Red List habitat classification > RL - Marine habitats > RLNEA - Atlantic > NEAA5.22 Estuarine Atlantic sublittoral sand

Estuarine Atlantic sublittoral sand

Quick facts

Red List habitat type code NEAA5.22
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 is characterised by clean sands that occur in the upper reaches of marine inlets, especially estuaries, where water movement is moderately strong, allowing the deposition of sand, but not the finer silt fraction. The habitat typically lacks a significant seaweed component and is characterised by brackish-water tolerant fauna, particularly amphipods, polychaetes and mysid shrimps.

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.

Many indicators of quality have been used for this habitat with particular parameters 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 of quality of this habitat are frequently linked to those for the whole estuarine environment and therefore include morphological and physical characteristics, carrying capacity and water quality parameters. For the mudflat itself benthic indices, contaminant levels and productivity are some of the frequently used measures of quality.

Indices developed to assess the ecological status of coastal waters, including estuaries, according to the Water Framework Directive, include physical indicators, water quality indicators and measures of benthic diversity, species richness and abundance. The latter group, which is particularly relevant to benthic habitats, includes a Benthic Quality Index, an Infaunal Trophic Index, a Marine Biotic index based on ecological groups, and the Benthic Opportunistic Polychaetes/Amphipods Index.

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

Threat status

Synthesis of Red List assessment

There is a lack of quantitative data on extent and condition of this habitat therefore no assessment of trends in quantity and quality can be made at the present time. The small AOO suggests this habitat could be Endangered under criterion B however given the lack of information on its trends in quantity and quality and because the distribution data not comprehensive, expert opinion is this habitat should be considered Data Deficient for both the EU 28 and EU 28+.
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

  • Urbanisation, residential and commercial development
    • Urbanised areas, human habitation
    • Discharges
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Marine water pollution
  • Natural System modifications
    • Human induced changes in hydraulic conditions
    • Removal of sediments (mud...)
    • Dredging/ Removal of limnic sediments
    • Estuarine and coastal dredging
    • Modification of hydrographic functioning, general

Habitat restoration potential


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 schemes to benefit estuarine habitats have been applied at a number of scales ranging from whole estuary systems to small areas within an estuary. They include the removal of dykes, and water quality improvement programmes to reduce the risk of toxic contamination or nutrient inputs leading to eutrophication.
Spatial management including zoning of activities as part of Integrated Coastal Zone Management Schemes and Marine Protected Areas that cover the entire estuary complex, as well as management of water quality throughout the surrounding catchment.

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 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)
Bay of Biscay and the Iberian Coast Present Unknown Unknown Unknown
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 >128,095 >19 Unknown EOO and AOO figures are known to be an underestimate.
EU28+ >19 Unknown EOO and AOO figures are 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 Capitella capitata
Invertebrates Crangon crangon
Invertebrates Eurydice pulchra
Invertebrates Macoma balthica
Invertebrates Macoma calcarea
Invertebrates Mya truncata
Invertebrates Neomysis integer
Invertebrates Nephtys cirrosa
Species scientific name English common name Species group
Capitella capitata Invertebrates
Crangon crangon Invertebrates
Eurydice pulchra Invertebrates
Macoma balthica Invertebrates
Macoma calcarea Invertebrates
Mya truncata Invertebrates
Neomysis integer Invertebrates
Nephtys cirrosa Invertebrates

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