Abstract
Agricultural/forestry damages caused by Hokkaido sika deer have been drastically increasing recently. So as to take appropriate responses to this issue, the Hokkaido government formulated a plan called ‘Conservation and Management Plan for Sika Deer' in 2000. Its main purpose is to reduce agricultural/forestry damages, but the ecological and economical validity of the target resource level has not been fully examined. This paper, therefore, addresses the optimal management of Hokkaido sika deer from a bioeconomic view point.
We examine three cases; in the first case, we regard a forest owner as a decision-maker, and the price of deer meat (venison) is exogenously given to the decision-maker. In the other cases, we regard a public authority as a decision-maker and assume that the price is a function of harvest. We compare the situation where the public authority behaves socially optimally with the situation where it acts as a monopolist.
Based on numerical simulations, the following results are obtained. Firstly, when the revenue from forestry products is sufficiently high, wildlife should be controlled below the population level corresponding to maximum sustainable yield. Secondly, there exists a unique population level where a certain sustainable resource level can be achieved regardless of the price level. If the decision-maker manages at other population levels, substantial change of the management might be required as changes in the price and/or the discount rate occur. Thirdly, in our cases of Hokkaido sika deer, the difference in sustainable resource levels between the social optimum case and the monopoly case is not very large.
