Abstract: Based on the MOD13Q1 vegetation index products and extreme temperature and extreme precipitation indices from 2000 to 2017, we examined the temporal and spatial variations of NDVI in Sichuan and Chongqing during the growing season, and analyzed the relationshipbetween NDVI and extreme indices with correlation analysis method and Lasso regression model. The results showed that the average NDVI value of Sichuan and Chongqing was 0.6134, with a change rate of 0.033 （10 a-¹）. The NDVI values and their change rates in the eastern region were higher than those in the western region. The NDVI value and change rates in Chengdu City and Chongqing City were significantly lower compared with the surrounding areas. The responses of eastwest borders and east of Sichuan and Chongqing and its northerly area to the extreme climate indices were more obvious. Except for the number of cold days and the maximum daily precipitation, other indices were positively correlated with NDVI. Among which, the area with positive correlation between average temperature and NDVI was the largest, accounting for 81.79% of the total, while the area with negative correlation between the number of cold days and NDVI was the largest, accounting for 76.57%. The predicted values calculated by the Lasso regression model were well fitted with the NDVI values extracted by remote sensing (R=0.81), and the model verified the correlation results and also made up the deficiencies of correlation analysis considering only a single extreme index. The NDVI in Sichuan and Chongqing region was more significantly affected by temperature than by precipitation, which were mainly positively correlated. Heavy rainfall was not conducive to the growth of vegetation in the short term.

Key words: habitat value., Yangtze River estuary, Phragmites australis, dominant species, zoobenthos