Graduate Theses & Dissertations


Shorebird Habitat Use and Foraging Ecology on Bulls Island, South Carolina During the Non-Breeding Season
Recent declines in North American shorebird populations could be linked to habitat loss on the non-breeding grounds. Sea-level rise and increased frequency of coastal storms are causing significant erosion of barrier islands, thereby threatening shorebirds who rely on shoreline habitats for foraging. I conducted shorebird surveys on Bulls Island, South Carolina in the winters of 2018 and 2019 and examined habitat selection and foraging behaviour in Dunlin (Calidris alpina), Sanderling (Calidris alba), Semipalmated Plovers (Charadrius semipalmatus), and Piping Plovers (Charadrius melodus). Area, tidal stage, and invertebrate prey availability were important determinants of shorebird abundance, behaviour, and distribution. My study highlights the importance of Bulls Island’s habitat heterogeneity to supporting a diverse community of non-breeding shorebirds. Considering both the high rate of erosion and the increased frequency of disturbance along the shoreline of the island, intertidal habitats should be monitored to predict negative effects of changes in habitat composition and area on non-breeding shorebirds. Author Keywords: foraging behaviour, habitat loss, habitat selection, invertebrate prey, non-breeding, shorebirds
Discriminating grey wolf (Canis lupus) predation events in a multi-prey system in central Saskatchewan
I investigated if spatio-temporal behaviour of grey wolves (Canis lupus) determined via GPS collar locations could be used to discriminate predation events generally, and among prey species, in Prince Albert National Park during winter, 2013-2017. I used characteristics of spatio-temporal GPS clusters to develop a predictive mixed-effect logistic regression model of which spatial clusters of locations were wolf kill sites. The model suffered a 60 % omission error when tested with reserved data due to the prevalence of deer kills with correspondingly low handling time. Next, I found a multivariate difference in the percentage of habitat classes used by wolves in the 2 hours preceding predation events of different prey species, suggesting that wolf habitat use reflects prey selection at a fine-scale. My results highlight the difficulty and future potential for remoting discriminating wolf predation events via GPS collar locations in multi-prey ecosystems. Author Keywords: Canis lupus, GPS clusters, GPS collars, grey wolf, habitat use, predation
multi-faceted approach to evaluating the detection probability of an elusive snake (Sistrurus catenatus)
Many rare and elusive species have low detection probabilities, thereby imposing unique challenges to monitoring and conservation. Here, we assess the detection probability of the Eastern Massasauga (Sistrurus catenatus) in contrast to a more common and conspicuous species, the Eastern Gartersnake (Thamnophis sirtalis). We found that patterns of detection probability differed between species, wherein S. catenatus was detected less often and under a more specific set of sampling conditions. Correspondingly, detection trials with S. catenatus found a high non-detection rate, while detection trials with artificial models suggest that regional differences in detection probability are driven by variation in population density and habitat use. Our results suggest that current monitoring efforts are not sufficient, and that S. catenatus is frequently undetected. Accordingly, we highlight the importance of species-specific monitoring protocols when monitoring rare and elusive species, and recommend a multi-faceted approach that estimates detection probability and identifies species-specific challenges to monitoring. Author Keywords: detection probability, elusive species, monitoring programs, non-detection, S. catenatus, snakes
Pervert’s New Statesman
Justice Weekly was a tabloid published in Toronto from 1946 to 1972. The popular narrative is that it was an unremarkable, obscure, and pornographic paper which was co-opted by gay and homophile voices in the 1950s. But why did a magazine best remembered, as Mordecai Richler put it, as “the pervert’s new statesman” publish this material? This thesis argues that Justice Weekly really was primarily about Justice, rather than titillation. The paper explored justice through topics such as juvenile delinquency and spanking, which allowed sexualized material to appear, as well as conversations surrounding gay men, race, criminality, and punishment. While the paper outed gay men and often argued for harsher prison conditions, it also published material from Canada’s earliest gay activists and prisoner presses. Justice Weekly’s focus on equitable justice allowed both sex and advocacy to emerge from its content. Author Keywords: Delinquency, Homosexuality, Jim Egan, Pornography, Pulp, Tabloid
That '70s Strike Support
This thesis examines three Ontario strikes during the 1970s: the Dare Foods, Ltd. strike in Kitchener, Ontario, 1972-1973; the Puretex Knitting Company strike in Toronto, 1978-1979; and the Inco strike in Sudbury, 1978-1979. These strikes highlight gender issues in the Canadian food production, textile, and mining industries in the 1970s, industries that were all markedly different in size and purpose, yet equally oppressive towards working women for different reasons, largely based on the regional character of each city the strikes took place in. In Kitchener, the women’s movement worked closely with the Dare union local and the left to mobilize against the company and grappled with the difficulties of framing women’s inequality within the labour movement. At Puretex, immigrant women workers were subject to electronic surveillance as a form of worker control, and a left-wing nationalist union needed to look outside of the Canadian Labour Congress (CLC) for allies in strike action. At Inco, an autonomous women’s group formed separate from the United Steelworkers of America (USWA) but struggled to overcome a negative perception of women’s labour activism in Sudbury. Ultimately, these strikes garnered a wide variety of support from working women and feminist groups, who often built or had pre-existing relationships with Canadian and American trade unions as well as the left-wing milieu of the 1970s. This thesis uses these strikes as case studies to argue that despite the complicated and at times uneven relationship between feminism, labour, and the left in the 1970s, feminist and left-wing strike support was crucial in sustaining rank-and-file militancy throughout the decade and stimulating activist careers for women in the feminist movement, in unions, and on the left. Author Keywords: 1970s, feminism, labour, left-wing, militancy, working-class
Effects of Local, Landscape, and Temporal Variables on Bobolink Nest Survival in Southern Ontario
Populations of grassland birds, including the Bobolink (Dolichonyx oryzivorus), are experiencing steep declines due to losses of breeding habitat, land use changes, and agricultural practices. Understanding the variables affecting reproductive success can aid conservation of grassland species. I investigated 1) whether artificial nest experiments accurately estimate the impacts of cattle on the daily survival rate of Bobolink nests and 2) which local, landscape, and temporal variables affect daily survival rate of Bobolink nests in Southern Ontario. I replicated an artificial nest experiment performed in 2012 and 2015 to compare the daily survival rate of artificial and natural nests at multiple stocking rates (number of cattle × days × ha-1). I also monitored Bobolink nests and modeled daily survival rate using local variables (e.g., stocking rate, field use, patch area), landscape variables (e.g., percent forest within 2, 5, and 10 km), and temporal variables (e.g., year, date of season). Results indicate that artificial nest experiments using clay shooting targets overestimated the impacts of stocking rate on the daily survival rate of Bobolink nests. With natural nests, region (confounded by year and field use), stocking rate, and date of season were the strongest predictors of daily survival rate; with stocking rate and date of season both having a negative effect. Management should focus on conserving pastures with low stocking rates (< 40 cattle × days × ha-1), late-cut hayfields, fallow fields, and other grasslands to protect breeding grounds for the Bobolink and other declining grassland bird species. Author Keywords: Bobolink, Daily survival rate, landscape variables, local variables, Nest survival, temporal variables
Impaired contextual fear discrimination learning after long-term amygdala kindling
Cognitive impairments, such as memory loss, are a frequent and devastating co-morbidity associated with epilepsy. The neurobiological mechanisms through which recurrent seizures induce cognitive impairments are not well understood. New neurons born after seizures develop abnormal morphological and functional characteristics that promote network hyperexcitability and hippocampal dysfunction. Previously, we found that kindling dramatically increases the rate of neurogenesis at early stages of seizure development, followed by a long-term suppression at later stages. These changes in the rate of cell proliferation coincides with aberrant modifications in the migration, excitability, and functional integration of these new neurons. It has been suggested that the long-term consequences of seizure-induced neurogenesis contributes to the development of cognitive impairment seen in chronic epilepsy. However, direct experimental evidence has been limited. The present series of experiments sough to determine if blocking aberrant seizure-induced neurogenesis can reduce cognitive deficits associated with chronic epilepsy. Our findings suggest that chronic seizures impair the ability of rats to differentiate between similar contexts. In addition, blocking aberrant seizure-induced neurogenesis through treatment with the cytotoxic agent temozolomide was capable of preventing some of the deficits in context discrimination learning when neurogenesis levels were reduced to non-epileptic control levels. This research provides further support of targeting aberrant neurogenesis as a novel treatment to restore cognitive functioning in individuals living with epilepsy. Author Keywords: Amygdala kindling, Dentate gyrus, Hippocampus, Neurogenesis, Pattern separation, Seizures
Is semantics activated automatically? Evidence from the PRP paradigm
Three experiments examined whether semantics is activated automatically by testing whether Arabic digits (e.g., 4), number words (e.g., four), and non-number words (e.g., rat) activate semantics in the absence of central attention within the Psychological Refractory Period (PRP) paradigm. In all three experiments, subjects performed colour discriminations as Task 1. In Task 2, subjects performed magnitude comparisons on digits (Experiment 1) and number words (Experiment 2) and size comparisons on animal words (Experiment 3). Task overlap was controlled by varying stimulus onset asynchrony (SOA). A distance effect arose in Task 2 and yielded underadditive effects with decreasing SOA for both digits and number words, consistent with these notations activating semantics in the absence of central attention, or automatically. A distance effect also arose for animal words, but it was additive with SOA, inconsistent with non-number words activating semantics automatically. Author Keywords: Automaticity, Central attention, Dual-task, Numerical cognition, Semantics, Word recognition
Representation Learning with Restorative Autoencoders for Transfer Learning
Deep Neural Networks (DNNs) have reached human-level performance in numerous tasks in the domain of computer vision. DNNs are efficient for both classification and the more complex task of image segmentation. These networks are typically trained on thousands of images, which are often hand-labelled by domain experts. This bottleneck creates a promising research area: training accurate segmentation networks with fewer labelled samples. This thesis explores effective methods for learning deep representations from unlabelled images. We train a Restorative Autoencoder Network (RAN) to denoise synthetically corrupted images. The weights of the RAN are then fine-tuned on a labelled dataset from the same domain for image segmentation. We use three different segmentation datasets to evaluate our methods. In our experiments, we demonstrate that through our methods, only a fraction of data is required to achieve the same accuracy as a network trained with a large labelled dataset. Author Keywords: deep learning, image segmentation, representation learning, transfer learning
To Sext or Not to Sext
The risks and benefits of sexting within an intimate relationship were explored. The present study focused on sexual gratification, relationship benefits, and sexual communication as benefits and risky sexual behaviour, unethical forwarding, and infidelity as risks. A cross-sectional online survey of both undergraduate students and a community sample was used. Results indicated that sexual gratification, relationship benefits (sexual and relationship satisfaction, relationship quality, and commitment), and sexual communication are related to sexting. It appears that risky sexual behaviour is not associated with sexting, instead those who sext frequently engage in more safer sex behaviours than those who sext infrequently. Unethical forwarding does not appear to happen very often in the context of intimate relationships. Lastly, the current research indicates that some participants are sexting secondary partners, and many consider sexting secondary partners infidelity. These results show that there are both risks and benefits of sexting, which can be used to develop sext education and therapeutic programs. Author Keywords: infidelity, relationship benefits, Sexting, sexual behaviour, sexual communication, sexual gratification
Neolithic Resource Use and Adaptation in the Eastern Gobi Desert
Stone axes and adzes first appeared in the eastern Gobi Desert at 8.0 cal BP and were incorporated into the technological package. At the same time, changes in local ecological conditions reflect a transition from continuous grass/shrub-steppe across the Mongolian Plateau to the development of dispersed patches of dune-field wetland oases and high-elevation forests. This thesis focuses on exploring the adoption and function of axes and adzes in the eastern Gobi Desert and their relationship to the development of these new forested ecologies. Using an experimental and use-wear approach, I analyze 29 axes and adzes from four sites in the eastern Gobi Desert of Mongolia and Inner Mongolia. Results indicate that axes and adzes were primarily used for woodworking but include other activities. Furthermore, the adoption and manufacture of axes and adzes represent an increasing investment in producing formal technologies as resources within these new diverse ecological patches were intensively utilized. Author Keywords: Adaptation, Axes and Adzes, Eastern Gobi Desert, Neolithic, Technological Intensification, Use-Wear
Perceive Me, Perceive You
The use of threats to feelings of intimacy and belonging, also known as relational aggression, has been previously explained using attachment representations and attributions in childhood. However, the combined role of attachment representations and attributions in explaining relational aggression in adult peer and romantic relationships has been unexplored. This study tested the associations between attachment, attributions, and relational aggression with a specific focus on the mediating role of attributions. A final sample of 258 undergraduate university students completed self-report surveys and vignettes to measure the variables of interest. Results suggested that attachment predicted relational aggression but, with one exception, attributions did not explain unique variance in relational aggression after controlling for attachment. Interestingly, hostile attributions mediated the relationship between dismissing attachment to romantic partners and romantic relational aggression. Therefore, individuals‘ attachment representations directly influenced their levels of relational aggression in relationships regardless of their attributions. Author Keywords: Adulthood, Attachment, Attributions, Mediation, Relational Aggression


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