A GIS model for predicting wetland habitat in the Great Basin at the Pleistocene-Holocene transition and implications for Paleoindian archaeology

The Great Basin's earliest inhabitants relied heavily on wetland systems that underwent a great decline culminating in the early Holocene. In this paper, we derive expectations for regional Paleoindian archaeology by modeling the distribution and disappearance of lake-margin wetland habitats. Basin geomorphology and hydrology are used to predict change through time in the occurrence of these habitats. Fifty-two pluvial lakes are drained from their Pleistocene highstands by computer simulation using GIS, and the changing extent of associated wetlands is quantified. We find that as these lakes declined to shallow depths, many experienced corresponding increases in wetland habitat prior to complete desiccation; thus, while the total area of wetland habitat in the region could have maintained some stability through this process, the number of available basin wetlands would have dropped relatively rapidly as smaller basins completely dried up. The model therefore implies that those lakes that disappeared earliest should hold the archaeological signatures most restricted to early Paleoindian times. Assemblages associated with these lakes should also reflect higher forager mobility corresponding with the greater number of basin wetlands available. We find preliminary support for the model in several archaeological cases but emphasize the need for further basin-specific research to clarify the nature and timing of wetland habitat loss and the extent to which this was a constraint for Paleoindian populations.