Evaluation Of Ecosystem Water Yield And Soil Erosion In The Loess Plateau Region Under Different Land Use-Climate Scenarios

The Loess Plateau area is not only a serious of water shortage area and soil erosion area,but also an important area of water supply in the Yellow River basin.It is of vital significance to discuss the ecological water yield and soil conservation services in the Loess Plateau region for resource management,ecological stability and sustainable development of human social system in the Yellow River basin.This study is based on the In VEST model,coupled with the FLUS model and MPIESM-MR model,quantitative assessment of water yield and soil erosion.Firstly,based on the land use data of two phases(2000 and 2015),combined with the driving factors of natural and social economy,the FLUS model was applied to simulate the spatial pattern of land use under three different scenarios in the study area in 2030.At the same time,based on the meteorological data of 2015 and the output data of the MPI-ESM-MR simulation of the atmospheric circulation model,the spatial analysis tool and grid resampling tool in the Arc GIS10.2 software were used to realize the climate simulation of different CO2 emission scenarios in the study area in 2030.And then the annual water yield sub-module and sediment delivery ratio sub-module of In VEST model were applied to carry out the scenario simulation of water yield and soil erosion in the study area.Comprehensive analysis of spatial-temporal and scenario differences in water yield and soil erosion,to reveal the action mechanism of land use and climate change on water yield and soil erosion.It is expected to provide theoretical and scientific references for the formulation of regional ecological construction plan,land development strategy and water resources management plan.The main conclusions are as follows(1)Under different scenarios of land use change,the land use change in the Loess Plateau region in 2030 generally shows a trend of decrease of arable land,grassland and unused land,and an increasing trend of forest land,water area and construction land.The absolute dominant land types are still arable land and grassland,the proportion of both is always greater than 72%.(2)In the Loess Plateau region,increased land for construction will increase water yield and reduce soil erosion,while returning farmland to forests will reduce water yield and soil erosion.Regional water yield and soil erosion increased with the increase of precipitation and decreased with the decrease of precipitation.The three scenarios of land use change constructed by the research will promote water yield and inhibit soil erosion.The RCP2.6scenarios of climate change will inhibit regional water yield and soil erosion,while the RCP4.5 and RCP8.5 scenarios will promote water yield and aggravate soil erosion.(3)Both land use change and climate change will affect water yield and soil erosion and their spatial distribution in the loess plateau,and climate change has a more significant impact.Among them,the contribution rate of climate change to water yield is as high as96.3%～99.9%,and the contribution rate to soil erosion is as high as 79%～96.8%;while the contribution rate of land use change to water yield and soil erosion is only 0.1%～3.7% and3.2%～21%.The study also shows that the technical route of this study can be used as a reference for decision-makers and researchers in other regions of the relevant research.The future ecological construction and land development in the loess plateau region should balance the benefits of ecological restoration and construction,the demands of social and economic development,and the balance of ecosystem services,so as to realize the sustainable development of human social system and ecosystem.