Time averaging and late Quaternary ecological replacement in Don's Gooseberry Pit, South Dakota, USA

Late Quaternary small mammal faunas document ecological change and biotic responses to past climates but are especially rare in some geographic regions such as the North American Great Plains. Don's Gooseberry Pit (DGP), a cave in the southeastern Black Hills of South Dakota, USA, contains a fauna documenting small mammal community composition shifts and environmental change over the last 18,000 yr in this data-depauperate region. Although the stratigraphy of the cave appears to be primary, disparate radiocarbon dates indicate that there is mixing of the fauna throughout. A paleoenvironmental signal consistent with regional reconstructions still emerges from an analysis of the stratigraphically ordered fauna. Dated taxa from DGP record the ecological replacement of Dicrostonyx by Myodes and later Microtus in response to late Quaternary warming. Individually dated specimens of Dicrostonyx richardsoni confirm late survival of this cold-adapted taxon in the Black Hills (17,083 cal yr BP). Our results indicate that a coarse paleoecological signal is present in DGP, and that the Black Hills served as a high-altitude refugium for cold-adapted species following the end of the last glacial period.