二種のモグラの分布境界線における14年間の変化

概要

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Two of the northern most frontiers in the distribution of larger Mogera kobeae that has driven away smaller M. wogura from the original habitat have been found at Agematsu and at Ono, Shiojiri in Nagano Prefecture, Honshu. Change of the boundary-line of the two moles' distributions between 1959 and 1973 was surveyed by means of trapping moles and measuring tunnels. In Agematsu Town, M. kobeae has enlarged the distribution for about 3 kilometers into the range of M. wogura in the 1959-73 period, while at Ono, the two moles have principally showed no change in the distribution in the 14 years. The latter may be due to that Ono is situated at the uppermost area of a branch stream of the Tenryu River, and the habitat (soil texture) is not suitable to the life of larger M. kobeae. M. kobeae has expanded the range to more northern district in the Tenryu River basin than in the Kiso River basin. This may be attributable to that the former basin has much wider habitat for the mole than does the latter, and, hence, the size of the population of the mole is much larger in the former than in the latter. Ecological relationships between the two moles at the abutting area were discussed with the nature of habitat and the morphological characters of moles which might have been produced in relation to the character displacement, the Bergmann's rule, and the general pattern of geographic variation in Japanese moles.
日本哺乳類学会の論文