[Spatiotemporal variations of normalized difference vegetation index in the Mu Us Sandy Land and the dri-ving forces:...

The Mu Us Sandy Land is a crucial component of China's northern ecological barrier. It is of paramount importance to clarify the spatiotemporal variations of the impacts of climate change and human activities on the normalized difference vegetation index (NDVI). Based on remote sensing imagery and meteorological data from 1990 to 2023, we analyzed the variations of NDVI and its response to meteorological factors in Uxin Banner, Inner Mongolia, and quantitatively delineated the spatiotemporal patterns for the impacts of climate change and human activities on NDVI. The results showed that the NDVI in Uxin Banner showed a overall significant increasing trend [0.03·(10 a)^-1]. The vegetation showed a predominance of moderate improvement (71.6%), but areas with low vegetation cover dominated (90.5%). Pixels with slight decline accounted for 28.4%, highly overlapping with the extremely low NDVI zones (<0.1) in the northwestern central region. Annual precipitation and mean annual temperature in Uxin Banner increased with rates of 49.40 mm·(10 a)^-1 and 0.37 ℃·(10 a)^-1, respectively, both showing significant positive correlation with NDVI. Relative importance analysis showed that mean annual temperature was the dominant climatic factor affecting NDVI, followed by annual precipitation, with relative importance contribution of 74.9% and 18.4%. Both climate change and human activities drove NDVI increases in the vast majority of the region (98.9%), with their relative contribution rates exhibiting distinct spatially differentiated and complementary characteristics. Climate change contributed 60%-80% to NDVI increases in localized areas of south-central Uxin Banner, while human activities contributed 60%-80% in the northern part. This study could provide scientific evidence for the ecological restoration and sustainable management of the core area in the central Mu Us Sandy Land.