Ecological coherence assessments of a Marine Protected Areas (MPA) network in the Baltic Sea
The Helsinki Commission (HELCOM), also known as the Baltic Marine Environment Protection Commission, is an intergovernmental organisation and regional sea convention in the Baltic Sea area. It comprises ten Contracting Parties (Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the EU) forming a platform for environmental policy making at a regional level, with the goal of protecting the Baltic Sea from all sources of pollution through intergovernmental co-operation. HELCOM’s aim is to have a healthy Baltic Sea environment with diverse biological components functioning in balance, leading to good ecological status and supporting a range of sustainable socio-economic activities.
A key element of the Baltic Sea Action Plan is to achieve “a favourable status of Baltic Sea biodiversity” and the designation of MPAs has been an important measure in working to meet this commitment under HELCOM Recommendation 35-1. HELCOM identified the further goal of reaching an ecologically coherent network of MPAs, in order to deliver more benefits than individual, separate sites. Authors therefore had to assess the ecological coherence of the current network and identify areas for improvement and the need for implementation of further management measures. The assessment considered four elements; representativity, replication, adequacy and connectivity, as well as the first attempt at a quantitative integrated approach for assessing ecological coherence, to determined if the overarching objectives of Recommendation 35-1 were being accomplished. Benthic habitat data for across the study area was therefore needed to assess the representativity of each habitat in MPAs.
EUSeaMap (2016) was used in the representativity assessment for the HELCOM MPA network. Benthic marine landscape categories were derived from the EUSeaMap project, based on light, bottom substrate and salinity in the Baltic Sea. This information was freely available, and covered the entire Baltic study area. For simplicity, the original 60 categories of benthic substrate were combined into 30, based on salinity values and bottom substrata. Benthic marine landscape categories were also used as a proxy for diversity. This marine habitat spatial data was combined with shapefiles of the Baltic Sea sub-basins, coastal zones and MPAs, and used to determine the coverage of each benthic habitat category within the HELCOM MPA network. This analysis identified that some of the criteria for representativity were met, but with some gaps. The minimum target of 10% of the marine area to be designated as ‘protected’ was met for some sub-basins but not all, and minimum targets for protection of habitats is not met for 40% of habitat types. Additionally, for those habitats identified as “rare”, none had met their protection target.
This assessment identified the marine benthic habitats for which there is currently not enough protection given in the Baltic Sea area, as well as the next steps for improving the coherence of the MPA network including maximising the chance of enhancing coherence when designating new MPAs and further development of the assessment methodology for the next ecological coherence assessment. HELCOM are aiming to include all Baltic Sea MPAs (e.g. Ramsar sites, national protected areas and Important Bird Areas) in future assessments, rather than just the HELCOM MPAs and Nature 2000 sites used in this initial assessment.