Master of Science (MS), Bowling Green State University, 2013, Biological Sciences

Species are threatened daily by human activities, the most devastating of which are habitat destruction and fragmentation, which can drastically decrease population size. One of the most severe consequences of these decreases in population sizes is the decrease in genetic diversity, which may affect fitness and reduce the adaptive potential of natural populations. These consequences, however, may not affect all species equally due to their past evolutionary history, migratory habits, and current demographic factors. This study focuses on the potential role of migratory habit on the maintenance of genetic diversity of avian species that live in a fragmented habitat. The mitochondrial control region sequences of six Passerine species that breed within the Oak Openings area of Northwest Ohio were compared based upon the species' migratory habit while controlling for the effects of phylogenetic history. Consistent with results from previous studies, species that migrate long distances showed higher levels of genetic diversity (higher numbers of haplotypes and average p-distance) than species that do not migrate. An analysis of variance based on within-population estimates of DNA sequence variation revealed a significant contribution of both phylogenetic history and migratory habit to species' genetic diversity. Overall, 50.72% of the total variation observed across multiple species could be explained by differences in migratory habit. These results emphasize the important role of migratory habit in determining overall levels of genetic diversity, an important consideration for the management and conservation of species that breed within fragmented habitats.

Committee: Juan Bouzat (Advisor); Gabriela Bidart-Bouzat (Committee Member); Scott Rogers (Committee Member) Subjects: Animals; Biology; Conservation; Genetics; Wildlife Conservation

Master of Science, The Ohio State University, 2012, Environment and Natural Resources

Animal communication systems, which rely upon complex cognitive behavior, specific social contexts, and environments that permit effective transmission, are vulnerable to disruption by anthropogenic disturbance. Forests in urban landscapes are known to differ from rural forests in terms of vegetation, avian communities, and anthropogenic noise. Although these urban-associated differences can elicit demographic consequences, little is known about sub-lethal behavioral effects. Recent studies have implicated anthropogenic noise as a cause of changing bird song in urban areas; however, few have considered alternative explanations, nor the evolutionary and ecological consequences of altered songs. I investigated song variation in an urban landscape by asking the following questions: 1) How do the structural and behavioral components of bird song change across a rural-urban landscape gradient? 2) Which aspects of urbanization best predict changes in song properties? and 3) Does urbanization alter relationships among song, indicators of fitness and male quality? I investigated these questions by recording vocal behavior and monitoring the breeding activity of individually-marked male Northern Cardinals (Cardinalis cardinalis) at nine sites distributed across riparian forests within a rural to urban landscape gradient in central Ohio. Forests within urban versus rural landscapes differed ecologically so that urban forests had greater densities of conspecifics, denser understory vegetation with greater numbers of large trees, louder ambient noise (primarily from traffic), and smaller birds than more rural forests. As expected, cardinal song also changed with urbanization, with songs becoming longer, faster and with higher minimum, maximum and peak frequencies (Hz) as urbanization increased. Ambient noise at the territory level explained shifts in minimum frequency, whereas changes in conspecific densities best explained temporal variation in song structure (e.g., length an (open full item for complete abstract)

Committee: Amanda D. Rodewald PhD (Advisor); Douglas A. Nelson PhD (Committee Member); Mazeika S.P. Sullivan PhD (Committee Member) Subjects: Ecology

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

Master of Science, The Ohio State University, 2008, Natural Resources

Because park managers must balance the competing interests of conservation and recreational uses of parks in urban areas, consideration must be given to the potential consequences of human disturbance to breeding birds. The central purpose of this study was to determine the extent to which trails affect nest predation and evaluate possible causes. Specifically, I tested the following three hypotheses about the impacts of human use of trails on breeding birds: 1) Human use of trails in urban forests reduces nest survival by reducing parental attendance rates, thereby leaving nests more vulnerable to predation; 2) Relationships between nest survival and trails derive from modified vegetation surrounding a nest, and these changes in habitat drive trail-related impacts on breeding birds; 3) Human use of trails in urban forests influences the sensitivity of breeding birds to disturbance and induces changes in nest placement through habituation and inherent individual differences. From April to August 2006 and 2007, I monitored the fate of 263 Northern Cardinal nests and quantified vegetation structure and composition around nests and at random plots within riparian forests in central Ohio. Trail cameras were utilized at 6 sites to estimate the amount of human recreational activity. One hour parental attendance observations were conducted at 125 nests to estimate variation in nest attendance. Two experimental trials were conducted on 63 nests recording Flight Initiation Distance (FID) as each nest was approached either directly or along a trail. In addition, FID was collected during routine nest checks where the nest was approached directly (n = 160). Results showed that birds were 6x more likely to flush when the nest was approached directly than when an observer passed along a trail. Nest height mediated the tendency to flush somewhat, as higher nests were less likely to flush, but flush tendency was not related to distance to trail. Interestingly, the distance at which (open full item for complete abstract)

Committee: Amanda Rodewald PhD (Advisor); Stanley Gehrt PhD (Committee Member); Virginie Bouchard PhD (Committee Member) Subjects: Ecology

Doctor of Philosophy, The Ohio State University, 2006, Evolution, Ecology, and Organismal Biology

West Nile virus (WNV) is a single-stranded RNA virus in the family Flaviviridae that first appeared in North America in 1999, and in Ohio in 2001. From 2002 to 2005, I examined the patterns of WNV antibody seroprevalence in Northern Cardinals (Cardinalis cardinalis), the ability of female cardinals to pass WNV antibodies to their offspring, the fitness consequences of a previous WNV infection, and the role of innate immunity in response to infection. Over the three years of the study, WNV antibody seroprevalence was 36% in female cardinals, and 21% in male cardinals. Most females lost antibodies after one year. In three summers, 44 female cardinals produced 59 nests with fledglings. Thirty of the females were seronegative, 13 were seropositive, and one was seropositive in the last of three years. None of these birds raised a seropositive nestling, and none of 23 other nestlings tested positive for WNV IgM antibodies. Although survival measures for female cardinals were slightly higher for seronegative than seropositive birds, there was no significant effect of seroprevalence on cardinal survival. Previous WNV infection also did not significantly influence the percentage of females fledging at least one nestling. Seropositive females, however, had half as many nestlings as seronegative females (0.90 ± 0.26 vs. 1.71 ± 0.24), and fledged half as many young as seronegative birds (0.84 ± 0.18 vs. 1.64 ± 0.23). These results suggest that female cardinals who survive WNV infection trade their survival for some reproductive success. In a related study of Downy Woodpeckers (Picoides pubescens), I found that wintering birds provided with supplemental food had greater ability to kill bacteria than unsupplemented birds. The ability to kill bacteria significantly decreased through the winter. Because innate immunity is crucial in the immune response to WNV, the results suggest that birds under greater energy stress may have a reduced immune response to WNV infection. The results (open full item for complete abstract)

Committee: Thomas Grubb, Jr. (Advisor) Subjects: