Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA1.22 Mytilus edulis and fucoids on moderately wave-exposed Atlantic littoral rock

Mytilus edulis and fucoids on moderately wave-exposed Atlantic littoral rock

Quick facts

Red List habitat type code NEAA1.22
Threat status
Europe Data Deficient
EU Data Deficient
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)

Summary

Mid- and lower eulittoral bedrock exposed or moderately exposed to wave action, often with nearby sediment, and which may be densely covered by large individuals of the mussel Mytilus edulis. Three biotopes have been described associated with this habitat: In the mid eulittoral, the mussels may form a band or large patches with scattered bladder wrack Fucus vesiculosus. In the lower eulittoral a range of red seaweeds including Mastocarpus stellatus and Palmaria palmata occur amongst the mussels (in higher abundance than the mid eulittoral). Clay outcrops in the mid to lower eulittoral may be bored by a variety of piddocks including Pholas dactylusBarnea candida and Petricola pholadiformis, while the surface is characterised by small clumps of the mussel M. edulis, the barnacle Elminius modestus and the winkle Littorina littorea. Ephemeral green seaweeds such as Ulva intestinalis and U. lactuca commonly occur on the shells of the mussels. Barnacles are common on both the mussel valves and on patches of bare rock, where the limpet Patella vulgata is found as well, often at high abundance. The whelk Nucella lapillus and a range of littorinids also occur within the mussel bed. A dense M. edulis community may be found on more sheltered coasts on mixed substrata 

Indicators of quality:

Both biotic and abiotic indicators have been used to describe marine habitat quality. These include: the presence of characteristic species as well as those which are sensitive to the pressures the habitat may face; water quality parameters; levels of exposure to particular pressure, and more integrated indices which describe habitat structure and function, such as trophic index, or successional stages of development in habitats that have a natural cycle of change over time.

There are no commonly agreed indicators of quality for this habitat, although particular parameters may have been set in certain situations e.g. protected features within Natura 2000 sites, where reference values have been determined and applied on a location-specific basis. Indicators which have been developed for the assessment of ecological quality of coastal water bodies for the Water Framework Directive (WFD) that are relevant to this habitat include a consideration of macroalgae species richness, proportions of different taxa of algae present, and the abundance and coverage of the rocky surfaces by typical species. The density and abundance of Mytilus edulis is also a potential indicator of habitat quality.

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

Local and/or seasonal factors often exert a substantial influence on intertidal habitats making it difficult to distinguish any long-term trend across the region. This is complicated further because differences between localities are often linked to differences in geographical latitude and, therefore, to differences in climatic traits like temperature and/or ice cover. Survey information confirms that this habitat has a wide range in the North East Atlantic. It has been studied in detail in some localities however there is insufficient information to determine whether there have been any historical, recent and possible future trends in quantity or quality.
This habitat has a large EOO and AOO, and therefore qualifies as Least Concern under criterion B but is assessed as Data Deficient both at the EU 28 and EU 28+ levels due to the lack of information on trends in quantity and quality.
EU
Red List Category Red List Criteria
Data Deficient -
Europe
Red List Category Red List Criteria
Data Deficient -

Confidence in the assessment

low
Red List of habitat categories and criteria descriptions

Pressures and threats

  • Urbanisation, residential and commercial development
    • Discharges
  • Biological resource use other than agriculture & forestry
    • Fishing and harvesting aquatic resources
    • Professional active fishing
    • Benthic dredging
    • Leisure fishing
    • Bait digging / Collection
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Nutrient enrichment (N, P, organic matter)
  • Natural System modifications
    • Human induced changes in hydraulic conditions
    • Modification of hydrographic functioning, general
  • Climate change
    • Changes in abiotic conditions

Habitat restoration potential

The mussel component can come back within 10 years and fucoids over shorter time scales so recovery of the habitat mosaic within 10 years is possible if conditions are favourable (e.g. good spatfalls and low storm frequency).

Trends in extent

Average current trend in quantity

Unknown Unknown
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

General beneficial measures include pollution control and regulation, development control and contingency plans to be followed in the event of a major pollution incident, survey and monitoring programmes, raised public awareness of their ecological value and vulnerability, representation in marine protected areas and measures to reduce global warming and sea level rise.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
  • Measures related to spatial planning
    • Other marine-related measures
    • Establish protected areas/sites
  • Measures related to hunting, taking and fishing and species management
    • Regulation/Management of hunting and taking
    • Regulation/Management of fishery in marine and brackish systems

Distribution

For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.

Geographic occurrence and trends

Seas Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Bay of Biscay and the Iberian Coast Present Unknown Unknown Unknown
Celtic Seas
Kattegat
Greater North Sea

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 466,615 142 Unknown EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status.
EU28+ 142 Unknown EOO and AOO have been calculated on the available data. Although this data set is known to be incomplete the figures exceed the thresholds for threatened status.
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).

Characteristic species

The full list of characteristic species and genus are available above from the Summary. The species available in the EUNIS database are shown here.
Algae Fucus vesiculosus
Algae Mastocarpus stellatus
Algae Palmaria palmata
Invertebrates Elminius modestus
Invertebrates Littorina littorea
Invertebrates Mytilus edulis
Invertebrates Nucella lapillus
Invertebrates Patella vulgata
Invertebrates Petricola pholadiformis
Invertebrates Pholas dactylus
Invertebrates Semibalanus balanoides
Species scientific name English common name Species group
Fucus vesiculosus Algae
Mastocarpus stellatus Algae
Palmaria palmata Algae
Elminius modestus Invertebrates
Littorina littorea Invertebrates
Mytilus edulis Invertebrates
Nucella lapillus Dog whelk Invertebrates
Patella vulgata Invertebrates
Petricola pholadiformis Invertebrates
Pholas dactylus Invertebrates
Semibalanus balanoides Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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