Research On The Linkage Of Ecosystem Services Based On Multi-Source Data

Ecosystem services can enhance human life and provide the basis for sustainable development with rational exploitation.China has achieved abundant results in promoting ecological restoration through the large-scale ecological restoration programs implemented to maintain and restore ecosystem services.However,at the same time,competition among ecosystem services has intensified.In the context of promoting ecologically sustainable development,it is important to clarify the relationships among ecosystem services,to discuss the driving factors of changes in ecosystem services and their relationships,and to propose a land cover adjustment strategy that meets the requirements of sustainable development,in order to enhance the risk resistance of regional ecosystem services and to maximize ecosystem services capacity.The study carries out quantitative assessment of environment and ecosystem services in Zhangjiakou section of the Guanting Reservoir basin,an important water conservation area in the Beijing-Tianjin-Hebei synergistic development zone,to identify the changes in meteorological elements,land cover and ecosystem services(regulating and provisioning)over time and spatial distribution characteristics in 2000 and 2016.The changes of multi-ecosystem service linkages and their driving mechanisms are further studied,and the analysis of the scale effects of ecosystem services and their interrelationships is carried out.Finally,feasible strategies for optimizing the spatial pattern of ecosystems are explored based on the realistic requirements for the construction of ecosystem services and the possible ecological problems faced in the study area.(1)Compared with 2000,precipitation increased significantly(135.45 mm)in2016 in the Zhangjiakou section of the Guanting reservoir basin,with the increase concentrated in the eastern part of study area.The temperature decreased insignificantly(0.05°C),with a decrease in the northeast and an increase in the southwest.The characteristics of the two-year changes in meteorological elements were consistent with their multi-year trends.Compared with 2000,forests and settlements increased in area,with forest area increasing by 3.32%(71,149.26ha),and settlements increasing by 1.04%(22,287.72ha).The remaining land cover types decreased in area,with the largest decrease in area being grassland,which decreased by 6.74%(42142ha).Shrubs decreased by 4.46%(8873ha),agricultural land decreased by 4.32%(39943ha),and water bodies and barren land decreased by 5.26%(2326ha)and 3.44%(208ha),respectively.The spatial distribution characteristics of land cover did not change significantly,presenting aggregated distribution of the same type of landcover,but the degree of aggregation decreased in 2016.Cropland is distributed along the river,with more concentrated distribution in central Huai’an,most of Yangyuan,central Yuxian,Xuanhua,and Huailai county.Southern Yuxian and Chongli are areas with concentrated forest distribution.Grassland is distributed in intervals between cropland and forest,with more concentrated distribution in the central part of the study area.(2)Compared with 2000,the ecological environment of study area has been significantly improved,with an increase of 0.29% in water yield,an increase of 1.98 times in water conservation,a decrease of 47.3% in sediment export,a decrease of23.13% in nitrogen export,a decrease of 51.2% in phosphorus export,and an increase of 72.51% in soil carbon content in 2016.The distribution of ecosystem services at different spatial scales is characterized by similar value aggregation.Four relationship characteristics exist between different ecosystem services values,namely high-high,high-low,low-high and low-low.The factors influencing the output of ecological processes at different spatial scales are different,the spatial distribution patterns of ecosystem services and meteorological elements are more similar at the subbasin scale,while the hydrological response unit(HRU)scale fits better with the spatial distribution patterns of land cover.(3)The correlation characteristics of ecosystem services at different spatial scales in different years were similar,with trade-offs between water yield and other ecosystem services,and the remaining ecosystem services were mainly synergistic.The strongest trade-off at different spatial scales is water yield-water conservation.Ecosystem services were more sensitive to meteorological factors at large scales,and precipitation had a stronger influence on ecosystem services than temperature,but some ecosystem services(soil conservation and phosphorus loss control)were also influenced more by land cover.Land cover,slope,soil type and properties had greater influence on ecosystem services at small scales,and the response characteristics of ecosystem services and(trade-off)relationship strength to land cover changes did not vary with spatial scale.The degree of difference in the contribution of different influencing factors to different ecosystem services is a determining factor in the degree of their contribution to the intensity of trade-offs.In general,the integrated impact of land cover changes on ecosystem services and their relationships at different scales is stronger than that of meteorological elements.(4)Different land covers differ in their contributions to ecosystem services,and using the difference characteristics can develop land cover optimization strategies for different ecological construction objectives.Evergreen forests can increase soil organic carbon content and significantly improve water conserving capacity,which is more suitable for planting in areas that need to improve water conservation and protect soil health.Deciduous forests have average water holding capacity,but can effectively increase soil carbon content and reduce runoff production,while reducing nitrogen loss.Planting deciduous forests is a good choice in areas where runoff regulation,nitrogen loss control and soil fertility enhancement are needed.The contribution of mixed forests to all ecosystem services is not significant,but the contribution varies widely,which can easily lead to multiple trade-offs.Under the premise of emphasizing the coordinated development of ecosystem services,mixed forests are not suitable for planting in areas with similar climatic conditions and topographical characteristics as the study area.Grasslands contribute to all ecosystem services except soil carbon sequestration and nitrogen loss control,and can mitigate multiple pairs of trade-offs.Considering the synergistic development of regional ecosystems,converting some of the land cover types that cause strong trade-offs to grassland is a feasible land cover adjustment option.It is important to note that when grassland is converted to forest,increase of slope at the corresponding location will weaken most ecosystem services and exacerbate most trade-offs,thus influence of topography on ecosystem service restoration/enhancement and on trade-off mitigation should be considered when developing different land cover adjustment strategies.