Land Use/Cover Change and Its Impact on Net Primary Productivity in Huangfuchuan Watershed Temperate Grassland, China

This study take the Huangfuchuan Watershed temperate grassland as the study area, RS and GIS techniques are used to explore the relationship between LUCC and NPP. With the combination of CASA model, the dynamic characteristics of NPP in 1987-2011 are studied. The main conclusions are as follows: (1) land use structure changes obviously in Huangfuchuan Watershed. The main trend of land use change was the gradual increase of construction land and woodland, the gradual decrease of water. Arable land, grass, shrub, bare rock and sand were fluctuant. It could be seen from land use dynamic degree. (2) Through the calculation of NPP model, the total value of NPP in 1987, 1995, 2000, 2007 and 2011 was 28.12GgC, 53.47GgC, 73.23GgC, 157.92GgC and 78.52GgC. (3) Through the analysis of land use change effects on NPP, it indicates the main reason for the increase of NPP is due to grassland transfer to shrub between 1987 and 1995. The decade of bare rock is the main reason for the increase of NPP in 1995-2000. Shrub transferring to grassland is the main reason for the increase of NPP in 2000-2007. Grassland transferring to shrub is the main reason for the reduction of NPP in 2007-2011. The results of the study is very meaningful for rational using of temperate grassland resources and improvement of the fragile ecological environment.