The Eco-hydrologcial Evolution Law of Natural Vegetation in Haihe River Basin

The Haihe River Basin is one of the most water scarce regions in china, in which natural vegetation plays an important role in the eco-hydrologcial process. In this study, the historical eco-hydrological evolution law of natural vegetation was studied in Haihe River Basin. Distributed hydrological model WEP and ecological model BIOME- BGC were applied to calculate changes of net primary product (NPP) and evaportranspiration (ET) of the basin in the last decades. The analysis demonstrated that the annual NPP increased slightly from 1980 to 2005 in the basin, mountain area and plain area, and the main impacting factor is the climate situation rather than land use change. The ET of forest, grass and wetland all decreased from 1956 to 2005 in the basin, mountain area and plain area