Global changes in crop diversity: Trade rather than production enriches supply

Abstract

Over the past decades, the choices of farmers and societies regarding what to grow and eat are being reshaped drastically, as suggested by the diversification of crop supply within countries and its simultaneous homogenization across them. Such a trend could be supported by parallel shifts in production (i.e. diversification within countries, homogenization across countries) or by the growing redistribution introduced by international trade which can even mask reductions in production diversity (i.e. specialization) within countries. Here we assessed the spatial and temporal trends in crop production, exports, imports, and supply diversity based on data from the Food and Agriculture Organization (FAO) for 152 countries and 49 crops from 1961 to 2013. Within countries, the diversity of crop supply increased at a faster rate than the diversity of production, which grew only slightly. Both were surpassed by the diversification of trade, which, within countries, involved a much faster diversity growth of imports compared to exports. Across countries, crop production homogenized at slower rates than crop supply, indicating that crop trade was important for explaining this decoupling. Mirroring country-based analyses, a crop-perspective indicates that crops are becoming more geographically ubiquitous for all the components of the food balance. However, this pattern had important exceptions, like oil palm which has increased its production concentrating in a few specialized countries. We evaluate our results in the context of the multiple social-ecological trade-offs related to international trade and the resilience of the global food system.