Ecological environment changes in Yangtze River Economic Zone in recent 20 years

Since the implementation of the Yangtze River Economic Zone strategy, the economy of provinces and cities along the Yangtze River has developed rapidly. At the same time of economic growth, the ecosystem has been strongly disturbed. The ecological environment of the Yangtze River Economic Zone is facing a severe challenge, which seriously restricts the sustainable development of the Yangtze River Economic Zone. The MODIS and Landsat remote sensing images in 2001 and 2020 were selected as the evaluation indexes of humidity, greenness, dryness and heat to calculate the Remote Sensing Ecological Index (RSEI) by means of principal component analysis method, and finally to quantitatively analyze and evaluate the ecological environment status and changes of 11 provinces and cities in the Yangtze River Economic Zone. The results show that the overall ecological environment grade of the Yangtze River economic zone is optimal, and especially it maintained the overall stable and slightly better trend from 2001 to 2020. The optima ecological environment regions are mainly distributed in Wuyi Mountain, Luoxiao Mountain, Xuefeng Mountain, Wuling Mountain, Wushan Mountain, Dabie Mountain, Xishuangbanna and other areas, while the poor and poor ecological environment regions are mainly distributed in large, medium and small towns, Hengduan Mountain Area in Western Sichuan. The eco-environment grade declining areas are mainly concentrated in the Yangtze River Delta, Taihu Lake, Jianghan Plain, Dongting Lake, Northwest Anhui, southern Hunan and Sichuan Basin. While, the eco-environment grade rising areas are mainly concentrated in most of Sichuan Basin, Chongqing mountain area and Three Gorges Reservoir area, most of Guizhou, Southeast Yunnan, central and Northern Anhui and Northern Jiangsu.