Land cover change and its influencing factors in the Southeast Xizang Autonomous Region, China

Persistent cloud cover and limited data availability hinder the understanding of land cover dynamics on the Southeast Xizang Autonomous Region, China. Existing studies often focus on subregions or specific land cover types, lacking long-term, region-wide assessments of change and its influencing factors. To address this gap, we integrated dense Landsat time series with the Continuous Change Detection and Classification (CCDC) algorithm, to track land cover changes from 1990 to 2020. We further analyzed vegetation trends during 2000-2020 using Normalized Difference Vegetation Index (NDVI) in combination with Sen's slope estimator. Subsequently, by integrating topographical (elevation, slope, aspect), climatic (precipitation, temperature, radiation), anthropogenic and other indicators, we employed the GeoDetector model to explore the influencing factors of land cover changes. The results showed that: (1) Land cover changed by 7.52%, with increases in cropland, forest, grassland, shrubland, and built-up land, and decreases in bareland, wetland, water bodies, and snow/ice. Bareland, cropland, and forest showed contrasting trends in the north and south; (2) NDVI increased overall (0.0008/a), with a higher growth rate in the south (0.0012/a) than in the north (0.0005/a); (3) For the three main land cover types (forest, shrubland, cropland), soil type and precipitation exhibited relatively higher explanatory power in the north, whereas in the south—with abundant moisture and strong elevation gradients—elevation and temperature played greater roles; (4) Human activities showed contrasting associations. In the north, areas with higher human activity (i.e. population density, light intensity) tended to coincide with forest expansion, and the proportion of significant NDVI increases was higher in these areas, which may largely reflect the effects of ecological restoration programs. The densely populated southern areas were more frequently associated with NDVI declines and forest degradation, driven by population growth and traditional farming practices. These findings highlight the spatial heterogeneity of land cover influencing factors and provide insights for sustainable land management and conservation in the region.