Based on Landsat data from 1990 to 2020, this study used the normalized difference vegetation index (NDVI) and spatial heterogeneity as indicators to monitor the grassland degradation in Kulusitai. The results showed that:1) During the study period, the NDVI in the central part of the study area exhibited an increasing trend, while the marginal area showed a decreasing trend. The spatial heterogeneity of grassland increased in the central and southwestern areas and decreased in the northern and southern areas. 2) About 54% of the grassland in the Kulusitai was degraded at different levels, 35% of grassland was improved and 10% of grassland showed regrowing conditions. 3) Temperature and precipitation had little influence on interannual variation of spatial heterogeneity. However, they showed significant impacts on NDVI yearly dynamics, in which precipitation was the dominant climate factor.
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