Trends in sika deer population in an urban–suburban area
摘要
As urbanization encroaches the habitats of wild animals, humans encounter and coexist with wild mammals more often. Wild mammals such as deer may negatively affect humans living urban or suburban areas by causing traffic accidents and spreading tick-borne pathogens. To control deer populations around urban areas, trends in deer population should be analyzed. However, long-term monitoring studies of deer population trends in urban areas and the surrounding forests are scarce. Hence, in this study, we analyzed the trends in sika deer population in forests surrounding Lake Shikotsu in Hokkaido, Japan, and determined its relationship with the distance from the study area to urban areas. We employed the spotlight count method to record the number of deer, and we calculated the relative densities of sika deer in the study area. Our results revealed that the density of sika deer in the study area increased by 3.5-fold over a 10-year survey period. In addition, our results confirmed the increase in deer populations around urban areas, not just the source population of deer far from urban areas, suggesting the possibility of further increases around urban areas. Therefore, to prevent conflicts with deer in urban areas, it is necessary not only to identify suitable habitats but also to implement intensive population control in source populations and populations around urban areas.