Invasive species compete with native species and damage ecosystems. Due to their limited resources, island ecosystems are vulnerable to impacts of invasive species. In the Deokjeok archipelago, South Korea, invasive sika deer (Cervus nippon ssp. taiouanus) introduced for economic purposes are causing harm through severe browsing. This study aimed to evaluate long-term browsing impacts of invasive deer by tracking vegetation index changes from 1986 to 2020 with Landsat satellite imagery and the LandTrendr algorithm. We compared vegetation index trend using Sen’s slope and Disturbance/Recovery area ratio (D/R ratio) between Gureop-do, where these deer were introduced with rapid population increase, and Deokjeok-do, Baega-do, and Mungapdo where these deer have not been introduced yet. Results showed a decreasing trend of the vegetation index in Gureop-do, while other islands without those deer increased. The cumulative D/R ratio on Gureop-do was 212.44%, meaning that disturbance exceeded the recovery area more than two-fold. In contrast, the D/R ratios for other islands remained under 50%. Sen’s slope and t-test showed a significant decrease of NDVI in Gureop-do after deer introduction in 2000. By quantifying the browsing impact of invasive ungulates in island ecosystems using satellite imagery, time and costeffective strategies for invasive species monitoring are provided.

This study aimed to conduct a comprehensive assessment of the potential impact of deforestation and forest restoration on carbon storage in North Korea until 2050, employing rigorous analyses of trends of land use change in the past periods and projecting future land use change scenarios. We utilized the CA-Markov model, which can reflect spatial trends in land use changes, and verified the impact of forest restoration strategies on carbon storage by creating land use change scenarios (reforestation and non-reforestation). We employed two distinct periods of land use maps (2000 to 2010 and 2010 to 2020). To verify the overall terrestrial carbon storage in North Korea, our evaluation included estimations of carbon storage for various elements such as above-ground, below-ground, soil, and debris (including litters) for settlement, forest, cultivated, grass, and bare areas. Our results demonstrated that effective forest restoration strategies in North Korea have the potential to increase carbon storage by 4.4% by the year 2050, relative to the carbon storage observed in 2020. In contrast, if deforestation continues without forest restoration efforts, we predict a concerning decrease in carbon storage by 11.5% by the year 2050, compared to the levels in 2020. Our findings underscore the significance of prioritizing and continuing forest restoration efforts to effectively increase carbon storage in North Korea. Furthermore, the implications presented in this study are expected to be used in the formulation and implementation of long-term forest restoration strategies in North Korea, while fostering international cooperation towards this common environmental goal.