[Variation trends of natural vegetation net primary productivity in China under climate change scenario].

Based on the widely used Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ) for climate change study, and according to the features of natural environment in China, the operation mechanism of the model was adjusted, and the parameters were modified. With the modified LPJ model and taking 1961-1990 as baseline period, the responses of natural vegetation net primary productivity (NPP) in China to climate change in 1991-2080 were simulated under the Special Report on Emissions Scenarios (SRES) B2 scenario. In 1961-1990, the total NPP of natural vegetation in China was about 3.06 Pg C a(-1); in 1961-2080, the total NPP showed a fluctuant decreasing trend, with an accelerated decreasing rate. Under the condition of slight precipitation change, the increase of mean air temperature would have definite adverse impact on the NPP. Spatially, the NPP decreased from southeast coast to northwest inland, and this pattern would have less variation under climate change. In eastern China with higher NPP, especially in Northeast China, east of North China, and Loess Plateau, the NPP would mainly have a decreasing trend; while in western China with lower NPP, especially in the Tibetan Plateau and Tarim Basin, the NPP would be increased. With the intensive climate change, such a variation trend of NPP would be more obvious.

[Spatial pattern of vegetation landscape diversity in longitudinal Range-Gorge Region, southwestern China].

Based on the China 1:1000000 vegetation type map, and by using GIS spatial analysis, the spatial pattern of major vegetation landscape diversity indices and its relationships with environmental factors in Longitudinal Range-Gorge Region (LRGR) were analyzed. The proper scale for studying the vegetation landscape diversity in LRGR was 2000 m. In the study region, an obvious regional difference was observed in the vegetation landscape diversity indices, exhibiting typical longitudinal "corridor" and latitudinal "barrier" characteristics. The correlations between the vegetation landscape diversity indices and environmental elements were significant, and the regional difference in the environmental elements was the main factor controlling the spatial pattern of vegetation landscape diversity indices. The "corridor-barrier" function of the longitudinal range-gorge terrain made a spatial redistribution of hydro-thermal conditions, being the main cause of the special pattern of the vegetation landscape diversity in LRGR.