The Change of Vegetation, Fauna of Frogs and Mousse as Small Animals, on Different Management Level in Step-like Paddy Fields

Abstract

The changes in vegetation and small animal fauna were investigated in terraced paddy with stone masonry in the hilly and mountainous areas of northeast Kyushu where cultivation has been progressively abandoned. Grassland which includes Imperata cylindrical - Miscanthus sinensis community and Juncus effusu community was formed depending on the soil moisture in the extensively managed sites. With the progression of vegetation succession in the abandoned managed sites, the M. sinensis community has attained dominant status. Although frog species diversity increased in the mountainside terraced paddy, the abandonment of paddy field cultivation led to a decline of frog composition. Rana ornativentris and Rhacophorus schlegelii had continually inhabited the moorland vegetation since the open water bodies required for breeding in frogs were disturbance-created by the rooting behaviour of mammals. With regard to the mouse fauna, Apodemus speciosus had colonized the extensively managed sites, and A. argenteus was found in the abandoned sites characterized by dense coverage of tall plants such as M. sinensis. Though the Micromys minutus population had increased in the extensively managed sites subject to continued mowing, they were absent from sites that had been abandoned for approximately 15 years. It was clarified that the vegetation succession is dependent on both land-form and management practice, and that vegetation and soil moisture are important factors in determining small animal fauna.