Low rates of hybridization between European wildcats and domestic cats in a human-dominated landscape

Hybridization between wild species and their domestic congeners is considered a major concern for species conservation. Genetic integrity of the European wildcat, for instance, is of interest as the species is outnumbered by domestic cats by several orders of magnitude throughout its range. We genotyped 1071 individual wildcat samples obtained from hair traps and roadkills collected across the highly fragmented forests of western central Europe, in Germany and Luxembourg, to assess domestic cat introgression in wildcats in human-dominated landscapes. Analyses using a panel of 75 autosomal SNPs suggested a low hybridization rate, with 3.5 % of wildcat individuals being categorized as F1, F2 or backcrosses to either parental taxon. We report that SNP data appeared to be more consistent than our set of 14 microsatellite markers and that SNPs showed higher accuracy to detect hybrids and their class in simulation analyses and were less affected by underlying population structure. Our results strongly suggest that very high hybridization rates previously reported for central Europe may be partly due to inadequate choice of markers and/or sampling design. Our example documents that a carefully selected SNP panel for hybrid detection may be used as an alternative to commonly applied microsatellite markers, including studies relying on non-invasively collected samples. In addition, our finding of overall low hybridization rates in central European wildcats provides an example of successful wildlife coexistence in human-dominated, fragmented landscapes.