Mytilus edulis and barnacles on very exposed eulittoral rock

Quick facts

EUNIS habitat type code MA1221
Relation to Resolution 4 habitat type (used for designation of Emerald sites)

Description (English)

On very exposed to exposed rocky shores the eulittoral zone, particularly the mid and lower shore, is typically characterised by patches of small individuals of the mussel Mytilus edulis interspersed with patches of the barnacle Semibalanus balanoides and individuls of the limpet Patella vulgata. Amongst the mussels small individuals of red seaweeds including Ceramium spp., Corallina officinalis and Mastocarpus stellatus can be found. The foliose red seaweeds Porphyra umbilicalis and Palmaria palmata are commonly found as epiphytes on M. edulis where they can form luxuriant growths. The abundance of the red seaweeds generally increases down the shore and in the lower eulittoral they may form a distinct zone in which mussels or barnacles are scarce (MA1-23, MA1-2321 or MA1-233). Where M. edulis occurs on steep rock, red seaweeds are scarce and restricted to the lower shore. The whelk Nucella lapillus and a few winkles such as Littorina spp. can occur where cracks and crevices provide a refuge in the rock. Fucoids are generally absent, although some non-vesiculate Fucus vesiculosus may occur where the shore slopes more gently. This biotope also occurs on steep moderately exposed shores which experience increased wave energy.
Situation: This unit is generally found above a zone of either mixed turf-forming red seaweeds (MA1-23), Himanthalia elongata (MA1-233) or above the sublittoral fringe kelp Alaria esculenta (MB1-211) zone. Above MA1-221 there may be a Verrucaria maura zone (MA1-2132), a V. maura and sparse barnacle zone (MA1-2131), often with P. umbilicalis or a denser barnacle and limpet zone (MA1-223; MA1-243). In addition, patches of lichen Lichina pygmaea with the barnacle Chthamalus montagui (MA1-2221) may also occur above this biotope, particularly on southern shores.
Temporal variation: Severe winter storms can cause periodic removal of this mussel and barnacle community.

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Algae Corallina officinalis
Algae Fucus vesiculosus
Invertebrates Patella vulgata
Species scientific name English common name Species group
Corallina officinalis Algae
Fucus vesiculosus Algae
Patella vulgata Invertebrates

History

Classification Code Habitat type name Relationship type Comment
EUNIS Habitat Classification 200410 A1.111 Mytilus edulis and barnacles on very exposed eulittoral rock same
EUNIS Habitat Classification 200308 A1.111 Mytilus edulis and barnacles on very exposed eulittoral rock same
EUNIS Habitat Classification 200202 A1.111 Mytilus edulis and barnacles on very exposed eulittoral rock same
EUNIS Habitat Classification 199910 A1.111 Mytilus edulis and barnacles on very exposed eulittoral rock same
MNCR BioMar 97.06 (Britain & Ireland) ELR.MB.MytB Mytilus edulis and barnacles on very exposed eulittoral rock same
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