From ecological opportunism to multi-cropping: Mapping food globalisation in prehistory
Many of today's major food crops are distributed worldwide. While much of this ‘food globalisation’ has resulted from modern trade networks, it has its roots in prehistory. In this paper, we examine cereal crops that moved long distances across the Old World between 5000 and 1500 BC. Drawing together recent archaeological evidence, we are now able to construct a new chronology and biogeography of prehistoric food globalisation. Here we rationalize the evidence for this process within three successive episodes: pre-5000 BC, between 5000 and 2500 BC, and between 2500 and 1500 BC. Each episode can be characterized by distinct biogeographical patterns, social drivers of the crop movements, and ecological constraints upon the crop plants. By 1500 BC, this process of food globalisation had brought together previously isolated agricultural systems, to constitute a new kind of agriculture in which the bringing together of local and exotic crops enables a new form of intensification.