LAUSR

In some countries, the red fox Vulpes vulpes has been rapidly expanding its range into urban and suburban areas, where it is referred to as the ‘urban fox’. In the city of Sapporo, northern Japan, the population of urban foxes has been increasing since the 1990s. Because the red fox carries several zoonoses, it is important to understand its population structure and migration status in urban areas, for not only basic biology but also public health. In this study, to clarify population genetic structure and gene flow, we examined the genotypes of nine microsatellite loci for 578 road-killed foxes collected in and around residential areas of Sapporo from 2002 to 2014 (except for 2009 and 2010). Based on the genotype data and spatial information for the sampled animals, we detected three subpopulations within the urban fox population. Boundaries separating the three subpopulations were a river and a railway crossing in central Sapporo. The subpopulations separated by the railway were more genetically differentiated than those separated by the river, and the railway, which is surrounded by crowded roads, may have had a greater effect on gene flow and genetic differentiation. Levels of genetic differentiation among the subpopulations in Sapporo, however, were lower than those of urban fox populations studied in other countries. Our results suggest that there is weak gene flow among the subpopulations in Sapporo.