Key connectors in protected forest area networks and the impact of highways: A transnational case study from the Cantabrian Range to the Western Alps (SW Europe)

The connectivity of protected area networks depends on key elements located in strategic positions within the landscape, which uphold the ecological fluxes and sustain the diversity and longterm viability of native biota. Landscape planning requires objective and quantitative approaches to identify those key elements and reinforce the spatial coherence of protected area designs and related conservation schemes. With this objective, we apply for the first time recent methodological developments that, deriving from the probability of connectivity index, allow evaluating the role of both individual protected areas and links in the intermediate landscape matrix as providers of connectivity between the rest of the sites in the network. We focus on a case study covering the forest protected areas from the Cantabrian Range to the Western Alps (N Spain, S France and NW Italy), considering different dispersal distances and the impact of highways. We show how the proposed approach is useful to identify those protected areas and links that most contribute to uphold functional connectivity in this transnational network, as well as those road sectors where the defragmentation and barrier effect mitigation measures should be prioritized. We compare our results with other more qualitative and expert-based approaches that have been reported in the same area. The methodological approach could be easily adopted in a variety of other related landscape planning applications at different scales, with the required quantitative tools being available as free and open source software packages. (C) 2011 Elsevier B.V. All rights reserved.