Faunal communities in estuarine Atlantic sublittoral coarse sediment

This habitat comprises clean gravels that occur in the upper reaches of marine inlets, especially estuaries, where water movement is sufficiently strong to remove the silt content of the sediment. It is one of the rarer habitat types to occur in estuaries. The gravel may be moved and reworked depending on tidal and river currents and may be infilled palaeo-river channels. The habitat typically lacks a significant seaweed component and is characterised by a sparse but very robust brackish water tolerant fauna. The epifauna of this habitat tends to be dominated by mobile predatory species. 

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.

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.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats