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Please use this identifier to cite or link to this item: http://hdl.handle.net/1807/17696

Title: The Effects of Biotic Interactions on Ambrosia artemisiifolia L.
Authors: MacDonald, Arthur Andrew Meahan
Advisor: Kotanen, Peter M.
Department: Ecology and Evolutionary Biology
Keywords: Invasions
Biotic interactions
Life cycle
Ambrosia artemisiifolia
Issue Date: 22-Sep-2009
Abstract: Plant invasions can ensue when plants are introduced to regions without their specialist enemies (the Enemy Release Hypothesis). This assumes natural enemies limit survival and fecundity in an invader's native range. I tested this assumption for a native invasive species, Common Ragweed (Ambrosia artemisiifolia), by excluding natural enemies from seeds, seedlings and adults. At the adult stage, I added disturbance and conspecific density treatments. Protection from herbivores slightly improved performance at the seedling stage only, while disturbance greatly increased survival and fecundity. Increasing conspecific density reduced performance only in disturbed plots. I also tested herbivore tolerance using simulated damage. Heavy (75%) damage did not reduce fecundity; light damage even increased seed production. These results suggest enemies do not limit Ambrosia in its native range, especially compared to the effects of habitat disturbance. While enemy release may have occurred during Ambrosia’s invasions, it is not likely to be their principal cause.
URI: http://hdl.handle.net/1807/17696
Appears in Collections:Master
Department of Ecology & Evolutionary Biology - Master theses

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