On the Community Gradient of Inectivores and Rodents in the District of Mt. Bandai

Abstract

The community gradient of insectivores and rodents was investigated in the district of Mt. Bandai, from August 1972 to October 1981. 657 insectivores and rodents, consisting of ten species, were obtained with snap traps from 40 sites of various vegetation types and various altitude. Each community site was located on a cordinate according to it's ecological distance from a reference one which was regarded to be in the lowest degree of naturalness among the 40 communities studied. This gradient turned out to be parallel to the degree of naturalness of the vagetation types.
Dymecodon pilirostris, Aschizomys andersoni and Apodemus argenteus show a tendency to increase their dominancy toward the natural side, while Urotrichus talpoides, Microtus montebelli and Apodemus speciosus, toward the opposite side.
The values of COLE's Index and the X² values show clear habitat segregation between D. pilirostris and U. talpoides on the one hand and a high degree of joint occurrence between D. pilirostris and A. andersoni on the other hand.