Large-Scale Patterns in the Agricultural Demographic Transition of Mesoamerica and Southwestern North America

Richard G Lesure,Katelyn J Bishop,Gregson Schachner,Thomas A Wake,R J Sinensky

doi:10.1017/aaq.2021.23

Abstract

This article examines large-scale spatial and temporal patterns in the agricultural demographic transition (ADT) of Mesoamerica and southwestern North America (“the Southwest”). An analysis of published settlement and subsistence data suggests that the prolonged ADTs of these regions involved two successive eras of rapid population growth. Although both periods of growth were fueled by the introduction or development of more productive domesticates, they had distinctive demographic and social consequences. The first phase of the ADT occurred only in a scattering of favorable regions, between 1900 and 1000 BC in Mesoamerica and 1200 BC–AD 400 in the Southwest. Its demographic consequences were modest because it was underwritten by still rather unproductive maize. During this phase, increased population was confined mainly to a few agricultural heartlands, whereas surrounding regions remained sparsely populated. The second phase of the ADT was more dramatic in the spatial scale of its impact. This “high productivity” phase unfolded between 1000 and 200 BC in Mesoamerica and AD 500–1300 in the Southwest, and it was fueled by more productive maize varieties and improving agricultural technologies. It was accompanied by sweeping social, economic, and political changes in both regions.

Highlights

This article examines large-scale spatial and temporal patterns in the agricultural demographic transition (ADT) of Mesoamerica and southwestern North America (“the Southwest”)
Most of the growth likely occurred after AD 500, as registered in published population estimates for the Tucson Basin and in the other regions considered in the figure. This second period of growth coincided with the rise of the previously sparsely settled Phoenix Basin as the demographic center of the macroregion. In the past this expansion has sometimes been linked to migration from outside the microregion—even from Mesoamerica (Haury 1976; Wallace et al 1995)—we suggest that it was instead the product of processes within the macroregion during the second phase of the ADT
We think that the preceding model can help make sense of population history in other macroregions of both Mesoamerica and the Southwest, even if only a handful of cases match it in detail

Summary

A Model of Macroregional Demographic History

Similarities between these two macroregions prompt the following preliminary, idealized model of macroregional population history during the ADT in Mesoamerica and the Southwest. The resulting population expansion was at this point mainly accommodated within the heartland, often yielding sizable communities This initial episode of growth was likely fueled by a relatively low-productivity agricultural package—a topic that we return to below. Notwithstanding its association with major sociopolitical transformations—urbanism and state formation in the Southern Highlands of Mexico, and the rise of the Hohokam regional system in the Sonoran Desert—this second episode was part of the ADT still in progress. We refer to this as the “high productivity” phase of the ADT—again, a point revisited below

A Look at Other Macroregions

12–16 Row Maize

Conclusions