Indigenous impacts on north american great plains fire regimes of the past millennium

Christopher I. Roos, Maria N Zedeno, Kacy L. Hollenback, Mary M.H. Erlick

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Fire use has played an important role in human evolution and subsequent dispersals across the globe, yet the relative importance of human activity and climate on fire regimes is controversial. This is particularly true for historical fire regimes of the Americas, where indigenous groups used fire for myriad reasons but paleofire records indicate strong climate–fire relationships. In North American grasslands, decadal-scale wet periods facilitated widespread fire activity because of the abundance of fuel promoted by pluvial episodes. In these settings, human impacts on fire regimes are assumed to be independent of climate, thereby diminishing the strength of climate–fire relationships. We used an offsite geoarchaeological approach to link terrestrial records of prairie fire activity with spatially related archaeological features (driveline complexes) used for intensive, communal bison hunting in north-central Montana. Radiocarbon-dated charcoal layers from alluvial and colluvial deposits associated with driveline complexes indicate that peak fire activity over the past millennium occurred coincident with the use of these features (ca. 1100–1650 CE). However, comparison of dated fire deposits with Palmer Drought Severity Index reconstructions reveal strong climate–fire linkages. More than half of all charcoal layers coincide with modest pluvial episodes, suggesting that fire use by indigenous hunters enhanced the effects of climate variability on prairie fire regimes. These results indicate that relatively small, mobile human populations can impact natural fire regimes, even in pyrogeographic settings in which climate exerts strong, top-down controls on fuels.

Original languageEnglish (US)
Pages (from-to)8143-8148
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Issue number32
DOIs
StatePublished - Aug 7 2018

Keywords

  • Anthropogenic burning
  • Bison hunting
  • Climate–fire relationships
  • Hunter-gatherers
  • Pyric herbivory

ASJC Scopus subject areas

  • General

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