Temporal and Spatial Changes in Vegetation Ecological Quality and Driving Mechanism in Kokyar Project Area from 2000 to 2021

The "Kokyar Greening Project" in the suburb of Aksu, Xinjiang, is a model of large-area artificial afforestation in an environment of drought and water scarcity. As an important part of the "3-North Shelter Forest Program", it plays an important role in promoting the economic development and the environmentally friendly construction of Aksu and even of the whole Xinjiang region. Based on multisource remote-sensing data and meteorological observation data, this study explored the temporal and spatial changes in the vegetation parameters (FVC, NPP, and VEQI) and the ecological parameters (RSEI and LULC) in the Kokyar Project Area from 2000 to 2021. Based on the Theil-Sen median and TSS-RESTREND, this study investigated the path of mutual influence among the FVC, NPP, VEQI, and RSEI, as well as their responses to climate change and human activities. The results show that: (1) from 2000 to 2021, the FVC, NPP, VEQI, and RSEI in the Kokyar Project Area showed a significant upward trend and showed the distribution characteristics of "high in the south and low in the north". (2) Over the past 22 years, the RSEI has shown a significant increase with the FVC, NPP and VEQI (p < 0.001), indicating that the "Kokyar Greening Project" has achieved significant ecological benefits. (3) The changes in the vegetation parameters and RSEI in the Kokyar Project Area were dominated by human activities. (4) The Kokyar Project Area has caused great changes to the ecosystem pattern of the region, and the vegetation parameters and RSEI in the Kokyar Project Area have increased, mainly in the form of cropland and grassland expansion over the past 22 years.