The emergence of agropastoralism: Accelerated ecocultural change on the Andean altiplano, ∼3540–3120 cal BP

Abstract

In the fourth millennium BP, there were major environmental and cultural changes on the Andean altiplano of South America, but the chronology remains vague. A recent synthesis describes a slow, gradual transition from hunting and gathering to agropastoralism. This proposal is tested by refining the date of the onset of more humid and stable conditions, around 3550 cal BP, based on a Bayesian model of 26 dates from Lake Wiñaymarka and an updated calculation of the lacustrine offset. This is compared to Bayesian models of 191 dates from 20 archaeological sites, which incorporate a number of recently processed radiocarbon dates. A synthesis is presented of 15 full coverage surveys, a summed probability distribution, and a Bayesian model of the transition to ceramics, which together support a scenario of a very rapid demographic increase. Fourteen models from archaeological sites are cross-referenced in a composite model, which identifies a brief, altiplano-wide emergence of agropastoralism with starting and ending boundaries of 3540 and 3120 cal BP, respectively. This starting boundary correlates strongly with the onset of improving environmental conditions, indicating synchronous cultural and environmental change. The suite of accelerating cultural changes included a marked reduction in mobility, a demographic surge, increased subsistence diversity, the adoption of ceramics, farming and the integration of camelid herding into a remarkably resilient economic strategy still in use today. This is a highly relevant but yet to be used comparative case study for the variable tempos of ‘big histories’, and ecocultural interactions that generate rapid, emergent episodes of wide-spread and enduring cultural change.

Keywords:

• Bayesian models
• Radiocarbon dates
• Synchronous cultural and environmental change
• Episodes of accelerating history
• Emergence of agropastoral practices
• Andes
• Altiplano
• Peru
• Bolivia
• South America

Acknowledgements

Thanks to the community of Lake Titicaca archaeologists for stimulating discussions and assistance finding references and data. Guidance on the Bolivian Archaic came from Sergio Calla Maldonado, José Capriles, Claudia Rivera Casanovas, and Nico Tripcevich. Ramiro Barberena, David Browman, Valeria Cortegoso, Randy Haas and two anonymous reviewers read earlier drafts and made suggestions that significantly improved the manuscript. Gustavo Lucero prepared Figure 1. Bayesian models were developed through enlightening discussions and patient guidance in OxCal's online forum; many thanks are due to Alex Bayliss, Christopher Bronk Ramsey, Dan Contreras, Ray Kidd, Andrew Millard and Dennis Ogburn. I am grateful to all of these people. Errors of fact or interpretation are my own.