Spatiotemporal Variations of Fractional Vegetation Coverage and Its Driving Mechanisms in Southwestern China

As a well-known ecological vulnerability region, monitoring and studying vegetation dynamics in southwestern China is important for resource management, ecological conservation, and climate adaptation strategies. The spatiotemporal dynamic characteristics of fractional vegetation cover (FVC) in southwestern China during the early 21st century was analyzed using MODIS Enhanced Vegetation Index (EVI) data. Additionally, this study employed the Geographic Detector Model (GDM), an innovative spatial statistical tool, to analyze the driving mechanism of FVC spatial patterns. The results indicated as follows: (1) the overall FVC in southwestern China exhibited a slight increasing trend, with distinct spatial heterogeneity; (2) the combined impacts of climate change and human activity could be the primary drivers of FVC changes, with relative contribution of 37.75% and 62.25%, respectively; (3) elevation was recognized as the key factor influencing this spatial variability, influencing hydrothermal conditions, vegetation types, soil types, and human activity intensity; (4) FVC increases steadily under high-emission scenarios of SSP370 and SSP585 from 2030 to 2100, while it exhibits an “increase–decrease” pattern under the low-emission scenarios of SSP126 and SSP245 from 2030 to 2100, with shifts occurring in 2080 and 2090, respectively. This pattern may result from the combined effects of moderate warming and fluctuations in precipitation, where initial hydrothermal conditions promote vegetation growth, but subsequent changes potentially inhibit it.