Late Quaternary biomes of Canada and the eastern United States John W. Williams1,3, Thompson Webb III1, Pierre H Richard2, and Paige Newby1 1 Department of Geological Sciences, Brown University, Providence, RI 02912, USA. 2 Géographie, Université de Montréal, C.P. 6128 Centre-ville, Montréal, QC, Canada H3C 3J7. 3 National Center for Ecological Analysis and Synthesis, 735 State St., Suite 300, Santa Barbara, CA 93101, USA. Address for correspondence: National Center for Ecological Analysis and Synthesis, 735 State St., Suite 300, Santa Barbara, CA 93101, USA (fax: 1-805-892-2510, email:
[email protected]) Ms for: Journal of Biogeography, BIOME 6000 special issue 1 March, 2000 Biome reconstructions for Canada and eastern US 2 (A) ABSTRACT 1 Pollen data have been used to construct biome maps for today, 6000 14C yr B.P., and 18,000 14C yr B.P. for Canada and the eastern United States 2 The inferred modern biome distributions agree well with independent reconstructions of North American vegetation prior to European settlement. Some discrepancies between the pollen data and the modern potential vegetation are caused by post-settlement clearing of the landscape and the consequent increase of herbaceous types in the recent pollen record. 3 Biome distributions at 6000 14C yr B.P. reflected the warmer and drier conditions then prevalent in the continental interior, but the overall position of biomes was similar to that today. Boreal treeline in North America was not significantly north of its present position, in contrast to the 100-300 km shift reported for Siberia. At the last glacial maximum (18,000 14C yr B.P.), steppe and tundra were prevalent in the Midwest and northwestern Canada, and coniferous forests and woodlands grew in eastern North America.