Landscape and local correlates with two green tree-frogs, Rhacophorus (Amphibia: Rhacophoridae) in different habitats, central Japan

Abstract

Changes in land-use and local factors have strong influences on amphibian distributions. However, the effects of both combined factors on assemblages are still unclear. The green tree-frogs, Rhacophorus, are sensitive to differences in landscape fragmentation. Herein, two species of Rhacophorus schlegelii and Rhacophorus arboreus have been surveyed, along the ecological gradient ranging from paddy-dominated plains to forest-dominated mountains (located in Toyota, Okazaki, and Shinshiro, central Japan). The effects of landscape and local factors on the existence of the above frogs were investigated using generalized linear models (GLMs); the Akaike Information Criteria (AIC) were used for model selection. The lowest AIC for R. schlegelii and R. arboreus were obtained at a 250-m-radius and 500-m-radius buffers, respectively. Habitat selections of each species showed distinct results in the paddy-field vs. ponds group. Nevertheless, both species exhibited a high abundance with increasing elevation and forest cover. At the local level, R. schlegelii displayed positive relationships with the presence of trees and the proportion of embankment vegetation. Our findings demonstrate that each species responded to various landscape scale and spatial composition, habitat, and species-dependent achievements of appropriate management actions to improve restoration practices are required.