Abstract
Frog is one of most popular rural animals in paddy fields. We studied the relationship between rural landscape structure and frog inhabitation in Tonami area where was famous as landscape of dispersed hamlet (houses surrounded by stands of trees dot the entire plain). The surveys conducted in paddy fields of three types conditions (mountain area, hilly area, plain area), and on transect lines with a grid of 250 by 250m cells. The number of eggs deposited and the density of each species calling were recorded as the relative abundance of frogs.
In result, the paddy fields on plain area have poor species composition (1-3 species). In contrast, the paddy fields on mountain and hilly area have rich species composition (4-6 species). It is considered that the absent of frog species is occurred by land consolidation involving formation of landscape structure which block frog migration and dispersal route. The entering distance from the foot of mountain and hillside to inner plain area, were maximum 1km on Rana japonica, Rana ornativentris and Rhacophorus arboreus, about 4km on Rhacophorus schlegelii, about 10km on Rana nigromaculata. And Hyla japonica was observed commonly on all types of paddy fields. It has not related the abundance of frogs to density of homesteads in cells. However, it seems that Rhacophorus schlegelii is observed only cells presenting homesteads on inner plain area.
We discussed the model of rural landscape structure for frogs and improvement of rural environment with rich biota. Especially, paddy fields of foot area have importance on the spatial arrangement to conserve frog. Because the concept of frog conservation in Tonami plain, which read the dispersal of frog from foot area to inner plain area. Therefore it is necessary to clear the dispersal route for frog of barriers in various scale level.
