Changes,Trade-offs,and Synergies Of Ecosystem Services In Changbai Mountain Regions

Terrestrial ecosystems are the foundation of human well-being and sustainable development.Ecosystems provide a wide range of services including provisioning,regulating,supporting,cultural services that are critical to achieve a balanced development among economic growth,social wellbeing and environmental protections.However,climate change and human disturbance have resulted in degradation or even losses of ecosystem services and altered trade-offs and synergies among services,which severely constrain regional sustainable development.Ecosystem services and their trade-offs/synergies are affected by multi-scale processes,having scale-dependent effects as well as high diversity and spatial heterogeneity.To date,a large number of studies on the changes of ecosystem services and shifts between trade-offs and synergies under climate change or land use/ cover change(LUCC)have been conducted.However,few studies focused on the combined effects of climate change and LUCC on changes,tradeoffs and synergies of ecosystem services,and strategies that balance the trade-offs to achieve the maximum benefits.Therefore,this study addressed two research questions: What are the effects of climate change and human disturbances on ecosystem services and trade-offs/synergies at different spatial scales? What are the optimal landscape configurations to achieve maximum ecosystem services?This study assessed the spatio-temporal changes,tradeoffs,and synergies of ecosystem services(water yield,soil retention,carbon storage and habitat quality)in Changbai Mountain regions(CBMR)under climate change and human disturbances(primarily LUCC)in the last 30 years(1990s-2020s)and the next 30 years(2020s-2050s).We employed an integrated approach that combined multi-source remote sensing data,field survey data,using In VEST model,ESTD model and SEM.The main findings were as follows:(1)In the past 30 years,the annual average temperature in CBMR increased by0.92℃ and the annual precipitation decreased by 120 mm.In the next future 30 years,the annual average temperature will continue to increase by 0.65℃ and the annual precipitation will decrease by 62 mm.In the past 30 years,there were substantial changes(4.57%)in the land use and land cover in CBMR that were primarily driven by multi-land use decisions.Specifically,large amounts of grasslands(-43.08%)were converted into croplands(+20.10%)and woodlands(-0.95%),while wetlands significantly increased(+76.77%)due to wetland restoration and protection policies.In the future 30 years,vegetation changes in CBMR remain obvious(20.10%),with decreases of 5.20% for woodlands and increases of 4.10%,1.86% and 0.63% for croplands,grasslands and wetlands,respectively.(2)In the past 30 years,provisioning and supporting ecosystem services in CBMR showed decreasing trends(water yield-8.77%,habitat quality-20.48%),while regulating ecosystem services showed increasing trends(soil retention +29.56%,carbon storage +9.90%).Regionally,the decrease in water yield was mainly affected by negative effects of climate change,the decrease in habitat quality was mainly affected by negative effects of LUCC and its interaction with climate change,and increases in soil retention and carbon storage were mainly affected by positive effects of LUCC and its interaction with climate change.(3)In the past 30 years,ecosystem services in CBMR were synergistic as whole,but with partial tradeoffs at local scales.There were great synergies(0.74,0.61,0.46)between soil retention and carbon storage,water yield and habitat quality,and soil retention and habitat quality,while trade-offs were observed between water yield and soil retention,water yield and carbon storage,and carbon storage and habitat quality(-0.88,-0.43,-0.32).Ecosystem services trade-offs and synergies were caused by the inherently incompatible relationships between services(e.g.,water production vs.soil retention),or the effects of co-drivers,for example,decreased precipitation increased soil retention while decreasing water yield.(4)To obtain the optimal configurations of landscape pattern for maximizing ecosystem services in CBMR,we proposed a group of landscape metrics(landscape composition and landscape configuration)which affected changes and trade-offs of ecosystem services.We then constructed linear mixed models to determine the optimalandscape configurations,which explained 92%,94%,and 93% of relative changes in the total ecosystem services,trade-offs,and synergies from 1990 s to 2020 s.Broadleaf forest area and landscape patch area were observed as the most important landscape metrics.Thus,in order to achieve the maximum benefits of ecosystem services,the northern and western regions should balance the areas of croplands,built-lands and woodlands;a large number of green infrastructures(e.g.,parks,constructed wetlands)with irregular shapes should be increased in urban areas;areas of mixed conifer-broad forests and broadleaf forests as well as landscape heterogeneity should be increased to alleviate ecosystem service trade-offs.(5)In the next 30 years,ecosystem services in CBMR will overall show an increasing trend.Specifically,soil retention,carbon storage and habitat quality will increase by 5.98%,6.43% and 18.23%,respectively,while water yield will continue to decrease by 2.16%.We used SEM to analyze the driving pathways and contributions of multiple influencing factors.We found that vegetation covers significantly facilitated all four ecosystem services;precipitation significantly facilitated water yield,soil retention and carbon storage;urban sprawl significantly inhibited soil retention,carbon storage and habitat quality;evapotranspiration and temperature only significantly inhibited water yield;and topographic factors only significantly inhibited soil retention and habitat quality.Therefore,changes in ecosystem services over the next 30 years would be mainly driven by vegetation cover and precipitation.In summary,provisioning and supporting ecosystem services in CBMR showed a decreasing trend and regulating services showed an increasing trend in the past 30 years,while these ecosystem services will overall increase in the next 30 years.Ecosystem service changes were mainly influenced by LUCC and its interaction with climate change in the past 30 years,while they were mainly influenced by precipitation and vegetation cover in the future.Ecosystem services in CBMR were synergistic as whole,but with partial tradeoffs at local scales.The maximum benefits of ecosystem services in CBMR can be achieved through managing landscape configurations to balance tradeoffs.This study provides a scientific basis for regional sustainable development and effective resource management in CBMR,and also provides a theoretical basis to enhance the ecological security in Northeast China.