Abstract
The distributional pattern of subalpine forest vegetation in the Akaishi Mountains, central Japan, was compared with that in the Hidaka Mountains, northern Japan, using aerial photographs and a geographic information system, to investigate the geographic variation in habitat differentiation. The two mountain ranges had similar subalpine forest vegetation components, but the altitudinal width of the subalpine region was narrower and the beta diversity was higher in the Akaishi Mountains than in the Hidaka Mountains. This indicates that in the Akaishi Mountains subalpine forest vegetation is established in a constricted temperature spectrum. The results of multivariate statistical analysis (Hayashi's Quantification Theory-II) suggested that both altitude and laplacian index affect the vegetation patterns in the Akaishi Mountains, whereas altitude has the only significant effect on the vegetation pattern in the Hidaka Mountains. Habitat overlap among forest types along the laplacian index was much smaller in the Akaishi Mountains. These results suggest that, in addition to altitudinal habitat, the vegetation pattern is finely differentiated by topographic habitat in the Akaishi Mountains. This multi-dimensional habitat differentiation seems to increase with the interspecific competition arising from species packing in the subalpine region of the Akaishi Mountains.
