EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A2 - Littoral sediment > A2.4 - Littoral mixed sediments > A2.43 - Species-poor mixed sediment shores > A2.431 - Barnacles and Littorina spp. on unstable eulittoral mixed substrata

Barnacles and Littorina spp. on unstable eulittoral mixed substrata

English name: Barnacles and Littorina spp. on unstable eulittoral mixed substrata

Quick facts

EUNIS habitat type code A2.431
Bern Convention Included in a Resolution 4 habitat type at a higher level (A2.4)

Description (English)

The eulittoral zone, particularly the mid shore zone, of sheltered to extremely sheltered mixed substrata shores is often characterised by flat banks or scards of cobbles and pebbles (on sediment) which are either too small or unstable to support a seaweed community. The boulders and larger cobbles are usually colonised by the barnacles Semibalanus balanoides or in areas with variable salinity Elminius modestus and often dense aggregations of the winkles Littorina littorea and Littorina saxatilis are present as well. Between the cobbles and pebbles the mussel Mytilus edulis occasionally occurs, but always at low abundance. Juvenile crabs Carcinus maenas and gammarids may occur between and underneath the pebbles and cobbles. Brown seaweeds are rare, although the wrack Fucus vesiculosus may occasionally occur on larger cobbles and small boulders in the mid and upper shore zones. Ephemeral green seaweeds such as Enteromorpha intestinalis may also be present. Shallow pools and patches of standing water may occur in low-lying areas and may contain amphipods and filamentous green seaweeds. Due to the unstable nature of the substratum the diversity and density of flora and fauna is characteristically low.
Situation: This biotope is found primarily on enclosed (estuarine) stony shores in wave-sheltered conditions (compare with unit A1.1133) and may be subject to variable levels of salinity. It is found predominately in the mid shore zone below or at the same level as the biotope dominated by ephemeral green seaweeds (A2.821). If it is found in the upper shore region it can be backed by salt marsh species such as Salacornia and Spartina sp. Below are biotopes dominated by the wracks Fucus serratus or F. vesiculosus (units A1.3152; A1.3132).

Source: EUNIS habitat classification

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Algae Enteromorpha intestinalis
Algae Fucus serratus
Algae Fucus vesiculosus
Invertebrates Carcinus maenas
Invertebrates Elminius modestus
Invertebrates Littorina littorea
Invertebrates Littorina saxatilis
Invertebrates Mytilus edulis
Invertebrates Semibalanus balanoides
Species scientific name English common name Species group
Enteromorpha intestinalis Algae
Fucus serratus Algae
Fucus vesiculosus Algae
Carcinus maenas Invertebrates
Elminius modestus Invertebrates
Littorina littorea Invertebrates
Littorina saxatilis Invertebrates
Mytilus edulis Invertebrates
Semibalanus balanoides Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 LR.FLR.Eph.BLitX Barnacles and <I>Littorina</I> spp. on unstable eulittoral mixed substrata source
CORINE Land Cover 4.2.3. Intertidal flats n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A2.431 Barnacles and Littorina spp. on unstable eulittoral mixed substrata same
EUNIS Habitat Classification 200308 A1.321 Barnacles and Littorina littorea on unstable eulittoral mixed substrata wider
EUNIS Habitat Classification 200202 A1.321 Barnacles and Littorina littorea on unstable eulittoral mixed substrata same
EUNIS Habitat Classification 199910 A1.321 Barnacles and Littorina littorea on unstable eulittoral mixed substrata same
MNCR BioMar 97.06 (Britain & Ireland) SLR.FX.BLlit Barnacles and Littorina littorea on unstable eulittoral mixed substrata same
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