Unvegetated Baltic infralittoral mixed sediment (hard and soft) with sparse or no macrofaunal community

This benthic Baltic Sea habitat occurs in the photic zone with a mix of more than 10%, but less than 90% coverage of either hard and soft substrata according to the HELCOM HUB classification. Typical examples include singular rocks or boulders/stones extending above the soft substrata as well as soft substrata aggregation between abundant rocks and stones/boulders. The amount of soft substrata is affected by energy, both in the lateral and horizontal dimension, leading to a typically continuous small-scale variation in substrate composition. Sessile/semi-sessile macroscopic epibenthic fauna and flora is present where there is a sparse macrofaunal community (less than 10% coverage). In these situations microphytobenthic organisms and grazing snails (e.g. Hydrobiidae, Theodoxus, Bithynia, Radix) dominate constituting 50% in biomass or volume. Elsewhere there may be no macrovegetation present and neither macroepifauna or macro infauna. 

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