Household-Based Research Of Grassland Degradation And Impacts On Ecosystem Services

China holds large grassland resource in the world,and grassland ecosystem plays an important role in Chinese ecological security.The serious degradation of grassland caused by years of climate change and human activities became the main obstacle for the development of social economy and the construction of ecological barrier in Northern China.Xilinhot county situated in the central part of Xilinguole League and located in the typical area of the eastern of Eurasian steppe region,its grassland ecosystem has experienced degradation and restoration in recent decades.Therefore,it is important to study the degradation and dynamics of grassland in this area,clarify its driving forces,and characterize the temporal and spatial dynamics of ecosystem services,and explore the changes of ecosystem services in the process of grassland restoration/degradation.Based on the results of remote sensing vegetation interpretation in 2000 and 2017,we calculated the grassland degradation and dynamics of 141 household in Xilinhot county by grassland degradation index(GDI).The key driving factors of grassland degradation status and dynamics were identified by variance decomposition and random forest method based on survey data,climate data and topographic data of household.The grassland ecosystem services such as aboveground biomas,soil conservation,water retention and carbon storage were quantified by remote sensing yield estimation model,RUSLE model and InVEST model.The relationship between different ecosystem services was analyzed,and the effects of grassland degradation status and dynamics on ecosystem services were discussed.The main results are as follows:1.In 2000,the degradation degree of pasture in the northern part of Xilinhot county was higher than that in the southern part of Xilinhot county.By 2017,central and northern pasture in Xilinhot county had recovered significantly,while southern pasture had slightly degenerated.2.Climatic factors,topographic factors and household social and economic factors have cooperate effect on grassland degradation.Climate and elevation are the main influencing factors for grassland degradation,and grassland degradation are also affected by social and economic factors such as weeding amount;For grassland restoration/degradation,elevation,annual sunshine hours,total amount of fossil fuel use,number of training in animal husbandry technology,number of land transfers and other factors have a greater impact.3.In 2000,the aboveground biomass,soil conservation,water retention and carbon storage of pasture were low,showing a decreasing trend from southeast to northwest in space.As of 2017,aboveground biomass,soil conservation,water retention and carbon storage of pastoral grasslands in central and western Xilinhot county increased significantly,while ecosystem services declined in southern and Northern grasslands in Xilinhot county.4.Aboveground biomass,soil conservation,water retention and carbon storage of pasture showed synergistic relationship in 2017;In terms of dynamics,carbon storage and soil conservation showed a trade-off relationship in 2000,But in 2017 it turned into synergistic relationship.The relationship between aboveground biomass and soil conservation changed from insignificant synergy in 2000 to extremely significant synergy in 2017(p < 0.01).The relationship between other ecosystem services was also significantly synergistic in 2000(p < 0.01),and did not change in 2017.5.The correlation analysis shows that the change of grassland degradation index(GDI)was negatively correlated with the increment of ecosystem services such as aboveground biomass,soil conservation,water retention and carbon storage of pastoral grassland from 2000 to 2017,which indicates that the process of grassland restoration/degradation had an important impact on grassland ecosystem services.