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dc.contributor.advisorChairperson, Graduate Committee: Bruce D. Maxwell.en
dc.contributor.authorSkurski, Tanya Christine.en
dc.contributor.otherBruce D. Maxwell and Lisa J. Rew were co-authors of the article, 'Quantifying non-native plant impacts for natural areas management: a review of experimental research' in the journal 'Journal of applied ecology' which is contained within this thesis.en
dc.contributor.otherLisa J. Rew and Bruce D. Maxwell were co-authors of the article, 'Mechanisms underlying non-native plant impacts: a review of recent experimental research' in the journal 'Biological invasions' which is contained within this thesis.en
dc.contributor.otherBruce D. Maxwell and Lisa J. Rew were co-authors of the article, 'Ecological tradeoffs in non-native plant management' in the journal 'Biological conservation' which is contained within this thesis.en
dc.contributor.otherLisa J. Rew and Bruce D. Maxwell were co-authors of the article, 'Abundance-impact relationships of non-native plants: an examination of Bromus tectorum L. in Southwest Montana sagebrush-grassland plant communities' in the journal 'Biological invasions' which is contained within this thesis.en
dc.date.accessioned2013-06-25T18:40:33Z
dc.date.available2013-06-25T18:40:33Z
dc.date.issued2012en
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/2292
dc.description.abstractNon-native plant species (NIS) are considered a significant threat to individual species, communities, and ecosystems; thus, NIS management is mandated in most natural areas (i.e. non-crop). Controlling NIS in natural areas should, ideally, not only reduce target NIS abundance, but also benefit broader management objectives such as conserving native species and improving wildlife habitat. In this context, the benefits of NIS control must be weighed against the impacts of NIS themselves. This dissertation examines ecological impacts of NIS through a synthesis of previous experimental research and field-based manipulative experiments. In a review and synthesis of experimental research, we found that NIS caused significant impacts in approximately half of all experiments. Negative impacts were most frequent on community structure, followed in descending order by individual species, ecosystem properties, and ecosystem processes. Contrary to common assumptions, NIS typically caused impacts by modifying the abiotic environment rather than outcompeting native species for resources. NIS impacts were also examined through experiments conducted in sagebrush-grasslands of the GYE. The first study compared plant community impacts of Centaurea stoebe L. and common herbicide treatment for C. stoebe. The broadleaf herbicide, picloram, was highly effective at reducing C. stoebe, but also significantly reduced native forb cover and significantly increased non-native grass cover. Native forb cover increased with manual removal of C. stoebe, suggesting C. stoebe had been suppressing native forbs. However, there was an equivalent increase with no treatment. In these communities, C. stoebe appears to have a negligible effect on native forb and grass cover and richness. The final study examined plant community impacts of the non-native annual grass, Bromus tectorum L, and relationships between impacts and NIS abundance. In a four-year field experiment, we did not detect significant impacts of B. tectorum on native plant cover and richness. Environmental factors, particularly climate variability, are likely more important determinants of current vegetation patterns in these communities rather than the presence of B. tectorum. Overall, the research shows NIS often do not have significant detectable impacts on native species and communities, and that the negative non-target effects of herbicide treatments may outweigh the benefits of NIS control.en
dc.language.isoengen
dc.publisherMontana State University - Bozeman, College of Agricultureen
dc.subject.lcshPlant communities.en
dc.subject.lcshInvasive plants.en
dc.titleQuantifying non-native plant impacts : Centaurea stoebe L. (spotted knapweed) and Bromus tectorum L. (downy brome) in sagebrush-grasslands of the greater Yellowstone ecosystem
dc.typeDissertation
dc.rights.holderCopyright Tanya Christine Skurski 2012en
thesis.catalog.ckey1932849en
thesis.degree.committeemembersMembers, Graduate Committee: Lisa J. Rew (co-chair); Daniel Goodman; Theodore W. Weaver; Catherine A. Zabinskien
thesis.degree.departmentLand Resources & Environmental Sciences.en
thesis.degree.genreDissertationen
thesis.degree.namePhDen
thesis.format.extentfirstpage1en
thesis.format.extentlastpage242en
mus.identifier.categoryLife Sciences & Earth Sciences
mus.relation.departmentLand Resources & Environmental Sciences.en_US
mus.relation.universityMontana State University - Bozemanen_US


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