Evaluation of the Effect of Culling on Browse Damage by the Japanese Serow in Gifu Prefecture, Japan

The Japanese serow (Capricornis crispus; serow) is a protected territorial ungulate native to Japan. However, locally overabundant serow populations can damage forest plantations and agriculture through browsing. Despite government permitted annual culling of serows on forest lands of Gifu Prefecture, Japan, browse damage continues to be reported in hinoki cypress (Chamaecyparis obtusa; cypress) plantations. Sika deer (Cervus nippon; deer), which are co-located with serows can also browse cypress, but their impacts have never been evaluated. The objective of our research was to evaluate the involvement of each species in browse damage and to establish the damage-causing mechanisms after serow culling at selected study sites (T1 [0.3 ha], T2 [0.2 ha], and T3 [1.1 ha]) in 3 cypress plantations in Takayama City, Gifu Prefecture, where serow culling was conducted. In 2019 and 2020, 2 and 2 serows were culled in T1, 3 and 0 in T2, and 1 and 1 in T3, respectively. Forestry workers also applied a chemical repellent (ziram-based fungicide) to some stands in T3 in October 2019 and May 2020. Between December 2018 and September 2020, we used camera traps to monitor activity patterns of serows and deer and the replacement of territorial serows before and after culling. We also investigated seasonal browsing impacts between August 2019 and June 2020 by thoroughly checking for browsing marks on the terminal shoot. Serows and deer accounted for 79% and 21% of camera-trap videos, respectively. Despite annual culling, serows were recorded at all browsed sites before the next growing season. Browse damage was higher in autumn and winter, but in T3 it was reduced when the repellent was applied. Management of ungulate browse damage to cypress will require accurate identification of species causing the damage, monitoring serow activity before and after culling, and a using repellent immediately before browsing seasons