Red List habitat classification > RL - Marine habitats > RLMED - Mediterranean > MEDA3.36 Communities of Mediterranean estuarine rock

Communities of Mediterranean estuarine rock

Quick facts

Red List habitat type code MEDA3.36
Threat status
Europe Vulnerable
EU Vulnerable
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


This habitat is composed of intertidal and shallow subtidal rocky habitats which support faunal-dominated communities, with seaweed communities only poorly developed or absent. The variations associated communities are linked to climatic conditions, mainly the very great seasonal differences in temperature and salinity, which in the summer is particularly warm salty water and in the winter very low temperatures and sometimes brackish water.

The habitat supports species that are able to withstand quick variations in environmental conditions such as salinity. Sudden influxes of salt water and drying up in the summer create recurrent disturbances that sometimes cause populations to disappear. In this case, recolonisation will always be very rapid. In the Adriatic the characteristic species of this association is the endemic brown alga Fucus virsoides. 

Indicators of quality:

Standard biotic and abiotic indicators have been used to describe marine habitat quality. Both biotic and abiotic indicators have been used to describe marine habitat quality. These include the presence of particular species, water quality parameters, levels of exposure to a particular exposure as well as more integrated indices which describe habitat function and structure, such as trophic index, or successful 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 be set in certain situations, e.g. protected features with Natura 2000 sites, where reference values may 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 can be reliably assumed as patchy as the proportion of estuary areas in the Mediterranean is limited and it relates to only 70 medium to large rivers and streams that flow into the Mediterranean. The whole infralittoral zone is especially subject to human activities that increase mud transport from the coast (mainly untreated urban waste discharge, major construction works in the maritime field, and leaching from soil). Hypersedimentation may eliminate vulnerable facies, resulting in biotope homogenization and a consequent reduction of the associated biodiversity and the exploitable living resources. The combined effects of urbanization, fisheries, aquaculture and sedimentation are leading to a shift in associated assemblages.
There is a lack of quantiative data however expert opinion is that it is reasonable to presume that this habitat has suffered declines in both quantity and quality in the last 50 years. The pressures leading to such declines are predicted to continue therefore a continuing decline is likely. This habitat has therefore been assessed as Vulnerable for both the EU 28 and EU 28+.
Red List Category Red List Criteria
Vulnerable A1, C/D1
Red List Category Red List Criteria
Vulnerable A1, C/D1

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Agriculture
    • Use of biocides, hormones and chemicals
    • Fertilisation
  • Urbanisation, residential and commercial development
    • Urbanised areas, human habitation
    • Industrial or commercial areas
    • Discharges
  • Biological resource use other than agriculture & forestry
    • Marine and Freshwater Aquaculture
    • Fishing and harvesting aquatic resources
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Marine water pollution
    • Soil pollution and solid waste (excluding discharges)

Habitat restoration potential

The capacity to recover once severely damaged of this habitat is unknown.

Trends in extent

Average current trend in quantity

Decreasing Decreasing
EU28 EU28+

Trends in quality

Average current trend in quality

Decreasing Decreasing
EU28 EU28+

Conservation and management needs

This habitat occurs in some protected areas. Beneficial conservation measures include regulating discharges to improve water quality, managing fisheries, establishing protected areas, coastal zone planning including zoning of developments, and whole estuary management including regulation of water abstraction from the river system and other activities which affect the hydrological regime. Direct engagement of stakeholders in the planning of the management process, and analysis of social and economic costs and benefits of different management options will be essential to the successful implementation of conservation actions.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
    • Restoring coastal areas
  • Measures related to marine habitats
    • Restoring marine habitats
  • Measures related to spatial planning
    • Establish protected areas/sites
    • Legal protection of habitats and species
  • Measures related to hunting, taking and fishing and species management
    • Regulation/Management of fishery in marine and brackish systems
  • Measures related to urban areas, industry, energy and transport
    • Urban and industrial waste management


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 Decreasing Decreasing
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 60,721 9 Unknown This habitat is present in all the Mediterranean sub-basins. AOO figures are believed to be an underestimate.
EU28+ 9 Unknown This habitat is present in all the Mediterranean sub-basins. AOO figures are believedto 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.
Algae Fucus virsoides
Invertebrates Actinia equina
Invertebrates Cyathura carinata
Invertebrates Gammarus aequicauda
Invertebrates Lekanesphaera hookeri
Invertebrates Mytilus galloprovincialis
Invertebrates Sphaeroma serratum
Species scientific name English common name Species group
Fucus virsoides Algae
Actinia equina Invertebrates
Cyathura carinata Invertebrates
Gammarus aequicauda Invertebrates
Lekanesphaera hookeri Invertebrates
Mytilus galloprovincialis Invertebrates
Sphaeroma serratum Invertebrates

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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