Study On The Driving Mechanism Of Ecological Effect Of Sloping Land Conversion Program In Loess Plateau

With the continuous development of China’s economy and the continuous growth of population,human activities have affected the ecological environment with unprecedented intensity,resulting in the degradation of the ecosystem,which has brought a series of environmental problems and seriously affected the process of sustainable development.The Loess Plateau is a typical area of this kind of environmental problems.In order to alleviate the soil erosion,the state has implemented the project of Sloping land conversion program in this area.After the implementation of the project,soil erosion on the Loess Plateau was significantly reduced,vegetation coverage was significantly increased,various ecosystem services were increased,and a series of social and economic effects were also brought.Study shows that the Sloping land conversion program ecological effect of regional natural,social and economic development and policy factors such as joint decision,scientific estimates of the loess plateau Sloping land conversion program to help promote ecological effect and explore its driving mechanism of complex project of ecological efficiency,for the subsequent implementation of sustainable ecological restoration to provide theoretical reference.And provide reference for the ecological protection and high quality development of the Yellow River basin.By reviewing domestic and foreign literatures on the ecological effects and driving mechanisms of the Sloping land conversion program,this study found out the shortcomings of the existing theories and methods on the driving mechanisms of the ecological effects of ecological restoration projects.Combined with the existing theoretical basis,the research breakthrough point was determined,taking 342 counties(districts and banners)on the Loess Plateau as the research object.First analyzes the implementation of Sloping land conversion program in the region after the spatial and temporal change of land use change,and combining the regional precipitation,soil,vegetation have land use data,using the revised universal soil loss equation(RUSLE model)after the implementation of Sloping land conversion program quantitative assessment of the loess plateau soil erosion and soil conservation of the change of time and space,Secondly calculated based on the amount of soil conservation,combined with the county on the loess plateau Sloping land conversion program implementation situation,the development of social economy and natural environment variable,build a structural equation model to explore the driving mechanism of the loess plateau of Sloping land conversion program ecological effect,identify the driver the ecological effects of specific factors and comprehensive analysis.The main results are as follows:(1)From 2000 to 2020,the cultivated land area of the Loess Plateau continued to decrease,and the regional forest area increased significantly driven by the Sloping land conversion program,with a total increase of 9850.14 km~2.From 2000 to 2020,the overall vegetation coverage of the Loess Plateau increased significantly.The mean vegetation coverage increased from 0.528 in 2000 to 0.697 in 2020,with an average annual increase of 1.6%.Most areas of the Loess Plateau realized the increase of vegetation coverage.(2)The average soil erosion intensity decreased from 63.26 t/(hm~2·a)in 2000 to 41.88t/(hm~2·a)in 2015,and the total soil erosion decreased by 13.88×10~8t in 15 years.An average annual decrease of 9.25×10~7t;The total amount of soil conservation services on the Loess Plateau was 210.47×10~8t in 2000,and increased to 224.35×10~8t in 2015,an increase of 6.59%in 15 years.Soil conservation services continued to increase in most regions of the Loess Plateau from 2000 to 2015,indicating that the area of improvement was more than 10 times that of deterioration.(3)The implementation of the Sloping land conversion program had a significant positive effect on the increase of soil conservation services in the Loess Plateau from 2000 to 2015,with an effect coefficient of 0.175 from 2000 to 2008 and 0.332 from 2008 to 2015,indicating that the ecological restoration efficiency in the former stage was lower than that in the latter stage.The implementation of the Sloping land conversion program also had a certain social and economic impact.From 2000 to 2008,the implementation of the Sloping land conversion program led to the decrease of agricultural development speed,with a direct effect coefficient of-0.097.(4)Sloping land conversion program not only directly leads to the increase of soil conservation services,but also indirectly affects the increase of soil conservation services through social and economic impacts.The indirect effects of the two stages are 0.044 and 0.010respectively,and the total effects are 0.219 and 0.342 respectively.In the follow-up implementation of the Sloping land conversion program,ecological restoration should be carried out according to local conditions,appropriate tree species and forestation intensity should be selected according to regional conditions,and maintenance and management should be strengthened after the implementation of the project.At the same time,measures should be taken to alleviate the pressure of social and economic development on ecosystem services and realize the coordinated development of social and ecosystem.