Current Distribution and Status of Non-Native Freshwater Turtles in the Wild, Republic of Korea

Globally, an increase in the transportation and expansion of the pet market is the most important cause of the invasion of non-native species. Invasion of non-native species disturbs native ecosystems and leads to socio-economic problems. The pet trade involving turtles has been globally recognized as the route through which non-native species enter ecosystems. As a result, the invasion of non-native turtles worldwide is causing problems such as competition, predation, transmission of parasites, and hybridization with native turtles. Every year, both the number of non-native turtles imported as pets in the Republic of Korea and the number of introduced species found in the wild is increasing. However, the current status of non-native turtles in the wild is not well known, posing major challenges to their management. In this study, we aimed to determine the current status of non-native turtles introduced into the wild in Korea. We analyzed the factors associated with the detection and distribution of non-native turtles. In total, 1587 of non-native turtles (three families, six genera, and 13 species including subspecies) were found in 648 sites in Korea: Chelydra serpentina, Mauremys sinensis, Chrysemys picta bellii, Graptemys ouachitensis, G. pseudogeographica pseudogeographica, G. p. kohni, Pseudemys concinna, P. nelsoni, P. peninsularis, P. rubriventris, Trachemys scripta elegans, T. s. scripta, and T. s. troostii. There was relationship between the distribution of non-native turtles and environmental factors such as precipitation and temperature. Moreover, human factors such as number of human populations and size of region were significantly related with the distribution and number of non-native turtles. In conclusion, it is likely that human factors are associated with the influx of invasive turtles to the natural habitat, while the possibility of survival and adaption for the turtles is associated mainly with environmental factors. Our result will be an essential guideline not only for understanding the current status of non-native turtles in Korea, but also for establishing strategies for management and control.