ROCKSHELTER GEOARCHAEOLOGY, PALEOENVIRONMENTAL RECONSTRUCTION, AND HUMAN EVOLUTIONARY ECOLOGY: AN EXAMPLE FROM THE BIGHORN BASIN, WYOMING

Rockshelters in Wyoming’s Bighorn Basin provide a near-continuous Holocene record of human occupation and variable climate as recorded in sediments. Of particular note are episodic eolian packages reflecting centennial-scale droughts. Here we explore connections between regional droughts, rockshelter formation processes, and human foraging patterns as evidenced by associated faunal records. Human evolutionary ecology informs this study in providing energetic models for hypothesized human response to changing environmental conditions. Specifically we use the diet breadth and prey-as-patch models to test hypotheses that during droughts human foragers harvest a wider range of lower-ranked resources and process more intensively lower ranked body parts of hunted game. Our work builds on classic biogeomorphic process-response models by adding a human dimension to coupled climate, biological, and geomorphic systems. Our findings indicate that while human forager diets respond to variable climate in a predictable fashion, the more mesic local habitats in which most rockshelters are found modulate broader environmental conditions across the eastern Bighorn Basin.