Annual algal communities on Baltic infralittoral sand
Quick facts
Red List habitat type | code BAL27 |
---|---|
Threat status | |
Europe | Least Concern |
EU | Least Concern |
Relation to |
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Source | European Red List habitat factsheet |
European Red List of habitats reports | |
European Red List of habitats (Excel table) |
Summary
This benthic Baltic Sea habitat occurs in the photic zone with at least 90% coverage of sand according to the HELCOM HUB classification. Annual algae cover at least 10%, while all other epibenthic biotic structures like rooted plants, unattached perennial algae or blue mussels cover less than 10%. The habitat occurs in the full salinity range of the Baltic Sea and is more common in moderate to sheltered, very shallow areas.
Two associated biotopes with different dominant species of algae (at least 50% of the biovolume of the annual algae) have been identified. ‘Baltic photic sand dominated by Chorda filum and/or Halosiphon tomentosus’ (AA.J1S2) usually down to a depth of 4 meters, in areas moderately exposed to wave action. These species give the appearance of growing on the sand but attach to small fractions of stable substrate like small stones, shell fragments or gravel buried in the sand. It is distributed in the whole Baltic Sea except in the most northern part of the Bothnian Bay. A second associated biotope, ‘Baltic photic sand dominated by Vaucheria spp.’ (AA.J1S3), is usually present down to a depths of 7 meters, in areas more sheltered areas and in salinities less than 7 psu. It is distributed in the whole Baltic Sea except for the Belt Sea and the Sound.
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.
Threat status
Synthesis of Red List assessment
The overall assessment for this EUNIS level 4 habitat has been based on the HELCOM (2013) assessments for the associated HELCOM HUB biotopes. Draft assessments were derived using a weighted approach whereby the HELCOM assessment outcomes were assigned a score. This was averaged across the relevant biotopes. The outcomes were reviewed by Baltic experts to reach a final conclusion. HELCOM (2013) assessed the two relevant Baltic biotopes (AA.J1S1 and AA.J1S2) as Least Concern (A1). With no additional information on changes in extent or quality of this habitat, the current expert opinion is an assessment of Least Concern for both the EU 28 and EU 28+.
EU | |
Red List Category | Red List Criteria |
Least Concern | - |
Europe | |
Red List Category | Red List Criteria |
Least Concern | - |
Confidence in the assessment
Pressures and threats
- No threats or pressures
- No threats or pressures
Habitat restoration potential
Trends in extent |
|
Average current trend in quantity |
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Stable ![]() |
Stable ![]() |
EU28 | EU28+ |
Trends in quality |
|
Average current trend in quality |
|
Unknown ![]() |
Unknown ![]() |
EU28 | EU28+ |
Conservation and management needs
List of conservation and management needs
- No measures
- No measures needed for the conservation of the habitat/species
Distribution
Geographic occurrence and trends
Seas | Present or presence uncertain | Current area of habitat (Km2) | Recent trend in quantity (last 50 years) | Recent trend in quality (last 50 years) |
---|---|---|---|---|
Baltic Proper | Present | Unknown | Unknown | Stable |
Gulf of Bothnia | ||||
Gulf of Finland | ||||
Gulf of Riga | ||||
The Sound | ||||
Belt Sea |
Extent of Occurrence, Area of Occupancy and habitat area
Extent of Occurrence (EOO) (Km2) | Area of Occupancy (AOO) | Current estimated Total Area | Comment | |
---|---|---|---|---|
EU28 | >50,000 | >50 | Unknown | This habitat is present in all the Baltic sub-basins. |
EU28+ | >50 | Unknown | This habitat is present in all the Baltic sub-basins |
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).
Characteristic species
Species scientific name | English common name | Species group |
---|---|---|
Chorda filum | Algae | |
Halosiphon tomentosus | Algae |