Challenges in managing invasive raccoons in Japan

Abstract

Context In Japan, the raccoon is an invasive, non-native mammal that causes significant agricultural damage and impacts on native biodiversity throughout the country. Local governments are mainly responsible for raccoon management. Intensive control campaigns focused on the early invasion stage have controlled raccoons in some regions but, generally, there are very few regions where raccoon numbers have been reduced sustainably, and no raccoon populations have been eradicated. Aims To improve national management of raccoons and canvass the opinions and perceptions of local government officers involved in raccoon control, and to review the efficiency and effectiveness of raccoon management strategies. Methods A questionnaire survey of 47 prefectural and 366 municipal governments was conducted, regarding raccoon management measures, during 2012 and 2013. The survey covered two topics: (1) management difficulties experienced by officers; and (2) details of the current raccoon management regime. Key results Efforts to manage raccoon populations have encountered some difficulties, including shortages of raccoon control officers, funding, expertise in raccoon biology and management, and lack of information about the invasion status of local raccoon populations and ecological traits of raccoons. Prefectures not currently managing raccoons indicated that they suffered from a lack of appropriate management procedures. However, current management programs were not generally functioning efficiently or effectively because many local governments did not implement appropriate monitoring. About 70% of local governments did not set control target indices, and there were very few quantitative datasets that could be used to measure the effectiveness of control in reducing raccoon impacts. Conclusions Best practice management programs have been being implemented in very few government areas, with institutional characteristics and difficulties in obtaining relevant information causing major problems. Implications Collecting and sharing information about effective raccoon management methods and case study examples from successful regions would enable other local administrations to select and implement the most effective and efficient control strategy, methods and monitoring program for their region.