Gap analysis of European wetland species: priority regions for expanding the Natura 2000 network

Abstract

Protected areas in the European Union under the Natura 2000 reserve system cover about 17 percent of the total land area. Systematic evaluations of the effectiveness of the current reserve system have been scarce and restricted to regional assessments. One reason for that may be the poor availability of comprehensive fine scale biodiversity data for the highly fragmented and densely human-populated European continent. We apply recently developed modeling tools for systematic conservation planning to conduct a detailed gap analysis using coarse scale species occurrence data. The employed mathematical model uses mixed integer programming to determine the cost-minimizing distribution of habitat locations subject to biophysical, economic, and policy restrictions. We include fine scale wetland habitat data as well as species-specific proxies for population density and viable population threshold. First, we evaluate the performance of the current Natura 2000 system in covering endangered wetland vertebrate species. Results show that five area-demanding vertebrates are not covered by the current reserve system. Second, we identify potentials for expanding the network to move toward complete coverage for the considered species mostly in countries of North-Eastern Europe. About 3 million hectares of additional reserve area at a cost of 107 million Euro per year would be required to achieve coverage of all considered species. Third, we present spatially explicit priority regions for a cost-effective expansion of the current reserve network.