Estimating relative population size included within protected areas

We propose and test a method to determine the proportion of specific animal national populations included in a network of protected areas. The proposed method further allows identifying the best potential new sites to be included in the network, to reach target population sizes and so to test whether a network extension is realistic or not. We used data from the French Breeding Bird Survey (BBS) and spatial interpolation models known as kriging to predict the relative abundance of species at a national scale. We applied the proposed methodology to Special Protection Areas (SPAs) and a sample of 20 bird species concerned by the Directive of the Council of the European Community on the Conservation of Wild Birds. We estimated which relative part of the national population is included within the boundaries of all national SPAs. Our results suggest that the current SPA network is probably not efficient to ensure favorable national conservation status for the most widespread species, but allows reaching a 5% target value for more localized ones. Consequently, we discuss the limit of such a protected area network to ensure the global conservation of widespread species, and therefore the need for other large-scale conservation measures.