Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA3.14 Encrusting algal communities on exposed Atlantic infralittoral rock

Encrusting algal communities on exposed Atlantic infralittoral rock

Quick facts

Red List habitat type code NEAA3.14
Threat status
Europe Least Concern
EU Least Concern
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)

Summary

This habitat comprises a community of crustose algae on rocky substrates. It occurs in locations which are exposed or moderately exposed to wave action. Algal cover is extremely poor, and almost completely restricted to encrusting species. Sessile animals are typically encrusting sponges, bryozoans, barnacles, serpulids and vermetids. Vertical surfaces may be occupied by patches of encrusting sponges and Corynactis viridis, while hydroids such as Aglaophenia pulma may be locally abundant. In deeper water the colonial coral Madracis asperula may be present. The herbivory of the sea-urchins is very important for the maintenance of this habitat. 

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

There is a lack of information on the quantity and quality of this habitat in the North East Atlantic region although it is likely to be widespread. Because of the robust nature of this habitat, occuring in wave exposed conditions, it is thought unlikely to have declined over the last 50 years. For the purposes of Red List assessment this habitat is therefore considered to be of Least Concern for both the EU 28 and EU 28+.
EU
Red List Category Red List Criteria
Least Concern
Europe
Red List Category Red List Criteria
Least Concern

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
  • Pollution
    • Marine water pollution

Habitat restoration potential

Unknown, although as present in high energy situations it likely to be a resilient habitat capable of recovery.

Trends in extent

Average current trend in quantity

Stable Stable
EU28 EU28+

Trends in quality

Average current trend in quality

Unknown Unknown
EU28 EU28+

Conservation and management needs

As this habitat occurs in exposed rocky areas it is likely to be resilient with few specific conservation measures required. It could however benefit from general measures to reduce the pressures of human activity on inshore rocky areas (e.g. controls on fishing) and to prevent pollution at sea.

List of conservation and management needs

  • Measures related to marine habitats
    • Other marine-related measures
  • 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 Stable
Celtic Seas
Kattegat
Greater North Sea
Macaronesia

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 Unknown 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.
Fishes Lipophrys trigloides
Fishes Ophioblennius atlanticus
Fishes Parablennius incognitus
Invertebrates Arbacia lixula
Invertebrates Calcinus tubularis
Invertebrates Corynactis viridis
Invertebrates Madracis asperula
Invertebrates Marthasterias glacialis
Invertebrates Megabalanus azoricus
Invertebrates Paracentrotus lividus
Invertebrates Percnon gibbesi
Invertebrates Sphaerechinus granularis
Invertebrates Stramonita haemastoma
Species scientific name English common name Species group
Lipophrys trigloides Fishes
Ophioblennius atlanticus Redlip Blenny Fishes
Parablennius incognitus Fishes
Arbacia lixula Invertebrates
Calcinus tubularis Invertebrates
Corynactis viridis Invertebrates
Madracis asperula Invertebrates
Marthasterias glacialis Invertebrates
Megabalanus azoricus Azorean barnacle Invertebrates
Paracentrotus lividus Invertebrates
Percnon gibbesi Invertebrates
Sphaerechinus granularis Invertebrates
Stramonita haemastoma Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
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