Frontiers in identifying conservation units: from neutral markers to adaptive genetic variation

Conserving endangered species is always a complex task. Our recent study on the endangered walia ibex Capra walie outlined that using multiple approaches, including molecular phylogeny, population genetics and ecological data, can considerably help to identify conservation units and management strategies (Gebremedhin et al., 2009). Crandall (2009), Festa-Bianchet (2009) and Schwartz (2009) all highlighted a central point: the importance of adaptive genetic variation in the identification of conservation units. In the near future, we believe that adaptive genetic variation will become an increasingly important topic of conservation genetics. Neutral genetic markers (or markers assumed to be neutral) are currently the most common tools to reconstruct phylogenies, assess gene flow and spatial structure and to identify conservation units (Hoffmann Storz Crandall, 2009; Schwartz, 2009). Models of genetic differentiation on specific loci, determined by geographic distance and ecological gradients. (a) Geographic isolation causes differentiation at neutral loci (grey lines), but not at loci under stabilizing or balancing selection (dashed line); (b) environmental gradients cause stronger differentiation at loci under directional selection (black line) than at neutral loci (grey lines). Note that in the case of Capra walie and Capra nubiana, geographical and ecological gradients are partially overlapping. Redrawn after Schmidt et al. (2008). Ecological data, and the recently available tools of ecological niche modelling, can provide important insights and help incorporate information on ecological traits when identifying conservation units (Guisan Crandall, 2009; Festa-Bianchet, 2009; Schwartz, 2009). Variation at adaptive loci might have profound effects on population dynamics, heavily impacting the response to environmental changes, stress, diseases and, finally population persistence (Reusch Hoffmann Bensch et al., 2006). Considering adaptive loci, in addition to supposedly neutral ones, can provide additional important information (Hoffmann strategies to increase the ecotourism towards this charismatic ibex might help to gather the money needed to secure the future of the unique biota of the Simen mountains. We thank the Editors of Animal Conservation for suggesting that our paper be published as Featured Paper. We greatly appreciated the insightful comments of K. Krandall, M. Festa-Bianchet and M. Schwartz.