Broad-scale mapping of seafloor habitats in the north-east Atlantic using existing environmental data

摘要

If marine management policies and actions are to achieve long-term sustainable use and management of themarine environment and its resources, they need to be informed by data giving the spatial distribution of seafloorhabitats over large areas. Broad-scale seafloor habitat mapping is an approachwhich has the benefit of producingmaps covering large extents at a reasonable cost. This approach was first investigated by Roff et al. (2003), who,acknowledging that benthic communities are strongly influenced by the physical characteristics of the seafloor,proposed overlaying mapped physical variables using a geographic information system (GIS) to produce anintegrated map of the physical characteristics of the seafloor. In Europe the method was adapted to the marinesection of the EUNIS (European Nature Information System) classification of habitat types under the MESHproject, andwas applied at an operational level in 2011 under the EUSeaMap project. The present study compiledGIS layers for fundamental physical parameters in the northeast Atlantic, including (i) bathymetry, (ii) substratetype, (iii) light penetration depth and (iv) exposure to near-seafloor currents andwave action. Based on analysesof biological occurrences, significant thresholds were fine-tuned for each of the abiotic layers and later used inmulti-criteria raster algebra for the integration of the layers into a seafloor habitat map. The final result was aharmonised broad-scale seafloor habitat map with a 250 m pixel size covering four extensive areas, i.e. Ireland,the Bay of Biscay, the Iberian Peninsula and the Azores. The map provided the first comprehensive perceptionof habitat spatial distribution for the Iberian Peninsula and the Azores, and fed into the initiative for a pan-European map initiated by the EUSeaMap project for Baltic, North, Celtic and Mediterranean seas.