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 availableSpecies mentioned in habitat description
Species scientific name | English common name | Species group |
---|---|---|
Enteromorpha intestinalis | Algae | |
Fucus serratus | Algae | |
Fucus vesiculosus | Algae | |
Carcinus maenas | Invertebrates | |
Mytilus edulis | 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 |
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 |