complexes form a functional unit on a landscape scale. Several different
biotopes and habitats can occur in a biotope complex, which is often defined by
biotopes and habitats being arranged in a specific pattern.
Ten biotope complexes were assessed by the Red List criteria and all biotope complexes were red-listed. Some of the biotopes that constitute the biotope complex were not red-listed as biotopes, indicating that the landscape pattern is more threatened than the smaller biotopes. All biotope complexes, except one, were assessed based on a decline in quality by Criterion C. The spatially restricted biotope complex Submarine structures made by leaking gas was assessed by the rarity Criterion B.
The ten biotope complexes recognized in HELCOM HUB are also listed in the EU Habitats Directive Annex 1. The HELCOM contracting parties that are also EU members monitor the trends in quantity and quality of the biotope complexes.
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 complex (HD Annex 1 description, EUR 27)
Confidence of threat assessment
Criterion for assessment
Submarine structures made by leaking gases
Sandbanks which are slightly covered by sea water all the time
Mudflats and sandflats not covered by seawater at low tide
Large shallow inlets and bays
Boreal Baltic narrow inlets
Baltic esker islands with sandy, rocky and shingle beach vegetation
and sublittoral vegetation
Boreal Baltic islets and small islands