Ecological niche modeling and diachronic change in Paleoindian land use in the northwestern Great Basin, USA

Abstract

The Great Basin underwent considerable environmental change during the Pleistocene-Holocene transition, such as lower precipitation, increased temperatures, and the diminishment of lakes and wetlands. Archaeologists have long hypothesized that people responded by altering their settlement-subsistence strategies. Models outlining these responses feature predictions that generally fall into two categories: (1) people should have spent more time in remaining productive patches and expanded their diet breadth; and (2) people should have added new habitats to their settlement-subsistence regimes. These responses are not mutually exclusive, and both may have occurred, but they have been difficult to evaluate using empirical data because the region’s archaeological record is predominantly comprised of open-air lithic scatters that lack food remains. Through ecological niche modeling, we test the hypothesis that early Holocene groups added new habitats. We develop two models—one for the Younger Dryas and one for the early Holocene—using recorded Paleoindian sites in Humboldt County, Nevada and a set of environmental variables. Our results show that Younger Dryas sites mostly occur around lowland and upland lakes and within ecotones, while early Holocene sites mostly occur around valley bottoms, riparian corridors, and upland springs. They demonstrate that people added new habitats, presumably in response to disappearing wetlands. This shift may be best explained using the patch choice model.