Korean endemic species no more: on the occurrence of Pelophylax chosenicus in China

Abstract

Understanding species distribution is the first requirement to work on their behaviour, conservation, and phylogeography. Over the last decades, the number of species described on the Korean peninsula has significantly increased, but areas around the boundaries of the Korean peninsula still have to be surveyed for the presence of these species, especially where the environment is similar and connected. Here, we conducted surveys in the continuous landscapes of the Republic of Korea, the Democratic Peoples Republic of Korea and the Peoples Republic of China to determine the range of the Gold-spotted pond frog, Pelophylax chosenicus. The surveys were conducted between 2016 and 2020 through visual and call encounters. We also used molecular tools to confirm the species identity of the northernmost population, in China, sequencing the mitochondrial DNA 16S gene fragment. We then determined the importance of landscape types for the species, and especially rice paddies, and used landscape models to define suitable habitats across the region. We found the species to be widespread in low elevation wetlands along the coast of the Yellow Sea, with two isolated populations on the south-east of the Korean Peninsula, and the northernmost population in the vicinity of Dandong in PR China. As this species is listed as threatened in the Republic of Korea, knowing its exact distribution will be important for conservation practices, and this first record for PR China provides a baseline for further surveys.