Landscape Genetic Analysis for the Japanese Wild Boar in the Early Expanding Stage in the Hokuriku Region of Japan

As a contribution to improving management of the Japanese wild boar (Sus scrofa leucomystax), which has recently expanded its range and is having some negative effects on the ecosystem, we conducted a landscape genetic study using individual-based genetic analysis and multiple landscape elements to elucidate its dispersal patterns in the early stage of its expansion. Microsatellite DNA analysis of Japanese wild boars in the Hokuriku region of Japan revealed the existence of two ancestral genetic clusters, that they had migrated via different pathways, and that they were inadequately admixed. We also inferred the most suitable habitats for Japanese wild boar using MaxEnt and concluded that lower elevation and snowfall may favor the occurrence of wild boar individuals. Landscape genetic analysis indicated regional differences in Japanese wild boar dispersal patterns, according to the spatial heterogeneity of genetic features and landscape elements. On the western side of the study area, where individuals with a high frequency of one of two ancestral clusters were more abundant, significant effects of isolation by distance and resistance due to the above two landscape factors were detected, suggesting unidirectional dispersion influenced by the alpine landscape. In contrast, on the eastern side, there was indication of resistance to dispersal of individuals predominantly possessing another ancestral cluster, suggesting the influence of irregularly arranged suitable habitats due to the complexity of the mountainous terrain. Based on our findings, we conclude that Japanese wild boar dispersal patterns may be influenced by landscape elements, such as alpine mountains.