Urbanization has impacted the population genetic structure of the Eurasian red squirrel in Japan within a short period of 30 years

Since many kinds of wildlife have started living in urban environments, urban environments have been recognized as places of biodiversity conservation. What kind of factors facilitate or prohibit wildlife from living in urban environments? Understanding the population genetic structure of urban wildlife living would suggest the hint. In this study, we investigated the population genetic structure of Eurasian red squirrels living in urban to rural areas in Obihiro City, Hokkaido, Japan. As a result, we found that ; (1) gene flow between urban and rural populations has decreased, resulting in genetic differentiation; (2) gene flow between urban and rural populations is still maintained through the intermediate sites connected by the green spaces with rural areas (e.g., forests and windbreaks); (3) genetic distance between study sites has expanded in urban areas; (4) genetic diversity has decreased in urban areas.

Since squirrels have inhabited the urban areas in Obihiro City since the 1990s, the change in genetic structure likely occurred in only about 30 years. The genetic structure of squirrels has been shaped by the presence of busy roads, a lack of green space, and supplemental feeding. These factors have likely contributed to the changes in genetic structure over a relatively short period of about 30 years.