Food Habits of Sika Deer at Otome Highland, Yamanashi, with Reference toSasa nipponica

Abstract

For the last two decades, sika deer in Japan have expanded their range. The Otome Highland in Yamanashi Prefecture, central Japan, is no exception, as the abundance of sika deer has increased in this region, particularly over the last decade. Because many populations of sika deer inhabiting the central or northern Pacific region of Japan are dependent on Sasa nipponica, a dwarf bamboo growing in the understory of deciduous broad-leaved forests, as a food plant (Takatsuki 1983, 1986; Ueda et al. 2002; Kobayashi and Takatsuki 2012), the deer population of Otome Highland, which belongs to the same climatic zone, is also expected to depend on this species. The forest of Otome Highland was once a montane forest of Fagus crenata, but was logged to become a secondary oak forest, which is common to other places. A unique point of this highland is that it was logged for skiing in 1951, and subsequently, a grassland composed of grasses and various forbs developed. Thus, sika deer would utilize both forest and grassland. In many habitats of sika deer, Sasa nipponica is an important food for the deer during the winter because other forbs and grasses senesce and trees and shrubs lose their leaves; thus, S. nipponica is the almost only evergreen forage plant. Therefore, documenting the extent of deer grazing on S. nipponica during winter is important. Thus, the objectives of this study were to quantitatively analyze the food habits of sika deer in the Otome Highland and to determine their grazing intensity on S. nipponica.