Spatiotemporal variation and driving factors of vegetation coverage in Xigaze section of Yarlung Zangbo River

Vegetation coverage regulates carbon cycling, conserves soil and water, and stabilizes ecosystems. The Xigaze section of the Yarlung Zangbo River (YZR) basin is a critical riparian zone affecting suspended sediment supply, channel migration, and sandstorm intensity. However, studies on its spatiotemporal dynamics and driving factors remain limited, largely due to reliance on low-resolution data. In this study, fractional vegetation cover (FVC) within a 5 km riparian buffer was reconstructed using Landsat8 imagery (2015-2024) and Sentinel 2 imagery (2019-2024) based on the pixel dichotomy model. Trends were quantified with Theil-Sen slope statistics and the Mann-Kendall test. Land use and cover change (LUCC) was mapped by random forest classifier, and meteorological data from 14 stations were used to evaluate climatic drivers. The results reveal a general FVC decline, with a shift during 2019-2020. LUCC (q = 0.704) was the dominant driver of vegetation variation, followed by temperature (q = 0.061). Elevation and slopes influence vegetation mainly through interactions with other variables. In the Rizi section, sparse vegetation and intense aeolian activity suggest an urgent need for wind-erosion control. In Lhaze and Xigaze, mixed forest-grass systems are recommended to improve resilience. Additionally, ongoing monitoring of the risk of riverbank collapse under hydrological-aeolian processes is also warranted.