Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA4.25 Faunal communities on variable salinity Atlantic circalittoral rock

Faunal communities on variable salinity Atlantic circalittoral rock

Quick facts

Red List habitat type code NEAA4.25
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

This habitat type occurs on wave-sheltered, variable/reduced salinity bedrock and boulders, subject to moderately strong to weak tidal streams. There may be large growths of the brackish-tolerant sponge Halichondria bowerbanki. It is characterised by sponges tolerant of variable salinity, barnacles and a sparse hydroid and bryozoan turf. Especially where low salinity is frequently present, ‘groves’ of the peacock worm Sabella pavonina may be present. Beds of mussels, Mytilus edulis, may also be present but may be ephemeral.

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.

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

Threat status

Synthesis of Red List assessment

The conditions which favour the occurence of this habitat are rare in the North East Atlantic however EOO exceeds 50,000km2 because it is present in locations as widespread as Loch Etive on the west coast of Scotland and the Tamar estuary in south west England (occurring naturally in, perhaps, less than 200 km²).
Although not considered likely to occur in many locations it is unlikely that the available data show its full distribution. It exceeds the threshold for threated status on the basis of a small range but there is a lack of information on trends. This habitat has therefore been assessed as Data Deficient for both the EU 28 and EU 28+.
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

  • Biological resource use other than agriculture & forestry
    • Fishing and harvesting aquatic resources
    • Professional active fishing
    • Demersal seining
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
  • Natural System modifications
    • Human induced changes in hydraulic conditions

Habitat restoration potential

The species that characterise this habitat are generally resilient to adverse impacts. The MarLIN sensitivity review for one of the associated biotopes (A4.252 Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity mixed substrata) suggests ‘High’ or ‘Very high’ recovery potential and the highest sensitivity as ‘Moderate’.

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

This habitat is afforded some protection within Marine Protected Areas. Beneficial management measures include the regulation of fishing methods and control of any activity, including the discharge of contaminants, which damages or disturbs seabed communities. The unusual nature and rarity of occurrence of the associated biotopes needs to be accounted for in the management of locations and in ecological impact assessments.

List of conservation and management needs

  • 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 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
Greater North Sea
Kattegat

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 209,008 unknown Unknown There is insufficient information for accurate calculation of EOO and AOO.
EU28+ unknown Unknown There is insufficient information for accurate calculation of EOO and AOO.
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.
Invertebrates Alcyonidium diaphanum
Invertebrates Asterias rubens
Invertebrates Balanus crenatus
Invertebrates Bugula plumosa
Invertebrates Carcinus maenas
Invertebrates Clavelina lepadiformis
Invertebrates Cliona celata
Invertebrates Dendrodoa grossularia
Invertebrates Distomus variolosus
Invertebrates Halichondria bowerbanki
Invertebrates Halichondria panicea
Invertebrates Leucosolenia botryoides
Invertebrates Metridium senile
Invertebrates Mytilus edulis
Invertebrates Nemertesia antennina
Invertebrates Nemertesia ramosa
Invertebrates Plumularia setacea
Invertebrates Sabella pavonina
Invertebrates Sagartia troglodytes
Invertebrates Salmacina dysteri
Invertebrates Suberites ficus
Invertebrates Tubularia indivisa
Species scientific name English common name Species group
Alcyonidium diaphanum Invertebrates
Asterias rubens Invertebrates
Balanus crenatus Invertebrates
Bugula plumosa Invertebrates
Carcinus maenas Invertebrates
Clavelina lepadiformis Invertebrates
Cliona celata Invertebrates
Dendrodoa grossularia Invertebrates
Distomus variolosus Invertebrates
Halichondria bowerbanki Invertebrates
Halichondria panicea Invertebrates
Leucosolenia botryoides Invertebrates
Metridium senile Invertebrates
Mytilus edulis Invertebrates
Nemertesia antennina Invertebrates
Nemertesia ramosa Invertebrates
Plumularia setacea Invertebrates
Sabella pavonina Invertebrates
Sagartia troglodytes Invertebrates
Salmacina dysteri Invertebrates
Suberites ficus Invertebrates
Tubularia indivisa Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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