Wisconsinan Pre-Pleniglacial Biotic Change in Southeastern New Mexico

Abstract

Interpretation of a 1.5-m mid- to late- Wisconsinan stratigraphic sequence containing fossil vertebrates from the Animal Fair Site in Dry Cave, Eddy County, New Mexico, suggests a progression of habitats, all cooler and moister than today. Mid-Wisconsinan semiarid, moderately warm grasslands or grassy woodlands initially were replaced by cooler, more mesic, grassy woodlands; these were followed by cool, relatively dense sagebrush-grassland-woodland with elements from mixed-coniferous forest. A minor reversal of trend toward earlier, warmer conditions appears at the top of the section. Species collected from each level were basically harmonious until climatic deterioration, documented by invasion of new biotic elements at the end of the mid-Wisconsinan, permitted incursion of taxa associated with more boreal areas; these replaced most of the local fauna but failed to dislodge several taxa with southern affinities.