Molecular Ecology and Evolution
Germain-Aubrey, Charlotte , Soltis, Pamela S. .
Testing the origins of the central Florida scrub: a study of Polygala lewtonii.
The central Florida scrub is a long strip of ancient dune systems dominated by the older Lake Wales and Mount Dora Ridges, with smaller and younger ridges nearby. Despite an exceptionally high level of endemism, more than 85% of its surface has been converted to citrus plantations and developments, creating an urgent need for the system to be better understood and better protected. Age estimates of the central Florida scrub vary widely, from 20 MYBP to 2 MYBP to 10,000 YBP. These estimates correspond to past shorelines from the Miocene, Pliocene, or Pleistocene, when sea levels varied greatly from much lower, extending the scrub habitat to the west, to much higher, with the peninsula smaller and perhaps even isolated from the continent. Whether the species currently found in the central Florida scrub represent an ancient community, dating back to the Miocene, or are more recent in origin, or a combinations of these hypotheses in unclear. To evaluate the different scenarios, we are placing several scrub species in the appropriate phylogenetic positions and estimating the dates of divergence of these species from their sister groups. Here, we focus on Polygala lewtonii, a federally listed species endemic to the Lake Wales Ridge.
Using the phylogenetic information that is now available, we can test hypotheses regarding the timing of the origin of Polygala lewtonii. Specifically, our goal is to statistically distinguish among the three hypotheses of the potential origin of the species. The method of Richards et al. (2008), combining past distribution modeling and statistical phylogeography, was used to evaluate each hypothesis. We discuss the temporal and spatial origins of extant P. lewtonii. Combined with the results of additional species, we can begin to piece together the history of this unique habitat and the incredible diversity that is found there.
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1 - University of Florida, Department of Biology, Florida Museum of Natural History - Dickinson Hall, P.O. Box 117800, Gainesville, FL, 32611, USA
2 - University of Florida, Department of Biology, Florida Museum of Natural History, P.O. Box 117800, Gainesville, FL, 32611-7800, USA
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM