The Heilongjiang-Lena River Basin is a major high-latitude transboundary watershed spanning northeastern China and the Russian Far East, representing a typical cold-region system under climate change. However, long-term assessments of eco-environmental dynamics and their multi-factor driving mechanisms in such climate-sensitive basins remain limited. Using multi-source remote sensing data from 2000 to 2024, this study constructed a Remote Sensing Ecological Index (RSEI) and integrated Sen's trend analysis, the Mann-Kendall test, and an optimized Geodetector model to examine spatiotemporal patterns and driving forces of eco-environmental quality. The mean RSEI ranged from 0.522 to 0.662, indicating overall stability, with 61.37% of the area showing no significant change, 22.45% improvement, and 16.18% degradation. A persistent north-south gradient was observed, characterized by relatively better conditions in the north and comparatively lower values in the south. Temperature emerged as the dominant driver, followed by land use and vegetation cover, with pronounced nonlinear enhancement effects-particularly between temperature and land use. Policy interventions contributed to ecological restoration in parts of China, while permafrost degradation and forest fires induced environmental fluctuations in the Russian sector. Overall, the basin exhibits considerable resilience despite localized vulnerabilities. The integrated RSEI-Geodetector framework provides transferable insights for long-term monitoring and governance of high-latitude and transboundary ecosystems.
Li et al. (Fri,) studied this question.