Master of Science, The Ohio State University, 2020, Environment and Natural Resources

Urbanization can have profound influences shaping patterns of songbird diversity. For many species, urbanization poses considerable challenges, yet in many instances urban areas provide important habitat for songbirds, most notably riparian urban areas. With renewed interest to maintain functioning urban forests, understanding the interactions between songbirds and their urban environments is critical to making informed land management decisions. My research addresses habitat usage of breeding urban songbirds in Columbus, Ohio, focusing on the relationship between urban songbird presence and behavior and the vegetation in urban riparian forests. Previous songbird studies have been conducted in the Columbus metropolitan area since 2001 and have focused primarily on the impacts of urbanization on abundance, nesting, and survival. My goals for this study were to add to this knowledge base by examining potential correlations between songbird territory density and structural vegetative characteristics in urban forests and to investigate the foraging strategies of urban songbirds. The first component of my study examines the relationship between the breeding territory densities of individual songbird species and the vegetation structure of urban sites. Given that vegetation structure has been linked to urban songbird abundance and survival, the number of trees, the size of trees, and the density of exotic or native stems in a site may influence the territory density of certain species. I tested the hypotheses that overall songbird territory density will be greater in areas will fewer exotic stems and Neotropical territory density will increase with structural diversity. I conducted spot maps in urban riparian forests in Columbus, Ohio from late April to August in 2019 and compared these data to spot maps conducted by my colleagues in 2007 and 2011 to determine territory densities for the most common species, which included the Blue-gray Gnatcatcher, Blue Jay, Carolina (open full item for complete abstract)

Committee: Stephen Matthews PhD (Advisor); G. Matthew Davies PhD (Committee Member); Charles Flower PhD (Committee Member); Christopher Tonra PhD (Committee Member) Subjects: Urban Forestry; Wildlife Conservation; Wildlife Management

Doctor of Philosophy, The Ohio State University, 2008, Natural Resources

Effective conservation of biodiversity in urban areas ultimately requires that ecologists understand both the patterns and mechanisms of urban-associated influences on native plant and animal communities. A neglected consequence of urbanization is the seasonal timing of life cycle events, particularly the tendency of many urban birds to breed earlier in the spring than their rural-breeding counterparts. The overall objectives of this dissertation were to (1) describe phenological and biological differences in avian reproduction in urban and rural forests, (2) identify underlying ecological mechanisms responsible for observed patterns, and (3) identify demographic consequences of phenological shifts in reproduction. First I evaluated vegetation phenology and temperature patterns, two potentially important variables influencing bird breeding phenology. There was an overall pattern of advanced phenology (e.g., bud break, leaf elongation) within species in more urban landscapes which might be associated with elevated temperatures in more urban areas. Results suggest that shifts in plant communities along the urbanization gradient, especially the increased dominance of the invasive and exotic Amur honeysuckle (Lonicera maackii) in urban forests, drove the earlier green-up of urban areas. Avian breeding phenology was also influenced by urbanization, although patterns, causes, and consequences differed between my two focal species. The non-migratory Northern Cardinal (Cardinalis cardinalis) nested earlier in urban versus rural sites, a pattern that was best explained by early spring temperatures. Contrary to findings from other studies, early-breeding cardinals apparently received no benefit in terms of survival or reproduction compared to later-breeding pairs. In contrast, the Neotropical migratory, Acadian Flycatcher (Empidonax virescens) arrived and initiated breeding later in the more urban landscapes – a phenological shift that ultimately reduced reproductive produ (open full item for complete abstract)

Committee: Amanda Rodewald (Advisor); Tomas Koontz (Committee Member); Thomas C. Grubb, Jr. (Committee Member) Subjects: Ecology

Doctor of Philosophy, The Ohio State University, 2013, Entomology

Global climate change concerns have increased the need for multiple mitigation scenarios to reduce carbon dioxide (CO2) emissions. Strategic management of urban forests at different times and levels (e.g. nursery and landscape) can contribute to CO2 sequestration over time. Sustainable urban forests can therefore indirectly slow down the effects of climate change, emphasizing the need for increased research on different aspects of urban forest management. The goal of this multidisciplinary research was to investigate the patterns of carbon sequestration in urban forests in response to management practices at different levels over time. I investigated patterns of carbon storage and sequestration of urban street trees in the City of Wooster, Ohio, in response to tree planting and removal practices. Municipally owned street trees in Wooster acted as net sinks of atmospheric CO2 in 2010, as they increased rates of carbon storage and sequestration by 3% over 2009 in a city wide basis. The assessment of the economic value of environmental benefits provided by Wooster's street trees, including carbon storage and sequestration, energy conservation, stormwater remediation, air pollution removal, and aesthetic/other benefits exceeded $270,000 USD in 2010. I also investigated the effects of nursery production practices on resource allocation, carbon sequestration, physiological tree and insect responses of common urban shade trees, both in the nursery and after they were planted in the urban forest. Specifically, the effects of imidacloprid and fertilization regimes on growth, biomass allocation, and gas exchange responses of hybrid elm (Ulmus × `Homestead') and river birch (Betula nigra) were quantified while growing in the nursery. Overall, a positive trend towards greater growth and biomass allocation was observed for hybrid elm and river birch when treated with imidacloprid, but the effects were not significant, nor were thus gas exchange parameters. Fertilization impac (open full item for complete abstract)

Committee: Daniel Herms (Advisor); Luis Cañas (Committee Member); Mary Gardiner (Committee Member); Parwinder Grewal (Committee Member); Davis Sydnor (Committee Member) Subjects: Entomology; Urban Forestry