Changes in vegetation spatial aggregation in reclaimed areas of open-pit coal mine spoil dumps within the Northern Sand Prevention Belt

Using the Google Earth Engine (GEE) platform and Landsat satellite data, this study quantified fractional vegetation cover, coefficient of variation of vegetation, and spatial autocorrelation index to investigate changes in vegetation spatial aggregation before and after reclamation of 359 open-pit coal mine spoil dumps in the Northern Sand Prevention Belt. The results showed that from 2000 to 2024, the average fractional vegetation cover of open-pit coal mine spoil dumps in the Northern Sand Prevention Belt increased from 18.90% to 32.7%, while the area with extremely low vegetation cover decreased by 335.5 km². The most significant improvement occurred in the eastern Inner Mongolia mining area. The coefficient of variation of vegetation in the spoil dumps decreased from 73.9% to 62.7%. Specifically, vegetation spatial variability increased in 7.9%, 42.1%, and 30.5% of the spoil dumps in the Dongsheng, eastern Jungar, and eastern Inner Mongolia mining areas, respectively, whereas it decreased in 23.6% and 46.2% of the spoil dumps in the Xinjiang and Wuhai mining areas, respectively. From 2000 to 2024, vegetation spatial aggregation increased, with the area of high–high clusters increasing by 30.1% and that of low–low clusters decreasing by 12.2%. Compared with vegetation in the original landscape, the correlation coefficients between reclaimed vegetation and moisture and temperature increased from 0.61 and −0.60 to 0.68 and −0.65, respectively. Reclamation effectively improved vegetation conditions, and reclaimed vegetation exhibited stronger spatial aggregation than vegetation in the original landscape. Long-term and multi-scale monitoring of reclaimed vegetation in spoil dumps should be strengthened to provide scientific support for vegetation management and stability maintenance in reclaimed areas.