Peirson, J. A. , Reznicek, Anton A. .
Biogeography and Evolutionary Ecology of Vascular Plant Endemism in the Great Lakes Region of North America.
AS recently as 15,000 years ago, the Great Lakes region of North America was completely covered by glacial ice. The contemporary flora assembled only after the recession of the continental ice sheets. The majority of this flora consists of wide-ranging species that inhabit basic vegetation formations in the region, but a small number of taxa are disjunct into and in some cases endemic to particular localized habitats. While several of the showier endemics (e.g., Cirsium pitcheri, Iris lacustris, and Solidago houghtonii) have received considerable scientific and popular attention, most species have not been examined beyond their initial taxonomic descriptions. The biogeographic history and evolutionary ecology of virtually all endemics remain unknown, and no comprehensive assessment of endemism has been performed. As a first step in synthesizing an up-to-date review of the endemic flora of the Great Lakes region, we performed an extensive literature survey to identify all proposed endemic vascular plants in the region. Not surprisingly, this endemic flora (ca. 50 proposed taxa) is considerably smaller than those in parts of North America widely recognized for their endemics (e.g., the Californian floristic province and southeastern United States glade and coastal plain communities). The northern Great Lakes region (the upper boundary of the Niagara Escarpment) appears to be a hot spot for endemism, while southern sections harbor fewer described endemics. Most endemics are restricted to habitats with severe edaphic and microclimatic conditions such as sand dunes, dolomite outcrops, and calcareous lakeshores and seeps. Selection pressures exerted by these habitats may be analogous to those found in other edaphically stressful and endemic-rich habitats (e.g., serpentine and metalliferous soils or limestone glades). Strong ecological selection in such habitats can drive rapid population differentiation, and it is possible that the evolution of many Great Lakes endemics has followed a similar pathway.
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1 - University of Michigan, Department of Ecology & Evolutionary Biology, 830 North University Avenue, Ann Arbor, Michigan, 48109-1048, USA
2 - University of Michigan, University Herbarium, 3600 Varsity Drive, Ann Arbor, Michigan, 48108, USA
Great Lakes region
Presentation Type: Oral Paper:Papers for Topics
Location: 134/Performing Arts Center
Date: Wednesday, August 2nd, 2006
Time: 10:45 AM