[Dynamic Assessment and Zonal Control of Ecological Environment Quality in the Upstream Region of the Honghe River...

The Honghe River is an important international river originating in Yunnan， serving as an ecological barrier for the province， and is a meeting point for the dry-hot valley's fragile zone and ecological corridor. Within the region， biodiversity coexists with ecological issues such as soil erosion and rocky desertification. A systematic analysis assesses the spatial differentiation and temporal changes in the ecological environment quality of the watershed and the driving factors， thereby proposing zoning control measures， which is significant for establishing Yunnan as a national leader in ecological civilization and can provide foundational information for decision-making in the development， protection， and collaborative management of the Honghe River. This study， focusing on the ecological environment characteristics of the region， explores constructing an improved remote sensing ecological index （MRSEI） that integrates the normalized difference vegetation index （NDMVI）， humidity （WET）， aridity （NDBSI）， and temperature （LST） as core parameters for evaluating ecological environment quality and analyzes its applicability， establishing MRSEI based on five periods of Landsat remote sensing data from 2000 to 2020 for evaluation， obtaining the spatial distribution and dynamic changes of ecological environment quality in the upper reaches of the Honghe River Basin， employing Sen-MK trend analysis， Hurst index， and partial derivative methods to reveal its evolution trends and driving mechanisms. Based on the characteristics of ecological environment quality evolution， the five types of control units with appropriate control measures were proposed. The results indicate that： ① Compared to the traditional RSEI， MRSEI could more accurately reflect changes in vegetation cover， showing better applicability in the study area. ② There was a significant spatial disparity in ecological environment quality in the study area； from 2000 to 2020， the overall trend of ecological environment quality in the watershed improved， with MRSEI mean increasing from 0.298 7 to 0.322 1. The vegetation in the southern part noticeably improved， while the rocky desertification area in the north continued to degrade. ③ It was predicted that 10.12% of the area in the future study region will continue to improve ecologically， as well as 26.18% of the improved areas at risk of reversal. ④ Precipitation was a major positive influencing factor， significantly contributing to the improvement of ecological environment quality， whereas human activities were negative influencing factors， serving as major driving forces for ecological environment quality degradation and fluctuations. ⑤ The watershed was classified into five types of control units： ecological protection core area， monitoring area， optimization area， restoration area， and potential governance area， with corresponding control measures proposed.