Infaunal communities of Baltic upper circalittoral sand not dominated by bivalves

This habitat occurs on Baltic aphotic bottoms with at least 90% coverage of sand according to the HELCOM HUB classification. Sessile/semi-sessile epibenthic macrofauna are generally not present while the biomass of infauna is typically dominated by polychaetes, crustaceans, or insect larvae. This habitat is encountered in sand typically at depths below 30m in moderate to high energy exposure areas. Three associated biotopes have been identified variously characterised by infaunal polychates (Pygospio elegans, Marenzelleria spp. and Hediste diversicolor), crustaceans (Monoporeia affinis and Saduria entomon) or midge larvae (Chironomidae). These species groups constitute at least 50% of the biomass.

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 overtime. 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. Diversity, abundance and biomass of fauna are potential indicators of quality.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats