Tsai, Yi-Hsin Erica , Manos, Paul S. .
Fossil pollen, cpDNA, hosts, and parasites: Synthesizing datasets and testing phylogeographic hypotheses.
Phylogeographers and paleoecologists are interested in many of the same biogeographic questions regarding community assembly. However, these research endeavors have progressed largely independently and have yet to be synthesized broadly. Furthermore, molecular data on individual species are increasing rapidly, and the next step is to develop ways of combining these existing molecular datasets with each other and to integrate them with their paleo-pollen counterparts to form regional multi-species biogeographies. We present a new method that quantitatively compares fossil and molecular datasets and show its application to a host-parasite system. Our work focuses on the following three datasets derived from an eastern North American tree, Fagus grandifolia (American beech; Fagaceae), and its parasitic plant, Epifagus virginiana (beechdrop; Orobanchaceae): host fossil pollen, host cpDNA, and parasite cpDNA. We first extracted the migration routes supported by each dataset using landscape interpolations and circuit theory. The three reconstructed migration routes were then used to parameterize a generalized linear model of parasite colonization. The fossil pollen and cpDNA datasets were used as proxies for different aspects of the hostís migration history. While the fossil pollen record tracks the spread of high density populations through time, the cpDNA patterns are sensitive to low density populations and founder events prevalent in the initial range expansion of the host. The results of the parasite colonization model reveal the relative contributions of host density and host range changes to the parasiteís ability to invade new areas. Specifically, the host fossil pollen record is by far a better predictor of parasite migration routes than the host cpDNA, which emphasizes the role of host density in maintaining parasite populations. Based on these results, we believe this is a promising method for synthesizing disparate datasets, and that this provides a valuable quantitative and statistical way of comparing multiple species' phylogeographies.
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1 - Duke University, Department of Biology, 139 Biological Sciences Building, PO Box 90338, Durham, North Carolina, 27708, USA
eastern North America
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood B/Snowbird Center
Date: Monday, July 27th, 2009
Time: 4:00 PM