Evolution in a Glaciated Landscape: Contribution of Endemism to Great Lakes Biodiversity
Jolls, Claudia L. .
Endemic Plants of the Great Lakes Dunes: Ecology, Biology and Rarity.
The Laurentian Great Lakes house the world’s largest concentration of freshwater dunes, which in turn support more endemics than any other part of the basin. Dune endemics can be rare as a result of not only their evolutionary history but also ecological factors. Environmental tolerance, reproductive biology, population dynamics and stochasticity also can help explain species range sizes and thus, rarity and endemism. We have studied aspects of the ecology of four dune endemics during the past decade: Cakile edentula var. lacustris, Cirsium pitcheri, Solidago houghtonii and Tanacetum huronense var. huronense. These taxa of sand beaches, open dunes and interdunal swales exhibit suites of characters that serve as adaptive responses to distinctive ecological factors, including sediment transport and lake level fluctuations. These characters include growth form, life history, breeding system, germination strategies, population dynamics and responses to abiotic and biotic factors such as light availability, sand burial, water-level fluctuations, pollinator abundance, herbivory and competition from native and invasive species. The spatial and temporal dynamics of the Great Lakes dunes, their anthropogenic history as well as the distinctive biology of these taxa present unique challenges for their conservation. Yet, many Great Lakes dune endemics are of unconfirmed taxonomic status and most are “orphan”, lacking any recent ecological or phylogeographic study. In addition to the natural and necessary dynamics of these systems, conservation is hampered by the relative lack of critical biological knowledge for the majority of these endemic taxa. I offer that these rare Great Lakes dune plants provide unique opportunities for our understanding of endemism and plant evolution and ecology, and present some examples of how studies of rare plants can provide inductive inferences and insights to their conservation.
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1 - East Carolina University, Department of Biology, Greenville, NC, 27858, USA
Great Lakes region.
Presentation Type: Symposium or Colloquium Presentation
Location: Boulevard A/Hilton
Date: Tuesday, July 10th, 2007
Time: 11:15 AM