Modeling the Spread of Agriculture: An Example from the Eastern Tibetan Plateau

New data from the Eastern Tibetan Plateau allows us to understand how populations dealt with the challenges of moving crops into altitudinally-constrained environments. Despite the interest in explaining the timing and the mechanisms via which agricultural products spread to the roof of the world, current models for the spread of agriculture to this region have been simplistic and the presence of crop domesticates is often straightforwardly interpreted as indicating the existence of an agricultural system at the site. This is largely due to a fundamental lack of understanding of where crops could be grown in prehistory on the Plateau. Although it has generally been assumed that moving agriculture into this area was challenging, little work has specifically addressed the constraints imposed on humans as they moved crops into this area. Employing an agro-ecological niche model, we formally model the constraints that were faced by humans as they moved a series of crops into the Tibetan Plateau between the 4^th and 1^st millennium cal. BC. Based on the results of this analysis, we argue that sites that have been previously considered as engaged directly in agricultural production may have been more distantly connected to an agricultural lifestyle than previously thought.