Dynamic monitoring of eco-environmental quality in the Greater Mekong Subregion: Evolutionary characteristics and country differences

As a global hotspot of biodiversity and conservation, eco-environmental changes in the Greater Mekong Subregion (GMS) are crucial to achieving global Sustainable Development Goals. However, the eco-environmental status of the GMS and its development trends remain unclear. In this study, we proposed an improved remote sensing ecological index (IRSEI) to assess eco-environmental quality (EQ) by integrating habitat quality into the remote sensing ecological index (RSEI) to consider the vegetation characteristics of the GMS. We then applied trend analysis and Hurst exponent analysis to explore the past and future spatiotemporal dynamic changes of EQ in the GMS. Our study revealed that the IRSEI exhibited better monitoring accuracy than the RSEI and could comprehensively and effectively evaluate the EQ of the GMS. Overall, more than 80 % of the GMS by area had moderate or greater EQ levels during the period 2000-2020. Good and excellent EQ levels were predominantly located in the southwestern Yunnan Province of China, northeastern Myanmar, Laos, and western Vietnam. From 2000 to 2020, the annual mean IRSEI value in the GMS exhibited an increasing trend (0.10 %/year), with the area of increased EQ concentrated in Yunnan Province and Myanmar. Additionally, the center of gravity of the IRSEI in the GMS showed an obvious migration to the northwest over the studied period. A total of 60.81 % of the study area exhibited Hurst values lower than 0.5, indicating anti-persistent changes in EQ over the past 21 years. Furthermore, the area in which the EQ was predicted to decrease was larger than that of predicted EQ improvement. Overall, these outcomes provide an important reference and new perspectives on ecoenvironmental protection in the GMS.