The Influence of Habitat Management and Landscape on Spider Assemblages within Urban Greenspaces of Cleveland, Ohio THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Caitlin Elizabeth Burkman, B.S. Graduate Program in Entomology The Ohio State University 2013 Master's Examination Committee: Mary M. Gardiner, Advisor Richard A. Bradley Daniel A. Herms Andrew P. Michel Copyright by Caitlin E. Burkman 2013 Abstract Many Midwestern cities in the United States have experienced high levels of economic decline and population loss. This deindustrialization has led to thousands of acres of vacant land left as grassy habitats. The remaining community has conceptualized a variety of reutilization strategies for this land, including urban agriculture and the creation of small parks of native plantings. In a two-year study, I used spiders as a model system for examining the impacts of vacant land conversion on arthropod generalist predators within residential vacant lots, community gardens, and planted prairies within the peri-urban park system of Cleveland, Ohio. I found that maintained vacant lots contained the most active spider assemblage, but was dominated by disturbance-tolerant habitat generalist species. Community gardens contained the fewest spiders with a somewhat more diverse assemblage than vacant lots. Similarly low numbers were also found in planted prairies but the assemblage was more diverse. The second year’s collections were lower than the first, most likely due to precipitation changes and the subsequent influence on the primary productivity within a site. I also compared these results at the family and genus level in order to assess the taxonomic sufficiency relevant for future studies, and found that genus level was important for elucidating the effects of urban land use on these spider assemblages. Urban vacant land reutilization will therefore ii influence the assemblage structure of these generalist predators, which has implications for their ecosystem functioning. Generalist predators are often integrated into traditional agroecosystem studies in order to determine the relative influence of local and landscape scale factors on their diversity and abundance. Studies of agriculture within cities will also benefit from a landscape scale perspective as generalist predators have been shown to be more abundant within ‘non-crop’ habitats such as vacant lands. Therefore, I further examined the relative influence of local vegetation factors and landscape greenspace on structuring spider assemblages within vacant lots and community gardens during the second year of study. I found evidence that the most commonly captured ground active spiders were responding to different local factors in these two habitats due to the differing management regimes. I predicted that gardens surrounded by more greenspace would contain higher numbers of spiders due to their high dispersal ability, but this was generally not the case. However, landscapes had a stronger influence on spiders within vacant lots at a variety of spatial scales examined. These findings highlight how both dispersal ability and microhabitat needs will impact spider assemblages in different urban greenspaces. This has implications for garden managers especially, as the incorporation of non-disturbed microhabitats within the site may be beneficial for overall spider abundance, which appear to be negatively influenced by the high levels of disturbance due to management. I conclude with a discussion on future research directions directly relevant for landscape managers and planners. iii Dedication To my parents, Melissa and Geoffrey iv Acknowledgments I would like to first thank my advisor, Mary Gardiner, for all of her support and advice throughout this process. A huge thank you to my lab mates, Scott Prajzner, Ben Phillips, and Chelsea Smith, who were there as extra hands in field work, ears for commiseration, and fellow bar dwellers. And I can’t forget all of the undergraduates! Andrea Kautz, first and foremost, as an assistant turned grad student. Alec Norris, Kelsey Greathouse, Shawn Probst, and Jared Power were all particularly helpful with field work or sample sorting. Thanks to my committee members, past and present, Drs. Herms, Bradley, Michel, and Grewal, for their advice and encouragement. A special thanks to those who helped me arrange sites, including the Cleveland ULTRA-Ex team, Terry Robison, and Ana Locci. Extra special thanks to Pete Clapham and Carolyn Merry for assisting me with eCognition. Extra extra special thanks to Alain Zuur for statistical clarification. And thanks to Raman Bansal, Yuting Chen, and Jake Wenger for assisting with the molecular project that unfortunately did not pan out. And I really couldn’t have done this without the enthusiasm of my family and friends, especially my fellow entomologists. I’m glad I could talk bugs with total normalcy. v Vita May 7, 1988 ...................................................Born, Dayton, Ohio 2006................................................................Kettering Fairmont High School 2010................................................................B.S. Biology with Honors, Case Western Reserve University 2010 to present ..............................................Graduate Fellow, Department of Entomology, The Ohio State University Publications Gardiner, Mary M., Scott P. Prajzner, Caitlin E. Burkman, Sandra Albro, and Parwinder S. Grewal. 2013. Vacant land conversion to community gardens: influences on generalist arthropod predators and biocontrol services in urban greenspaces. Urban Ecosystems DOI 10.1007/s11252-013-0303-6 Fields of Study Major Field: Entomology vi Table of Contents Abstract ............................................................................................................................... ii Acknowledgments............................................................................................................... v Vita ..................................................................................................................................... vi Table of Contents .............................................................................................................. vii List of Tables ...................................................................................................................... x List of Figures .................................................................................................................. xiii Chapter 1 : Urban greenspace design and landscape context influence natural enemy community composition and function ................................................................................ 1 Abstract ................................................................................................................... 1 Introduction ............................................................................................................. 2 Incorporating spatial structure to study natural enemy community composition and function ............................................................................................................ 4 Fine-scale patchiness affects natural enemies and their activity in urban landscapes ............................................................................................................... 8 Coarse-scale landscape mosaics and natural enemy diversity and abundance ..... 14 vii Land cover descriptions to study natural enemy communities in heterogeneous urban mosaics........................................................................................................ 22 Informing future conservation of natural enemies in urban greenspaces ............. 24 Research Objectives .............................................................................................. 28 Chapter 2 : Alternative greenspace designs affect spider assemblages within an urban landscape ........................................................................................................................... 31 Abstract ................................................................................................................. 31 Introduction ........................................................................................................... 32 Materials and Methods .......................................................................................... 38 Results ................................................................................................................... 43 Discussion ............................................................................................................. 48 Chapter 3 : The influence of local patch and landscape composition on spider assemblages in urban greenspaces .................................................................................... 76 Abstract ................................................................................................................. 76 Introduction ........................................................................................................... 77 Materials and Methods .......................................................................................... 82 Results ................................................................................................................... 92 Discussion ............................................................................................................