Graduate Theses & Dissertations

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Intra-seasonal Variation in Black Tern Nest-site Selection and Survival
Resources and risk are in constant flux and an organism’s ability to manage change may improve their likelihood of persistence. I examined intra-seasonal variation in nest-site selection and survival of a declining wetland bird, the Black Tern (Chlidonias niger surinamensis). I modelled nest site occupancy and survival of early and late-nesting birds as a function of static and dynamic factors. Early-nesting birds selected nest sites based on the degree and direction of habitat change that occurred over the nesting cycle, while late-nesting birds selected sites based on static conditions near the time of nest-site selection. Nest age had the strongest influence on daily survival rate for both early and late-nesting birds, but the shape of this relationship showed intra-seasonal differences. Additionally, early-season survival improved slightly with increasing vegetation coverage and distance between conspecific nests, while late-season survival increased with clutch size. My results suggest that intra-seasonal variation in nest-site selection and survival is driven by changing habitat conditions and predator behavior. Author Keywords: Black Tern, Chlidonias niger surinamensis, daily survival rate, intra-seasonal variation, nest-site selection
Impact of Agricultural Land Use on Bobolink Occurrence, Abundance, and Reproductive Success in an Alvar Landscape
Pastures and hayfields provide surrogate habitat for many declining grassland birds. Understanding agricultural land use dynamics and habitat quality can impact conservation of grassland species. I investigated 1) patterns of land use change in protected and unprotected sites in relationship to Bobolink occurrence in Carden, Ontario, Canada and 2) whether continuous grazing at lowmoderate cattle densities provided suitable breeding habitat, using both real and artificial nests. I replicated the 2001-2005 Ontario Breeding Bird Atlas to evaluate site habitat changes and Bobolink population trends. In continuously grazed pastures and late-cut hayfields, I monitored Bobolink abundance and reproductive success and modeled daily survival rate of nests using habitat management, vegetation structure, and prey availability. Results indicated that Bobolink have declined by -15.3% since 2001 in Carden; losses were explained almost entirely by changes from suitable breeding habitat (e.g. hayfields) to tilled land or by the colonization of shrubs. For pastures, stocking densities of ≤ 1Animal Units/ha did not negatively impact Bobolink. Year and caterpillar biomass, and vegetation height were the strongest predictors of nesting success in pastures and hayfields, respectively. Focus on the preservation of suitable habitat on the breeding grounds and management on small-scale beef farms can contribute to conservation action for this declining species. Author Keywords: agricultural management, avian ecology, Bobolink, continuous grazing, grassland birds, nest success
Using DNA Barcoding to Investigate the Diet and Food Supply of a Declining Aerial Insectivote, the Barn Swallow (Hirundo rustica)
Barn Swallow (Hirundo rustica) populations have declined in North America over the past 40 years and they are listed as Threatened in Ontario, Canada. Changes in the food supply have been hypothesized as a potential cause of this population decline. I used DNA barcoding to investigate the diet and food supply of Barn Swallows and to determine if the food supply affects their reproductive performance. In two breeding seasons, I monitored nests, collected fecal samples, and monitored prey availability by collecting insects from the habitat surrounding breeding sites using Malaise traps. I used DNA barcoding to identify insect specimens collected from the habitat and to identify prey items from Barn Swallow nestling fecal samples. I found that Barn Swallow nestlings were fed a very broad range of prey items but were fed larger prey items more frequently. Prey availability was not related to the timing of reproduction, the number of nests at a breeding site, or the reproductive output of individual nests. This study provides information on the diet composition of Barn Swallows in North America and suggests that food limitation during the breeding season may not be a major factor in their population decline. Author Keywords: aerial insectivore, diet, DNA barcoding, Hirundo rustica, metabarcoding, reproductive success
Using automated radio-telemetry to link food availability, reproductive success, and habitat use of Barn Swallows (Hirundo rustica erythrogaster)
Drivers of North American Barn Swallow population declines are not well understood, but foraging habitat loss is thought to be a contributing factor. Determining patterns of habitat use is challenging for swallows because they move rapidly but are too small to carry GPS tags. We showed that automated radio-telemetry could be used to track the movements of swallows with enough accuracy (median error 250 m) to monitor local habitat use. We then combined information on breeding Barn Swallows habitat use, land cover, aerial insect abundance, and fledging success to test for a link between foraging habitat quality and reproductive success. Foraging activity was concentrated within 600 m of nest sites and varied with land cover; however, responses to land cover were not consistent across birds. Aerial insects were most abundant near wetlands and least abundant near open water and over cropland. Consistent with a link between foraging habitat and reproductive success, nests in barns with more wetland and less open water within 1 km, and with less field area within 2 km occupied by row crops, on average fledged more young swallows. Author Keywords: aerial insectivores, automated telemetry, habitat use, land cover, movement, nest success
Scripted Sexual Beliefs and Behaviours
Sexual script theory suggests that sexual behaviours have social meaning, and that individuals perceive certain behaviours as normative and expected. Previous research has indicated that there is a common belief in a cultural sexual script for (hetero)sexual behaviour sequences (CSSHS). Study 1 compared perceived norms with behaviours in first ever penile-vaginal intercourse (PVI) sex events, as well as first and recent events with most recent partners. Many participants reported the CSSHS as typical, but few reported personal experiences that followed the CSSHS. Script adherence was not strongly related to physical pleasure. Study 2 found that committed relationships predicted greater female pleasure in first ever PVI sex. This link was mediated by communication during sexual activity. Results are discussed in the context of sexual script theory. Findings suggest that common scripted assumptions regarding PVI sex events should be reviewed for their value and representation of norms. Author Keywords: female pleasure, first sexual experiences, penile-vaginal intercourse, perceived norms, sexual behaviours, sexual script theory
Functional Investigation of A Ustilago maydis Xylose Metabolism Gene and its Antisense Transcripts
Ustilago maydis is a biotrophic fungal plant pathogen that causes ‘common smut of corn’ disease. During infection, U. maydis develops a metabolic dependency on its host, relying on uptake of the carbon molecules provided within Zea mays tissues. The research presented indicated a requirement for metabolism of the pentose sugar D-xylose through functional investigation of a U. maydis xylitol dehydrogenase (uxm1), an enzyme involved in the bioconversion of D-xylose. This work is the first to outline the importance of pentose metabolism during biotrophic plant pathogenesis, as U. maydis haploid cells lacking this gene were impaired in their ability to cause disease and grow on medium containing only D-xylose. This thesis also explored the possibility that expression of this carbon-related gene is controlled by antisense RNAs (asRNAs), endogenous molecules with complementarity to mRNAs. Previous investigation of U. maydis asRNAs identified some that are exclusively expressed in the dormant teliospore, suggesting they have a functional role within this cell-type. A subset of these asRNAs at the uxm1 locus were investigated, with the purpose of identifying the mechanism(s) by which they influence U. maydis pathogenesis. This investigation involved the creation and functional analysis of a series of U. maydis deletion and expression strains. Together, these findings provided additional knowledge regarding the possible functions of U. maydis asRNAs, and their involvement in controlling important cellular processes, such as carbon metabolism and pathogenesis. Author Keywords: antisense transcripts, fungal carbon metabolism, non-coding RNAs, pathogenesis, Ustilago maydis, xylitol dehydrogenase
Habitat use within and among roosts of chimney swifts (Chaetura pelagica)
Chimney swifts are listed as Threatened nationally and in many provinces within Canada due to rapid population declines. I examined large-scale spatial variation in the maximum size of chimney swift roosts at the northern edge of their range to identify where larger roosts occur. I used multi-sourced data collected across Ontario and Quebec between 1998 and 2013. I found that larger roosts were found at more northerly latitudes, and that very large roosts (>1000 birds) only occurred north of 45°. I also investigated fine-scale patterns of chimney swift positioning inside one of the largest roosts in Ontario. Using digitally recorded images, I calculated the angular position of swifts inside the roost relative to ambient and roost temperature. I found that swifts showed a strong preference for clinging to the south facing wall and clustered more when ambient air temperature was warmer. Thus, huddling in swifts provides additional or alternate benefits, other than serving purely to reduce costs of thermoregulation at low ambient temperatures. This research contributes to the understanding of chimney swift roosting ecology and identifies large roosting sites that should be retained for conservation. Author Keywords: chimney swift, communal roosting, conservation, group size, social thermoregulation, species-at-risk
Agriculture as Niche Construction
The Neolithic Period (c. 6200 – 4900 BC) in the Struma River Valley led to numerous episodes of cultural diversification. When compared with the neighbouring regions, the ecological characteristics of the Struma River Valley are particularly heterogeneous and the Neolithic populations must have adapted to this distinctive and localized ecological setting. It then becomes reasonable to ask if the evolution of cultural variability in the Struma River Valley was at least partially driven by the ecological setting and differentiation in the evolution of the early agricultural niche. In this thesis, I apply an approach based on niche construction theory and Maxent species distribution modeling in order to characterize the relationship between culture and ecology during each stage of the Neolithic Period and to assess diachronic change. An interpretation of the results demonstrates that the continuous reconstruction of the early agricultural niche allowed for settlement expansion into new eco-cultural niches presenting different natural selection pressures and that cultural change followed. I also found that cultural and historical contingencies played an equally important role on the evolution of populations and that ecological factors alone cannot account for the numerous episodes of cultural diversification that occurred throughout the region. Author Keywords: Agriculture, Bulgaria, Eco-cultural Niche Modeling, Greece, Neolithic, Niche Construction
relationship of policy aims and implementation
Background: Ontario’s Ministry of Health and Long Term Care (MOHLTC) claims people with mental illnesses/addictions need improved care/overuse emergency departments. MOHLTC expects Coordinated Care Planning (CCP, teams of mental/physical health professionals, social workers and informal caregivers) to improve care and lower emergency department returns/healthcare costs. CCPs are directed by policies, Smith’s “problematics,” or Deleuze’s “expressions,” supposedly reflecting “contents”/“everyday worlds.” Research Question: How do Ontario health/allied professionals come together with a person with mental illness/addictions and informal caregiver(s) to address health needs through a CCP? Method: 1) Analyzed CCP policies; generated questions about creation/implementation. 2) Interviewed eight professionals about interpreting/enacting policies. 3) Connected interview data to policies. Findings: Opportunities for fragmentation exist in gaining consent; determining eligibility; persons in care, informal caregivers and professionals’ participation; person-centeredness; “shame-free” environments; health literacy; records of medications. Conclusion: CCP participants need to minimize fragmentations which takes time, space, money; creates contradictions in lowering costs/improving care. Author Keywords: Addiction, Dual Diagnosis, Health Care Policy, Institutional Ethnography, Integrated Health Care, Mental Illness
wind tunnel and field evaluation of the efficacy of various dust suppressants
A series of experiments was designed to assess the relative efficacy of various dust suppressants to suppress PM10 emissions from nepheline syenite tailings. The experiments were conducted in the Trent University Environmental Wind Tunnel, Peterborough, Ontario, and on the tailings ponds at the Unimin Ltd Nephton mine near Havelock, Ontario. Treated surfaces were subjected to particle-free airflow, abrasion with blown sand particles, particle-free airflow after physical disturbance, and were measured independently using a pin penetrometer. In the particle-free wind tunnel tests, three of the surfaces performed well, and PM10 emissions scaled inversely with crust strength. Light bombardment of each surface by saltating sand grains resulted in PM10 emission rates two orders of magnitude higher. All treated surfaces emitted significantly more PM10 after physical disturbance in both the laboratory and field research. The results suggest that the site conditions, inclusive of the potential for dust advection and resuspension, must be taken into account when considering the use of a commercial dust suppressant. Author Keywords: dust suppression, field testing, mine tailings, wind tunnel experiment
Time to adapt
To better understand species’ resilience to climate change and implement solutions, we must conserve environments that maintain standing adaptive genetic variation and the potential generation of new beneficial alleles. Coding trinucleotide repeats (cTNRs) providing high-pace adaptive capabilities via high rates of mutation are ideal targets for mitigating the decline of species at risk by characterizing adaptively significant populations. Ultimately, adaptive genetic information will inform the protection of biological diversity below the species level (i.e., “Evolutionarily Significant Units” or “ESUs”). This dissertation investigates cTNRs within candidate genes to determine their prevalence and influence under selection in North American mammals. First, I evaluated the potential for somatic mosaicism in Canada lynx (Lynx canadensis), and found that tissue-specific mosaicism does not confound cTNR genotyping success in lynx. Second, I assessed a selection of clock gene cTNRs across characterized mammals and found that these repeats are abundant and highly variable in length and purity. I also identified preliminary signatures of selection in 3 clock gene cTNRs in 3 pairs of congeneric North American mammal species, highlighting the importance of cTNRs for understanding the evolution and adaptation of wild populations. I further evaluated the influence of selection on the NR1D1 cTNR within Canada lynx sampled across Canada using environmental correlation, where I estimated the variation in NR1D1 cTNR alleles explained by environmental and spatial variables after removing the effects of neutral population structure. Although most variation was explained by neutral structure, environment and spatial patterns in eastern lynx populations significantly explained some of the variation in NR1D1 alleles. To examine the role of island populations in the generation and distribution of adaptive genetic variation, I used 14 neutral microsatellites and a dinucleotide repeat within a gene linked to mammalian body size, IGF-1, and found that both genetic drift and natural selection influence the observed genetic diversity of insular lynx. Finally, I estimated the divergence dates of peripheral lynx populations and made recommendations towards the conservation of Canada lynx; high levels of genetic differentiation coupled with post-glacial colonization histories and patterns of divergence at cTNR loci suggest at least 4 ESUs for Canada lynx across their range. Author Keywords: adaptation, Canada lynx, candidate genes, coding trinucleotide repeats, evolution, natural selection
Code of Bimadiziwin
Indigenous peoples and organizations have a long history of incorporating cultural knowledge and teachings into program and organizational design and structure. The approach to incorporating cultures into Indigenous organizations is not uniform, nor is the ways that they are understood. This dissertation focuses on Nogojiwanong Friendship Centre, in Peterborough Ontario and their approach to incorporating Indigenous cultures into their organization from 2010-2014. The intention of this dissertation is to build knowledge of Indigenous perspectives of organizational structure, grounded in Anishinabe teachings. The teaching circle, vision- time – feeling –movement, guides my learning process and the structure of the dissertation. In using an Anishinabe framework the importance of relationships and the Anishinabe clan system are foundational to my understanding, and will be discussed at length. The purpose and goal of this research is twofold. First, to show the complexity, intentionality and depth to an Indigenous research process; a process that is often nuanced in the literature. Second, to show how Anishinabe thought can (and does) provide a framework for a service delivery organization, in its governance and program and service delivery. The thesis of this dissertation is that Anishinabe knowledge is not always visible to outsiders, but it was present at Nogojiwanong Friendship Centre in the ways they approached research, governed themselves and delivered programs and services. Key Words: Indigenous Knowledge, Indigenous Governance, Indigenous Research Ethics, Indigenous Research Framework Author Keywords: Indigenous Governance, Indigenous Knowledge, Indigenous Research Ethics, Indigenous Research Framework

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1974 - 2024
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Format: 2024/03/29