Copyright by Kimberly Michelle Ballare 2018 The Dissertation Committee for Kimberly Michelle Ballare Certifies that this is the approved version of the following Dissertation: Multi-scalar drivers of native bee community composition and population genetic structure in human-altered landscapes Committee: Shalene Jha, Supervisor Daniel Bonick Caroline Farrior Timothy Keitt Kenneth Young Multi-scalar drivers of native bee community composition and population genetic structure in human-altered landscapes by Kimberly Michelle Ballare Dissertation Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy The University of Texas at Austin December 2018 Acknowledgements First, I would like to thank my supervisor, Shalene Jha, without whose support, encouragement, and guidance this research would not have been possible. Her feedback has been invaluable for improving every manuscript, grant proposal, presentation, and this dissertation. I also thank my committee for providing valuable feedback and helping to improve my projects each year. I am extremely lucky to have been a part of a supportive, helpful, and brilliant lab group. I thank everyone who has been part of the Jha Lab for their advice and comments on project ideas, early manuscripts, and research presentations throughout the years. In particular I would like to thank our former lab manager Rebecca Ruppell who was a true collaborator on much of this research. I also thank Antonio Castilla, Hollis Woodward, and Elinor Lichtenberg for their mentorship and guidance, and Nathaniel Pope, Sarah Cusser, and Megan O’Connell for their collaboration, commiseration, advice, and friendship. I also thank the EEB support staff for their patience and help throughout my time at UT, especially Tamra Rogers and Sylvia Moore. I would like to thank individual landowners, Texas State Parks, the Lower Colorado River Authority, as well as the cities and community gardens of Austin, Dallas, and Fort Worth for allowing access to properties for collecting insect specimens and field data. There were many, many undergraduate assistants, technicians, and volunteers who helped sample, curate, and organize the insect collection. In particular I thank Clare Glinka, Alan Ritchie, Alexa Kusmik, Sarah Cunningham, Kelvey Merrill, and Brittany French for assistance with field collection of insects and vegetation surveys, as well as Nicole Vojnovich, Marci Rolbiecki, Tess Ortega, Lee Stevens, and Nina Fogel for assistance with insect preservation and curation. I cannot thank Dr. Jack Neff enough for his expert advice and taxonomic skills, and for putting up with drawers and drawers of tiny and terrible Lasioglossum specimens. I received financial support for this research from the Texas Parks and Wildlife Department, Texas Ecolabs, the Native Plants Society of Texas, The National Science Foundation, and the Graduate Program in Ecology, Evolution, and Behavior at the University of Texas at Austin. I also thank my supportive and patient family: my parents Dan and Gail Ballare, my sister Dana Ballare-Davidson, and my partner Tyruss Cramer. iv Abstract Multi-scalar drivers of native bee community composition and population genetic structure in human-altered landscapes Kimberly M. Ballare, PhD The University of Texas at Austin, 2018 Supervisor: Shalene Jha One of the most well-documented ecological impacts of human-caused landscape change is the fragmentation of natural habitats by human infrastructure, with potential implications for 1) community composition, and 2) species-level gene flow patterns. By including quantifiable measurements of local habitat composition, regional land-use, and the composition of the landscape matrix in ecological studies, we can better understand how multi-scalar environmental factors drive changes in wildlife community composition and dispersal processes, and infer subsequent consequences for ecosystem functions and services across human-altered landscapes. Pollination is a critical ecosystem service driven in part by wildlife community composition and dispersal processes, but despite the importance of bee pollination for ecosystem function, very little is known about how land-use drives native bee community composition and their population gene-flow patterns. This research addresses this literature gap by investigating native bee communities (Chapter 1) and native bee gene flow (Chapter 2) across heterogeneous human-altered landscapes in Texas, and proposes methods for expanding conservation genetic research of pollinators using curated bee specimens (Chapter 3). v In Chapter 1, we conducted an extensive survey of bee communities across two urban landscape gradients in Austin and Dallas, Texas, USA comparing communities within agricultural and native grassland habitat types. In Chapter 2, we investigate the genetic structure and gene flow patterns of the native eastern carpenter bee, Xylocopa virginica across a 450 km corridor spanning multiple land-uses in Texas. In Chapter 3, we test the effects of sampling and curation methods on next-generation sequencing of three widespread North American native bee species. Our results indicate that the composition of regional land-use differentially impacts bee abundance and diversity depending on local habitat management and between bee functional groups, and that contemporary land-use as well as regional and fine-scale geographic distance influence the gene flow patterns of a large wood-nesting bee. Lastly, we find that sampling and storage method influence sequence assembly quality, and that curated and trapped specimens can be successfully utilized for next-generation sequencing research. vi Table of Contents List of Tables ......................................................................................................................... xii List of Figures ....................................................................................................................... xiv Chapter 1. Multi-scalar drivers of biodiversity: local management mediates wild bee community response to regional urbanization ..................................................................1 Abstract ............................................................................................................................1 Introduction .....................................................................................................................2 Methods ...........................................................................................................................6 Study Area ...........................................................................................................6 Bee Collection .....................................................................................................7 Local Vegetation Surveys ..................................................................................8 Landscape Characterization ...............................................................................9 Data Analysis ................................................................................................... 10 Bee community composition in agriculture and grassland management ...................................................................................... 10 Effects of local environmental drivers and landscape context on bee abundance and diversity in agriculture and grassland management ...................................................................................... 11 Results ........................................................................................................................... 13 Bee community composition in agriculture and grassland management ..... 14 Effect of local environmental drivers and landscape context on bee abundance and diversity in agriculture and grassland management ...... 15 Abundance .............................................................................................. 15 Species Richness .................................................................................... 16 Evenness ................................................................................................. 17 vii Discussion ..................................................................................................................... 19 Landscape context mediates bee abundance and diversity differently for agriculture and grassland habitats ............................................................ 19 Bee community composition is differentially influenced by agriculture and grassland management, but similar local environmental drivers influence bee abundance and diversity across sites ................................ 22 Conservation implications and management recommendations ................... 24 Chapter 1 Tables........................................................................................................... 26 Chapter 1 Figures ......................................................................................................... 28 Chapter 1 Appendix ..................................................................................................... 33 Chapter 2. Genetic structure at multiple spatial scales reveals resource specialization and philopatry in the eastern carpenter bee, Xylocopa virginica.................................. 47 Abstract ........................................................................................................................