Spruce Forests and Parklands
Artist's reconstruction of a Spruce Parkland environment at the Boney Spring locality (Benton County, Missouri). Painting by Robert Larson.
As the glaciers receded, pioneering tundra vegetation was replaced with spruce forests and sedge-dominated wetlands. There is no modern analogue for this biome. Grasses and scattered trees were present in the uplands. These trees would have been largely white and black spruce. Lowlands along rivers and streams were dominated by black spruce, a species that is adapted to cold, saturated environments. Sedges were also common in lowland habitats (Yansa and Adams 2012; Gonzalez and Grimm 2009).
Although some open-ground, tundra-dwelling animals were still present on the landscape (mammoths, stag-moose), others followed these open habitats northwards. For instance, tundra muskoxen are absent from post-LGM deposits in the Midwest. The tundra fauna is replaced with a higher diversity of large herbivores, including: Mastodons, Megalonychid ground sloths, Helmeted Muskoxen, and peccaries. The broader availability of above-ground biomass provided a variety of grazing/browsing niches to these herbivores.
- Northeastern Illinois: 19,000-14,100-cal BP (Gonzalez and Grimm 2009, Saunders et al. 2010)
- Southern Wisconsin: 15,500-14,100 cal BP (Fredlund et al. 1996)
- Lower Michigan: 15,300-11,400 cal BP (Hupy and Yansa 2009)
Curry, B. B., & Yansa, C. H. (2004). Evidence for stagnation of the Harvard sublobe (Lake Michigan lobe) in northeastern Illinois, USA, from 24 000 to 17 600 BP and subsequent tundra-like ice-marginal paleoenvironments from 17 600 to 15 700 BP. Géographie physique et Quaternaire, 58(2-3), 305-321.
Fredlund, G. G., et al. (1996). Late Pleistocene vegetation of Hebior mammoth site, southeastern Wisconsin. Current Research in the Pleistocene 13, pp. 87–89.
Hupy, C. M., & Yansa, C. H. (2009). The last 17,000 years of vegetation history. Michigan Geography and Geology. Edited by RJ Schaetzl, JT Darden, and D. Brandt. Pearson Custom Publishing, Boston, MA, 91-105.
Gonzales, L. M., & Grimm, E. C. (2009). Synchronization of late-glacial vegetation changes at Crystal Lake, Illinois, USA with the North Atlantic Event Stratigraphy. Quaternary Research, 72(2), 234-245.
Grimm, E. C., & Jacobson Jr, G. L. (2004). Late-Quaternary vegetation history of the eastern United States. The Quaternary Period in the United States, 1, 381-402.
Jackson, S. T., Webb, R. S., Anderson, K. H., Overpeck, J. T., Webb III, T., Williams, J. W., & Hansen, B. (2000). Vegetation and environment in eastern North America during the last glacial maximum. Quaternary Science Reviews,19(6), 489-508.
Saunders, J. J., Grimm, E. C., Widga, C. C., Campbell, G. D., Curry, B. B., Grimley, D. A., ... & Treworgy, J. D. (2010). Paradigms and proboscideans in the southern Great Lakes region, USA. Quaternary International, 217(1), 175-187.
Yansa, C. H., & Adams, K. M. (2012). Mastodons and Mammoths in the Great Lakes region, USA and Canada: new insights into their diets as they neared extinction. Geography Compass, 6(4), 175-188.
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