| Geographic information system(GIS)technology has undergone constant improvement,as thus,its applications have been expanded and deepened,and it has become a powerful tool for mapping and evaluating ecosystem services.Ecosystem services are essential to human survival and development.Throughout the history of human development,people’s well-being has depended on the functioning of the ecosystem around them.However,in recent years,anthropogenic disturbances and climate change have put increase pressure on ecosystem services,affecting the ecosystem services provisioning at various spatial and temporal scales.A major problem for human society in this situation is how to put scientific management ideas into practice to achieve sustainable supply of global and regional ecosystem services.GIS technology could effectively deal with the complexity of data at various spatial and temporal scales,which offered an appropriate methodological foundation for research on ecosystem services.As a typical ecologically fragile zone,the ecological environment of farmingpastoral ecotone in northern China is sensitive and vulnerable,particularly prone to perturbations from human activity and climate change.There is a great challenge to figure out scientific sustainable management techniques to produce a sustainable supply of ecosystem services in the context of global change.Therefore,based on multi-source physical geographic and socio-economic data,this study integrated the ecosystem service assessment model,GIS spatial analysis and quantitative model to conduct a study framework on the spatial and temporal changes,trade-offs and synergies farmingpastoral ecotone of northern China.And on this basis the paper analyzed the driving mechanisms of ecosystem services and their relationships and explored how to scientifically conduct land use management and landscape planning in the study area in2030.The main contents and conclusions of the study are as follows:(1)This study developed a multi-level and multi-scale methodological framework for ecosystem services research.The framework integrated ecosystem services assessment models and GIS spatial analysis methods and quantitative assessment models,including In VEST model,RWEQ model,scenario analysis,MGWR model and Geo SOS-FLUS model,and then carried out research on the spatio-temporal changes of ecosystem services – tradeoff and synergy relationship – future land use management and landscape patten.Through the framework of this method,the paper could not only deeply analyze the driving mechanism of ecosystem services and their relationships,but also effectively be applied to the future ecosystem management and decisionmaking of the farming-pastoral ecotone of northern China.Simultaneously,the findings also demonstrate that GIS technology can be used for ecological management planning and decision making,providing new ideas and perspectives for regional management and planning of ecologically fragile areas.(2)Based on climate data and land use data,this study used trend analysis and dynamic land use trajectory analysis,combined with spatial analysis methods,to analyze climate change and land use changes in farming-pastoral ecotone of northern China from 2000 to 2020.From 2000 to 2010,the climate in 69.35% of the study area showed a warm and dry trend,mainly in the central-eastern region.During 2010-2020,the climate in 88.70% of the study area showed a warm and wet trend,mainly in the central-eastern region.The land use structure of the farming-pastoral ecotone of northern China was dominated by farm land and grassland,and the conversion between farm land and grassland was the main land use conversion characteristic of the region.From 2000 to 2010,ecological restoration were the main land use changes in the study area.The forest land area and grassland area increased while the farmland area decreased.From 2010 to 2020,the land use dynamics of the study area changed more strongly.The farmland,forest land and built-up land area increased,while the grassland area decreased significantly.(3)The study used the In VEST model and RWEQ model to assess the ecosystem services under climate change and land use change from 2000 to 2020,and combined scenario analysis and spatial analysis methods to analyze the direction and extent of the impact of climate and land use change.From 2000 to 2020,under the influence of climate change and land use change,the water yield and soil retention showed a trend of first decreasing and then increasing,and sand fixation showed a continuous decreasing trend in farming-pastoral ecotone of northern China.On a regional scale,climate change was the dominant factor in the change of ecosystem services in the study area.During 2000-2010,warm-dry climate trend had a negative impact on water yield and soil retention,while during 2010-2020 warm-wet climate trend had a positive impact on water yield and soil retention.And the decrease of sand fixation services was mainly due to the decrease of wind speed in the region during the past 20 years.At the raster scale,land use changes in the study area had a significant impact on ecosystem service changes.In the past 20 years,the expansion of built-up land significantly increased the water yield in the region;while the increase of forest land area significantly increased the soil retention;and the interconversion between farmland and grassland led to substantial changes in sand fixation.(4)The study used correlation analysis,root mean square analysis,MGWR model and ordered weighted average algorithm to clarify the trade-offs and synergistic relationships among ecosystem services and their response mechanisms to natural and socio-economic factors from multiple spatial scales,and to identify priority protected areas for ecosystem services.With changes in spatial scales,the trade-offs and synergistic relationships between ecosystem services varied in strength and direction in the farming-pastoral ecotone of northern China.At the regional scale,water yield showed a weak synergistic relationship with soil retention,and a medium trade-off relationship with sand fixation.The soil retention showed a high trade-off relationship with sand fixation.The direction of the relationship between ecosystem services at the sub-regional scale was basically the same,but the strength of the relationship differed.When refined to the county scale,water yield and soil retention were dominated by trade-off relationships,while soil conservation and sand fixation were dominated by synergistic relationships.The strength of trade-offs and relative benefits among ecosystem services in the study area have changed over the past 20 years.Natural factors,such as precipitation and vegetation cover,were the dominant factors affecting the strength of trade-offs among ecosystem services.Socio-economic factors also had an important influence.There was significant spatial heterogeneity in the degree and direction of influence of different drivers.(5)By coupling the Geo SOS-FLUS model with multi-objective planning,the study set three possible land use scenarios(natural development scenario,economic development scenario and ecological conservation scenario)for 2030 in farmingpastoral ecotone of northern China,quantified the three ecosystem services under different scenarios,and explored the effects of landscape pattern composition and configuration on ecosystem services under different scenarios by combining the boosting regression tree algorithm.Ecosystem services showed different changes under different land use scenarios in 2030.Among them,the total ecosystem services increased by 0.59% and 0.72% in the natural development scenario and ecological conservation scenario,respectively,while the total ecosystem services decreased by0.38% in the economic development scenario.The study used boosting regression tree to analyze the impact of landscape pattern on total ecosystem services and marginal effects.It was found that the proportion of grassland area and the proportion of cropland area had a larger relative contribution to total ecosystem services.The difference was that the proportion of grassland area had a positive effect on total ecosystem services,while the proportion of cropland area had a negative effect.The proportion of forest land area had a positive effect within a certain threshold.In the landscape configuration,the Shannon diversity index,connectivity index and contagion index had a positive influence on the total ecosystem services,while the landscape shape index and patch density had a negative influence on the total ecosystem services.In the future land use management and landscape planning of the farming-pastoral ecotone of northern China,the policymakers could coordinate the area ratio of grassland to farmland and regulate the landscape pattern configuration obtain better ecosystem service supply.In summary,based on GIS spatial analysis and quantitative modeling as the primary technology,this multi-level ecological service research framework could be effectively applied to the future management and decision-making of the agriculturalpastoral intersection zone in northern China.In the past 20 years,as a typical ecologically fragile zone,three ecosystem services(water yield,soil retention,and sand fixation)in the farming-pastoral ecotone of northern China had been dominated by climate change at the regional scale.It is evident that,for farming-pastoral ecotone of northern China,it is necessary to strengthen the monitoring and prediction of future climate change in order to develop reasonable strategies to reduce the negative effects of climate change.As the spatial scale changes,the trade-offs and synergistic relationships of ecosystem service pairs change in magnitude and direction.Natural drivers were the dominant factors affecting ecosystem service relationships.However,natural drivers,especially climatic factors,are difficult to change,so it is necessary to develop reasonable land use management and landscape planning strategies to achieve sustainable development of the region.In order to achieve regional sustainable development in the farming-pastoral ecotone of northern China,it is unavoidable to adjust the structural ratio of agriculture and livestock,restore and protect grassland ecosystems,and carry out ecological construction projects according to local conditions.This is demonstrated by the relative contribution of landscape patterns on ecosystem services in possible land use development scenarios in 2030.The results of this study provide a scientific basis and a theoretical foundation for the future regional planning and management in farming-pastoral ecotone of northern China. |
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