UNIVERSITY OF CALIFORNIA Los Angeles ! ! ! Elucidating the Joint Effects of Biotic and Abiotic Factors on Species Invasion: A Trait-based Approach ! ! ! A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Biology ! by ! Margaret Webster Simon ! ! 2017 ! ! ! ABSTRACT OF THE DISSERTATION ! Elucidating the Joint Effects of Biotic and Abiotic Factors on Species Invasion: A Trait-based Approach ! by ! Margaret Webster Simon Doctor of Philosophy in Biology University of California, Los Angeles, 2017 Professor Priyanga A. Amarasekare, Chair ! Species invasions present a major environmental challenge due to their negative impacts on biodiversity, natural and agricultural ecosystems, and human health. Climate warming increases rates of invasion, but the field lacks a full understanding of the processes generating this pattern. To mitigate the negative effects of warming-facilitated invasions, we must understand the role that temperature plays in invasion success. A critical component of this agenda is to understand the effects of temperature on the invasion of ectothermic species in particular, as a large proportion of high-impacting pest and pathogen invaders are ectotherms. A successful invasion requires that an invader colonize the thermal environment, as well as establish into the biotic environment, the latter of which exposes the invader to competitive and ii antagonistic interactions with native residents. Because temperature affects both invader colonization and establishment, ectotherm invasions represent a complex interplay between temperature, invader persistence, and biotic interactions. Here we develop a conceptual framework for predicting the outcome of such complexity. The framework links the thermal environment to ectotherm population dynamics and interactions through impacts of temperature on life history and interaction traits. We integrate the temperature response of these traits into delay differential equations to make mechanistic predictions regarding the effects of warming on stage-structured populations and community-level dynamics. We use the framework to examine the effect of temperature on exotic invasion success by characterizing the fundamental thermal niche of an invader and the ways in which a resident competitor might constrain the thermal niche. We then ask how climate warming impacts these invasions. Within the fundamental thermal niche of ectotherms, we find that high temperatures maximize the probability of colonization, but low temperatures maximize invader abundance. We find that ectotherms adapted to low latitudes (tropical climates) are more successful invaders of high latitudes (temperate climates) as compared to the other way around. Further, we find that warming can allow tropical invaders to establish when they could not under ambient temperate climates. Taken together, the dissertation clarifies our understanding of the mechanisms by which exotic species insert themselves into native communities under ambient and warming climates.! ! ! iii The dissertation of Margaret Webster Simon is approved. James O. Lloyd-Smith Van Maurice Savage Alan Garfinkel Priyanga A. Amarasekare, Committee Chair ! ! ! University of California, Los Angeles 2017 ! ! ! ! ! ! ! ! ! ! iv TABLE OF CONTENTS ! ACKNOWLEDGMENTS ………………………………………………………..…… vi VITA/BIOGRAPHICAL SKETCH ……………………………………………………. vii ! ! CHAPTER 1 ………………………………………………..………………………….. 1 Appendix A …………………………………………………………………….. 28 Table Legends ………………………………………………………………….. 30 Tables ….…………………………………………………………………..…… 32 Figure Legends ………………………………..………………………..……… 35 Figures ………………………………………………………………..………… 38 Supplementary Information ……………………………………………………. 45 References .………………………………….………………………………….. 47 ! ! CHAPTER 2 ………………………………………………..………………..………… 53 Appendix A …………………………………………………………………….. 79 Appendix B …………………………………………………………………….. 82 Appendix C ……………………………………………………….……………. 86 Figure Legends ………………………………………………………………… 87 Figures …………………………………………………………………………. 90 References ……………………………………………………………………… 97 ! ! CHAPTER 3 ………………………………………………………………..………….. 102 Table Legends ………………………………………………………………….. 121 Tables …………………………………………………..………………………. 122 Figure Legends ……………………………………………..………………….. 123 Figures ………………………………………………….……………………… 129 Supplementary Information ……………………………………………………. 135 References ……………………………………………………………………… 140 v ! ACKNOWLEDGMENTS I would like to acknowledge the contribution of Renato M. Coutinho. The code used to solve the delay differential equations in Chapter 3 that describe competition between native and exotic stage-structured populations (eqs. 1-4) was built from code that he developed to solve delay !differential equations for a single stage-structured population. The project described would not have been possible without partial support by a Doctoral Dissertation Improvement Grant from the National Science Foundation, and a Systems and Integrative Biology Training Grant (Grant Number T32GM008185) from the National Institute of General Medical Sciences. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Science Foundation, the National Institute !of General Medical Sciences, or the National Institute of Health. I would like to thank my advisor, Priyanga Amarasekare, for whose guidance, training, and patience I am eternally grateful. I thank my committee members Alan Garfinkel, Van Savage, and Jamie Lloyd-Smith for their valuable feedback and unique perspectives throughout my graduate career, and I thank the Amarasekare and Savage lab members for delightful conversation and insightful feedback. I extend a special thank you to Katie Scranton, from !whom I have learned a great deal in a short time. I thank the many friends who have positively impacted my life during my graduate career, and whose support made the journey possible. There are many of you and I am grateful for you all. I would like to acknowledge a few friends who I found always there to lift me up when I struggled to stand: Lucy Levers, Heather Hulton VanTassel, Grace John, Casey terHorst, Erin Conlisk, !Pamey Rueda-Cediel and Elise Gornish. From the bottom of my heart, I thank you. Finally, I would like to thank my family, whose love, support, and unique perspectives have enriched my life in so many ways. I cherish the many ways in which you contribute to my continued growth. vi VITA/BIOGRAPHICAL SKETCH ! !EDUCATION Bachelor of Science, May 2008 Major: Biology Minor: Physics Haverford College, Haverford, PA ! !RESEARCH EXPERIENCE Santa Fe Institute Complex Systems Summer School Student !Santa Fe Institute, Santa Fe, NM 6/15 to 7/15 Lab Assistant II !Anderson Lab, University of California, Riverside, CA 2/10 to 8/11 Biological Research Technician !Inouye Lab, Florida State University, Tallahassee, FL 1/09 to 12/09 Marine Science Research Experience for Undergraduates Intern Harris Lab, Virginia Institute of Marine Science, Gloucester Point, VA 5/07 to 8/07 ! !FELLOWSHIPS AND AWARDS 2016 Department Research/Conference Travel Award ($1,500) 2015 Department Research/Conference Travel Award ($2,000) 2015 NSF DOE GAANN Research/Travel Allowance ($1,500) 2015 NSF Doctoral Dissertation Improvement Grant recipient ($20,000) 2014-2015 NSF DOE Graduate Assistance in Areas of National Need (GAANN) Fellow 2014-2015 Department Research/Conference Travel Award ($1,100) 2013-2014 NIH Systems and Integrative Biology Predoctoral Research Trainee 2013-2014 Department Research/Conference Travel Award ($835) 2012-2013 NIH Systems and Integrative Biology Predoctoral Research Trainee 2012 NSF Graduate Research Fellowship Program Honorable Mention 2008 Enhancing Linkages between Mathematics and Ecology (ELME) Summer Fellow ! !TEACHING EXPERIENCE !Department of Physiological Science UCLA, Los Angeles, CA 1/16 to 3/16, 1/17 to 3/17 • Dynamical Systems Modeling of Physiological Processes !Department of Ecology and Evolutionary Biology UCLA, Los Angeles, CA 10/14 to 12/14, 10/15 to 12/15, 10/16 to 12/16 • Ecology !Department of Life Sciences UCLA, Los Angeles, CA 3/12 to 6/12, 3/13 to 6/13, 1/14 to 3/14, 3/17 to 6/17 • Evolution, Ecology, and Biodiversity ! • Mathematics for Life Science Majors vii !Department of Physics Haverford College, Haverford, PA 1/08 to 5/08, 9/06 to 12/06, 1/06 to 5/06 • Living in a Fluid World: Physics of Everyday Life • Physics in Modern Medicine ! PUBLICATIONS Hulton VanTassel, H.L., A.M. Hansen, C.W. Barrows, Q. Latif, M.W. Simon, K.E. Anderson. 2014. Declines in a ground-dwelling arthropod community during an invasion by Sahara mustard (Brassica tournefortii) in aeolian sand habitats. Biological Invasions 16: 1675-1687. ! SELECTED PRESENTATIONS 1. Characterizing the fundamental thermal niche from first principles. (Simon*, M.W. and Amarasekare, P.) Oral presentation at 2017 Ecological Society of America Annual Meeting in !Portland, Oregon (August 9, 2017). 2. An introduction to game theory. Invited lecture for PHYSCI 135 Dynamical Models in the !Physiological Sciences (two hour class; February 7, 2017). 3. Elucidating the effects of temperature and competition on native-invasive interactions: A trait-based framework. (Simon*, M.W. and Amarasekare, P.) Oral presentation at 2015 !Ecological Society of America Annual Meeting in Baltimore, Maryland (August 12, 2015). 4. A trait-based approach for understanding the effects of temperature and competition on species coexistence. (Simon*, M.W. and Amarasekare, P.) Oral presentation at 2014 Ecological