Past maize consumption correlates with population change in Central Western Argentina

Abstract

This paper explores the relationships between population change and human diet after the adoption of domesticated resources in northwest Mendoza, a subregion of central western Argentina (CWA). To estimate population, we used summed probability distributions of radiocarbon ages (RC-SPD). We used carbon and nitrogen stable isotope values (ẟ13Cco, ẟ13Cca, and ẟ15N) obtained on human bone (collagen and carbonate) to reconstruct human diet. The population trend of late Pleistocene-Holocene hunter-gatherers changed its trajectory ca. 2300 cal years BP coincident with the adoption of domesticates. After this date, a significant increase in human population occurred. We observe population increases (“booms”) followed by notable drops (“busts”). Stable isotopes (ẟ13C) on human bone follow a similar trend, indicating an increased consumption of maize during the “boom” periods and a decreased consumption during the “bust” periods. Based on the association between estimated changes in human population and changes in human bone isotope values over the last 2300 cal years BP, we propose that levels of maize consumption emerge from human predator–prey and plant-herbivore interactions. The use of maize, thus, is not part of a social evolutionary stage, but, rather, an outcome of continuous social-ecological process in which maize use may increase or decrease over time.