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Ramsar wetlands are known for their high ecological and economic value; however, in some cases, the indigenous species community is rapidly changing owing to the presence of invasive alien plants (IAPs). To address this issue, we conducted a plant survey of five Ramsar wetland sites on Jeju Island from August 2021 to August 2022 and constructed a list of IAP species. A total of 24 IAP plant species belonging to 13 families were identified. Species of the Asteraceae and Poaceae families, which have high seed production, high adaptability to damaged ecosystems, and a wide range of organisms, from annuals to perennials, were found to be abundant. The distribution of IAP species was consistent with the pattern expected during the early stages of IAP invasion in Korea. Additionally, a positive correlation was observed between the distance from residential areas and the number of IAP species. Wetlands not visited by people were found to be relatively intact, while those frequented by tourists and visitors were susceptible to IAPs. These results suggest that the introduction of IAP species into the Jeju Ramsar wetlands may have been the result of anthropogenic activities, such as tourism. Our study demonstrated that the introduction of IAPs into the Jeju Ramsar wetlands is in its early stages and is mainly attributable to human activity. Therefore, it is necessary to identify the invasion pathways, develop strategies to control or reduce invasion, and control the geographic expansion of these species. Our study highlights the threat of alien species to Jeju Ramsar wetlands, providing the basis for a strategy to protect these wetlands from the threat of invasive species. [ABSTRACT FROM AUTHOR]

Several alien species of freshwater turtles have been imported to the Republic of Korea from various countries, and then released to the wild by breeders and as a part of religious practices throughout Korea. Here, we evaluated the number of subspecies of the alien freshwater turtle Trachemys scripta in the wild on Jeju Island, Korea. We confirmed the presence of three alien subspecies of freshwater turtles with higher number and broader distribution compared to previous studies in 2007 and 2015. There were 134 adult and 48 juvenile Trachemys scripta elegans in 41 locations; nine adult Trachemys scripta scripta in seven locations; and two adult Trachemys scripta troostii in two locations. Illegal release by humans and potential reproduction in the wild probably contributed to the increase in their numbers. Early detection of invasive alien species is crucial for preventing their spread. Therefore, to minimize their negative impacts on the natural ecosystem of Jeju Island, we suggest the continuous monitoring of invasive freshwater turtles (including the evaluation of their survival, growth, and reproduction) and the strengthening of regulations to prevent continued releases to the wild. [ABSTRACT FROM AUTHOR]