Influence of Regional Climate Change on Vegetation Cover in the Middle and Lower Yangtze River Basin

The temporal-spatial vegetation coverage changes in the lower and middle Yangtze River basin were studied based on the MODIS EVI( enhanced vegetation index) and meteorological data from 2000-2010. The results showed that: 1) Vegetation coverage increased successively as indicated by the annual EVI index change from 0. 302 in 2000 to 0. 318 in 2010,with an increment of 5. 57%.The increments mainly happened in the spring. Among all vegetation types,evergreen broad-leaved forests,deciduous broad-leaved forests,mixed forests and artificial farmland vegetation coverage increased significantly. 2) The study areas were well covered by various vegetations with distinct regional differences. For instance,the southeast,Nanling and Mounts Wuyi and Jiuling were highly covered. The areas close to the rivers and lakes in the middle Yangtze basin and near the metropolis had poor vegetation coverage. 3) Temperature was a main factor influencing the vegetation coverage change,especially in the spring. For abundant precipitations,rainfall had less effect on vegetation than temperature. Sunshine duration had impacts on vegetation coverage only in the summer. Average relative humidity had low correlation with vegetation coverage,though the impacts in the autumn could last for three months. 4) The impact of climate change on the natural vegetation was mainly manifested in western Hunan and Hubei Provinces. In central Hunan and the north-central Anhui Provinces,climate change had an obvious impact on artificial farmland vegetation. 5) The spatial correlation coefficients indicated that the vegetation coverage increments in the lower and middle Yangtze River basin did not only benefit from the naturalconditions improvement,but also from the ecological programs launched by the central government over the past years.