气候变化;生态恢复;退耕还林;EVI;土地覆盖

After the severe Yellow River drought in 1997 and massive flooding in the south China in 1998, China launched a huge ecological restoration project, “Grain-for-Green (Sloping Land Conversion Programs)”, in 1999 to promote afforestation and reforestation to reduce severe runoff and erosion. So far, there have been researches on the Grain-for-Green focusing on the north of China. However, the research on the vegetation change with large scale in the south of China after the Grain-for-Green is rare. In this study, we used the MODIS-250m Enhanced Vegetation Index (EVI) and trend analysis method to analyze the vegetation dynamics in the south of China from 2000 to 2009 and integrated the meteorological data, land use data, terrain data, statistical data and field observation data to analyze the effects of climate change and human activities on the vegetation cover changes. The results showed that 5.25% (54.00 million hectares) of the study areas significantly increased in EVI value, which mainly focus on the Yangtze River Plain and southwestern mountain area; 0.98% (9.38 million hectares) significantly decreased in EVI (p<0.05) around in the Yangtze River Delta, the Pearl River Delta and the Tibetan Plateau. The seasonal analysis of EVI trend showed that EVI in spring contributed most to the EVI increases (39.69% of all the significantly increased EVI area) and EVI in summer took the second place(20.59%). The analysis of climate trend showed that 51 of 323 weather stations in the research area showed significant increase in temperature (p<0.05), which mainly distribute on the Tibetan Plateau, and 9 weather stations showed significant decrease in precipitation (p<0.05). According to the relevance analysis between EVI and meteorological data, only three of the 51 stations had significant relevance between temperature and EVI dynamics (p<0.05); there was no significant relevance between precipitation and EVI changes. The results indicated that climate change did not have significant influence on vegetation change. The analysis of the land cover changes showed that the amount of farmland area decreased by 10 million hectares while that of the forest, shrub and grassland increased 3 million hectares respectively. The total area of the farmland distributed on more than 15 degree slope decreased by 3.17 million hectares and that of the forest increased by 1.61 million hectares with significant EVI increase. The vegetation improvement was likely associated with human-induced ecological restoration policy. Our study provided a complete picture of the vegetation changes during the period of 2000-2009 for accessing the impacts of the “Grain-for-Green” project on vegetation change and for better serving vegetation construction in the south of China in the future.