NPP distribution related to the terrains along the North-South Transect of Eastern China

Vegetation net primary productivity (NPP) is defined as the accumulative amount of organic matters per unit area and time, which is calculated from the difference between accumulative photosynthesis and accumulative autotrophic respiration by green plants. Since the NPP reflects the physiological and ecological characteristics of the plants and the interactive results of the environmental factors, it is an important index to evaluate a structure of ecological system, functional features and …

NPP distribution related to the terrains along the North-South Transect of Eastern China

The time series NDVI distribution maps of the study area were calculated with AVHRR images acquired from May 1999 to April 2000 on the North-South transect of Eastern China. Based on the analysis of the characteristics and their contributions to NPP on the transect, the RS NPP distribution maps were created by zones and the quantitative models were established between NDVI maps and field measured NPP sample data collected from Central and South China for forest and cultivated land. Furthermore, the spatial distribution and quantitative result were obtained through an overlapping and fitting analysis between the NPP maps and DEM. The result shows that the NPP distribution features are not only distinguished on detail zonation of natural vegetation in vertical, latitudinal and longitudinal distribution but also reflected an obvious effect from the crop growing period of agricultural area. According to the results above, an opposite opinion was given that the NPP values for the forest and agricultural areas vary greatly in different regions, with the forest areas having a higher value than the agricultural areas in Southern China. In the Huang, Huai and Hai Plains, agricultural regions have higher NPP values than the surrounding low mountains. In Northeastern China, the NPP values form a gradient across the mid-to-high mountain forest zone to plains and low mountain areas. Further, for most of the agricultural areas, NPP values range between 25–35 t · hm² · a⁻¹ and do not show significant areal differentiation.