Keywords: 
• ecology /
• net primary productivity /
• MODIS /
• spatio-temporal characteristics /
• climate factors /
• land cover types

Abstract: Vegetative net primary productivity （NPP） is an important indicator of terrain ecosystem quality. In order to improve the comprehension on vegetation response to human activity and global changes, spatio-temporal characteristics of NPP in the lower-middle reaches of the Yangtze River from Moderate Resolution Imaging Spectroradiometer （MODIS） data were analyzed by GIS technology. Then influential factors affecting these characteristics were explored in the lower-middle reaches of the Yangtze River from 2001-2010. The linear regression coefficients among different annual NPP maps were used to assess the changing trend of NPP and a correlation analysis was also used for the analysis. Results showed that the annual NPP varied from 420 to 670 gm－2a－1, with an average of 562 gm－2a－1. With respect to inter-annual variation, NPP decreased in most regions, but only 7% regions reached the significance level （P＜0.05）. In regards to spatial distribution, NPP in the southern parts of the region seemed to be higher than in the northern parts, and NPP in coastal regions was higher than inland areas. The correlation analysis revealed that vegetative NPP was significantly sensitive to climate changes （P＜0.05） with annual NPP positively correlated to temperature （r = 0.49） and sunshine duration （r = 0.19） but negatively correlated to precipitation （r = －0.22）. In addition, land cover type transformations also played an important role with vegetative NPP variation. This paper proved that the concentrated human activities and cliamte changes severely affected the natural ecosystems, and might give a deep impression on carbon cycles. ［Ch, 4 fig. 1 tab. 26 ref.］