FAUNAL TRANSITIONS IN RESPONSE TO AN ICE AGE: THE LATE WISCONSINAN RECORD OF COLEOPTERA IN THE NORTH-CENTRAL UNITED STATES'

Species lists are compiled for Coleoptera occurring as fossils at 13 sites in the northcentral United States. These fossil assemblages, ranging in age from 27,900 to 11,700 yr B.P., provide a nearly complete chronologic record of coleopteran faunal transition in response to climate change and ice movement during the late Wisconsinan glaciation. As glaciation progressed, beetle faunas characteristic of closed spruce forest were replaced by those representative of tundra and forest-tundra. By 14,000 yr B.P., populations of arctic and subarctic beetles had been extirpated by climatic warming throughout the north-central United States and, as ice retreated, replaced by open-ground faunas of taiga and western-montane affinities. The impact of Wisconsinan glaciation is still evident in the modem ranges of many northern beetle species. Consequent patterns of modern distribution are defined and applied in analyses of the relationships of the beetle fauna of northern North America to the late Wisconsinan fossil record in the north-central