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Concept: Mussel and/or barnacle communities in the eunishabitats vocabulary

Concept URI http://eunis.eea.europa.eu/eunishabitats/A1.11
Preferred label Mussel and/or barnacle communities
Definition Communities on very exposed to moderately exposed upper and mid eulittoral bedrock and boulders dominated by the mussel [Mytilus edulis] (A1.111), barnacles [Chthamalus] spp. and/or [Semibalanus balanoides] and limpets [Patella] spp. (A1.112, A1.113). Several variants are identified. Some shores are characterised by dense bands of the barnacle [Semibalanus balanoides] and the limpet [Patella vulgata] (A1.113). The barnacles may be covered by [Porphyra umbilicalis] on the upper shore of exposed sites. Cracks and crevices in the rock provide a refuge for small individuals of the mussel [M. edulis], winkles [Littorina saxatilis] and the whelk [Nucella lapillus]. Red seaweeds also frequently occupy damp crevices, particularly [Ceramium shuttleworthianum], [Corallina officinalis], [Osmundea pinnatifida] and encrusting coralline algae, but the non-vesiculate form of the wrack [Fucus vesiculosus] might be present (A1.1132). Large numbers of the winkle [Littorina littorea] often dominate fields of large boulders or shores with a more mixed substratum (A1.1133). There is much regional variation affecting the zonation of barnacles in the British Isles. In the north-west [C. montagui] and/or [C. stellatus] can form a distinct band above [S. balanoides]. In the south-west [C. montagui] and/or [C. stellatus] can be the dominant barnacles throughout the eulittoral zone (A1.1121). On the east coasts [S. balanoides] is able to extend to the upper shore due to the absence of [Chthamalus] spp. and thereby any competition. The lichen [Lichina pygmaea] may be prominent, especially in the south, where it can form distinct patches or even a separate zone among the [Chthamalus] spp. (A1.1122). In areas of soft rock (e.g. shales), the barnacles may be scarce or absent and the rock dominated by [P. vulgata]. Situation: This habitat type is found in the mid to upper eulittoral on very to moderately exposed shores below the lichen dominated biotopes (B3.11) and is typically characterised by patches of mussels [M. edulis] interspersed with barnacles. Below A1.11 is a community dominated by the wrack [Himanthalia elongata] and red seaweeds such as [C. officinalis], [Mastocarpus stellatus] and [O. pinnatifida] (A1.12). With decreasing wave exposure [F. vesiculosus] is able to survive, gradually replacing the barnacles and [P. vulgata] biotope (A1.213). On such moderately exposed shores A1.11 may occur on steep and vertical faces, while fucoids dominate the flatter areas (A1.1132, A1.213).
Notation A1.11
Status Valid
Status Modified 31.01.2014
Accepted Date 31.01.2014
Not Accepted Date
Has broader
Has narrower
Has exact match