Hodel, Richard .
Phylogeography of sea oats (Uniola paniculata), an ecologically important coastal dune grass in the southeastern United States.
Sea oats (Uniola paniculata) are a coastal dune grass native to the southeastern United States that are valuable for preventing dune erosion and protecting the health of coastal ecosystems. We tested the hypothesis that U. paniculata populations are divided into eastern and western lineages, with the southern tip of Florida acting as the primary geographic break, as observed in co-distributed animal taxa. Additionally, we asked whether the geographic distribution of chloroplast DNA (cpDNA) variation in U. paniculata corresponds to 1) genetic structure in nuclear variation reported in previous studies, and 2) the geographic distribution of morphological adaptive traits reported in previous studies. We sampled 66 populations of U. paniculata throughout its range in the United States and performed phylogeographical analyses using sequence variations in maternally inherited cpDNA. We used TCS software to reconstruct the intraspecific phylogenetic network and Monmonier's algorithm to identify phylogeographic breaks in the species. We found six cpDNA haplotypes and two major lineages: eastern (Atlantic) and western (Gulf), with a phylogeographic break at the southern tip of Florida. The phylogeographic analysis suggests that U. paniculata survived the last glacial maximum (LGM) in southern refugia. Following the LGM, vicariance and dispersal explain the current distribution of haplotypes into eastern and western lineages. Most populations that contain a haplotype from outside its native range are likely due to human-mediated transplantation. The genetic structure of cpDNA sequence variations has a weak correlation with nuclear DNA variation, and there is partial concordance between the geographic distribution of cpDNA and morphological variation.
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Presentation Type: Oral Paper:Papers for Topics
Location: Franklin B/Hyatt
Date: Monday, July 9th, 2012
Time: 9:45 AM