Risk Evaluation on the Impact of Deer Overabundance Consisting with Global Warming and Natural Park Management Policy, A Case Study on the Tanzawa Mountains, Central Honshu, Japan

摘要

We analyzed spatial model on sika deer (Cervus nippon) habitat selection and their distribution as well as the future risks for the forest ecosystem aiming to evaluate the influence of global warming and park management system in Pacific climate zone in Japan. We chose a local deer population on the Tanzawa Mountains., Central Japan where is less snow and employs typical natural park management system. The area has thereby suffered serious forest degradation due to deer overabundance earlier than other areas. In first part, we summarized the causes of deer overabundance with the ecological viewpoints. Second part consists of a GIS macro-scale analysis on the limiting factor of current deer distribution and the habitat selection of recent deer populations with special reference to terrain future and park management system. Regression analysis showed urban area was limiting factors of current deer distribution and such factors as slope angle, intensity of solar radiation and the presence of hunting area among well-explained deer density. These findings showed good agreements with the current spatial distribution of deer impact on the mountains. Final parts provided discussions on the future risk of deer overabundance consisting with warmer future and sustaining current natural park management policy. Thus we concluded that the risk of deer overabundance will be worsening and expanding without the bold reforms of natural park management policy and hunting system.