Study On Spatio-Temporal Changes And Driving Factors Of Ecosystem Services In The Loess Plateau

Ecosystem can provide a variety of services for human survival and development,and is an irreplaceable precious resource.The sustainable ecosystem services are of great significance to regional and even global ecological security.The Loess Plateau has a fragile ecological environment.Therefore,this paper takes the Loess Plateau as the study area,uses remote sensing data and socio-economic data,and uses the In VEST model to quantitatively evaluate four key services,namely habitat quality,carbon storage,water yield and soil conservation in 1990,2000,2010 and 2020.Clarified the spatiotemporal variation characteristics of various services,analyzed the trade-offs and collaborative relationships of ecosystem services at different spatial scales,and explored the driving factors for spatial differentiation of ecosystem service functions.In order to improve people’s understanding of the status quo of ecosystem services on the Loess Plateau,and to provide reasonable and effective theoretical reference for the optimization of territorial spatial pattern,sustainable development of ecosystem and scientific decision-making of ecological management.The results are as follows:(1)Analysis of land use change:construction land and forest land had the most obvious increase in area,while the area of cultivated land decreased significantly.The interconversion among different types is mainly manifested as the transfer of cultivated land,grassland and forestland.Grassland and forestland are the important types of transferred land,and construction land is the main type of transferred land.Spatial transfer of ecological land and cultivated land mainly occurred in the eastern,central and southwestern parts of the Loess Plateau.(2)The spatial and temporal differentiation of ecosystem service function is obvious.During the study period,different levels of habitat quality were spatially cross-distributed.The spatial distribution characteristics of carbon storage,water yield and soil conservation service were high in southeast and low in northwest.The habitat quality was high,with an annual mean of 0.636,showing a trend of"declining,increasing and declining".The total carbon storage increased first and then decreased,and the average carbon storage was 35.48×10~8t.The water yield per unit area decreased first and then increased,and the average water yield was 262.12mm.The total amount of soil conservation decreased first and then increased,and the average total amount of soil conservation was 89.31×10~8t.Woodland had the highest quality of habitat,and grassland had the highest capacity of other three services.(3)The tradeoffs and synergies of ecosystem services have obvious scale effects.There are trade-offs or synergistic relationships among the four ecosystem services at the 1km and 5km scales,and there is no correlation between water production at the scale of 10km and the other three services in 2020.Except for habitat quality and carbon storage,the correlation between other service pairs was stronger at city scale than county scale.The spatial distribution of hot and cold spots of the four services overlaps but also differs,and the hot spots of forest land are the largest.The analysis of integrated ecosystem services shows that the area providing a class of services is the largest,and there are at most four overlapping hot spots of services in a grid cell,and there are also grid cells without overlapping hot spots.(4)The first and second dominant factors for spatial differentiation of habitat quality are elevation and population density,respectively.NDVI and slope are important driving factors of carbon storage spatial differentiation.Precipitation and NDVI have high influence on water yield.Slope and NDVI were the main factors of soil conservation service.The interaction of any two driving factors has a higher impact on ecosystem services than that of a single factor,indicating that the interaction of two factors has a stronger explanatory power on the effects of various ecosystem services.In summary,the spatiotemporal changes of the four ecosystem services are significant,and there is a spatial scale effect in the balance and synergy relationship.The impact of various driving factors on ecosystem services varies.Therefore,in the future,it is necessary to optimize the land use structure,scientifically and reasonably delineate ecological protection zones,provide decision-making basis for ecological management at different levels,improve the service capacity of the Loess Plateau ecosystem,and promote coordinated and sustainable development of the ecological environment.