Show simple item record

dc.contributor.advisorChairperson, Graduate Committee: Lisa J. Rew.en
dc.contributor.authorLehnhoff, Erik Adamen
dc.date.accessioned2013-06-25T18:43:45Z
dc.date.available2013-06-25T18:43:45Z
dc.date.issued2008en
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/1716en
dc.description.abstractInvasive plant species are considered to be one of the greatest threats to ecosystems and biological diversity throughout the world, and are thus often aggressively managed. The degree of plant invasiveness, however, varies both with environment and with type of landscape disturbance. This research was designed to understand how the factors of environment and disturbance affect the invasiveness of Linaria vulgaris (yellow toadflax) in southwest Montana and to quantify the varying degrees of invasiveness resulting from each factor. Data were obtained through four separate projects. The effects of disturbance size and propagule pressure on L. vulgaris establishment were evaluated through a series of experiments in both disturbed and undisturbed plots. L. vulgaris establishment and survival were low in all plots, but followed the general trend of more successful establishment in larger disturbed plots and in disturbed plots with a higher seeding density. An invasiveness index was developed that quantified invasiveness between -4 and +4 based on changes in population density and plant occupancy within permanent monitoring grids. This index was applied to L. vulgaris populations in three distinct environments, and invasiveness was found to range from -1.9 (declining population) to 1.8 (invasive population), indicating that invasiveness varied widely based on environment. The effects of the disturbances of herbicide, digging, burning and vegetation clipping on established L. vulgaris populations were evaluated in four environments. In the first year after treatment, herbicide reduced invasiveness of L. vulgaris in all environments, while digging and burning increased invasiveness and clipping had no effect. In the second year, herbicide resulted in increased L. vulgaris invasiveness at the three sites dominated by forbs, while it still reduced invasiveness at the grass-dominated site. The other treatments had minimal effects. Finally, effects of the above disturbances on the whole plant community were assessed using relative species abundance, richness and diversity metrics. Treatments generally decreased these metrics initially, but values recovered over time, with the exception of the herbicide treatment. The results demonstrated that L. vulgaris population invasiveness and treatment effectiveness varies with environment, suggesting that prioritizing management on an environment basis may be appropriate.en
dc.language.isoenen
dc.publisherMontana State University - Bozeman, College of Agricultureen
dc.subject.lcshLinaria.en
dc.subject.lcshInvasive plants.en
dc.subject.lcshEnvironmental degradation.en
dc.subject.lcshAlien plants.en
dc.titleInvasiveness of Yellow Toadflax (Linaria Vulgaris) resulting from disturbance and environmental conditionsen
dc.typeDissertationen
dc.rights.holderCopyright Erik Adam Lehnhoff 2008en
thesis.catalog.ckey1327467en
thesis.degree.committeemembersMembers, Graduate Committee: Bruce D. Maxwell (co-chair); Cliff Montagne; Steve Sutherland; Cathy Zabinskien
thesis.degree.departmentLand Resources & Environmental Sciences.en
thesis.degree.genreDissertationen
thesis.degree.namePhDen
thesis.format.extentfirstpage1en
thesis.format.extentlastpage259en
mus.relation.departmentLand Resources & Environmental Sciences.en_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record