Red list

​Red List of biotopes and habitats

A Red List threat assessment was made for 209 biotopes of which 59 were red-listed. Of the assessed biotopes, 73% were classified LC and are therefore currently not seen to be at risk of collapse.

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Only one biotope was categorized in the most severe threat category CR, the biotope delineated by aphotic muddy bottoms dominated by the ocean quahog (Arctica islandica) mussel. The Red List assessment results indicate that many of the threatened biotopes occur in the deep areas of the Baltic Sea. The reason for most of these biotopes becoming threatened is eutrophication, indirectly causing oxygen depletion in the deep areas. Many of the deep biotopes occurring on soft sediments have declined due to destructive fishing methods such as bottom trawling. Furthermore, many of the red-listed biotopes occur in the southwestern Baltic Sea due to the salinity restricted distribution of the species that are characteristic of the biotope.

Data availability is relatively poor for many biotopes and long time series are generally lacking. Therefore the threat assessment is supported by expert judgement. The confidence in the threat assessment is described as High (H), Medium (M) or Low (L).

The assessment methodology is described in detail in the BSEP138 Red List of Baltic Sea underwater biotopes, habitats and biotope complexes.

 

Biotope code

Biotope/Habitat name

Threat category

Confidence of threat assessment

Criterion for assessment

AB.H3L3

Baltic aphotic muddy sediment dominated by ocean quahog (Arctica islandica)

CR

M

A2

AA.M1Q2

Baltic photic mixed substrate dominated by stable aggregations of unattached Fucus spp. (dwarf form)

EN

L

A1

AA.H1Q2

Baltic photic mud dominated by stable aggregations of unattached Fucus spp. (dwarf form)

EN

L

A1

AA.I1Q2

Baltic photic coarse sediment dominated by stable aggregations of unattached Fucus spp. (dwarf form)

EN

L

A1

AA.J1Q2

Baltic photic sand dominated by stable aggregations of unattached Fucus spp. (dwarf form)

EN

L

A1

AA.D

Baltic photic maerl beds (unattached particles of coralline red algae)

EN

M

B1+2a(ii)

 

AB.D

Baltic aphotic maerl beds (unattached particles of coralline red algae)

EN

L

B1+2a(ii)

 

AB.B1E4

Baltic aphotic hard clay dominated by Astarte spp.

EN

M

B2c(ii)

 

AB.H3L5

Baltic aphotic muddy sediment dominated by Astarte spp.

EN

M

A1

AB.H2T1

Baltic aphotic muddy sediment characterized by sea-pens

EN

M

A1

AB.H1I2

Baltic aphotic muddy sediment dominated by Haploops spp.

EN

M

A1

AE.O5

Baltic Sea aphotic pelagic below halocline oxic

EN

L

A3

AA.G

Baltic photic peat bottom

VU

M

B2b

AB.J3L3

Baltic aphotic sand dominated by ocean quahog (Arctica islandica)

VU

M

A1

AC

Baltic Sea seasonal ice

VU

L

A1+2a

AA.E1F1

Baltic photic shell gravel dominated by vase tunicate (Ciona intestinalis)

VU

L

B1a(ii)

AB.E1F1

Baltic aphotic shell gravel dominated by vase tunicate (Ciona intestinalis)

VU

L

B1a(ii)

AA.E3Y

Baltic photic shell gravel characterized by mixed infaunal macrocommunity in fine sand-like shell fragments

NT

L

B1a(ii)

AB.E3Y

Baltic aphotic shell gravel characterized by mixed infaunal macrocommunity in fine sand-like shell fragments

NT

L

B1a(ii)

AA.E1C4

Baltic photic shell gravel dominated by kelp

NT

L

B1a(ii)

AA.A1H2

Baltic photic rock and boulders dominated by erect moss animals (Flustra foliacea)

NT

L

A1

AB.A1H2

Baltic aphotic rock and boulders dominated by erect moss animals (Flustra foliacea)

NT

L

A1

AA.M1H2

Baltic photic mixed hard and soft substrates dominated by erect moss animals (Flustra foliacea)

NT

L

A1

AB.M1H2

Baltic aphotic mixed hard and soft substrates dominated by erect moss animals (Flustra foliacea)

NT

L

A1

AA.H1B4

Baltic photic muddy sediment dominated by Charales

NT

M

A1

AA.I1B4

Baltic photic coarse sediment dominated by Charales

NT

L

A1

AA.J1B4

Baltic photic sand dominated by Charales

NT

L

A1

AA.M1B4

Baltic photic mixed substrate dominated by Charales

NT

L

A1

AA.H1B7

Baltic photic muddy sediment dominated by common eelgrass (Zostera marina)

NT

M

A1

AA.I1B7

Baltic photic coarse sediment dominated by common eelgrass (Zostera marina)

NT

M

A1

AA.J1B7

Baltic photic sand dominated by common eelgrass (Zostera marina)

NT

M

A1

AA.M1B7

Baltic photic mixed substrate dominated by common eelgrass (Zostera marina)

NT

M

A1

AA.H1A2

Baltic photic muddy sediment dominated by sedges (Cyperaceae)

NT

M

A1

AA.H1B5

Baltic photic muddy sediment dominated by spiny naiad (Najas marina)

NT

M

A1

AA.J1B5

Baltic photic sand dominated by spiny naiad (Najas marina)

NT

L

A1

AA.H3L3

Baltic photic muddy sediment dominated by ocean quahog (Arctica islandica)

NT

M

A1

AA.J3L3

Baltic photic sand dominated by ocean quahog (Arctica islandica)

NT

M

A1

AA.H3L6

Baltic photic muddy sediment dominated by Unionidae

NT

L

A1

AA.I3L10

Baltic photic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.

NT

L

A1

AB.I3L10

Baltic aphotic coarse sediment dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.

NT

L

A1

AA.J3L10

Baltic photic sand dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.

NT

L

A1

AB.J3L10

Baltic aphotic sand dominated by multiple infaunal bivalve species: Macoma calcarea, Mya truncata, Astarte spp., Spisula spp.

NT

L

A1

AA.I3L11

Baltic photic coarse sediment dominated by multiple infaunal polychaete species including Ophelia spp. (disregarding present bivalves)

NT

L

A1

AB.I3L11

Baltic aphotic coarse sediment dominated by multiple infaunal polychaet species including Ophelia spp. (disregarding present bivalves)

NT

L

A1

AA.J3L11

Baltic photic sand dominated by multiple infaunal polychaete species including Ophelia spp. and Travisia forbesii (disregarding present bivalves)

NT

L

A1

AB.J3L11

Baltic aphotic sand dominated by multiple infaunal polychaete species including Ophelia spp. and Travisia forbesii (disregarding present bivalves)

NT

L

A1

AB.A1F1

Baltic aphotic rock and boulders dominated by sea squirts (Ascidiacea)

NT

L

A1

AB.M1F1

Baltic aphotic mixed hard and soft substrates dominated by sea squirts (Ascidiacea)

NT

L

A1

AB.A1G2

Baltic aphotic rock and boulders dominated by sea anemons (Actiniarida)

NT

L

A1

AB.M1G2

Baltic aphotic mixed hard and soft substrates dominated by sea anemons (Actiniarida)

NT

L

A1

AB.A1G3

Baltic aphotic rock and boulders dominated stone corals (Scleractinida)

NT

L

A1

AB.M1G3

Baltic aphotic mixed hard and soft substrates dominated stone corals (Scleractinida)

NT

L

A1

AB.A1G4

Baltic aphotic rock and boulders dominated by soft corals (Alcyonacea)

NT

L

A1

AB.M1G4

Baltic aphotic mixed hard and soft substrates dominated by soft corals (Alcyonacea)

NT

L

A1

AB.A1J

Baltic aphotic rock and boulders dominated by sponges (Porifera)

NT

L

A1

AB.M1J

Baltic aphotic mixed hard and soft substrates dominated by sponges (Porifera)

NT

L

A1

AB.H3N1

Baltic aphotic muddy sediment dominated by Monoporeia affinis and/or Pontoporeia femorata

NT

M

A1

AB.H4U1

Baltic aphotic muddy sediment dominated by meiofauna

NT

L

A1

AB.J3L7

Baltic aphotic sand dominated by striped venus (Chamelea gallina)

NT

L

A1

 Publications

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