黄河流域水-粮-碳关联耦合的时空演变特征OACHSSCD

The complex interconnections and coupling relationships among water supply,food production,and ecological carbon sequestration which were centered on water issues are crucial for ecological protection and sustainable development in the Yellow River Basin(YRB).From the perspective of ecosystem services,this study constructed a Euclidean three-dimensional spatial geometric analytical model to represent the Water-Food-Carbon(WFC)nexus,using water yield,food supply and carbon sequestration as key indicators.The coupling characteristics of the WFC nexus and their spatio-temporal changes in the YRB from 1982 to 2017 were investigated,and the dominant variables influencing the coupling degree of the WFC nexus were further identified.The results indicated that:(1)The coupling degree of the WFC nexus was at a moderate level across most of the YRB,accounting for 55.32％of the area.From 1982 to 2017,the coupling degree showed an overall increasing trend.Areas with a significant increase were mainly located in the Mu Us Sandy Land and northern Shaanxi,where remarkable revegetation occurred,while significant decreases mainly occurred in arid oasis areas and the loess hilly-gully region,which were dominated by food production services.(2)The coordinated development degree of the WFC nexus exhibited a southeast-to-northwest declining gradient in the YRB during 1982-2017.Areas with high-development and high-coupling degree were concentrated in the Guanzhong Plain and the lower reaches of the YRB,whereas areas with low-development and low-coupling degrees were mostly distributed in arid and water-scarce regions such as the Mu Us Sandy Land.Notably,spatial-temporal changes in the coordinated development degree showed opposite spatial patterns between the periods 1982-2000 and 2001-2017.Specifically,areas that experienced an increase in the coordinated development degree during 1982-2000 showed a decreasing trend afterward,and conversely,areas with a prior decrease demonstrated a subsequent increase.(3)Areas dominated by carbon sequestration,water yield,and food supply services in terms of the coupling degree of the WFC nexus accounted for 47.7％,36.8％,and 15.5％of the YRB,respectively.In food security zones(food production-dominated),increasing the coordinated development degree reduced the coupling degree of the WFC nexus,underscoring the prerequisite of implementing water conservation and agricultural water-saving technologies.In ecological priority zones(carbon sequestration-dominated),vegetation restoration significantly improved both the coupling and development degrees of the WFC nexus.In synergistic regulation zones(water yield-dominated),caution was needed to avoid declines in development degree resulting from both excessive greening and vegetation degradation.These findings provide a scientific basis for spatially refined management of the WFC nexus,supporting the achievement of regional sustainable development goals for water conservation,food security,and enhanced carbon sequestration.