Economic importance and structural robustness of the international pesticide trade networks

Pesticides are agricultural inputs that can significantly reduce yield losses, regulate plant growth, effectively liberate agricultural productivity, and improve food security. The availability of pesticides in economies worldwide is ensured by redistribution through international trade, with different economies playing different roles in this process. In this study, we measured and ranked the importance of economies using nine node metrics. We found that the clustering coefficient was negatively correlated with the other eight node metrics, whereas the other eight node metrics were positively correlated with each other and could be grouped into three communities (betweenness; in-degree, PageRank, authority, and in-closeness; out-degree, hub, and out-closeness). We further investigated the structural robustness of international pesticide trade networks proxied by large component size under three types of shocks to economies (node removal in descending, random, and ascending orders). The results showed that, except for the clustering coefficient, international pesticide trade networks are relatively robust under shocks to economies in ascending order but fragile under shocks to economies in descending order. By contrast, removing nodes with a clustering coefficient in ascending and descending order yielded similar robustness curves. Moreover, the structural robustness related to large component size evolved over time and exhibited an inverse U-shaped pattern.