Red List of European Habitats
Habitat code & name
AA.A1C–Baltic photic rock and boulders characterized by perennial algae
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 habitats 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. Perennial attached algae such as Fucus spp., perennial
red algae or kelp cover at least 10% of the seabed and more than other perennial
attached erect groups. In areas of low salinity, the dominating species can be plants with
their roots between and their canopy spreading over the boulders. Mapping should take
place during the months when the vegetation is fully developed. Salinity range: all;
Exposure range: all, more common in exposed areas; Depth range: photic zone usually
down from about 0.5 meters.
Five sub-biotopes with different dominant species of algae can be identified. ‘Baltic
photic rock and boulders dominated by Fucus spp.’ (AA.A1C1) can be identified where
Fucus spp. such as Fucus radicans, F. serratus or F. vesiculosus constitute at least 50% of
the biovolume of the perennial attached algae. The biotope is found in the photic zone,
usually at a depth of 0.5 – 5 meters and in salinities over 5 psu. It’s distributed in the whole
Baltic Sea except in the Bothnian Bay and the most eastern part of the Gulf of Finland.
‘Baltic photic rock and boulders dominated by perennial non-filamentous corticated red
algae’ (AA.A1C2) can be identified where corticated red algae species such as
Furcellaria lumbricalis constitute at least 50% of the biovolume of the perennial attached
algae. The biotope is found in the photic zone, usually at a depth of 2 – 10 meters and in
salinities over 5 psu. It’s distributed in the whole Baltic Sea except in the Bothnian Bay and
the most eastern part of the Gulf of Finland.
‘Baltic photic rock and boulders dominated by perennial foliose red algae’ (AA.A1C3)
can be identified where foliose perennial red algal species such as Coccotylus spp.,
Phyllophora spp. and Delesseria spp. constitute at least 50% of the biovolume of the
perennial attached algae. The biotope is found in the photic zone, usually at a depth of
2 – 10 meters and in salinities over 4 psu. It’s distributed in the whole Baltic Sea except in
the Gulf of Bothnia north of the Archipelago Sea and the eastern half of the Gulf of
Finland.
‘Baltic photic rock and boulders dominated by kelp’ (AA.A1C4) can be identified where
perennial attached kelp species such as Saccharina latissima and Laminaria digitata
constitute at least 50% of the biovolume of the perennial attached algae. The biotope is
found in the photic zone, usually at a depth of 2 – 10 meters and in salinities over 11 psu.
It’s distributed only in the Sound and the Belt Sea.
‘Baltic photic rock and boulders dominated by perennial filamentous algae’ (AA.A1C5)
can be identified where perennial filamentous algal species such as Polysiphonia spp,
Aegagrophila linnaei, Cladophora rupestris constitute at least 50% of the biovolume of
the perennial attached algae. The biotope is found in the photic zone, usually at a depth
of 0.5 – 10 meters and in all salinities. It’s distributed in the whole Baltic Sea.
Characteristic species
Fucus spp., Furcellaria lumbricalis, Coccotylus truncatus, Phyllophora spp., Deleseria
sanguinea, Saccharina latissima, Laminaria digitata , Polysiphonia spp., Cladophora
rupestris, Sphacelaria spp.
Indicators of quality
Lower limit of vegetation, especially Fucus spp. where applicable; amount of epiphytic
algae.
Relationships with other schemes
Annex 1 relationships
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped
by HELCOM.
MAES relationships
Marine - Marine inlets and transitional waters
Marine - Coastal
MSFD relationships
Littoral rock & biogenic reef
Shallow sublittoral rock & biogenic reef
EUSeaMap relationships
Shallow photic rock or biogenic reef
IUCN ecosystem relationships
9.2 Subtidal rock and rocky reefs
9.7 Makroalgal/Kelp
Other relationships
Level 5 of the HELCOM HUB classification (2013). This habitat has five sub-habitats on HUB
level 6;
‘Baltic photic rock and boulders dominated by Fucus spp.’ (AA.A1C1),
‘Baltic photic rock and boulders dominated by perennial non-filamentous corticated red
algae’ (AA.A1C2),
‘Baltic photic rock and boulders dominated by perennial foliose red algae’ (AA.A1C3),
‘Baltic photic rock and boulders dominated by kelp’ (AA.A1C4), and
‘Baltic photic rock and boulders dominated by perennial filamentous algae’ (AA.A1C5).
Photograph
-
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






Map
This will be inserted by NatureBureau based on the Regional Sea information above.
References
-