Understanding the mechanisms of invasion is critical in order to control an invasive species. Poa pratensis L. (Kentucky bluegrass) is an invasive species that has been present in the northern Great Plains (NGP) for over 100 years, but has become a dominant species in the mixed grass region recently. My dissertation seeks to answer one critical question—why has P. pratensis become such a successful invasive species in the NGP? I first asked if the invasion was caused by adaptation and/or propagule pressure. I screened the genetic fingerprint of invasive P. pratensis in the NGP along with measuring the genomic content of wild plants and compared them to common cultivars. I found virtually no overlap between lawn cultivars and invasive P. pratensis populations. This was further supported by a narrow range of genomic content in wild individuals compared to the lawn cultivars. I also found no evidence of geographical patterning which is consistent with the hypothesis that local adaptation is not pervasive in P. pratensis. I then asked whether P. pratensis was a strong competitor compared to dominant plant species native to the tallgrass prairie. I studied competitive effect between Poa pratensis, Nassella viridula, Pascopyrum smithii, and Bouteloua gracilis through a species-pair competition experiment. Based on the relative interaction indices, P. smithii and P. pratensis were competitive against B. gracilis, and P. smithii was competitive against N. viridula. Additionally, P. pratensis was facilitated by all three species in the experiment. This study indicates that P. pratensis may be somewhat competitive. Finally, I asked whether the increase in the frequency of P. pratensis in the NGP may be attributed to environmental factors. In order to understand long-term correlations between P. pratensis invasion and environmental variables, I resampled plots that were previously sampled for species composition in 1978, 1979, and 1999. I found that P. pratensis levels did increase across plots and was corrrelated with higher levels of precipitation. My research indicates that increased precipitation in the NGP as a result of climate change is correlated with P. pratensis invasion in the NGP. / United States Fish and Wildlife Service (FWS-R6-POAPRATENSISGENETICS) / North Dakota State University. Department of Biological Sciences / North Dakota State University. Department of Natural Resource Management / North Dakota State University. Graduate School / Cross Ranch Fellowship
| Identifer | oai:union.ndltd.org:ndsu.edu/oai:library.ndsu.edu:10365/28229 |
| Date | January 2016 |
| Creators | Dennhardt, Lauren Alexsandra |
| Publisher | North Dakota State University |
| Source Sets | North Dakota State University |
| Detected Language | English |
| Type | text/dissertation, movingimage/video |
| Format | application/pdf, video/quicktime |
| Rights | NDSU Policy 190.6.2, https://www.ndsu.edu/fileadmin/policy/190.pdf |
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