Desert vegetation in the Southwestern United States influences sediment transport. Specifically, rainsplash processes create mounds beneath shrubs which regulate the sediment flux on hillslopes. In turn, complex plant community dynamics make it difficult to predict changes in transport rates over climate-change timescales. Southwestern climate predictions suggest changes in precipitation, which affect desert shrub populations and sediment transport rates. We use a coupled, physically based model of shrub population dynamics and sediment transport to understand the implications of arid-region climate change and compare normal precipitation to precipitation scenarios influenced by climate change. Using this model, we track changes in shrub populations and resulting fluctuations in transport rates. In particular, we track changes in the vegetation, measured in terms of biomass, using the validated WBE scaling model, and relate it to sediment transport rates. This allows for biomass calculations from structural measurements defined in the coupled model. Furthermore, simulated values from the model confirm the idea that increasing amounts of biomass, for two analyzed shrub species, indeed lead to decreasing sediment flux values. This correlation opens an opportunity to use biomass as a common currency to describe sediment flux. Variations in shrub morphology between species leads to differences in shrub response to climate change, particularly aridification. This work provides an opportunity for large scale monitoring, and possibly prediction, of changes in shrub populations and associated sediment transport on Southwestern desert hillslopes when considering shrub sensitivity to fluctuations in precipitation.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-07052013-100959 |
| Date | 17 July 2013 |
| Creators | Fathel, Siobhan L. |
| Contributors | David Jon Furbish, Dan Morgan |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-07052013-100959/ |
| 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 Vanderbilt University 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. |
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