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Marine Habitat Classification


Description of biotope or habitat type

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   Fucus vesiculosus and barnacle mosaics on moderately exposed mid eulittoral rock


Habitat (physical) description

Salinity Full (30-35 ppt)
Wave exposure Exposed, Moderately exposed
Tidal streams
Substratum Bedrock; boulders
Zone Eulittoral - mid
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.MLR.BF.FvesB <I>Fucus vesiculosus</I> and barnacle mosaics on moderately exposed mid 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

Exposed to moderately exposed mid eulittoral bedrock and boulders are frequently characterised by a mosaic of the barnacle Semibalanus balanoides and the wrack Fucus vesiculosus. The limpet Patella vulgata and the whelk Nucella lapillus are typically present, whilst the anemone Actinia equina and small individuals of the mussel Mytilus edulis are confined to crevices. Underneath the F. vesiculosus is a community of red seaweeds, including Corallina officinalis, Mastocarpus stellatus and Osmundea pinnatifida, usually with the winkles Littorina littorea and Littorina spp. present. Opportunistic seaweeds such as Enteromorpha intestinalis may occur in patches recently cleared on the rock or growing on the M. edulis.

Situation

On exposed shores FvesB is found below the black lichen Verrucaria maura and sparse barnacles biotope (Ver.B) and/or below the Chthamalus spp. and P. vulgata biotopes (Cht.Cht). FvesB is found above the biotope dominated by the wrack Himanthalia elongata (Him) or the red seaweed biotopes (Coff; R). FvesB forms an intermediate along the wave exposure gradient between the exposed shore barnacle-P. vulgata biotopes (Sem.FvesR) and the sheltered shore F. vesiculosus biotope (Fves). Vertical surfaces tend to be dominated by the barnacle-P. vulgata biotope (Sem).

Temporal variation

On some shores, particularly those, which are moderately exposed to wave action, temporal fluctuations in the abundance of limpets, barnacles and fucoid seaweeds may occur. As a result, over a number of years, a single shore may cycle between the barnacle-P. vulgata dominated biotope (Sem.FvesR), through this mosaic (FvesB) to a F. vesiculosus-dominated biotope (Fves).

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 Occasional 41-60 %
Semibalanus balanoides 21 Abundant 81-100 %
Patella vulgata 16 Common 81-100 %
Littorina 7 Common 21-40 %
Littorina littorea 2 Frequent 41-60 %
Nucella lapillus 3 Frequent 61-80 %
Mytilus edulis 5 Occasional 61-80 %
Corallinaceae 2 Occasional 61-80 %
Corallina officinalis 2 Occasional 41-60 %
Mastocarpus stellatus 2 Occasional 41-60 %
Osmundea pinnatifida 3 Occasional 41-60 %
Fucus vesiculosus 18 Common 81-100 %
Enteromorpha intestinalis 4 Occasional 61-80 %

Similar biotopes

LR.HLR.MusB.Sem.FvesR
Occurs at a similar wave exposure, but also on steeper slopes and vertical faces. The community is similar to FvesB, but F. vesiculosus is present at lower abundance (Occasional) and wracks such as Fucus serratus and Ascophyllum nodosum are usually not present. F. vesiculosus can be non-vesiculate (i.e. bladderless).

LR.LLR.F.Fves
Occurs on more sheltered shores on bedrock and large boulders. F. vesiculosus dominates (Abundant) and there is a lower red seaweed diversity. S. balanoides, P. vulgata and N. lapillus occur less frequently and at lower abundance when present.

Biotope history

Classification Habitat code
6.95 LRK.FVES.BP
97.06 MLR.FvesB

Photos

LR.MLR.BF.FvesB Fucus vesiculosus and barnacle mosaics on moderately exposed mid eulittoral rock, Point of Nichol's Croo, Wyre Sound. Sue Scott © JNCC
LR.MLR.BF.FvesB Fucus vesiculosus and barnacle mosaics on moderately exposed mid eulittoral rock, Point of Nichol's Croo, Wyre Sound. Sue Scott © JNCC
LR.MLR.BF.FvesB Fucus vesiculosus and barnacle mosaics on moderately exposed mid eulittoral rock, N of Oigh Sgeir, Small Isles. Mark Davies © JNCC
LR.MLR.BF.FvesB Fucus vesiculosus and barnacle mosaics on moderately exposed mid eulittoral rock, N of Oigh Sgeir, Small Isles. Mark Davies © JNCC
LR.MLR.BF.FvesB Fucus vesiculosus and barnacle mosaics on moderately exposed mid eulittoral rock, Point of the Graand, Rousay Sound. Sue Scott © JNCC
LR.MLR.BF.FvesB Fucus vesiculosus and barnacle mosaics on moderately exposed mid eulittoral rock, Point of the Graand, Rousay Sound. Sue Scott © JNCC

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