Doctoral Dissertation Improvement Grant: The Paleoecology of Diet Breadth in the Basin-Plateau Region, USA

University Of Washington, Seattle WA

Investigators

Abstract

The intense use of small seeds from many plant species was a crucial turning point in human dietary history. Often termed the "broad spectrum revolution", this change in the use of potential food resources occurred in many of the world's cultures beginning as early as 12,000 radiocarbon years ago. Many dietary staples, from bread to breakfast cereals, are produced from heavily processed small seeds. Between 8,500 and 8,000 years ago, the Great Basin and northern Colorado Plateau of arid western North America seemed to go through their own version of a broad spectrum revolution, one that saw the incorporation of intensive small seed processing and grinding stone technology. The mechanisms responsible for these dietary changes are not well understood. Under the guidance of Dr. Donald Grayson, Lisbeth Louderback will generate patterns of plant resource use from North Creek Shelter (NCS), a well-stratified archaeological site in southern Utah. The research will include the identification of plant macrofossils (leaves, twigs, and seeds), and microfossils (pollen and starch grains) from NCS sediments, archaeological features such as hearths, and found on artifacts themselves. The results will provide a fine-grained view of changes in the array of food resources ("diet breadth") incorporated into the diet, including the use of intensively-processed small seeds from 10,000 to 6,000 years ago. Specifically, this project will test whether a) a change in human diet breadth occurs at NCS, b) if it occurred at 8,000 years ago, as predicted and c) if it coincides with increasing local aridity that decreased the range of food resources available to people. The rich assemblage of animal and plant material excavated from NCS can be used to characterize changes in diet breadth during the past 10,000 years. The animal material will be re-examined within time-sequenced sediment layers thus detailing patterns of animal foods. The novel incorporation of plant macro- and microfossils within this same temporal frame will identify the inception of small seed use as well as its intensity. The prevalence of technology for exploiting such resources will also be examined. These analyses will offer a rigorous examination of the range of food resources in the diets of the Basin-Plateau people. Such a comprehensive analysis of plant macro- and microfossil remains in relation to animal use, grinding stone technology and environmental change has never been attempted in western North America. This full description of diet breadth will provide a concrete example of human innovation in the face of challenging environmental conditions. This project will be widely disseminated in major scientific journals (e.g. Journal of Archaeological Science, American Antiquity, Journal of Ethnobiology) and its datasets made available in National Park Service archives. Public presentations will be made locally at the BLM Grand Staircase-Escalante National Monument Visitor Center. For the past year, Ms. Louderback has been training and supervising undergraduate students in paleobotanical methods at the University of Washington and has incorporated the results of her previous research in the large introductory courses in archaeology that she has taught. She plans to continue teaching and to expand her tutorial offerings in archaeology and paleoenvironmental analysis to deliver the broadest possible educational impacts.