Red List of Biotope Complexes

Biotope 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.