扇状地水田におけるカエル類の生息量と畦畔環境との対応関係

Abstract

The research was conducted to clarify relationships between frogs abundance and environments such as arrangement, grass height, and grass coverage of levees around paddy fields in an alluvial fan. Target species ware Rana porosa porosa adults, yearlings, and Hyla japonica yearlings that were widely distributed in study region. Walking on the levees, frogs abundance and the condition of levees were recorded. When a ditch was adjacent to the levees, the environments of ditch were investigated. R. porosa porosa adults were abundant levees where the earth ditch was adjacent, whereas R. porosa porosa yearlings were abundant levees where plant height was low. On the other hand, H. japonica yearlings were abundant levees where a concrete ditch and the woods are adjacent or plant height was high. In the agricultural landscape, It is important to conserve the habitat for R. porosa porosa whose range of environmental preference is narrower than that of H. japonica. We should be conserved the good ditch environments such as the earth ditch with high grass coverage, and clarified the best management practices of levees for frogs.