In partial fulfillment of the requirements for the degree of

Master of Science in Biology

in the

School of Biological Sciences

Emily Skibinski

Will defend her thesis

“Testing Darwin's Naturalization Hypothesis and Elton's Bio-Resistance Hypothesis in North American Breeding Birds”

1st, April, 2024

12 PM, EBB 4029

https://gatech.zoom.us/j/95409236044

Thesis Advisor:

Dr. Lin Jiang

School of Biological Sciences

Georgia Institute of Technology

Committee Members:

Dr. Benjamin Freeman

School of Biological Sciences

Georgia Institute of Technology

 Dr. Katie Stumpf

School of Biological and Environmental Sciences

Georgia College and State University

Abstract: Invasive species cause environmental and ecological havoc, so it is of great importance to understand why and how they naturalize. Two influential hypotheses have long been at the center of debate around invasive species success: Darwin's naturalization hypothesis; which states that invaders which are less closely related to natives will be more successful, and Elton's bio-resistance hypothesis; which states that communities with higher levels of biodiversity will be more difficult to invade. Many studies have been conducted to test these hypotheses, to mixed results. However, studies which examine these hypotheses through the lens of functional traits and functional diversity are rare. I use data from the Breeding Bird Survey (BBS) to analyze if the native functional diversity has any effect on the non-natives, and if the difference between native and non-native traits is larger, or smaller than expected by chance. I found that what affects the non-native species is extremely variable depending on multiple factors such as non-native metric used, or native functional diversity metric used. Additionally, which non-native traits are more or less similar to the natives is variable, depending on which trait is being compared. Overall, this study highlights several issues in the literature which tries to solve Darwin’s conundrum and the invasion paradox: what metrics are used to answer these questions matters a great deal, and more examinations of  how these hypotheses relate to functional diversity and functional traits needs to be carefully examined further.