Final Report Summary - COMPAG (Comparative Pathways to Agriculture: the archaeobotany of parallel and divergent plant domestications across world regions)
With hindsight, the development of agriculture was a revolutionary leap in the history of human societies and economies, but archaeology now indicates that it was a drawn-out episode rather than a true revolution, and this evolutionary process took place in parallel in several world regions at different times, drawing on difference crop species. This project set out to understand this transition in 4 ways, all based on the empirical evidence of plant remains recovered from archaeological excavations. (1) We pulled together a systematic and quite comprehensive database on archaeobotanical evidence, published and of our own research, on the distribution of economic crops in time and space from archaeological sites throughout Asia and Africa (in total 2670 sites/ site phases): this allows users to map in time and space the creation, expansion and modification of crop packages. (2) We looked in detail at the evolution of domesticated forms in numerous key taxa, through quantitative changes including in grain size, seed dispersal, and seed coat thickness; this involved both efforts at measuring dataset of our own and compiling published sources where available. In total have created datasets for some 22 crop species, some with more than 1 domestication and more than one trait. (3) We looked at the ecology of early agriculture, the new ecological niches created through cultivation, as evident in arable weed flora and the evolution of arable weeds, in particular in Southwest Asia, the Yangtze valley and the British Isles, with some initial work on early weed floras of North and South India, Sri Lanka, and parts of Africa and Southeast Asia. (4) We considered how the evolution of domesticated crops and agricultural ecologies was entangled with wider economic and social changes, including those relating to sedentism, population growth, domestication of animals, and technologies of harvesting and food preparation. This required stepping back from the empirical evidence of archaeobotany and situating it alongside wider bodies of other archaeological evidence, leading to new regional and comparative syntheses that we produced for North and South China, North and South India, the Near East, the East Africa Sudan region and the West African Sahelian region. We established, for example, that pastoralism preceded plant domestication in West Africa and South India but not Sudan, co-evolved with crop domestication in West Asia but not China, and that while boiling vessels long pre-dated rice that was domesticated to be boiled, bread preceded wheat domestication. This project was broadly comparative and the first of its kinds to work on the same questions, using the same methods, across empirical datasets from several regions in the Old World simultaneously, including sub-Saharan Africa (the West African Sahel, Sudan, eastern Africa), West Asia (the Near East), South Asia (Northern India, Southern India, Sri Lanka), China, both northern and southern China. Our results are both truly comparative, but also quite comprehensive and forward looking, providing a new baseline for discussions and explaining how and why agriculture began while avoiding the trap of imposing the experience of one regional area of the world in terms of domestication on the history of other areas. One of our conclusion is that given the slow pace of change and different timings in different regions is it unlikely that a single big causal factor lies behind the origins of agriculture (such as a major climate change event) in any one case specifically or more generally. Instead, each instance of agricultural origins has to have been pushed along by a concatenation of casual processes, including social pulls and environmental nudges that persisted for 3000-4000 years through to domestication and agriculturalization, after which reversal became difficult if not impossible.