Arthropod Abundance and Diversity in Miscanthus x giganteus, Panicum virgatum, and Other Habitat Types in Southeastern Ohio A thesis presented to the faculty of the Voinovich School of Leadership and Public Affairs of Ohio University In partial fulfillment of the requirements for the degree Master of Science Taylor L. Snelick May 2018 © 2018 Taylor L. Snelick. All Rights Reserved. 2 This thesis titled Arthropod Abundance and Diversity in Miscanthus x giganteus, Panicum virgatum, and Other Habitat Types in Southeastern Ohio by TAYLOR L. SNELICK has been approved for the Program of Environmental Studies and the Voinovich School of Leadership and Public Affairs by Kelly S. Johnson Associate Professor of Biological Sciences Mark Weinberg Dean, Voinovich School of Leadership and Public Affairs 3 ABSTRACT SNELICK, TAYLOR L., M.S., May 2018, Environmental Studies Arthropod Abundance and Diversity in Miscanthus x giganteus, Panicum virgatum, and Other Habitat Types in Southeastern Ohio Director of Thesis: Kelly S. Johnson Bioenergy could help reduce CO2 emissions from agriculture that contribute to climate change, while at the same time supply energy to a growing population. Varying levels of inputs within bioenergy crop fields, such as pesticide use or annual tilling, can impact arthropod biodiversity and abundance. The research presented here examines the impact of habitat type (Miscanthus x giganteus, Panicum virgatum, abandoned agriculture, and forested edge) on the diversity and abundance of arthropods in small (The Ridges Land Lab) and larger (The Wilds) planted plots in southeastern Ohio. A variety of collection methods (sweep nets, flight traps, and Berlese funnels) were used over a three month period to collect arthropods from different trophic groups. Overall, 25,390 arthropods were captured with the highest abundance consistently seen in forested edge habitats, followed by abandoned agriculture, switchgrass, and lastly miscanthus. Flying insects found in the forested edge were three fold more abundant than those found in miscanthus plots, with intermediate levels in switchgrass and abandoned agriculture. Dominant flying arthropod groups included leaf hoppers, flies and rove beetles. Abundance of litter arthropods was almost two fold higher in switchgrass than in miscanthus plots: dominant taxa included oribatid mites, ants, ground beetles, and collembolans. Taxonomic richness and Shannon diversity were lower in litter samples 4 compared to flight/ sweep samples. Compared to forested edges, miscanthus supported fewer omnivores, pollinators, and predator/parasites. Detritivorous arthropod abundances did not differ across habitat types. No significant differences were noted between arthropod diversity and abundance between the larger fields of biofuel grasses at the Wilds compared to the Ridges Land Lab. This current study shows that cellulosic ethanol crop type does have an impact on arthropod communities; with miscanthus consistently supporting the least diverse and lowest arthropod abundances compared to more diverse natural areas such as forested edges. This project is meant to be a relative measure of arthropod diversity and abundance in two different size field settings in Southeastern Ohio and results may be different in other field settings. 5 DEDICATION This thesis is dedicated to my parents, Lisa Ann and John Gregory Snelick, whose love, unselfish support, and example over my lifetime laid the foundations for the discipline necessary to complete this work. 6 ACKNOWLEDGMENTS This thesis could not have been completed without the knowledge and wisdom provided to me from my advisors, Kelly Johnson, Sarah Davis, and Arthur Trese as well as the support of other faculty and staff at the Voinovich School. I thank you all for your continued support over the course of this project. The tremendous amount of field work and arthropod identification could also not have been done without the help from undergraduate assistants, Tristan Hoffman, Lillian Rudolf, and Monica Ciszewski. I thank my roommates and friends over the past two years for keeping me sane through this process as well as listening to me practice my presentations and speeches over and over again; Nina Fuller and Johanna Ansel. I thank my partner, Scotty Farey, for his unfailing love, support and continuous encouragement as I completed my degree. My family has raised me to be the person I am today and without their support I would not have made it through my undergraduate and graduate careers. My family’s love for the outdoors and all living things is what embedded in me love for the environment in the first place. I thank my dad for letting me use his car as I traveled to and from college, and my mom for letting me store my bugs in her freezer every time I came home. I thank my youngest sister, Brooke Snelick, for sitting with me as I sorted my arthropods for countless hours that could have been spent playing games with her instead. I have had the pleasure of seeing my sister, Jordan Snelick, transformed into a student professional herself at the Voinovich School as we attended our last year of college together; she also created the ArcGIS maps for this thesis. Thank you, all. 7 TABLE OF CONTENTS Page Abstract ............................................................................................................................... 3 Dedication ........................................................................................................................... 5 Acknowledgments............................................................................................................... 6 List of Tables ...................................................................................................................... 9 List of Figures ................................................................................................................... 10 Chapter 1: Literature Review ............................................................................................ 11 1.1 Introduction to Biofuels: Cellulosic Ethanol and Biodiesel ................................. 11 1.2 Current Trends in Biofuel Crop Production .......................................................... 16 1.2.1 Development of Biofuel Policies Abroad and in the US ............................. 16 1.2.2 Available American Cropland ..................................................................... 17 1.3 Global Arthropod Declines ................................................................................... 18 1.4 Arthropod Community Dynamics in Biofuel Feedstocks .................................... 19 1.4.1 Miscanthus x giganteus ................................................................................ 20 1.4.2 Panicum virgatum ........................................................................................ 21 1.4.3 Abandoned Agriculture and Forested Areas ................................................ 22 1.5 Decision Making and Adaptive Management....................................................... 23 Chapter 2: Arthropod Abundance and Diversity in Miscanthus x giganteus, Panicum virgatum, and Other Habitat Types in Southeastern Ohio ................................................ 26 2.1 Introduction ........................................................................................................... 26 2.2 Methods................................................................................................................. 28 2.2.1 Study Areas .................................................................................................. 28 2.2.2 Experimental Design .................................................................................... 31 2.2.3 Sampling Methods ....................................................................................... 32 2.2.4 Arthropod Identification and Counting ........................................................ 34 2.2.5 Statistical Methods ....................................................................................... 34 Chapter 3: Results ............................................................................................................. 36 3.1 Summer Sampling Event: The Ridges Land Lab ................................................. 37 3.1.1 Impact of Habitat Type on Total Arthropod Number .................................. 37 3.1.2 Impact of Habitat Type on Family Level Richness ..................................... 39 3.1.3 Impact of Habitat Type on Arthropod Diversity.......................................... 43 8 3.1.4 Impact of Habitat Type on Trophic Groups ................................................. 45 3.2 September Sampling Event: The Wilds ................................................................ 47 3.2.1 Impact of Habitat Type and Site on Arthropod Abundance ........................ 48 3.2.2 Impact of Habitat Type on Family Level Richness ..................................... 49 3.2.3 Impact of Habitat Type on Diversity ........................................................... 50 Chapter 4: Discussion ....................................................................................................... 51 4.1 Summer Sampling Event ...................................................................................... 51 4.1.1 Arthropod Abundance and Family Richness related to Habitat Type ......... 51 4.1.2 Arthropod Diversity Related to Habitat Type .............................................. 53 4.1.3 Trophic Group Response to Habitat