Pleistocene-Holocene Variation of Vegetation Pattern in Upper Great Lakes Region

Our understanding of how the first people came to North America is still incomplete. The most common idea is that the earliest people have traveled the ice-free corridor between the Laurentide ice sheet and the Cordilleran ice sheet at around 12,000 14C yrs BP. These early people are recognized as great hunters who followed mammoth and other megafauna which supplied most of their food needs. After the extinction of the mammoth these early humans may have switched to hunting caribou (Rangifer sp.) and other smaller species. Caribou traveled in herds which made them easier to hunt and also provided hides to make warm winter clothing. In this work, we attempt to trace presumed caribou habitat in the post-glacial North America by tracking open spruce-sedge forest ecosystem which is postulated to have been the prime habitat for caribou. We produced series of vegetation maps for a portion of north-central North America from the time when the earliest people entered North America to the time period when the whole of ice sheet drained completely to the Hudson Bay i.e. from 12,000 14C yrs. BP to 8,000 14C yrs. BP. We used existing pollen records in the Neotoma database with additional records from the literature centered on Minnesota and Wisconsin. The caribou vegetation suitability mapping from point data was accomplished using IDW and cluster analysis. Using our maps, one can locate most optimal future sites for the archaeological analysis of possible caribou kills and/or earliest human habitat in north-central North America.