Abstract:

The interaction between vegetation and atmosphere is a research focus and hotspot in the field of earth science under the background of global change. Net primary productivity (NPP) has become a key link of biogeochemical cycle process of terrestrial ecosystems in the global and regional scale, which embodies the complex interaction between vegetation, soil and climate, and is strongly influenced by human activities and global environmental change. Therefore, it has important significance to know the spatial and temporal pattern, variation characteristic and the relationship between terrestrial NPP and climate factors, especially temperature and precipitation, in the evaluation of environment quality, estimation of the terrestrial carbon source/sink potentials, and the management and use of natural resources. Based on the average annual NPP data of MOD17A3 data and temperature and rainfall data from meteorological stations during 2001-2010, the temporal and spatial pattern and dynamic change of vegetation NPP in southeastern China and their relationship with climate elements were analyzed using GIS spatial analysis technology and mathematical statistics method. The results indicate that average annual vegetation NPP in southeastern China gradually decreased from the southern to the northern parts and from the eastern to the western parts as a whole. Different vegetation types had different average annual NPP, with evergreen broad-leaved forest had the highest average annual NPP and deciduous coniferous forest had the lowest NPP. In addition to deciduous coniferous forest, the NPP of high forest was significantly higher than that of low vegetation such as field crops and herbaceous plants. The average annual vegetation NPP reduced slightly as a whole in southeastern China during 2001-2010, and it increased rapidly during 2001-2004, after then it reduced gradually. Spatially, vegetation NPP decreased significantly in the southern regions, but increased significantly in the northern regions. In Jiangsu, southern Anhui, Zhejiang, Jiangxi, western Fujian, central and southern Hunan and northern Guangdong, vegetation NPP decreased at a rate of over 150 g/m² per year in carbon value, but in southwestern Shanxi, western and central Henan, northwestern Hubei and northwestern Anhui, vegetation NPP annual carbon value increased at a rate of over 150 g/m² per year in carbon value. The correlation between vegetation NPP and rainfall and temperature showed significant regional differences, with closer relationship between vegetation NPP and rainfall in northern regions, where precipitation increased in most areas in the past 10 years, and in the southern regions, where plum rains were removed northerly, and temperature increased in most of areas.

Key words: vegetation, net primary productivity, climate, the southeastern China