Red deer in the Pyrenees: a risky secondary contact zone for conservation genetics

Natural events over time, and human interventions, influence the genetic structure of species. The red deer (Cervus elaphus) is widely distributed in Europe, with a large-scale genetic structure largely determined by Pleistocene climatic oscillations. The Iberian Peninsula acted as one of the main glacial refuges for many species; a particular red deer lineage remains on the peninsula and is subjected to special conservation policies. The mountain range of the Pyrenees might be a contact zone where Iberian red deer (Cervus elaphus hispanicus) could hybridize with other central European genetic lineages. In the late twentieth century, the natural distribution areas of red deer on both sides of the Pyrenees became closer because of restocking from central Iberia to areas south of the Pyrenees and from French populations to areas north of the Pyrenees. We analyzed the genetic structure of red deer populations in the Pyrenees to investigate the underlying processes of population contact and hybridization. The analysis of microsatellite genotypes showed 2 genetic clusters. One of these clusters associated with Iberian red deer, whereas the other presented European non-Iberian genetic composition. Migration and hybridization events occurred between both genetic clusters, mostly in the eastern part of the sampling area. The Pyrenees is currently a secondary contact zone caused by anthropogenic translocations, and a risky hybrid belt for red deer genetic conservation.