Unvegetated epifaunal communities on Baltic infralittoral coarse sediment

This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is coarse sediment according to the HELCOM HUB classification.  Three associated biotopes have been identified. ‘Baltic photic coarse sediment dominated by Mytilidae’ (AA.I1E1) is encountered in salinities higher than 5 psu, and is identified by a large representation of Mytilidae, at least 50% of the biomass among the epibenthic bivalves, and covering at least 10% of the seabed. The other two biotopes are 'Baltic photic coarse sediment characterized by mixed epibenthic macrocommunity' (AA.I1V) and 'Baltic photic coarse sediment dominated by microphytobenthic organisms and grazing snails' (AA.12W) where the benthic organisms or grazing snails (e.g. Hydrobiidae, Theodoxus spp, Bithynia spp, Radix spp) constitute at least 50% of the biomass or volume.

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. 

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats