Comparison of frog communities between floodplain water bodies and paddy fields.

Abstract

Inter-levee floodplain water bodies (FWBs) have been highlighted as an important habitat for aquatic animals. However, no study has examined the function of FWBs as a frog habitat. We studied the reproductive status of frog communities in FWBs and paddy fields, which are well known as frog habitats, along the Kiso and Ibi Rivers. Four frog species, Hyla japonica, Fejervarya kawamurai, Pelophylax nigromaculatus, and P. porosus brevipodus, were more abundant in the paddy fields than the FWBs. Additionally, the mating calls of the male frogs were mainly recorded in the paddy fields, indicating that they selected paddy fields as reproductive sites. In contrast, the mating calls of Glandirana rugosa were only recorded in the FWBs, and the tadpoles of G. rugosa and Rana japonica were only captured in the FWBs. Furthermore, these two species were recorded in multiple FWBs of our two study rivers in previous studies. These results suggest that FWBs can serve as critical habitats for G. rugosa and R. japonica, which require water bodies as winter-spawning and/or overwintering habitats during a non-irrigation period in paddy fields.