Core cities dominate and shape food supply resilience in the Pearl River Delta

Mega city regions contain a large share of the global population and depend on complex but often unseen food supply networks, yet their structure and vulnerability remain poorly understood. Here, we use corporate-level food transaction records from 2013 to 2024 to reconstruct the food supply network of China’s Pearl River Delta, one of the world’s most populous urban regions. We combine spatial network analysis with numerical cascade failure simulations to link network structure with systemic risk. We identify a polycentric network dominated by two major population centers that rely little on external suppliers. Although this structure suggests a compact and locally oriented system for leading cities, it also creates specific vulnerabilities. Simulations show that disruptions targeting these core cities cause larger breakdowns than random disruptions. Resilience declines with increasing food transport distance and population density. These results demonstrate how urban food networks can be evaluated to identify systemic risks in mega city regions. Food supply in China’s Pearl River Delta is dominated by two self-contained cities, yet is highly vulnerable to targeted disruptions, with resilience declining as food travel distance and population density increase, according to a decade of corporate transaction network analysis.