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Causes and management of exotic riparian plant invasion in Canyon de Chelly National Monument, Arizona

dc.contributor.authorReynolds, Lindsay Vail, author
dc.contributor.authorCooper, David J. (David Jonathan), 1952-, advisor
dc.contributor.authorStohlgren, Thomas J., committee member
dc.contributor.authorWohl, Ellen E., 1962-, committee member
dc.contributor.authorHobbs, N. Thompson, committee member
dc.contributor.authorBrown, Cynthia Stokes, committee member
dc.coverage.spatialCanyon de Chelly National Monument (Ariz.)
dc.descriptionDepartment Head: N. LeRoy Poff.
dc.description.abstractThe ecological, economic and social impacts of invasive plant species on native plant communities have stimulated broad concern among researchers, land managers and the general public. Riparian areas are of particular concern because they are critical to regional biodiversity despite covering a small percentage of the landscape. Controlling harmful invasive plants is an important challenge for land managers and understanding how to effectively remove exotic species is essential to managing native ecosystems such as riparian areas. In the southwestern United States (U.S.), the most dominant riparian plant invaders are the woody species tamarisk (Tamarix ramosissima Ledebour, T. chinensis Loureiro, and their hybrids) and Russian olive (Elaeagnus angustifolia L.). Tamarisk and Russian olive have invaded riparian habitats throughout Canyon de Chelly National Monument in northeastern Arizona. The goals of my research were to: 1) describe the history and mechanisms of exotic plant invasion into Canyon de Chelly, 2) understand the niche space requirements of tamarisk, Russian olive and native cottonwood in terms of light and water and determine if tamarisk and cottonwood are facilitating the invasion of Russian olive, and 3) describe response of the riparian ecosystem to exotic plant removal and determine the effectiveness of two different removal strategies. My results from analyzing the history of invasion showed that although plantings and river regulation by dams probably played a role in tamarisk and Russian olive invasion into Canyon de Chelly, these species required hydroclimatic drivers and stream bed adjustments for wide-spread establishment. Controlled experiments and field surveys in my second research study demonstrated that Russian olive is exploiting empty niches along wide gradients of water and light availability in southwestern riparian ecosystems. However, Russian olive invasion does appear to be limited by seed dispersal. Finally, I found that both cut-stump and whole plant removals similarly reduced exotic species cover and increased native species cover after two years. Both removal methods also reduced aerial seed rain inputs of tamarisk seeds, cut-stump removals increased available nitrogen near dead Russian olive boles within two years of removal, and both treatments seem to have no effect on ground water levels. This research helps guide the management of riparian plant communities in Canyon de Chelly, across the southwestern U.S., and informs our understanding of exotic plant invasions.
dc.format.mediumdoctoral dissertations
dc.publisherColorado State University. Libraries
dc.relationCatalog record number (MMS ID): 991012544669703361
dc.relationQH87.3.R49 2009
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see
dc.titleCauses and management of exotic riparian plant invasion in Canyon de Chelly National Monument, Arizona
dcterms.rights.dplaThis Item is protected by copyright and/or related rights ( You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). State University of Philosophy (Ph.D.)


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