Abstract
We examine the influence of grazing effect on grassland ecosystem by assessing spatio-temporal change in grazing pressure and incorporating the effect into a vegetation model. The recent grazing pressure in Mongolia ranges 0.34-0.54 Sheep Unit/ha, increasing in the normal years and dropping in drought/dzud (snow disaster) years. An experiment using a vegetation model Sim-CYCLE forced with outputs of a climatic model showed that the leaf area index was approximately halved for 0.1 SU/ha grazing pressure and shrunk to zero for 1.2 SU/ha. This result indicates that consideration of grazing pressure give non-negligible effects on the output of vegetation models.
