Tsai, Yi-Hsin Erica , Manos, Paul S. .
The hitchhiker’s guide to the forest: A parasitic plant’s account of the range expansion of its host.
Studies of population structure and range shifts of forest trees often have limited resolution due to lack of signal from slowly evolving DNA. In contrast, non-photosynthetic parasitic plants can offer a rich source of information because of their faster cpDNA mutation rates, faster generation times, and different life history characters. We use an obligate, host-specific, and highly selfing parasitic plant, Epifagus virginiana (beechdrop; Orobanchaceae), to trace the migration history and forest development of its host tree, Fagus grandifolia (American beech; Fagaceae). We present a range-wide, cpDNA based phylogeography of Epifagus and describe likely glacial refugia and post-glacial migration routes. These data are compared with the molecular phylogeography and paleo-pollen record of the host to elucidate the broader picture of beech forest development and post-glacial range expansion. We identify multiple glacial refugia for Epifagus, one or more giving rise to the diversity seen in the southern part of the range, and one located in the central Appalachians from which Epifagus migrated northward along the Appalachians then westward into the Midwest. These northern migration routes largely mimic changes in host density seen in the paleo-pollen record, but the Epifagus data provide additional, higher resolution information on how and when the beech climax community assembled. This study provides significant data on herbaceous plant migration that is currently missing and can answer broader questions about the cohesiveness of communities during migration and the development of post-glacial beech communities.
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homepage for Yi-Hsin Erica Tsai
1 - Duke University, Department of Biology, 139 Biological Sciences Building, PO Box 90338, Durham, North Carolina, 27708, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Lake Michigan/Hilton
Date: Tuesday, July 10th, 2007
Time: 3:00 PM