

Temporal variation

Unknown.

Characterising Species

Taxon Relative importance of taxon for defining this community (%) Typical abundance - SACFOR scale % of core records where taxon was recorded
Actinia equina 2 Frequent 21-40 %
Chthamalus montagui 22 Common 81-100 %
Chthamalus stellatus 9 Frequent 81-100 %
Patella vulgata 15 Abundant 61-80 %
Littorina 6 Frequent 61-80 %
Littorina saxatilis 17 Common 81-100 %
Melarhaphe neritoides 6 Common 61-80 %
Mytilus edulis 3 Occasional 41-60 %
Lasaea adansoni 1 Occasional 21-40 %
Lichina pygmaea 12 Frequent 81-100 %

Similar biotopes

LR.FLR.Lic.Ver.Ver
Occurs above Cht.Lpyg. V. maura is the dominant lichen. C. montagui occurs at a lower density.

LR.HLR.MusB.Cht.Cht
Occurs in similar physical conditions. Similar species composition though red and green seaweeds such as coralline algae and Enteromorpha spp. can be present in small numbers. L. pygmaea do not form a distinct band, but may be present in small patches.

Biotope history

Classification Habitat code
97.06 ELR.BPat.Lic
96.7 ELR.BPat.Lpyg
6.95 LRK.LPYG

Photos

LR.HLR.MUSB.Cht.Lpyg Chthamalus spp. and Lichina pygmaea on steep exposed upper eulittoral rock, Beadnell Point, Seahouses. Judy Foster-Smith © JNCC
LR.HLR.MUSB.Cht.Lpyg Chthamalus spp. and Lichina pygmaea on steep exposed upper eulittoral rock, Beadnell Point, Seahouses. Judy Foster-Smith © JNCC
LR.HLR.MUSB.Cht.Lpyg Chthamalus spp. and Lichina pygmaea on steep exposed upper eulittoral rock, Unspecified location. ANON © JNCC
LR.HLR.MUSB.Cht.Lpyg Chthamalus spp. and Lichina pygmaea on steep exposed upper eulittoral rock, Unspecified location. ANON © JNCC
LR.HLR.MUSB.Cht.Lpyg Chthamalus spp. and Lichina pygmaea on steep exposed upper eulittoral rock, Old Man of Hoy Shore, NW Hoy. Keith Hiscock © JNCC
LR.HLR.MUSB.Cht.Lpyg Chthamalus spp. and Lichina pygmaea on steep exposed upper eulittoral rock, Old Man of Hoy Shore, NW Hoy. Keith Hiscock © JNCC

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