Abstract: We used two NDVI datasets (GIMMS3g NDVI and MODIS NDVI) and a monthly dataset of basic meteorological elements in China to analyze the temporal and spatial variations of vegetation cover in the Yangtze River Economic Belt, based on the average NDVI and its dynamics in the warm season (April–October) from 1982 to 2019. The contribution of climatic and nonclimatic factors to the spatiotemporal variation of vegetation cover was quantified. The results showed that, during 1982-2019, the average warm season NDVI of most regions in the Yangtze River Economic Belt was higher than 0.5, suggesting a favorable vegetation coverage. From 1982 to 2019, the average warm season NDVI of the Yangtze River Economic Belt showed a significant increasing trend, but with distinct stage characteristics. From 1982 to 1990, vegetation coverage significantly increased, with the dominant contribution of non-climatic factors. The typical areas in this stage included Sichuan, Central South and Northwest Yunnan, eastern Hunan, and Jiangxi. From 1990 to 2003, vegetation coverage was generally stable, but decreased in some particular locations. The intensity of the enhancement dominated by climatic factors was equal to that of the reduction dominated by non-climatic factors, which were basically offset. The typical regions with increases of climate-driven NDVI included southern Jiangxi, Chongqing and Guizhou, while the typical regions with decreases of non-climate-driven NDVI included Yangtze River Delta, Huanghuai Plain, plains of the middle and lower reaches of the Yangtze River, and Sichuan Basin. From 2003 to 2019, the vegetation coverage increased significantly, driven by both climate and non-climate factors, and with almost equal contributions. In general, the impacts of non-climatic factors on vegetation cover were greater than that of climatic factors during 1982 to 2019.

Key words: NDVI, green vegetation cover, climatic element, non-climatic element, multiple regression residual analysis.