The structure and robustness of the global wheat trade dependency networks

Abstract

Food security is a cornerstone of human survival and development, and food trade serves to alleviate shortages and ensure food security. Specifically, wheat is the staple food for about one-third of the global population, so the stability of its global trade directly determines the food security of many countries. To this end, with the ability to holistically uncover structural characteristics and capture dynamics of complex systems, the complex network framework has been widely used to study the trade system of various foods, such as wheat. Most of these studies use trade volume as edge weights, which can represent bilateral relationship but has difficulty in characterizing the third-party effect. Besides, trade networks constructed in these studies always overlook the asymmetry of inter-country dependencies. To more accurately capture the trade relationships between countries, this study uses dependency to define the edge weight and construct the global wheat import and export dependency networks for the years 2000 to 2022. This research examines not only the structural characteristics of the networks but also their resilience, efficiency, and vulnerability, providing a comprehensive evaluation of the performance of the global wheat trade dependency network. The findings reveal that: (1) The global wheat trade dependency network exhibits scale-free properties, negative assortativity, and low reciprocity, with resilience improving over time. (2) The import dependency network demonstrates a highly concentrated structure, with most countries relying heavily on a few core nations, whereas the export dependency network shows a more dispersed and increasingly diversified community structure. (3) Deliberate attacks have a greater impact on network vulnerability compared to random attacks. Moreover, the clustering coefficient changes more gradually under most attack scenarios, highlighting the robustness of local clusters. (4) African countries, Latin American countries, and Caribbean countries are more vulnerable to trade shocks. In conclusion, this study uses complex network analysis to uncover the dependency relationships and vulnerabilities inherent in the global wheat trade network. The results provide valuable insights for policymakers and researchers in safeguarding food security and hedging for future risks.