LR.LLR.F.Fves - Fucus vesiculosus on moderately exposed to sheltered mid eulittoral rock

LR.LLR.F.Fves
Fucus vesiculosus on moderately exposed to sheltered mid eulittoral rock

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Habitat (physical) description

Distribution

Salinity:	Full (30-35 ppt), Variable (18-35 ppt)
Wave exposure:	Moderately exposed, Sheltered, Very sheltered
Tidal streams:
Substratum:	Bedrock; boulders
Zone:	Eulittoral - mid
Depth Band:	Mid shore
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.

Previous code

This biotope occurred in previous versions of the classification as:
LRK.FVES.LIT - Version: 6.95

Distribution of habitat LR.LLR.F.Fves Fucus vesiculosus on moderately exposed to sheltered mid eulittoral rock, based on records on the JNCC marine database. Red dots represent records on which the biotope is based. Blue dots show orther certain records, black dots show records tentatively assigned to this biotope.

Biotope description

Moderately exposed to very sheltered mid eulittoral bedrock and large boulders characterised by a dense canopy of the wrack Fucus vesiculosus (Abundant to Superabundant). Beneath the seaweed canopy the rock surface has a sparse covering of the barnacle Semibalanus balanoides and the limpet Patella vulgata. The mussel Mytilus edulis is confined to pits and crevices. A variety of winkles including Littorina littorea and Littorina saxatilis can be found grazing on the fucoid fronds. The whelk Nucella lapillus is found beneath the seaweed canopy. In areas of localised shelter the wrack Ascophyllum nodosum may occur, though never at high abundance. The crab Carcinus maenas may be present in pools or among the boulders. Two variants have been described: Bedrock and large boulders (Fves.FS) and mixed substrata (Fves.X). Please notice that a F. vesioculosus biotope subject to variable salinity (FvesVS) has been identified.

Situation

This biotope usually occurs between the wrack Fucus spiralis (Fspi) and the Fucus serratus (Fserr) zones; both of these fucoids may be present in this biotope, though never at high abundance (typically less than Frequent). In some sheltered areas F. vesiculosus forms a narrow zone above the A. nodosum zone (Asc). Where freshwater runoff occurs on more gradually sloping shores F. vesiculosus may be replaced by the wrack Fucus ceranoides (Fcer).

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).

Similar biotopes

LR.HLR.MusB.Sem.FvesR Occurs on more exposed shores or on steep or vertical faces. Sparse F. vesiculosus is present (Occasional) and the density of S. balanoides and P. vulgata is high (Abundant). More species of red seaweeds are present, while the wracks A. nodosum and F. serratus are absent.
LR.MLR.BF.FvesB Occurs on more exposed shores on bedrock and large boulders. F. vesiculosus is dominating, though less abundant (Common) and there is a higher diversity of red seaweeds. S. balanoides, P. vulgata and N. lapillus occurs more frequently and at a higher abundance.

Characterising Species

Taxa	Typical Abundance	% Contribution to similarity
Semibalanus balanoides	F	10
Carcinus maenas	O	3
Patella vulgata	F	6
Littorina littorea	F	3
Littorina saxatilis	O	11
Nucella lapillus	O	4
Mytilus edulis	O	2
Ascophyllum nodosum	O	2
Fucus vesiculosus	A	41
Enteromorpha intestinalis	F	5

Example photographs of biotope

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This report should be cited as:
DAVID W. CONNOR, JAMES H. ALLEN, NEIL GOLDING, KERRY L. HOWELL, LOUISE M. LIEBERKNECHT, KATE O. NORTHEN AND JOHNNY B. REKER (2004)
The Marine Habitat Classification for Britain and Ireland Version 04.05 JNCC, Peterborough<
ISBN 1 861 07561 8 (internet version)
www.jncc.gov.uk/MarineHabitatClassification