THE SYNERGISTIC EFFECTS OF ENVIRONMENTAL CHANGE ON THE POPULATION DYNAMICS OF LOCALIZED ENDEMIC SPECIES, A CASE STUDY IN HAWAI‘I A DISSERTATION SUBMITTED TO THE GRADUATE DEVISION OF THE UNIVERSITY OF HAWAI‘I AT MA̅NOA IN PARTIAL FULFILLMENT OF THE REQUIRMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN BOTANY April 2017 By Lala Bialic-Murphy Dissertation Committee: Orou Gaoue: Chairperson Kasey Barton Tom Ranker Tamara Ticktin Qi Chen i ii Acknowledgements There are many people who have helped in the development and completion of this work that I would like to recognize. In particular, I would like to thank my PhD advisor, Orou Gaoue, for his mentorship and unwavering encouragement. Dr. Gaoue’s insight and thoughtfully feedback have been an invaluable source of direction over the course of my PhD. He has provided me with support and guidance on how to prepare manuscripts for publication, write grants, and effectively communicate the results of my research at large international conferences and the broader scientific community. I would also like to recognize Kapua Kawelo, who has been an amazing mentor and friend to me for over a decade. Kapua has taught me valuable lessons on how to manage endangered species and promote ecosystem recovery. Kapua’s passion for field ecology has had a profound impact on my life and her inspiration is among one of the main reasons why I have became an ecologist with a keen interest in applied research and for this, I am extremely grateful. I would like to thank Tiffany Knight for her mentorship and thoughtful feedback, which has greatly improved my dissertation. I am also thankful to Kasey Barton for her mentorship, guidance, and encouragement. Dr. Barton has provided me with extremely thoughtful feedback on my research and has helped me deepen my understanding of plant physiology. I would also like to thank Tom Ranker, Tamara Ticktin, and Qi Chen for their comments and discussions on my work, which has greatly improved my research. I would recognize and thank O‘ahu Army Natural Resources Program staff for their help with data collection and keen insight regarding rare plant conservation, particularly Joby Rohrer, Dan Sailer, Michelle Akamine, Lauren Weisenberger, Tyler Bogardus, Stephanie Joe, Katie Franklin, Matt Kier, and Jessica iii Hawkins. I am also extremely thankful to Robert McElderry for his continual support and help with data collection and demographic modeling. I am grateful to thank Michael Coe and Mathew Bond for their support and encouragement over the course of my PhD. I am also thankful to Kari Bogner for her friendship and never-ending help in the greenhouse. Lastly, I want to recognize the United States Army Corps of Engineers (Cooperative Agreement grant ID W91269-11-2-0066) for funding this research. iv Abstract The spatial distribution and abundance of organisms are shaped by interactions with the environment. Human-induced changes in the environment can have varying effects on plant vital rates across ontogeny, sometimes in opposite directions. It is commonly thought that plant endangerment is the result of the combined effects of multiple environmental stressors. The influences of environmental stressors on components of plant fitness have been well examined. Few studies, however, have explicitly evaluated the synergistic effects of environmental stressors on the geospatial distribution of endangered species. In this dissertation I examined the population dynamics of three Hawaii endangered plants, Schiedea obovata, Cyrtandra dentata, and Delissea waianaeensis. Furthermore, I used a combination of size and stage structured demographic models to quantify the individual and combined impacts of dominant non- native pests and changing abiotic conditions on plant dynamics. I also compared the economic costs of various restoration strategies, including the suppression of non-native frugivores and seedling herbivores. I found that for S. obovata and C. dentata, fine-scale changes in microhabitat heterogeneity and inter-annual precipitation patterns had a greater effect on plant dynamics than top-down stressors. Furthermore, I found that the endangered plant populations were not always at, or close to, their equilibrium state (i.e., stable stage distribution SSD). There are many factors that contributed to the populations moving away from equilibrium, including population augmentation and the suppression of non-native pests. For the D. waianaeensis and C. dentata populations, there was a greater proportion of individuals in later life stages than would be expected if the populations were at a stable equilibrium. High reproductive value of these populations v caused them to grow faster in the near-term transient phase (i.e., 10 years) than over the long-term as the population reached equilibrium (i.e., transient amplification). Furthermore, I found that there were numerous combinations of restoration actions that would likely shift the growth rate of endangered species from declining to growing. However, the yearly economic costs of targeted restoration actions were highly variable. From a global perspective, this study illustrates that changing precipitation patterns and alterations in microhabitat can have a greater negative impact on plant dynamics than non-native frugivores and seedling herbivores and thus should be considered when developing rare plant restoration strategies. This research also emphasizes how important it is to evaluate both the near term transient and asymptotic dynamics of endangered species in order to fully capture the likely outcome of restoration effort vi Table of Contents Acknowledgements .................................................................................................................................iii Abstract ........................................................................................................................................................ v List of Figures ........................................................................................................................................... ix List of Tables ...........................................................................................................................................xii Chapter 1 Introduction ....................................................................................................................... 1 Declaration ........................................................................................................................................................ 6 Chapter 2 Microhabitat heterogeneity and a non-native avian frugivore drive the population dynamics of an island endemic shrub, Cyrtandra dentata ...................................... 7 Abstract .............................................................................................................................................................. 8 Introduction .................................................................................................................................................. 10 Materials and methods ............................................................................................................................. 13 Results.............................................................................................................................................................. 20 Discussion ...................................................................................................................................................... 22 Supporting information ............................................................................................................................ 28 References ...................................................................................................................................................... 29 Chapter 3 Low inter-annual precipitation has a greater negative effect than seedling herbivory on the population dynamics of a short-lived herb, Schiedea obovata (Caryophyllaceae) .................................................................................................................................. 46 Abstract ........................................................................................................................................................... 47 Introduction .................................................................................................................................................. 49 Material and methods................................................................................................................................ 53 Results.............................................................................................................................................................. 61 Discussion ...................................................................................................................................................... 63 References ...................................................................................................................................................... 67 Chapter 4 Evaluating both the transient and asymptotic dynamics is critical for assessing the efficacy of species reintroductions ......................................................................... 77 Abstract ........................................................................................................................................................... 78 vii Introduction