PLANT AND INSECT-MEDIATED INVASIVENESS OF PHRAGMITES AUSTRALIS AND THE LITTER DYNAMICS AND BIODIVERSITY OF SIX FRESHWATER MACROPHYTES

My thesis involves two distinct projects related to wetland plants. The first evaluates plant traits for their contribution to the success of invasive Phragmites australis in North America and their interaction with herbivores. The second investigates the relative effects of six plant species, with different growth forms, status (native v. nonnative) and tissue quality, on litter dynamics and invertebrate diversity in a New York freshwater wetland. Prevention is the most cost-effective and successful means of managing invasive plants. Predicting future invasions depends on identifying plant traits that facilitate invasive success. We investigated the influence of above-ground growth phenology and increased stem height on the success of invasive Phragmites australis in North America, using a phylogenetically-controlled comparison with a native, non-weedy P. australis subspecies. We also measured the effects of specialist stem-galling Lipara flies and a generalist aphid (Hyalopterus pruni), both nonnatives to North America, on these above-ground traits. Comparisons were made in 1) a commo