A Study On Ecosystem Service Assessment And Trade-offs And Synergistic Relationships In Ecological Counties

Analyzing the spatial and temporal changes of ecosystem services in ecological counties,exploring the trade-offs and synergies between ecosystem services and the driving forces of ecosystem services are important to promote ecological counties to practice the concept of "Lucid waters and lush mountains are invaluable assets" and achieve win-win situation of economic development and ecological benefits.This study takes Wuning County,an ecological county,as the study area,and uses Arc GIS platform and In VEST model to quantitatively evaluate the key ecosystem services in Wuning County from 2000 to 2020 based on meteorological data,land use data and statistical yearbook data from meteorological stations in Wuning County and its surrounding areas,combined with relevant data obtained from field surveys.The spatial patterns and temporal trends of key ecosystem services(water conservation,soil conservation,carbon storage and food supply)in Wuning County were quantitatively assessed in 2000-2020 based on meteorological data,land use data and statistical yearbook data.Then,the correlation coefficient method and bivariate spatial autocorrelation were used to analyze the spatial and temporal trade-offs of the four key ecosystem services in Wuning County over the past 20 years.Finally,the driving factors affecting the functions of the 4 ecosystem services and the explanatory power of each influencing factor on the functions of the 4 ecosystem services after interaction were obtained using a geographic probe.The main study findings are as follows:1)From 2000 to 2020,the conversion frequency of grassland and cropland is relatively high,with grassland having the largest conversion area.The land used for urban expansion mainly comes from cropland and grassland,and the conversion of cropland to woodland is also relatively obvious.The average annual water content of regional grassland in Wuning County increased from 173.14 mm to 283.92 mm,and the food supply increased from 114.73 MJ to 166.97 MJ.The soil conservation capacity showed a fluctuating trend of first decreasing,then increasing,then decreasing again.over 20 years,the soil conservation capacity decreased by 15.71%.The carbon storage capacity showed a weak increasing trend.2)In the south and north of the study area,forest land is widely distributed with extensive vegetation cover,which is a high value area for water conservation,soil conservation and carbon storage.In contrast,watershed,construction land and unused land have less vegetation cover and are low-value areas for water connotation,soil conservation and carbon storage.Among the four types of ecosystem services,forest land and cropland are very critical sites in the development of ecosystem services in the study area.3)There is a synergistic relationship between the three regulating services of water harvesting,soil conservation and carbon storage,and there is a trade-off between food supply and these three regulating services.Compared with elevation,the effect of slope on these 4 ecosystem services is more significant.The trade-offs and synergistic relationships among ecosystem services were the same at regional and grid scales.The synergistic relationships were mainly distributed in high elevation woodlands and watersheds,showing "high-high" and "low-low" clustering.The trade-off relationship is mainly distributed in arable land,showing the characteristics of "high-low" and "lowhigh" clustering.4)Wuning County is mainly dominated by Type 1 ecosystem services,followed by Type 2 services,with an area of over 26%.0 and Type 1 services show a gradual decrease over time,while the area of Type 2 and Type 3 services gradually increases,and the ecosystem service function of Wuning County is gradually improving.There is basically no change in the type of dominant service hotspots in the county during 2000-2020,but there is a large change in the spatial pattern.The area of services dominated by carbon storage is the largest and most widely distributed,while the area of hotspots dominated by soil conservation services is the smallest and close to 0.5)Slope and elevation are the key factors determining the spatial heterogeneity of the four ecosystem services.In water conservation,the explanatory power of slope and elevation factors increases year by year.And in terms of soil conservation,slope had the highest explanatory power of more than 50%.The degree of influence of population density and GDP on the four ecosystem services was relatively small.The interaction of the two factors on ecosystem services in Wuning County was more significant.The explanatory power of some single factors,which is usually small,can become significant even under the condition of the combination of two factors.