Community Interactions and Impacts of Exotic Plant Species in the Southeastern United States Public Deposited

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  • March 20, 2019
Creator
  • Tarasi, Dennis
    • Affiliation: College of Arts and Sciences, Curriculum in Environment and Ecology
Abstract
  • Native to other regions of the world, exotic species can disrupt the ecology and function of natural areas where they are introduced. Exotic species successfully establish in and dominate natural areas via multiple pathways and ecological processes. Given that many of these interactions remain difficult to measure, it is imperative to properly identify environmental factors that predict exotic species success and quantify the impacts of exotic species dominance on natural communities. Here, I explore the interactions between exotic plant species and communities where they have been introduced in the southeastern United States to address the predictors of invasion, community responses to invasion and subsequent removal of dominant invaders. Chapter 2 considers whether biotic communities predictably incorporate or resist exotic species by examining the relationship between native species richness and exotic species richness at multiple spatial scales across a broad range of environmental conditions. Chapter 3 explores the predictive ability of environmental characteristics concerning exotic species success in a large vegetation database. Chapter 4 quantifies the abiotic and biotic community changes with invasion of a dominant exotic shrub, including assessments of species diversity and the physical structure of the community. Chapter 5 assesses the abiotic community differences resulting from exotic shrub invasion, including abiotic responses to removal of that dominant shrub from the community. Exotic species success generally and predictably responds to changes in the scale of observation and local environmental conditions. Several environmental characteristics correlate with exotic species success, including soil pH, calcium, tree stem density and cover of wetland species. The unique predictive ability of any individual variable remains limited, reflecting the complex interactions driving exotic species success and the differences among exotic species. Invaded communities exhibit several distinct responses to exotic species dominance, including changes in both richness and physical forest structure. Such changes must be considered in context, as invaders of similar structure, function and origin differentially affect the communities they invade. Although shrub invasions, and the subsequent removal of dominant invaders, may cause demonstrable abiotic changes in the community, such as in temperature and light availability, responses in soil moisture and nutrient levels are limited.
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  • In Copyright
Advisor
  • Weakley, Alan S.
  • Bruno, John
  • Peet, Robert K.
  • White, Peter
  • Wright, Justin
Degree
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2016
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