Germain-Aubrey, Charlotte , Soltis, Pamela , Neubig, Kurt , Thurston, Taylor , Soltis, Douglas , Gitzendanner, Matthew .
Testing hypotheses in a comparative phylogeography study: the case of four plants endemic to the central Florida scrub.
The highly threatened central Florida scrub encompasses an exceptional proportion of endemic species, making it a biodiversity hotspot in North America. However, the origins of this unique community are poorly understood. To study phylogeographic patterns, we used available sequence data, along with our own, to place four endemic plant (Prunus geniculata, Persea humilis, Ilex opaca var. arenicola and Polygala lewtonii) in their respective generic-level phylogenies. The four phylogenetic trees provided tests of the monophyly of each taxon and identified their sister species, shedding light on the geographic origins of the central Florida scrub. The origin of the central Florida scrub has been debated, but never tested in a phylogeographic context. Here, we take the two most widely accepted hypotheses and build simulations of topologies for each scenario, for each of the species. The first scenario argues for a fragmentation of the Pliocene xeric belt extending from Florida to Texas and the southwestern US, with subsequent speciation leading to the sister species of the Florida endemics having a western distribution. The second hypothesis focuses on the Pleistocene glacial cycles leading temperate species to take refuge in Florida, including the scrub, resulting in the endemic species being most closely related to widespread species distributed in eastern and northeastern North America. Statistically testing the departure of each observed phylogeny from the simulated ones, we reject the western hypothesis in three cases, while the fourth phylogeny fails to reject both hypotheses. These results provide an initial view of the geographical origins of the species that shape the central Florida scrub and support a single major migration event rather than several smaller ones. The implications of our findings for the conservation of this community are briefly discussed.
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1 - University of Florida, Department of Horticultural Sciences, Gainesville, FL, 32611, United States
2 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA
3 - University of Florida, Department of Biology, Po Box 118526, Gainesville, FL, 32611, USA
4 - University of Florida, Department of Biology, Gainesville, FL, 32611, USA
5 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, GAINSVILLE, FL, 32611-7800, USA
Presentation Type: Poster:Posters for Topics
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM