Abstract
Deer population management plans formulated by 40 prefectural governments in Japan were reviewed in terms of their
current status and issues for refinement. Many management plans proposed control levels of density/abundance and implemented
a hierarchical Bayesian model to estimate deer density. However, the validity of the estimated population densities could not
be evaluated due to a paucity of prior distributions, model structures, and posterior probability distributions, in addition to a
lack of relevant references. Acceptable levels of negative deer impact were proposed qualitatively for agriculture/forestry and
ecosystems. However, only two plans proposed quantitative levels to control the impact on the ecosystem. Many plans monitored
understory vegetation as an index of the impact of deer on ecosystems, but the monitoring was qualitative in most plans.
Furthermore, there was insufficient monitoring of other impacts on ecosystems. To review their management plans, only seven
prefectures used scientist discussion groups that were independent of the administrative council. Consequently, the current deer
management plans have several flaws, and relevant scientific data must be incorporated to increase their credibility.
