Evaluation Of Ecosystem Service Of Desert Steppe In Inner Mongolia Under Different Grazing Intensity

Desert Steppe is an important type of grassland in Inner Mongolia. Due to the harsh climate condition and irrational utilization, the degradation of desert steppe become more and more serious and the ecosystem is very fragile.The natural condition of desert steppe in Siziwangqi,Inner Mongolia is very poor. Overgrazing is big challenge for desert Steppe utilization, which have caused serious damage to grassland ecosystem services.It woud be benefit to the utilization and protection of grassland resources by assessing grassland ecosystem services.Based on the field trial and lab analysis,we evaluate the ecosystem services of grassland under different grazing intensities. The evaluation indicators included the net primary productivity of community, the coverage of plant community, biodiversity of grassland, soil organic matter and soil total nitrogen.InVEST model was introduced into the grassland ecosystem services spatial analysis.We use the InVEST model to analyze the spatial distribution of grassland vegetation carbon storage. Finally combined with the social and economic survey results, we use DPSIR model to give a comprehensive assessment of each herdsman’s grassland sustainability index, and get grassland sustainable spatial prediction map by using the ordinary Kriging interpolation.The results show that:1)with the increase of intensity,the aboveground net primary productivity and the coverage of plant community decreased. There was no significant change of the biodiversity of grassland vegetation communities, with the increase of intensity,the richness decreased;2)The grazing intensity had no significant impact on soil organic matter and total nitrogen in the short term;3)the above net primary productivity,the coverage of plant community, the biodiversity of grassland and the organic matter in the surface of the soil were negative correlation.4)We use the carbon storage and sequestration module of InVEST model to estimate each grazing grassland vegetation carbon storage under different grazing intensity, the highest value is the second treatment of light intensity(LG2), while the lowest value is the second treatment of heavy intensity(HG2),the highest value of the average carbon density is the light intensity,followed by the control group(CK).moderate intensity(MG) and high intensity(HG); 5) the potential index for the household survey farmer is from 0.263 to 0.704.The potential index in 2014 is higher than that of in 2009,that shows the subsidy mechanism for grassland ecological protection has been worked; the potential index is increasing with the stocking rate decreases, and the prediction map for the Siziwangqi showed the high potential area in the southeastern area.