Abstract: The aim of this research is to reveal the response of vegetation cover to climate change before and after the Three Gorges impoundment. The correlation between vegetation cover and climate factors in the upstream of the Yangtze River from Cuntan to Yichang and 100 km around was analyzed by using partial correlation coefficient method based on SPOT NDVI and observed meteorological data. Meanwhile, the non-linear mapping relationship was also investigated. Results unveiled high spatial heterogeneity of the dynamic response of vegetation cover to temperature and precipitation in the study area. Temperature is the major driving factor of vegetation cover variations. Second-order non-linear mapping effectively characterizes the response of vegetation cover to temperature, and well explains the physical mechanism of the relationship between vegetation cover and temperature. The response of vegetation cover to temperature is affected by the impoundment of the Three Gorges Reservoir to a certain extent, and the influence degree attenuates with the distancing from the river.

Key words: vegetation cover, normalized difference vegetation index(NDVI), climate response, impoundment, Three Gorges Reservoir