Anuran Community Patterns in the rice fields of the mid-western region of the Republic of Korea

Abstract

The wildlife that inhabits natural wetlands has been threatened in recent years because of human activities, such as land use changes. Rice fields, however, have been receiving attention as possible substitutes for natural wetlands. Amphibians are one of the representative taxa that inhabit rice fields and are critical for their food webs and ecosystem maintenance. This study was conducted to understand the community characteristics of anuran species living in the rice fields in the mid-western region of the Republic of Korea, in accordance with their habitat characteristics. The distribution and abundance of each of the Anura species identified in 40 rice fields was examined, from March to October in 2016 and 2017. Similar anuran communities were patternized using a self-organizing map (SOM). Furthermore, this study analyzed the relationships between the patternized anuran communities and environmental variables (landscape, atmospheric, physical, and aquatic) using random forest analysis. Key indicator species were also identified to understand the environmental characteristics of each SOM group. The results of this study showed that the anuran species that were assessed could be classified into four clusters using the SOM, and each cluster reflected a breeding season. Moreover, they also reflected the relationship between the indicator species of each cluster and the environmental variables. Clusters 1 and 4 represented summer, and the number of species, species diversity, and species richness were all high in these two clusters. Landscape variables, such as the forest or rice field area, were important for the species belonging to these two clusters. There were four indicator species in Cluster 1, the black-spotted frog, Wrinkled frog, American bullfrog, and Japanese tree frog, and they preferred high altitudes and large forested areas. However, the two indicator species of Cluster 4, the Gold-spotted pond frog and Suweon tree frog, which are endangered in the Republic of Korea, favored low altitude and large rice field areas. Various anuran species, including the endangered species, densely inhabit the rice fields in the mid-western region of the Republic of Korea, and the relationship between the patterning of anuran communities and environmental variables was identified in this study. This information will be valuable for the future conservation and management of amphibian species in the Republic of Korea.