Going west-invasion genetics of the alien raccoon dog Nyctereutes procynoides in Europe

Abstract

The raccoon dog, a medium-sized carnivore, has long been recognised as a prominent example of an invasive alien species in Europe with a wide distribution, significant ecological impact and remarkable dynamics of spread at both national and continental scales. We conducted a study of genetic diversity of 73 individuals collected at 20 sites across North and Central Europe to (1) identify major phylogenetic lineages and (2) elucidate spatial patterns of population genetic structure. Reconstructed phylogenies reveal two major clades differing on average by Tamura-Nei corrected distance of 3.4% for a 599-bp segment of the mitochondrial control region corresponding to a coalescence time of approximately 457,800 years ago (95% CI, 223,300-773,900). Many expectations based on introduction history, such as the presence of signatures of repeated founder effects and subsequently rapid population expansion, were not confirmed by our demographic analyses, probably due to an insufficient amount of time since translocations. Nevertheless, global FST = 13.9% and landscape approaches provided evidence for weak population genetic structure that followed a pattern of isolation by distance. Finally, we found no congruence between previously reported morphological differentiation and the sorting of mtDNA variation. We therefore conclude that an exceptional combination of factors including multiple translocations, secondary contact and admixture of divergent matrilineages, as well as natural processes of colonisation associated with a wide ecological tolerance, promoted the successful spread of the raccoon dog into Europe. © Springer-Verlag 2009.