Socioecological Dynamics Structuring the Spread of Farming in the North American Basin-Plateau Region

ABSTRACT

The spread of agriculture is a major driver of social and environmental change throughout the Holocene, yet experimental and ethnographic data indicate that farming is less profitable than foraging, so why would individuals choose to adopt agriculture leading to its expansion? Ideal distribution models offer one framework to answer this question: Individuals should adopt less profitable subsistence strategies and occupy more marginal environments when local population density increases competition to the point where the suitability of the best strategies and habitats becomes equal to what can be gained in poorer strategies and habitats. Coupling radiocarbon-dated archaeological sites with a validated measure of agricultural suitability, we evaluate the emergence of farming in the Basin-Plateau region of North America. Our results show that farming first occurs in the more suitable Colorado Plateau physiographic region, and only spreads into the less suitable Great Basin after population density on the Plateau increases. This produces an approximate 300- to 400-year lag between the onset of farming on the Plateau and in the Basin. These findings support the ideal distribution hypothesis for the spread of farming, and suggest a general socioecological process that may help explain global patterns in the timing and tempo of agricultural expansions.

KEYWORDS:

• Ideal free distribution model
• population ecology
• behavioural ecology
• maize agriculture
• Ancestral Puebloan
• Fremont Complex

Acknowledgment

Thanks to Jim O'Connell, Frank Bayham, Robert Kelly, and Elic Weitzel for comments and support. We are grateful to two anonymous reviewers who provided detailed comments on an earlier version of the manuscript; their thoughtful reviews allowed us to greatly improve the final paper. This paper was originally presented at the 84th Annual Meeting of the Society for American Archaeology in Albuquerque, NM, USA.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is supported in part by the National Science Foundation under Awards BCS-1749059 and BCS-1921072; the U.S. Bureau of Land Management under Cooperative Agreement L16AS00140; the University of Utah Research Foundation, and the Global Change and Sustainability Center at the University of Utah.

Notes on contributors

Brian F. Codding

Brian F. Codding is Associate Professor of Anthropology and Director of the Archaeological Center at the University of Utah. His research examines human-environment interactions in the past and present through the lens of behavioural ecology. Current research is focused on explaining the dynamics structuring subsistence and land use decisions, and the feedbacks these decisions have on social and ecological systems and across western North America.

Joan Brenner Coltrain

Joan Brenner Coltrain is Research Associate Professor at the University of Utah and runs the Archaeological Research Facility for Stable Isotope Analysis in the University of Utah Archaeological Center. Her research interests include stable isotope chemistry and AMS dating of human and faunal remains for paleo-economic reconstruction. She has pioneered these methods to evaluate the chronology and intensive use of maize on the Colorado Plateau and Great Basin.

Lisbeth Louderback

Lisbeth Louderback is Assistant Professor Anthropology at the University of Utah. She brings a strong interdisciplinary background to archaeology with technical expertise in archaeobotany and paleoecology, exploring how people coped with environmental change during the late Pleistocene and Holocene in western North America, with a particular focus on the Great Basin and Colorado Plateau. Ongoing projects include starch grain analysis from ground stone technology to evaluate the processing of tubers in the Colorado Plateau and the cultivation/domestication of wild plant species in western North America.

Kenneth Blake Vernon

Kenneth B. Vernon is pursuing a PhD in Anthropology at the University of Utah and is the assistant director of the University of Utah Archaeological Center. His research explores variation in human behaviour within the framework of behavioural ecology. Currently, he is using sophisticated geographic and spatial modelling techniques to investigate the dynamical interaction of conflict, subsistence, and settlement as reflected in the archaeological record of the American West. In addition, he is working to advance data management and data science in archaeology.

Kate E. Magargal

Kate E. Magargal is a postdoctoral research associate in the Department of Anthropology at the University of Utah. Her research examines how landscape and cooking fires influences subsistence decisions and create ecological consequences. Her current research focuses on understanding the contemporary social and ecological drivers and impacts of Tribal firewood harvesting on the Colorado Plateau.

Peter M. Yaworsky

Peter Yaworsky is a Ph.D. candidate in Anthropology at the University of Utah. His research uses insights from behavioural ecology to explore the variation in both past and present human behaviour. Peter is particularly interested in decisions people make regarding land use on regional scales. His current research focuses on the distribution of archaeological sites in the Grand Staircase-Escalante National Monument, Utah and the site placement of early agriculturalists in Nine Mile Canyon, Utah as a function of risk mitigation.

Erick Robinson

Erick Robinson is the Director of the Center for Applied Archaeological Sciences and Assistant Professor of Anthropology at Boise State University. His research integrates archaeological, paleo-climate, and paleo-environmental records to build interdisciplinary and comparative research on the long-term growth of human social-ecological systems. To this end, he co-leads interdisciplinary projects, including the Past Global Changes (PAGES) People3000 Working Group, examining hunter-gatherers and early farmers in western North America and northern Europe.

Simon C. Brewer

Simon C. Brewer is Assistant Professor of Geography at the University of Utah. He specialises in understanding past and present climate and vegetation change through the application of paleoecological methods and environmental modelling. Current research explores the functional diversity of past ecosystems relative to climate and fire regimes.

Jerry D. Spangler

Jerry D. Spangler is executive director of the Colorado Plateau Archaeological Alliance, a non-profit dedicated to protecting cultural resources in the West. He is an expert on the prehistory of the northern Colorado Plateau, and his research approaches are rooted in the compilation, refinement, and synthesis of quantitative databases that can facilitate land management decisions that foster greater resource protection.