EFFECTS OF FOREST EDGES, EXOTIC ANTS AND NONNATIVE PLANTS ON LOCAL ANT (HYMENOPTERA: FORMICIDAE) DIVERSITY IN URBAN FOREST FRAGMENTS OF NORTHEASTERN OHIO KALOYAN IVANOV Master of Science in Entomology Sofia University Sofia, Bulgaria 2000 Submitted in partial fulfillment of requirements for the degree DOCTOR OF PHILOSOPHY IN REGULATORY BIOLOGY at the CLEVELAND STATE UNIVERSITY December, 2010 This dissertation has been approved for the Department of Biological, Geological, and Environmental Sciences and for the College of Graduate Studies by Date: Dr. Joe B. Keiper, Virginia Museum of Natural History Major Advisor Date: Dr. B. Michael Walton, BGES / CSU Advisory Committee Member Date: Dr. Robert A. Krebs, BGES / CSU Advisory Committee Member Date: Dr. Jaharul Haque, The Cleveland Clinic Advisory Committee Member Date: Dr. Daniel R. Petit, National Fish and Wildlife Foundation Advisory Committee Member Date: Dr. F. Paul Doerder, BGES / CSU Internal Examiner Date: Dr. Carl D. Anthony, Department of Biology, John Carroll University External Examiner “The worst thing that can happen - will happen [in the 1980s] - is not energy depletion, economic collapse, limited nuclear war, or conquest by a totalitarian government. As terrible as these catastrophes would be for us, they can be repaired within a few generations. The one process ongoing in the 1980s that will take millions of years to correct is the loss of genetic and species diversity by the destruction of natural habitats. This is the folly our descendants are least likely to forgive us.” Wilson EO (Harvard Magazine 1980) ACKNOWLEDGMENTS Numerous people provided help, as diverse as it was important, that made this work possible. I am deeply grateful to all these individuals. My original advisor, Dr. Tarun Mal, believed in me and took me as his student. He provided mentorship, valuable advice, and enormous help during the initial stages of my work and I take pride acknowledging his contribution to the research presented here. I would like to thank my major advisor, Dr. Joe Keiper, who stepped in and gave me the opportunity and freedom to study what I desired. His expertise helped me improve my critical thinking, presentation and writing skills. He put up with me and always was there when I needed help. I also thank my advisory committee members, Dr. Michael Walton, Dr. Robert Krebs, Dr. Daniel Petit, and Dr. Jaharul Haque for their support and encouragement over the course of my work at Cleveland State University. Dr. Ralph Gibson and Dr. Paul Doerder inspired me and provided good conversation along the way. I am grateful for their help and above all for their friendship. I thank Dr. Gibson for his thorough and critical reviews of the different components of my written work, for the good beer and for the even better food. I thank Dr. Doerder for the numerous hours of entertaining conversations and for keeping my mind on track when my head was somewhere else. I gratefully acknowledge those who assisted with the data collection and contributed many hours of hard work in the field. In particular, I thank Jen Milligan, without whom the data collection would have been impossible, and Owen Lockhart, for all his help, advice, and for showing me that there are other organisms out there besides ants. I am most fortunate to have many friends and colleagues who helped in various ways over the course of my study. In particular, I take pleasure in acknowledging Shim Balanson, Nick Mikash, Dr. Cari Hickerson, Dr. Carl Anthony, Tom Pucci, Sara Laux, Dr. Cal Borden, Mark Lyons, Krystal Hans, Dr. Terry Robison, Rick Tyler and Chuck Thomas. I thank Gary Coovert, Dr. James Trager, Dr. Andre Francoeur, Dr. Brian Fisher, and the Antcourse team for introducing me to the fascinating world of ants, and for teaching me the skills of ant identification. I will be in debt forever to these talented and generous people. The Cleveland Metroparks, the Cleveland Museum of Natural History, and the Shaker Lakes Nature Center provided permission to collect samples within their protected areas and preserves making my study possible. Cleveland State University, Cleveland Metroparks, the Ohio Biological Survey and the Geauga County Park District funded various components of my field work. I thank my family for their love, for always believing in me and supporting me in my chosen career. I never would have done this without you. Finally, I thank all my friends and colleagues I left in Bulgaria for their strong support despite the space/time limitations. I will be grateful to them forever. I do not know how to express my gratitude to all these who helped me through the years of my graduate career. I hope only that the work presented here will do justice to your love and support. If this work is good, it is because of you. EFFECTS OF FOREST EDGES, EXOTIC ANTS AND NONNATIVE PLANTS ON LOCAL ANT (HYMENOPTERA: FORMICIDAE) DIVERSITY IN URBAN FOREST FRAGMENTS OF NORTHEASTERN OHIO KALOYAN IVANOV ABSTRACT Urbanization has resulted in massive transformation of natural habitats with profound effects on biodiversity. Addressing the problems associated with anthropogenic deterioration of the environment requires solid understanding of the factors driving these changes. Habitat patch size, edge effects, and the presence of invasive species are among the key features of the urban landscape affecting local communities. My study focused on the effects of habitat edges, the exotic ant Nylanderia flavipes, and the invasive herb garlic mustard on local ant diversity in deciduous forest fragments of northeastern Ohio. In addition, I explored the value of common ant collecting techniques for estimating ant diversity. When compared to pitfall trapping, Winkler litter extraction showed greater species richness and higher abundance of ants and exhibited the advantage of a more complete inventory. Winkler extraction may completely replace pitfall trapping in temperate forests with well-developed litter layer, and inventorying programs may benefit from the inclusion of this technique as a rapid and effective ant-collecting tool. vi Our study documents predictable edge-associated changes in species richness, community composition and functional groups, occurring in local forest ant assemblages. Edge effects are most pronounced within the first 25m, which may have implications for the conservation of forest-dwelling fauna. At the sites where Nylanderia flavipes occurred, we found a 6-fold increase in ant abundance, with 87% of the ants being N. flavipes. The numerical dominance of this species did not lead to detectable changes in the species richness and abundance of the native ant community, but was responsible for decreased community evenness. This is likely indicative of a recent introduction with populations still being in their latency period. The high local abundance of N. flavipes may give it a competitive advantage and affect native ants through exploitative competition. Plots invaded by garlic mustard showed significant reduction in leaf-litter depth, correlated with increased abundance of nonnative earthworms, but no detectable effects on ant species richness or community composition. My results suggest that regional sylvan ant communities are unaffected by the generally presumed negative effects of garlic mustard, or that these effects are more subtle or confounded by other dominating factors. vii TABLE OF CONTENTS ABSTRACT ...................................................................................................................... vi LIST OF TABLES ............................................................................................................. xi LIST OF FIGURES .......................................................................................................... xii CHAPTER I – INTRODUCTION TO DISSERTATION ...................................................1 Literature cited .........................................................................................................7 CHAPTER II - EFFECTIVENESS AND BIASES OF WINKLER LITTER EXTRACTION AND PITFALL TRAPPING FOR COLLECTING GROUND DWELLING ANTS IN NORTHERN TEMPERATE FORESTS ....................................12 Abstract ..................................................................................................................12 Introduction ............................................................................................................14 Materials and methods ...........................................................................................19 Results ....................................................................................................................27 Discussion ..............................................................................................................38 Acknowledgments..................................................................................................43 Literature cited .......................................................................................................44 CHAPTER III - EFFICIENCY OF THE WINKLER METHOD FOR EXTRACTING ANTS (HYMENOPTERA: FORMICIDAE) FROM TEMPERATE-FOREST LITTER 52 Abstract ..................................................................................................................52 Introduction ............................................................................................................54 Materials and methods ...........................................................................................56 Results