Cost-effectiveness of temporary electric fencing for preventing wild boar intrusion into small-scale paddy farmlands

Crop damage by wild boar is a serious problem globally. Temporary electric fences, installed only during periods when the damage occurs, are widely used in Japan to prevent wild boar intrusion. The exclusion method is effective, but the cost burden involved makes considering cost-effectiveness necessary, especially for small-scale paddy rice farmers. Group fences may be used to reduce the cost burden. Although enclosing an area this way is effective, it may lead to free-riding when the scale of the project becomes large. Measures like reducing the number of people involved are suggested, but few indicators exist regarding the appropriate scale of management. Therefore, in Chiba Prefecture, where the distribution of wild boar is expanding, we conducted i) a six-year survey on the amount of damage to paddy rice fields in the Awa region; ii) an evaluation of the cost-effectiveness of temporary electric fences; and iii) an extrapolation of the cost-effectiveness to the entirety of Chiba Prefecture. The results show that the optimal installation length can be calculated by considering the maximum damage area, but without a government subsidy, the fence cost-effectiveness will be low because the installation cost will exceed the maximum damage amount. A group enclosure of small farmlands, which is not currently cost-effective in Chiba Prefecture, is recommended as a management decision for planners and farmers in future damage control plans. Although the empirical data were specific to small-scale farmers in Japan, the validation process was considered broadly applicable.