CLIMATE CHANGE AND CULTURAL RESPONSE IN THE PREHISTORIC AMERICAN SOUTHWEST

Abstract

Comparison of regional tree-ring cutting-date distributions from the southern Colorado Plateau and the Rio Grande region with tree-ring-based reconstructions of the Palmer Drought Severity Index (PDSI) and with the timing of archaeological stage transitions indicates that Southwestern Native American cultures were periodically impacted by major climatic oscillations between A.D. 860 and 1600. Sitespecific information indicates that aggregation, abandonment, and out-migration from many archaeological regions occurred during several widespread megadroughts, including the well-documented middle-twelfth- and late-thirteenth-century droughts. We suggest that the demographic response of southwestern Native Americans to climate variability primarily reflects their dependence on an inordinately maize-based subsistence regimen within a region in which agriculture was highly sensitive to climate change.