Graduate Theses & Dissertations

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Range dynamics of two closely related felids
Species ranges are changing and the rate at which the climate is warming is faster than anything previously seen in the past, consequently species will need to adapt quickly, track the climate or perish. Cold adapted terrestrial species are the most vulnerable, because they are limited by the availability of land at the cold edge of their range. This means that many alpine, boreal and polar species essentially have nowhere to go as the climate warms. Habitat generalists are widely distributed across the globe and are highly adaptable to anthropogenic change. Our future biodiversity may only consist of several habitat generalists. The Canada lynx (Lynx canadensis) is a boreal species that has limited range expansion potential at the cold end of its range and its range has already contracted by 40%. The lynx has nowhere to go as climate warming progresses in this current century. Therefore, understanding the causes of its range contraction could enlighten us on conservation and management strategies that we might undertake as climate warms. My analyses indicated that the Canada lynx seems to have tracked the habitat that it is adapted to in more northern homogenous boreal forests and the bobcat (Lynx rufus), a habitat generalist, has simply replaced it in the south. Author Keywords: Anthropogenic Change, Competition, Connectivity, Lynx canadensis, Lynx rufus, Range change
Breeding Phenology and Migration Habits of Whimbrel (Numenius phaeopus) in the Hudson Bay Lowlands, Canada
Understanding breeding and migration habits of Whimbrel (Numenius phaeopus) in the Hudson Bay Lowlands is important for the conservation of this population. I monitored Whimbrel at two breeding sites: the Churchill region of Manitoba and Burntpoint, Ontario. Annual average nest initiation timing was highly variable and successful nests were initiated significantly earlier than those that failed. Although nests were initiated significantly earlier at Burntpoint than Churchill, annual nest success quantified in program R MARK was similar across sites. Observed nest success rates were lower than historical records and most failure was due to predation. Annual nest survival varied widely and I used a generalized linear model to relate annual nest survival to annual average weather conditions. I observed weak relationships between annual nest survival and weather conditions in the northbound staging grounds. I tracked post-breeding migratory movements using the MOTUS radio telemetry system and observed consistent use of the mid-Atlantic coast of the United States during migration, especially among birds emerging from Churchill. In Burntpoint, I observed more variability in post-breeding migratory trajectories and significantly earlier post-breeding departure as compared to Churchill. The results of my study suggest differences in breeding and migration habits exist across nearby breeding populations, indicating that there is a need for population-specific conservation approaches for this declining species. Author Keywords: Migration, Movement Ecology, Nesting Ecology, Nest Success, Shorebird conservation, Whimbrel
Passage population size, demography, and timing of migration of Red Knots (Calidris canutus rufa) staging in southwestern James Bay
Many shorebirds rely on small numbers of staging sites during long annual migrations. Numerous species are declining and understanding the importance of staging sites is critical to successful conservation. We surveyed endangered rufa Red Knots staging in James Bay, Ontario during southbound migration from 2009 to 2018. We used an integrated population model to estimate passage population size in 2017 and 2018 and found that up to 27% of the total rufa population staged in James Bay. We also extended the model to incorporate age composition of the passage population. In future applications, this method could improve our understanding of the role of breeding success in population declines. We then estimated annual apparent survival from 2009 to 2018. Survival remained near constant, though lower than estimated elsewhere in the Red Knot range, which may reflect higher permanent emigration rates rather than truly lower survival. This work demonstrates that this northern region is a key staging site for endangered Red Knots and should be included in conservation planning. Author Keywords: integrated population model, mark-recapture, migratory stopover, shorebirds, species at risk, survival
Effect of Aging and Movement Variability on Motor Adaptation
Aging is associated with a multitude of changes, including changes in the motor system. One such change that has been documented is increased levels of inherent movement variability (the inability to consistently replicate movements over time) with increasing age. Previous research has had controversial findings regarding the effect that movement variability has on motor learning and motor adaptation. Some research suggests that movement variability is beneficial to motor learning, while other research indicates that movement variability is the by-product of a noisy motor system and is a detriment to learning new skills. How do changes in movement variability associated with aging affect the ability to adapt to a mass perturbation? We tested younger and older individuals on a mass adaptation task (applying mass to the lateral side of the arm to perturb inertial forces of the limb during reaches). We analyzed baseline levels of movement variability, learning during the adaptation block and how baseline levels of movement variability explained differences in learning. We focused on measures of accuracy, speed and precision. We found that younger individuals displayed greater levels of movement variability throughout the experiment and that they also learned to adapt to the mass perturbation more successfully than their older counterparts. Multi-joint movements displayed greater degrees of learning in comparison to single-joint movements, likely due to the difference in difficulty when completing the two movements. Taken together, our results suggest that purposeful movement variability may be beneficial to motor adaptation. Author Keywords: aging, mass adaptation, motor adaptation, motor learning, movement variability
This Is It, I Guess
Queer youth are an at-risk group, with an incredibly high rate of harm and death as they grow into themselves. They are often advised to wait until they finish school to express their sexuality more openly, when they can leave to somewhere that is “better”, which in this context can mean safer, more accepting, or far away from friends and family who may reject them. Unfortunately, much of the media representation of queer people is regressive or stereotypical, usually involving the suffering or death of its queer-identified characters. It is telling that a recurring theme in queer stories is that empathy and understanding for queer people can only be attained through their suffering. Non-queer people do not have to suffer to be understood. In this thesis I discuss the potential of creativity in academic works, I examine queer stories that buck the trend of tragedy through queer and pop culture theory, and I write a queer young adult novel in response, featuring a self-actualized protagonist whose sexuality does not cause him pain or trauma. Author Keywords: creative writing, queer literature, queer protagonist, queer theory, queer youth, young adult literature
Enhancing interpretive trails with technology
Enhancing interpretive trails with smartphone technology may enrich the visitor’s educational experience by stimulating deeper engagement and enjoyment that will improve immediate knowledge and help promote the development of environmental literacy. This connection between technology and environmental education can only be considered successful if enhanced enrichment and educational value is found in the integration. Currently there is a substantial gap in research on the incorporation of technology into an interpretive trail experience. For this study, information on the local fauna and flora was produced and linked to Quick Response Codes (QR codes) installed along an outdoor trail. The QR codes were designed to be read using the participant’s personal smartphone. Immediately after completing the trail participants could volunteer to describe their smartphone-led experience through a self-administered cross-sectional questionnaire offered in hard copy at the study site. A non-experimental quantitative research methodology was employed to evaluate the survey data and determine the educational and enjoyment value of the experience. This research is of potential benefit to educators of science, technology and the environment. The research may also assist parks and recreation facilities wishing to offset the costs of building and maintaining traditional interpretive trails by eliminating the need for the printing of booklets, maps and signage. Author Keywords: education, environment, interpretive trails, science, smartphone technology
What Nature is Best?
Connecting with nature benefits human and environmental health, however it is unclear whether certain types of nature influence people differently. Research has primarily focused on green spaces (vegetation-rich areas), but recent cross-sectional studies suggest that green spaces with blue space (natural water elements) may have additional well-being benefits. A quasi-experimental design compared the effects of green spaces with or without water on mood and environmental concern. Students (N = 193) were randomly assigned to walk along campus green (drumlin) or blue (river) spaces. Both walks improved students’ mood, especially for those who had a stronger preference for the area. Students in both conditions reported more sustainable behaviours when followed up one week and one month later, but decreased in nature contact and well-being. These findings highlight the challenges of promoting regular nature contact as a mood regulation strategy. Implications and future directions are discussed. Author Keywords: blue space, green space, nature connectedness, well-being
Effects of Recycled Media on Culture Growth and Hormone Profiles in Heterotrophic Euglena gracilis
The rapid expansion of the worldwide population has caused an urgent need for the development of new, more environment-conscious, food sources. In this context, algae, such as Euglena, are of interest thanks to their capacity to naturally produce essential nutrients such as proteins and oils commonly found in animals and plant sources. While these processes are currently being investigated, underlying measures affecting growth of Euglena gracilis like hormonal influences and growth stress like nutrient deprivation are poorly understood. From this vantage point, this thesis seeks to understand the role of phytohormones cytokinin (CKs) and abscisic acid (ABA) in complex mechanisms underlying heterotrophic growth of Euglena gracilis under recycled, organic media conditions with no supplementation. Hormone profiles were quantified by HPLC-ESI-MS/MS and compared to culture growth dynamics of pH, weight accumulation, glucose content, cell count and morphology. It was expected that ABA acted as an inhibitory hormone and this was confirmed by its higher levels when CKs where low and vice versa. Contrastingly, it was expected that CKs stimulated growth, in which this was shown not to be the case. Interestingly, it was revealed that both hormone groups increase with increasing recycling. Other key findings include: E. gracilis synthesizes CKs via the tRNA-degradation pathway and is cZ and iP dominated, recycling E. gracilis medium is viable for growth, however, the percentage (25% or less) is crucial to cell viability and markedly no ABA was detected in E. gracilis pellet fractions from recycled media. Therefore, this data revealed that recycled media has a striking influence on physiological aspects of growth and illustrated unique changes in hormone profiles of which could be manipulated to help the food industry. Author Keywords: cytokinin, endogenous hormones, Euglena gracilis, heterotrophic, large scale microalgae cultivation, recycled medium
Problem Solving as a Path to Understanding Mathematics Representations
Little is actually known about how people cognitively process and integrate information when solving complex mathematical problems. In this thesis, eye-tracking was used to examine how people read and integrate information from mathematical symbols and complex formula, with eye fixations being used as a measure of their current focus of attention. Each participant in the studies was presented with a series of stimuli in the form of mathematical problems and their eyes were tracked as they worked through the problem mentally. From these examinations, we were able to demonstrate differences in both the comprehension and problem-solving, with the results suggesting that what information is selected, and how, is responsible for a large portion of success in solving such problems. We were also able to examine how different mathematical representations of the same mathematical object are attended to by students. Author Keywords: eye-tracking, mathematical notation, mathematical representations, problem identification, problem-solving, symbolism
Forensic Epistemology
Forensic epistemology is the study of knowledge as it relates to forensic science and can be broken into four sources; intuitive, authoritative, logical and empirical. In a four-phase research approach, I explored reasoning skills (logical knowledge) used by crime scene experts and methods (empirical knowledge) for forensic case-specific experimentation. First, the reasoning skills of crime scene investigators (CSI) and bloodstain pattern analysts (BPA) were tested, correlated to demographics and reasoning categories were compared. Practitioner’s with graduate level education performed better on the reasoning test, however, significant differences were not found between test scores and years of experience. Similarly, there was no difference between test scores and employment status (specifically, police or civilian employees), for the CSI group nor within the BPA group. This information suggests that level of education plays the most important role in the development and use of reasoning skills, whereas experience and employment status are not as influential. Second, I investigate potential strategies in selecting data types for case-specific experimentation in pattern-interpretation disciplines within forensic science. I also examined the epistemic status of practitioner case experimentation in forensic science. Practitioners were more confident in a mixed-method approach when conducting case-specific experimentation. In addition, there is a knowledge gap in experimental design for some forensic practitioners. Third, is a reprint of the introductory section of my published book entitled The Scientific Method in Forensic Science: A Canadian Handbook that abridges knowledge gained from this dissertation with further evidence-based literature review and experiential examples. This phase summarizes the scientific method in forensic science and provides guidance for forensic science students and practitioners. The final phase merges the findings from the primary studies with a literature review; offering scientific evidence supporting suggested research and pedagogic strategies that can help increase the epistemic status of forensic science. Author Keywords: case-specific research, epistemology, forensic science, hypothetico-deductive reasoning, logic, research models
Material Worlds of the Idle and the Industrious
This thesis explores middling reform-minded representations of plebeian children’s material worlds in England from 1720 to 1780. Specifically, it examines depictions of chattel and place in imagery of children, to convey messages aligned with the reform initiatives of the eighteenth century. Using the Old Bailey Proceedings, prints by William Hogarth, and novels, it argues that contemporary concerns about idleness, vagrancy, consumerism, and delinquency, were reflected in the way the middling sort conceived of plebeian childhood. Ultimately these representations of plebeian children followed two major narratives: industry or idleness. If poor children were not industrious, they were idle. The culture of reform targeted these children with initiatives to instruct and control them. The producers spread their middling ideologies through a range of visual, fictional, and legal productions, all of which framed plebeian children as dependent and in need of education or training. Author Keywords: Children, Eighteenth-century, England, Material History, Plebeian, representations
Wastewater Impacts on Freshwater Mussels and Water Quality in a Tributary of the Lower Grand River in Southwestern Ontario, Canada
The main goal of this thesis was to assess the potential impacts of discharges of treated effluent from a small facultative sewage lagoon serving approximately 300 residents of the Mississaugas of the Credit First Nation to freshwater mussel populations in Boston Creek, a small tributary of the lower Grand River. The current resident mussel populations inhabiting Boston Creek were assessed using semi-qualitative visual surveying methods. In addition to various population level observations, other possible point and non-point influences on water quality in Boston Creek were identified. Following this, Lasmigona costata mussels were deployed as biomonitoring organisms alongside passive samplers during the October 2017 lagoon discharge period. Time weighted average (TWA) concentrations of select Contaminants of Emerging Concern (CECs) and Polycyclic Aromatic Hydrocarbons (PAHs) were estimated from levels of these compounds accumulated on passive samplers to understand the influence of wastewater on water quality in Boston Creek. Finally, mussel tissues were analyzed for various biomarkers of exposure to contaminants. Population surveys indicated that Boston Creek supports a plentiful and diverse community of freshwater mussels and may be a refuge for the Species of Special Concern, Villosa iris. Passive sampling revealed that most PAHs measured were present at concentrations below detection limits, while CECs were typically detected at relatively low concentrations (ng/L) directly downstream of the lagoon discharge. Biomarker responses detected in Lasmigona costata generally could not be attributed to exposure to the lagoon effluent but these data may indicate response to other point and non-point sources of pollution that could be affecting resident freshwater mussel populations in Boston Creek. The mussels surveyed in Boston Creek may be displaying community level effects of exposure to other sources of pollution in the area. The results of this thesis will help in establishing water quality guidelines in the lower Grand River watershed that will assist in the recovery strategy for freshwater mussel species at risk in Ontario. Author Keywords: Biomarkers, Biomonitoring, CECs, First Nations, Freshwater Mussels, SAR

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Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

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1974 - 2024
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