Invasion is associated with unexpected increases in aboveground net primary productivity and altered ecosystem function, including increased nitrogen availability and cycling. These shifts are well documented, however many previous studies have been observational, focused on a single plant species, or have not examined belowground microbial communities. I combined field and experimental techniques to examine changes in productivity and ecosystem function, and the abundance of ammonia- oxidizing bacteria (AOB) for the exotic invaders Bromus tectorum, Centaurea stoebe, Euphorbia esula, and Potentilla recta. To quantify effects of these invasive species on N cycling and AOB abundance we compared soil from invaded and native communities in the field and in an experimental garden. AOB are bacteria responsible for a rate-limiting step in nitrification. We found that invasion was associated with increased abundance of AOB across all species of invader. For other variables, the magnitude of response to invasion varied by species, but we found in general invasion was associated with increased aboveground net primary productivity and soil nitrogen cycling. In addition results from the experimental garden suggest some species of invader may drive increases observed in the field. Finally we report on a novel relationship between aboveground net primary productivity and soil NO3-N indicating that invaders may drive ecosystem processes in ways different from native communities.
| Identifer | oai:union.ndltd.org:MONTANA/oai:etd.lib.umt.edu:etd-01152014-123349 |
| Date | 07 February 2014 |
| Creators | Luce, Morgan Marie |
| Contributors | Ragan M. Callaway, Cory Cleveland, John L. Maron, Laurie Marczak |
| Publisher | The University of Montana |
| Source Sets | University of Montana Missoula |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.umt.edu/theses/available/etd-01152014-123349/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Montana or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
Page generated in 0.002 seconds