LIn this study, we investigated the habitat characteristics of a Jeonju Duckjin lake in Jeonju City, Jeonbuk, in which a large group of reeve’s turtle(Mauremys reevesii)(endangered species Class II and natural monument No. 453 in Korea) was discovered. The lake where reeve’s turtle(M. reevesii) was discovered, was beside Jeonbuk National university. That lake was surrounded by lotuses, dam, and reeds. We found 12 reeve’s turtle(M. reevesii)(included with 2 juveniles), 30 red eared slider (Trachemys scripta elegans)(included with 4 juveniles), 22 river cooter(Pseudemys concinna)(included with 5 juveniles), and 6 Chinese stripe necked turtle(Mauremys sinensis)(included with 4 juveniles) from June to September, 2024, respectively. A number of red-eared sliders(Trachemys scripta elegans) which threaten the survival of reeve’s turtle(M. reevesii), were also found in and around the lake. Newborn turtles in this year were not observed. However, we estimated that natural breeding had sufficiently occurred since we observed many young turtles in the lake. Furthermore, the presence of young red-eared slider individuals can be a persistent problem for reeve’s turtle(M. reevesii) as they are competing species. In conclusion, in-situ conservation method should be considered for protecting the endangered turtle and their habitat.

The main factor of biodiversity decline in major biological populations around the world is invasion of alien species. To protect native species, it is necessary to manage alien species. Recently, to eradicate ecosystem disturbance caused by alien species in Korea, many efforts have been made to capture individuals using nets and purchase captured individuals. However, there is no standard for classifying species due to the form of nest site or external characteristics of eggs of freshwater turtles. Thus, Mauremys reevesii eggs might be discarded due to mistaking as eggs of alien turtles. Based on more data, this study aims to compare and analyze external differences among eggs of Trachemys scripta elegans, Pseudemys concinna, and M. reevesii and use them as reference materials in the process of eradicating alien turtles. This study measured characteristics of eggs of the three turtle species. As a result of comparison, all variables of external characteristics of alien turtles and M. reevesii eggs showed significant differences. The shape of egg was also different, with eggs of T. scripta elegans and P. concinna showing a bicone shape and those of M. reevesii showing an ellipsoid shape. In conclusion, based on results of previous studies and the present study, eggs of M. reevesii, T. scripta elegans, and P. concinna are different in shape and structure. Thus, it is possible to distinguish between M. reevesii and invasive alien turtle using their eggs.