archives@tulane.edu / Mounting evidence suggests that microbial symbionts can play a crucial role in promoting plant invasion. Still, ecologists lack a complete understanding of how microbially-mediated invasion mechanisms operate across different abiotic and biotic contexts. In this dissertation, I characterize the microbial communities associated with and invasive grass, Phragmites australis, and native marsh species in coastal Louisiana, and examine how saltwater intrusion may differentially alter microbially-mediated interactions among these species. In a field survey, I found that P. australis associates with root and soil fungal communities with higher richness, diversity, and pathogen abundances compared to native species; however, I found no evidence of compositional changes or pathogen spillover in native species in close proximity to the invasion front. Additionally, in a greenhouse mesocosm experiment, I found that salinity-induced changes in microbial communities may enhance P. australis invasion in freshwater wetlands, but the magnitude of these effects depended on plant community context. Finally, using a plant-soil feedback experiment, I found that salinity and microbes adapted to salinity synergistically promote native coexistence in native communities, but may facilitate invasive dominance in invaded communities. This dissertation demonstrates that outcomes of plant-microbe interactions may shift across heterogenous abiotic and biotic landscapes. Furthermore, results presented here may help in predicting how saltwater intrusion will influence microbially-mediated invasion dynamics as global change progresses. / 1 / Carolyn Schroeder
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_122474 |
| Date | January 2021 |
| Contributors | Schroeder, Carolyn (author), Farrer, Emily (Thesis advisor), School of Science & Engineering Ecology and Evolutionary Biology (Degree granting institution) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | electronic, pages: 92 |
| Rights | No embargo, Copyright is in accordance with U.S. Copyright law. |
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