Spatiotemporal Variation and Driving Forces of Ecological Quality in the Ili Grassland Based on the Remote Sensing Ecological Index: Implications for Sustainable Ecotourism

Yupei Yu, Dong Cui , Zhicheng Jiang, Weiwei Wang, Guihao Yuan, Le Zhou, Yao Hou, Yixuan Zheng, Xin Gong, Haijun Yang

Abstract: The Ili Grassland is an important ecological security barrier in northwestern China and a region with abundant ecotourism resources. Scientifically evaluating the spatiotemporal variations in ecological environmental quality and identifying its key driving factors are essential for regional ecological conservation and sustainable ecotourism development. In this study, MODIS remote sensing data from 2000 to 2025 were used to construct the Remote Sensing Ecological Index (RSEI) based on four ecological indicators, including greenness, wetness, dryness, and heat. Principal component analysis (PCA) was applied to integrate these indicators, while the Sen’s slope estimator combined with the Mann–Kendall (Sen+MK) trend analysis was employed to characterize the spatiotemporal dynamics of ecological environmental quality. Furthermore, the optimal parameters-based geographical detector (OPGD) model was used to identify the dominant driving factors influencing ecological environmental quality.The results showed that: (1) From 2000 to 2025, the ecological environmental quality of the Ili Grassland was mainly characterized by moderate and good levels. Areas with high ecological quality were primarily distributed in the central-eastern and southern mountainous grassland regions, whereas low-quality areas were mainly concentrated in the northwestern part of the study area. (2) The mean RSEI exhibited a slight decreasing trend during the study period. Ecological environmental quality experienced an initial fluctuating improvement followed by a continuous decline; however, the overall ecosystem maintained relatively high stability. (3) The Sen+MK analysis indicated that non-significant improvement and non-significant degradation dominated the study area, suggesting that the ecological environment underwent gradual and low-intensity changes without extensive ecological degradation. (4) The OPGD results revealed that annual precipitation, annual mean temperature, and tourism economic factors were the primary drivers of spatial differentiation in ecological environmental quality. All driving factors exhibited either bivariate enhancement or nonlinear enhancement effects, indicating that regional ecological patterns were jointly shaped by natural environmental conditions and tourism-related human activities.These findings provide scientific support for ecological conservation, ecotourism planning, and sustainable regional development in the Ili Grassland.