Red List of European Habitats
Habitat code & name
AA.A1E–Baltic photic rock and boulders characterized by epibenthic bivalves
Author and Date
HELCOM RED LIST Biotope Expert Team, November 2013.
Relationship to EUNIS
The biotope does not correspond directly to any EUNIS (2004) level 4 habitat due to
structural differences the classification systems. The closest correspondence in EUNIS is to
sub-habitats of ‘Baltic exposed infralittoral rock’ (A3.4), ‘Baltic moderately exposed
infralittoral rock’ (A3.5) and ‘Baltic sheltered infralittoral rock’ (A3.6).
Habitat description
Baltic bottoms in the photic zone with at least 90% coverage of rock, boulders or stones
of more than 63 mm in diameter. Sessile/semi-sessile epibenthic bivalves such as Mytilus
spp. or Dreissena polymorpha cover at least 10% of the seabed and more than other
perennial attached erect groups. Salinity range: All; Exposure range: all, more common in
exposed areas; Depth range: photic zone.
Two sub-biotopes with different dominant mussel species can be identified. ‘Baltic photic
rock and boulders dominated by Mytilidae’ (AA.A1E1) can be identified where Mytilidae
such as Mytilus spp. or Modiolus modiolus constitute at least 50% of the biomass. The
biotope is found in the photic zone, usually at a depth of 5 – 20 meters, in all exposure
classes and in salinities over 5 psu. It’s distributed in the whole Baltic Sea except for the
northern parts of the Bothnian Bay.
‘Baltic photic rock and boulders dominated by zebra mussel (Dreissena polymorpha)’
(AA.A1E2) can be identified where Dreissena polymorpha constitute at least 50% of the
biomass. The biotope is found in the photic zone, usually at a depth of 2 – 10 meters, in
sheltered to moderate exposure and in salinities less than 5 psu. It’s distributed only in the
eastern parts of the Gulf of Finland and along the Estonian west coast.
Characteristic species
Mytilus spp., Modiolus modiolus, Dreissena polymorpha.
Indicators of quality
Diversity, abundance and biomass of fauna associated with the mussel beds.
Relationships with other schemes
Annex 1 relationships
A list of equivalent habitat types from Annex 1 of the Species & Habitats Directive at
http://ec.europa.eu/environment/nature/legislation/habitatsdirective/docs/2007_07_im.
MAES relationships
Marine - Marine inlets and transitional waters
Marine – Coastal
MSFD relationships
A list of equivalent MSFD Predominant habitat types
http://biodiversity.europa.eu/maes/crosswalks-between-european-marine-habitattypologies_10-04-14_v3.pdf
EUSeaMap relationships
A list of the equivalent EUSeaMap categories
http://biodiversity.europa.eu/maes/crosswalks-between-european-marine-habitattypologies_10-04-14_v3.pdf
IUCN ecosystem relationships
A list of equivalent habitat types from
http://www.iucnredlist.org/documents/Dec_2012_Guidance_Habitats_Classification_Sch
eme.pdf
Other relationships
Level 5 of the HELCOM HUB classification (2013). This habitat has two sub-habitats on HUB
level 6; ‘Baltic photic rock and boulders dominated by Mytilidae’ (AA.A1E1) and ‘Baltic
photic rock and boulders dominated by zebra mussel (Dreissena polymorpha)’(AA.A1E2).
Photograph
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Countries list
To be inserted when data sheets completed.
Regional Sea
Baltic Sea
Baltic Proper
Belt Sea
Gulf of Bothnia
Gulf of Finland
Gulf of Riga
The Sound
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Map
This will be inserted by NatureBureau based on the Regional Sea information above.
References
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