[Response of Vegetation Spatiotemporal Evolution to Climate Change and Human Activities in Gansu Province from 2001 to 2021].

Located in the transitional zone of three major natural regions in China， Gansu Province serves as a critical area for investigating vegetation dynamics in response to climate change and human activities， providing a scientific basis for regional vegetation conservation and ecological engineering policies. Based on normalized difference vegetation index （NDVI） data and influencing factors datasets from 2001 to 2021， this study employed Theil-Sen Median trend analysis， partial correlation analysis， spatial autocorrelation analysis， and residual analysis to systematically analyze the spatiotemporal variations of vegetation NDVI and their driving mechanisms in Gansu Province. The results indicate that： ① The mean NDVI value during the study period was 0.352， exhibiting a distinct "high in the southeast， low in the northwest" spatial pattern. Both the entire province and individual geomorphic units showed significant upward trends， with 74.25% of the area experiencing vegetation improvement， particularly pronounced in the Loess Plateau of Longzhong and the southern mountainous regions. ② Climatic factor analysis revealed that temperature and precipitation exerted positive effects on vegetation NDVI in over 66% of the study area， with precipitation demonstrating a stronger influence than temperature. ③ Human activities predominantly enhanced vegetation NDVI， with stable grassland and cropland areas contributing the most （cumulatively 60%）. The change rates of nighttime light （NTL） and NDVI exhibited a weak positive spatial correlation， displaying "low-low" clustering in the Gannan Plateau， Hexi Corridor， Qilian Mountains， and Beishan Mountains， while "low-high" clustering characterized the southern mountainous area of Gansu and the Loess Plateau in central Gansu. ④ Contribution analysis highlighted that human activities （70.61%） had a greater overall impact on vegetation changes than climate change （29.39%）， though spatial heterogeneity was evident-the Gannan Plateau was the only geomorphic unit where climate change dominated. These findings elucidate the differential driving mechanisms of vegetation dynamics in transitional zones and offer critical insights for optimizing regional ecological management strategies.