Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA1.17 Low coverage of fauna and flora of mediolittoral rock and boulders

Low coverage of fauna and flora of mediolittoral rock and boulders

Quick facts

Red List habitat type code NEAA1.17
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)


This habitat can be very extensive. It occurs in very exposed conditions, comprising rocks and boulders in upper, mid- and lower mediolittoral with lichens, barnacles, limpets, mussels and fucoids but not organised in communities. There is a high percentage of bare rock and a low species diversity.

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. 

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

Threat status

Synthesis of Red List assessment

This habitat is believed to have a large natural range but there are insufficient data for accurate calculation of EOO and AOO. Expert opinion is that although there may have been some short term and cyclical changes in the extent of this habitat, it is most likely to have been stable over the last 50 years. For the purposes of Red List assessment it is therefore considered to be Least Concern for both the EU 28 and EU 28+.
Red List Category Red List Criteria
Least Concern -
Red List Category Red List Criteria
Least Concern -

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Pollution
    • Marine water pollution
    • Oil spills in the sea
  • Climate change
    • Changes in abiotic conditions
    • Temperature changes (e.g. rise of temperature & extremes)
    • Wave exposure changes
    • Sea-level changes
    • Changes in biotic conditions
    • Habitat shifting and alteration
    • Migration of species (natural newcomers)

Habitat restoration potential

This is a very dynamic habitat with few associated species. Those which do occur are adept at colonising empty space hence it has a high capacity to recover. Timescales for recovery will depend on removal of the impact as well as the availability of larvae and successful spatfalls.

Trends in extent

Average current trend in quantity

Stable Stable
EU28 EU28+

Trends in quality

Average current trend in quality

Stable Stable
EU28 EU28+

Conservation and management needs

There are limited opportunities and need for specific conservation and management measures directed at this habitat.
More general beneficial measures include pollution control and regulation, contingency plans to be followed in the event of major pollution incidents, and measures to reduce global warming and sea level rise.

List of conservation and management needs

  • Measures related to marine habitats
    • Other marine-related measures
  • Measures related to spatial planning
    • Other marine-related measures


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 Stable Stable
Celtic Seas
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 unknown unknown unknown Insufficient records for reliable estimate.
EU28+ unknown unknown Insufficient records for reliable estimate.
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

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Phone: +45 3336 7100