Contrasted hybridization patterns between two local populations of European wildcats in France

Abstract

The European wildcat (Felis silvestris silvestris) is threatened across the totality of its area of distribution by hybridization with the domestic cat F.s. catus. The underlying ecological processes promoting hybridization, remain largely unknown. In France, wildcats are mainly present in the North-East but signs of their presence in the Pyrenees have been recently provided. However, no studies have been carried out in the French Pyrenees to assess the genetic status of wildcats. We have compared a local population of wildcats living in a continuous habitat in the French Pyrenees and a local population of wildcats living in a fragmented habitat in Northeastern France to evaluate how habitat fragmentation influence the population structure of European wildcats. Close kin were not found in the same geographic location contrary to what was observed for females in the Northeastern wildcat population. Furthermore, there was no evidence of hybridization in the Pyrenean wildcats and only one domestic cat raised suspicions while hybridization was categorically detected in northeastern France. The two wildcat populations were significantly differentiated (Fst = 0.08) and the genetic diversity of the Pyrenean wildcats was lower than that of other wildcat populations in France and in Europe. Taken together, these results suggest that habitat fragmentation, and in particular the absence of agricultural fields, may play an important role in lowering the probability of hybridization by reducing the likelihood of contact with domestic cats. Moreover, our results suggest that the French Pyrenean wildcat populations is isolated and may be threatened by a lack of genetic diversity.