Relationship between agro-environmental variables and breeding Hylids in rice paddies.

When natural wetlands are destroyed, many anuran species are forced to breed in alternative habitats such as rice paddies. We conducted field surveys for the endangered Dryophytes suweonensis and the numerous D. japonicus, from the beginning of the breeding season until two weeks after its peak. We recorded the presence, number of individuals and calling indices for each species. We hypothesized that D. japonicus would start breeding earlier than D. suweonensis, which would have originally been breeding solely in floodplains. The results of our analyses demonstrate that the rice cultivation phase was the most important factor in predicting the calling activities of both species. Furthermore, peak calling activities of both species matched the optimal hydroperiod in rice paddies. In addition, D. japonicus breeding behaviour was influenced by environmental variables such as temperature, whereas D. suweonensis seemed to require the planting of rice seedlings to initiate breeding. Therefore, as both Dryophytes species' breeding activities are influenced by agro-environmental variables, this study highlights the importance of also preserving anthropogenically modified landscapes for the conservation of species.