Year: 2014
Type: dissertation
Abstract: The colonization of wetlands by invasive plant species negatively impacts vegetation structure, nutrient and organic matter cycling, and ultimately alters native wetland ecosystem functions and services. It is unclear if the spread of invasive species can be attributed to their chemical composition. To further understand mechanisms of plant invasion, it is important to assess secondary chemistry of aggressive invaders. Phenolic compounds are important due to their diverse functionality including pathogen resistance, herbivore deterrence, and allelopathic interference. I conducted a broad field survey and a field experiment to better understand the importance and variability of wetland plant phenolic compounds and the relationship between abiotic and biotic environmental factors. I examined the relationship between leaf phenolic content and environmental conditions for 21 noninvasive and invasive plant species from ten sites. The environmental factors included soil moisture, extractable nitrate and ammonium, and total phosphorus, along with herbivory, and neighboring plant cover. The field experiment targeted two invasive species of cattail (Typha latifolia, T. angustifolia) in created wetlands at the Rochester Institute of Technology and High Acres Nature Area. I manipulated nutrient availability and herbivore pressure to investigate effects on growth and phenolic content. There was no predictable difference between invasive and noninvasive plants, but there were differences among sites for each species. The difference among sites for invasive species was more pronounced, with significant relationships with different combinations of abiotic and biotic factors, depending on the species. For four of the invasive species examined in detail, season, nutrients and/or herbivory were important factors influencing phenolic content. There were no predictable relationships for noninvasive species. There were no significant differences in growth, phenolic content, or herbivory among treatments in the field experiment suggesting that either the effects tested are unimportant for Typha spp., or the threshold was not met for an observable effect. We conclude that interspecific differences in the response of invasive plants to environmental factors preclude drawing general conclusions about the role of total phenol content in invasion success, but that invasive plants may be more responsive to environmental conditions, perhaps enhancing invasion.
Author: Melissa M. Maurer
Language: English
Subfield: Nature and Landscape Conservation
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: green
OpenAlex ID: W852832442