Smithsonian researchers said charcoal and plant microfossil evidence from Mexico’s Central Balsas Valley links a pivotal cultural shift in crop domestication in the New World with local and regional environmental history.

Our climate and vegetation studies reveal the ecological settings in which people domesticated plants in southwestern Mexico, said Dolores Piperno, curator of archaeobotany and South American archaeology at the Smithsonian’s National Museum of Natural History and the Smithsonian Tropical Research Institute in Panama. They also emphasize the long-term effects of agriculture on the environment. The study by Piperno — along with Smithsonian co-authors Enrique Moreno and Irene Holst; Jose Iriarte of the University of Exeter in England; Assistant Professor Matthew Lachinet of the University of Nevada— Las Vegas; Assistant Professor John Jones of Washington State University; Professor Anthony Ranere of Temple University; and Ron Castanzo, a research collaborator at the National Museum of Natural History — appears in the early online issue of the Proceedings of the National Academy of Sciences.