Doctoral Dissertation Improvement Award: Response to Environmental Alteration on the US Great Plains

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Periods of extreme aridity and drought pose significant challenges to humans and the resources on which they depend. Under the direction of Dr. David Meltzer, Ryan Breslawski will undertake research to understand how past peoples responded to one especially severe and long-lasting episode of aridity and drought on the North American Great Plains: the Altithermal, which took place ca. 8,000 to 5,000 years ago. Importantly, while aridity and drought are challenges to human societies, their effects are rarely uniform over large geographic areas, and thus a diversity of human adaptive responses may develop, especially in foraging societies lacking domesticated foods. Did geographic variability in Altithermal aridity and drought drive subsistence variability across space in past foraging societies? Can this variability be linked to declines in the availability of prey animals? Archaeology is an essential tool for resolving these questions and clarifying the processes through which human societies have adapted over millennia. The investigators will explore these questions through work with past bison hunting peoples on the Great Plains. Results from the project will shed light not only on Great Plains prehistory, but also on the effects of climate change on North America’s grasslands. Millions of people depend on the Greats Plains ecosystem today, as does the ongoing recovery of the iconic American bison. As climate change continues, the full picture of its past impacts on the Great Plains will only become more relevant.Previous research suggests that 8000–5000 years ago much of western North America experienced hyperaridity and drought. Overall, surface water became scarce, vegetation cover decreased, and animal populations declined. However, not all areas were impacted in similar ways or to the same degree, and human responses to these impacts would not have been uniform throughout the region. Regional variation in these impacts and the human responses to them remain poorly documented. Further, much remains to be learned about how bison, a vital resource for Great Plains peoples, were impacted by Altithermal drought and aridity, and the degree to which these impacts were mediated by geography. To resolve these issues, the project will analyze bison remains from over two dozen previously excavated archaeological sites dating to this period and located throughout the Great Plains.The project will collect data on the butchery activities of past human hunters represented by each set of bison remains, as well as data on the environmental stresses experienced by these prey animals. Environmental stresses will be examined through dental defects that result from malnutrition, and through the stable isotope chemistry of teeth, which reflects the food and water that past bison consumed. The results will be used to identify potential links between geographic variability in climate change, bison population declines, and human responses to those declines during this period of extreme aridity and drought.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.