Combined application of biophysical habitat mapping and systematic conservation planning to assess efficiency and representativeness of the existing High Seas MPA network in the Northeast Atlantic
The High Seas are increasingly the subject of exploitation. Although Marine Protected Areas (MPAs) are seen as a useful tool in the sustainable management of the oceans, progress in the implementation of MPA networks in areas beyond national jurisdiction has been limited. Specifically, the criteria of “representativeness” has received little consideration. This study uses the systematic conservation planning software Marxan coupled with a biologically meaningful biophysical habitat map to investigate representative MPA network scenarios and to assess the efficiency and representativeness of the existing High Seas MPA network in the Northeast Atlantic. Habitat maps were created based on the layers of water mass structure and seabed topography resulting in 30 different habitats, in six distinct regions. Conservation targets were set at 10 and 30% representation of each habitat within the final network. Two portfolios were created. The first portfolio (P1) ignored the presence of the existing MPA network within the study area allowing a non-biased selection of planning units (PUs) or sites to be chosen. The second (P2) enforced the selection of areas within the existing MPA network. Efficiency was measured as the difference in the percentage area contained within the “best scenario” MPAs from the un-bias run (P1) compared with (P2). Representativety of the existing network was assessed through the investigation of the properties of PUs included within MPAs in the “best scenario” Marxan output of P2. The results suggest that the current MPA network is neither efficient nor representative. There were clear differences in the spatial distribution of PUs selected in P1 compared with P2. The area required to be protected to achieve that the representation of 10 and 30% of each habitat was 8–10 and 1–4% higher, respectively, in P2 compared with P1. Abyssal areas in all regions are underrepresented within the current MPA network.