Red List habitat classification > RL - Marine habitats > RLMED - Mediterranean > MEDA1.41 Communities of Mediterranean mediolittoral rockpools

Communities of Mediterranean mediolittoral rockpools

Quick facts

Red List habitat type code MEDA1.41
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)


Rockpools occur where the topography of the shore allows seawater to be retained within depressions in the bedrock. As the associated communities are permanently submerged they are not directly affected by height on the shore and normal rocky shore zonation patterns do not apply. Factors such as pool depth, surface area, volume, orientation to sunlight, shading, internal topography, sediment content and type, together with wave exposure, shore height, and hence flushing rate, and the presence of absence of freshwater runoff, results in large spatial variation in community structure, even between adjacent pools at
the same shore height. 

The provision of seawater to this habitat can be completely interrupted during long periods of calm sea conditions. In these cases, the habitat may face important changes in temperature, pH, salinity and oxygen concentration. Nitrogen concentration is very often high and seasonal changes more abrupt than
in the adjacent, regularly swashed communities. In these conditions, the development of macroalgal communities is hindered and green algae can dominate. Large numbers of benthic species and juvenile stages of some commercial species of fish may be present in rockpools.

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. Most of the associated species are opportunistic and show high turnover however changes in species richness and percent algae cover could indicate changes in the quality of the environment.

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

Threat status

Synthesis of Red List assessment

There is a lack of published data on trends of this habitat and very little available information about its extent of occurrence or its area of occupancy. There have been no quantitative analyses examining the probability of extinction of the rockpools and the pressures affecting their quality. This habitat has a large EOO and AOO, and therefore qualifies as Least Concern under criterion B. However the habitat is assessed as Data Deficient both at the EU 28 and EU 28+ levels because of a lack of information on any trends in quantity and quality.
Red List Category Red List Criteria
Data Deficient -
Red List Category Red List Criteria
Data Deficient -

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Nutrient enrichment (N, P, organic matter)
    • Oil spills in the sea
    • Toxic chemical discharge from material dumped at sea
    • Marine macro-pollution (i.e. plastic bags, styrofoam)
    • Input of litter (solid waste matter)
  • Climate change
    • Temperature changes (e.g. rise of temperature & extremes)
    • Wave exposure changes
    • Sea-level changes

Habitat restoration potential

The heterogeneity of this habitat in terms of rock pool size, shape, assemblage composition and hervibores determine its recovery capacity. If conditions reverse, the habitat might be able to recover relatively quickly but this is largely dependant on the previous conditions and their effects.

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

Conservation and management measures which would benefit this habitat are mostly general rather than specific measures. They include pollution control and regulation, development control and contingency plans to be followed in the event of a major pollution incident and measures to reduce global warming and sea level rise. Beneficial actions include mapping of the distribution of this habitat in the Mediterranean and the associated species, monitoring representative sites to examine trends in quantity and quality and further evaluation of the main pressures and required conservation actions to safeguard and restore this habitat where it has been degraded.

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


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)
Adriatic Sea Present Unknown Unknown Unknown
Aegian-Levantine Sea
Ionian Sea and the Central Mediterranean Sea
Western Mediterranean 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 2,208,801 455 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+ 457 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

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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