Tracing the agro-pastoral ecotone transition in northern China from the human-Earth system perspective

The agro-pastoral ecotone in northern China (APENC) is an ecologically fragile region with a variable climate and unbalanced socioeconomic development.Identifying the spatial range and transitional dynamics of the APENC is crucial for understanding the delicate balance between regional ecology,the economy,and society.The human-Earth system provides a comprehensive research framework in which human activities and the natural environment are viewed as interdependent and dynamically interactive.Guided by the principles of human-Earth system science,in this study,the boundaries of the APENC are identified by integrating core parameters,including water,land,climate,ecology,and human factors.Raster-based spatial data analysis is employed to examine the spatial and temporal evolution of the APENC from 1990 to 2020.The APENC extends from northeast to southwest along the central axis of northern China,displaying trends of contraction and fragmentation over time,with its centre of gravity shifting closer to the Hu Huanyong Line.The peripheral areas exhibit heightened sensitivity to environmental and ecological changes,highlighting the region’s vulnerability to external pressures.In this study,management strategies grounded in sustainable development principles are proposed,a framework for integrating ecological changes with socioeconomic strategies is established,and actionable guidance for policymakers to promote sustainable development in this fragile and dynamic region is provided.