Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA3.71 Robust faunal cushions and crusts in Atlantic infralittoral surge gullies and caves

Robust faunal cushions and crusts in Atlantic infralittoral surge gullies and caves

Quick facts

Red List habitat type code NEAA3.71
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

Infralittoral rocky habitats subject to strong wave surge conditions, as found in surge gullies and shallow caves, on open rocky coasts with moderate or greater wave action. This habitat is typically colonised by faunal communities of encrusting or cushion sponges, colonial ascidians, short turf-forming bryozoans, anthozoans, barnacles and, where there is sufficient light, by red seaweeds.

The surge gullies and caves usually consist of vertical bedrock walls, occasionally with overhanging faces, and support communities which reflect the degree of wave surge they are subject to, and any scour from mobile substrata on the cave/gully floors. The larger cave and gully systems typically show a marked zonation from the entrance to the rear of the gully/cave as wave surge increases and light reduces. This is reflected in communities of anthozoans, ascidians, bryozoans and red seaweeds near the entrance, leading to sponge crust-dominated communities and finally barnacle and spirobid worm communities in the most severe surge conditions. Gully/cave floors usually have mobile boulders, cobbles, pebbles or coarse sediment. The mobile nature of the gully/cave floors leads to communities of encrusting species, tolerant of scour and abrasion or fast summer-growing ephemeral species. The lower zone of the gully side walls are also often scoured, and typically colonised by coralline crusts and barnacles. Winter storms may result in scouring on gully/cave walls whilst some ephemeral growth may occur in calmer summer months.

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 overtime.

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

This habitat has a large natural range in the North East Atlantic region extending from the Canaries and Azores in the west to the Skagerrak coast of Sweden. There are insufficient data to identify and trends although both increases and decreases in extent are to be expected through the natural process of erosion.
This habitat has large EOO and therefore qualifies as Least Concern under criterion B1. The AOO figure is known to be an underestimate. Given the lack of information on trends in quantity and quality, and the fact that the overall distribution is unknown, expert opinion is this habitat should be considered 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

  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
  • Natural System modifications
    • Human induced changes in hydraulic conditions
    • Modification of hydrographic functioning, general
    • Siltation rate changes, dumping, depositing of dredged deposits

Habitat restoration potential

Unknown. Surge gully habitats develop in conditions of moderate to severe exposure to wave action. They are likely to be able to recover if there is successful settlement of larvae and conditions are favourable. Timescales for recovery will depend on the species which dominate as some are essentially annual such as the sea squirts Cliona intestinalis and Ascidiella aspersa and others such as the soft coral Alcyonium digitatum colonies are more than 10 years old.

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

There are few conservation and management measures specifically directed at this habitat although some are within designated protected areas. Codes of Conduct which provide guidance on avoiding damage to these habitat are promoted in some areas where cave diving takes place.

List of conservation and management needs

  • Measures related to marine habitats
    • Other marine-related measures
  • Measures related to spatial planning
    • Establish protected areas/sites

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
Macaronesia
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 293,633 >35 Unknown Based on a limited data set. AOO is known to be an underestimate.
EU28+ >35 Unknown Based on a limited data set. AOO is known to be an underestimate.
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 Alcyonium digitatum
Invertebrates Asterias rubens
Invertebrates Balanus crenatus
Invertebrates Botryllus schlosseri
Invertebrates Calliostoma zizyphinum
Invertebrates Cancer pagurus
Invertebrates Clathrina coriacea
Invertebrates Corynactis viridis
Invertebrates Echinus esculentus
Invertebrates Metridium senile
Invertebrates Myxilla incrustans
Invertebrates Pachymatisma johnstonia
Invertebrates Pomatoceros triqueter
Invertebrates Tubularia indivisa
Species scientific name English common name Species group
Alcyonium digitatum Invertebrates
Asterias rubens Invertebrates
Balanus crenatus Invertebrates
Botryllus schlosseri Invertebrates
Calliostoma zizyphinum Invertebrates
Cancer pagurus Invertebrates
Clathrina coriacea Invertebrates
Corynactis viridis Invertebrates
Echinus esculentus Invertebrates
Metridium senile Invertebrates
Myxilla incrustans Invertebrates
Pachymatisma johnstonia Invertebrates
Pomatoceros triqueter Invertebrates
Tubularia indivisa Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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