Aquatic moss communities on Baltic infralittoral rock and mixed substrata (predominantly hard)

This is a Baltic Sea benthic habitat in the photic zone where at least 90% of the substrate is rock, boulders or stones according to the HELCOM HUB classification, or mixed (predominantly hard) substrates where the percentage of rock is lower but between 10- 90%. Perennial mosses cover at least 10% of the seabed and more than other perennial attached erect groups. In some places the mosses form extensive underwater meadows which provide shelter and food for benthic animals. The habitat typically occurs where the salinity is <5 psu and usually from depths of 1-7m. Whilst more common in exposed areas, it does occur under other conditions of exposure to wave action and currents. 

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.Depth range, biodiversity and the amount of epiphytic ephemeral filamentous algae are potential indicators of quality.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats