Identifying priority areas for island endemics using genetic versus specific diversity – The case of terrestrial reptiles of the Cape Verde Islands

Abstract

Genetic diversity is critical for conservation of endemic populations. It enhances adaptation to rapid environmental changes and persistence over evolutionary time-scales. In small and isolated populations, such as on islands, this is even more relevant. Nevertheless, few studies regarding the establishment of protected areas (PAs) on islands have taken genetic diversity into account. The Cape Verde Islands are in a biodiversity hotspot and present to resource planners unique problems and possibilities, hence are a good case study. This work primarily aims to compare targeting evolutionary significant units (ESUs) versus species in reserve selection algorithms for the conservation of the endemic Cape Verdean reptile diversity by assessing the PAs network adequacy, identifying its gaps, and optimizing it based on ‘realistic’ (considering areas inside PAs with lower cost) and ‘ideal’ (considering all non-humanized areas with higher potential for conservation) cost scenarios. Results clearly indicate that analyses targeting ESUs are more effective in the protection of genetic diversity and less costly in terms of selected area, in total and inside PAs. Results also indicate that most ESUs and species are insufficiently protected and that extra PAs are needed on most islands to reach conservation targets. Surprisingly, the total area selected in ‘ideal’ and ‘realistic’ prioritization scenarios are identical on most islands both for analyses targeting ESUs or species. Therefore the ‘realistic’ scenario should be largely followed. The work provides an innovative methodological framework for supporting the use of genetic diversity in reserve design and its results should assist in local-scale conservation planning.