Modeling constraints on the spread of agriculture to Southwest China with thermal niche models

Understanding how, why and by what mechanisms agricultural practices, technologies and products spread out of their zones of original development is a central theme of archaeology. To date, very few studies have combined agro-ecological modeling with detailed analyses of archaeobotanical remains to outline the kinds of challenges that ancient humans faced as they moved crops into environments different from their original homeland of domestication. This paper employs ecological niche modeling to outline the constraints faced by ancient humans as they moved rice, millets and eventually wheat and barley into the mountainous region of Southwest China. In particular, we propose that moving rice into this region presented considerable challenges for its cultivators and we infer that its spread into this area was facilitated by breeding cold adapted varieties of rice or by combining its cultivation with that of millet. High altitude areas did not take up full-scale agriculture until the introduction of cold adapted western Eurasian domesticates such as wheat and barley. The temperature niche models reinforce the adoption of these regionally varied agricultural strategies and support the significance of domesticates other than rice for the spread of agriculture into Southwest China.