From structures to mechanisms: A network-based analysis of food provision service flow paths

Abstract

Food provision service (FPS) flows, which connect remote supply and demand areas, form complex spatial patterns that are critical yet inadequately understood for managing regional food systems. This study systematically identifies the typical spatial structures of FPS flows in China's Yellow River Basin from 2000 to 2020 and unravels their underlying formation mechanisms. We simulated inter-regional flow paths and intensity using an enhanced two-step floating catchment area model and a minimum-cost allocation approach. The resulting networks were then analyzed through topology metrics to classify distinct flow structures, whose driving mechanisms were interpreted by integrating eXtreme Gradient Boosting with SHapley Additive exPlanations. Results revealed a significant increase in the supply-demand ratio from 1.65 to 3.90, with flow intensity weakening post-2000 before recovering by 2020. Spatially, FPS flows were oriented from mid-downstream production zones toward upstream demand centers. We identified and characterized three archetypal structures: (1) Proximity-oriented flows, occurring in regions with limited production capacity that relied on nearby surplus areas, facilitated short-range transfers and enhanced local resilience, primarily driven by population density and transport accessibility; (2) Multi-source-oriented flows, developed in ecologically fragile areas, maintained system stability through diversified supply sources, reflecting constraints from terrain relief and climate; (3) Dominance-oriented flows, originating from highly productive and accessible zones, formed efficient yet vulnerable centralized networks, predominantly shaped by landscape concentration and topography. These structures elucidate fundamental organizational principles of FPS flows, and the proposed framework offers a systematic tool for developing targeted food security strategies within the basin and beyond.