Reconstructing an Evolutionary History of Sea Oats using a Phylogeographic Approach

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Disturbances such as hurricanes have always posed a threat to coastal ecosystems. Recently, anthropogenic factors have added stress to coastal ecosystems. These factors include overdevelopment, rising sea level, and warmer sea temperatures, which can lead to more intense disturbances. Fortunately, there is relief available: sand dunes provide coastal ecosystems with a natural defense and recovery mechanism. Coastal vegetation traps sand to build dunes and provide stability.
In the Southeastern United States, sea oats (Uniola paniculata) are an abundant coastal grass that help stabilize dunes. Sea oats are salt- and drought-tolerant, which makes them a good colonizing species. Their rhizome growth habit and root structure helps prevent dune erosion. By stabilizing sand dunes, sea oats provide a habitat for many animal species.
Sea oats are valuable for preventing and repairing damage caused by disturbances. Coastal restoration projects frequently use sea oats to restore native habitats and human-occupied areas. Often, sea oats are introduced without regard to the origin of the individual plants. The populations of sea oats in North Carolina can have different life history traits than populations native to Florida. For example, northern populations often require a period of cold weather to germinate their seeds, whereas the Florida populations do not need a temperature change for germination.
The goal of this project is to construct an evolutionary history of sea oats using a phylogeographic approach, and to apply this knowledge to inform management practices. Chloroplast DNA (cpDNA) is maternally inherited, making it useful for establishing evolutionary histories and identifying independent lineages. Presumably, these lineages (Evolutionary Significant Units, ESUs) have accumulated unique genetic variation and morphologically adaptive traits. However, the correlation between evolutionary history and adaptive traits remains unclear and controversial. I will use cpDNA variations to divide the geographic range of sea oats into ESUs. Then I will compare genetic data with published morphological variations to examine how sea oats' adaptive traits differ among ESUs, and whether they are correlated. Coastal protection and restoration projects would benefit from using propagules that are well-adapted to the particular region.
Improved knowledge of the genetic variation of sea oats will contribute to sustainable management of coastal ecosystems, identification of appropriate propagules and protection of genetic diversity in sea oats. This research will enable the optimal use of sea oats to protect sand dunes, both in natural coastal ecosystems and in human-inhabited areas. Finally, it will promote maintenance of the evolutionary potential of sea oats to adapt to new challenges in a continuously changing environment.

Contact Information

Mr. Richard Hodel
Appalachian State University
270 Wood Circle
Boone, NC 28607