抄録
Rana japonica is a frog that lays eggs in still water, like shallow areas in ponds, or paddy fields where water is left in early spring, and it mainly lives in the forested areas during the non-breeding season. From May through to November 2009, a non-breeding season for the frog, we sampled 255 food items from 93 adult frogs by gastric lavage in the "Toyota Nature Sanctuary" in Aichi Prefecture, Japan. In the examination, although the adult frogs preyed frequently in the lower part of the broad leaf and coniferous forests and grassland, the frogs did not seem to predate selectively. In other words, the frogs preyed on animals appearing frequently in each environment and season. However, the individual densities differed according to microhabitats and seasons. From these results, maintenance of the lower part of forests and grassland in SATOYAMA is particularly important to conserve this species. Moreover it is important that both forest and grassland exist nearby, because the seasonal change in individual densities between microhabitats suggests that frogs move between forests and grassland seasonally.
