Land use change via urbanization is one of the major factors causing serious decreases in biodiversity. Landscape changes result in decrease in habitat-area, degradation of habitat quality, habitat fragmentation and split, which are the major drivers of amphibian declines in urban areas. The impacts of these changes are expected to differ among species with different dispersal habits. Therefore, a quantitative comparison of genetic structure in urban populations between dispersive and sedentary amphibian species may give new insights into future conservation and management plans for urban amphibian diversity.

In this study, we applied landscape genetics approaches to two paddy-associated frog species, sedentary Pelophylax nigromaculatus and dispersive Hyla japonica along a rural-urban gradient in the Osaka-Kobe metropolitan area, Japan.

We found that genetic diversity of P. nigromaculatus populations decreases with a loss of agricultural lands whereas that of H. japonica populations was not influenced by surrounding landscape. Genetic diversity of both species decreased with habitat quality degradation in urban areas. Artificial constructions were suggested to act as a barrier to dispersal by individuals in both the species. Based on these results, we discuss a conservation planning of these frog species in urban areas.