Native American depopulation, reforestation, and fire regimes in the Southwest United States, 1492–1900 CE
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Edited by Patricia L. Crown, The University of New Mexico, Albuquerque, NM, and approved December 21, 2015 (received for review November 3, 2015)

Significance
Debates about the magnitude, tempo, and ecological effects of Native American depopulation after 1492 CE constitute some of the most contentious issues in American Indian history. Was population decline rapid and catastrophic, with effects extensive enough to change even the earth’s atmosphere? Or was depopulation more moderate, with indigenous numbers declining slowly after European colonization? Through a study of archaeology and dendrochronology, we conclude that neither of these scenarios accurately characterizes Pueblo peoples in the Southwest United States. Among the Jemez pueblos of New Mexico, depopulation struck swiftly and irrevocably, but occurred nearly a century after first contact with Europeans. This population crash subsequently altered the local environment, spurring the growth of trees and facilitating the spread of frequent forest fires.
Abstract
Native American populations declined between 1492 and 1900 CE, instigated by the European colonization of the Americas. However, the magnitude, tempo, and ecological effects of this depopulation remain the source of enduring debates. Recently, scholars have linked indigenous demographic decline, Neotropical reforestation, and shifting fire regimes to global changes in climate, atmosphere, and the Early Anthropocene hypothesis. In light of these studies, we assess these processes in conifer-dominated forests of the Southwest United States. We compare light detection and ranging data, archaeology, dendrochronology, and historical records from the Jemez Province of New Mexico to quantify population losses, establish dates of depopulation events, and determine the extent and timing of forest regrowth and fire regimes between 1492 and 1900. We present a new formula for the estimation of Pueblo population based on architectural remains and apply this formula to 18 archaeological sites in the Jemez Province. A dendrochronological study of remnant wood establishes dates of terminal occupation at these sites. By combining our results with historical records, we report a model of pre- and post-Columbian population dynamics in the Jemez Province. Our results indicate that the indigenous population of the Jemez Province declined by 87% following European colonization but that this reduction occurred nearly a century after initial contact. Depopulation also triggered an increase in the frequency of extensive surface fires between 1640 and 1900. Ultimately, this study illustrates the quality of integrated archaeological and paleoecological data needed to assess the links between Native American population decline and ecological change after European contact.
Footnotes
- ↵1To whom correspondence should be addressed. Email: liebmann{at}fas.harvard.edu.
Author contributions: M.J.L., J.F., C.I.R., and T.W.S. designed research; M.J.L., J.F., A.S., S.M., and T.W.S. performed research; M.J.L., J.F., C.I.R., and T.W.S. analyzed data; and M.J.L., C.I.R., and T.W.S. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1521744113/-/DCSupplemental.
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