Red List habitat classification > RL - Marine habitats > RLMED - Mediterranean > MEDA5.38x Communities of Mediterranean circalittoral muddy detritic bottoms

Communities of Mediterranean circalittoral muddy detritic bottoms

Quick facts

Red List habitat type code MEDA5.38x
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)


This habitat develops in areas where a detritus bottom is covered with mud formed by terrigenous deposits from rivers. The sediment is a very muddy sand or sandy mud, or even a rather compacted mud, rich in shell debris or volcanic fragments (scoriae). Sedimentation deposits slow enough to allow the development of sessile epifauna. Gravel, sand and mud are mixed in varying quantities, but mud always predominates.

This biocenosis hosts the facies of the brittlestar Ophiothrix quinquemaculata. This species in some places forms an extremely dense population which is formed almost by 90% ophiurans.

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

This is a very poorly studied habitat type and only few reports exists regarding its distribution at few locations. Moreover, data on quality or quantity is lacking, although a slight to moderate decrease on quality is considered likely due to current pressures.
The habitat has a large Extent of Occurrence (EOO) and Area of Occupancy (AOO), and therefore it qualifies as Least Concern under Criterion B. However, the habitat is assessed as Data Deficient both at the EU 28 and the 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

  • Biological resource use other than agriculture & forestry
    • Fishing and harvesting aquatic resources
    • Professional active fishing
    • Benthic or demersal trawling
    • Benthic dredging
  • Natural biotic and abiotic processes (without catastrophes)
    • Silting up
    • Accumulation of organic material
    • Eutrophication (natural)

Habitat restoration potential

Information regarding the recovery capacity of this habitat is being reported only from the north Adriatic Sea due to anoxic events. Here, after the anoxic events, the recolonization process has been slow: the total biomass and the relative contribution of the main species have remained distinctly below previously recorded values. It is believed that additional anthropogenic influences (such as intensive dredging) may further halt recolonization.

Trends in extent

Average current trend in quantity

Decreasing Unknown
EU28 EU28+

Trends in quality

Average current trend in quality

Decreasing Decreasing
EU28 EU28+

Conservation and management needs

Recommended actions for conservation and management include: i) the designation of Marine Protected Areas (MPAs) in areas where this habitat occurs, particularly where facies of Ophiothrix quinquemaculata are present, ii) strengthening fishing restrictions, especially bottom trawling in the network of MPAs and decrease the sources of eutrophication to prevent further decrease of the condition of the habitat; and iii) enhance greater understanding on the distribution, ecology and dynamics of the communities of circalittoral muddy detritic bottoms to facilitate the identificaiton of conservation needs and suggest further management measures and protection actions.

List of conservation and management needs

  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
  • Measures related to spatial planning
    • Establish protected areas/sites
  • Measures related to hunting, taking and fishing and species management
    • Regulation/Management of fishery in marine and brackish systems
  • Measures related to special resouce use
    • Regulating/Managing exploitation of natural resources on sea


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 >50,000 >50 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+ >50 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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1050 Copenhagen K
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