To elucidate the role of snow avalanches in shaping the feeding habitat of Japanese hare (Lepus brachyurus) on Mt. Fuji, we surveyed habitat use, population density, feeding habits, and food availability on 3 avalanche tracks, which were restored with Larch (Larix kaempheri) following avalanches in 1945, 1980, and 1992. The number of hare pellets on avalanche track 8 years post-avalanche was 10 times larger in the snow-free period and 19 times larger in the snowfall period than that in the adjacent climax forest. On the avalanche track, hares fed mainly on herbs during the snow-free period and on Larch branches during the snowfall period. Population density (estimated by fecal pellet count) during the snowfall period from 2015 to 2018 was 0.18 ha −1 on the 1992 avalanche track and 0.01 ha −1 on the 1980 avalanche track; no fecal pellets were found on the 1945 avalanche track. Based on the fluctuation of food availability and snow depth, the period during which avalanche tracks are used as a feeding habitat was estimated to be about 25-35 years, which supports the change in hare population densities observed post-avalanche. Meanwhile, on avalanche tracks that experience frequent avalanches (1.6-6-year return intervals), plant communities in the early seral stage have been permanently maintained as a feeding habitat. These findings suggest that snow avalanche disturbances of various frequency and severity strongly affect the feeding habitat diversity of hares on Mt. Fuji.
View full abstract