Graduate Theses & Dissertations

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Automated Separation and Preconcentration of Ultra-Trace Levels of Radionuclides in Complex Matrices by Online Ion Exchange Chromatography Coupled with Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
Radionuclides occur in the environment both naturally and artificially. Along with weapons testing and nuclear reactor operations, activities such as mining, fuel fabrication and fuel reprocessing are also major contributors to nuclear waste in the environment. In terms of nuclear safety, the concentration of radionuclides in nuclear waste must be monitored and reported before storage and/or discharge. Similarly, radionuclide waste from mining activities also contains radionuclides that need to be monitored. In addition, a knowledge of ongoing radionuclide concentrations is often required under certain ‘special’ conditions, for example in the area surrounding nuclear and mining operations, or when nuclear and other accidents occur. Thus, there is a huge demand for new methods that are suitable for continuously monitoring and rapidly analyzing radionuclide levels, especially in emergency situations. In this study, new automated analytical methods were successfully developed to measure ultra trace levels of single or multiple radionuclides in various environmental samples with the goal of faster analysis times and less analyst involvement while achieving detection limits suitable for typical environmental concentrations. Author Keywords: automation, ICP-MS, ion exchange, radionuclide
Ontario's Aboriginal Education Strategy
Since 2007, Aboriginal education initiatives in Ontario have been supported by the Aboriginal Education Strategy (Strategy) under provincial Liberal governments. Using a comparative analysis, this thesis seeks to identify how the Strategy supports and/or does not support components of critical pedagogy to promote transformational learning for all students in Ontario's publicly funded schools. A brief historical timeline of Aboriginal education in Canada and the current situation of educational attainment for Aboriginal and non-Aboriginal peoples provides context for the thesis. Through an examination of policy documents and resources related to the Strategy, I identify both strengths and areas for improvement in the Strategy to meet expectations of critical pedagogy. Finally, I suggest recommendations to improve the Strategy in order to achieve its potential for the benefit of all students in Ontario's public schools. Author Keywords: Aboriginal students, Critical pedagogy, Education, Ontario, Policy
Archaeology and Reconciliation in the Williams Treaties Territory
This thesis examines the history of Indigenous inclusion in the discipline of archaeology and how archaeologists can provide reconciliation when working with Indigenous peoples in their territory. This thesis focuses on the territory of the Williams Treaties with a particular focus on the location of Nogojiwanong (Peterborough). My data consists of in-depth interviews from ten informants and studying three case studies that happened in the area. I take my informants’ suggestions and apply them to my case studies, to show practical examples of how we can provide reconciliation in the field of archaeology. Author Keywords: Decolonization , Heritage Management , Indigenous, Reconciliation
Assessing Canada Lynx Dispersal Across an Elevation Barrier
Mountain ranges are often thought to restrict movement of wildlife, yet previous studies evaluating the role of the Rocky Mountains as a dispersal barrier for Canada lynx (Lynx canadensis) have been contradictory. Our study uses neutral microsatellite loci to evaluate the role of the Rocky Mountains as a barrier to gene flow for lynx. Although lynx exhibited low genetic differentiation, we detected a limited effect of the mountains. Furthermore, we inferred the role played by landscape variables in gene flow (genetic differentiation predicted by landscape resistance). Limited gene flow most strongly related to resistance from physical factors (low snow cover and elevation), rather than other topographic and ecological factors (high terrain roughness, low forest cover, low habitat suitability, and geographic distance). Structural connectivity was a relatively poor predictor of functional connectivity. Overall, the Rockies represent an area of reasonably high functional connectivity for lynx, with limited resistance to gene flow. Author Keywords: Canada lynx, connectivity, gene flow, genetic structure, landscape genetics, Rocky mountains
Equilibria and distribution models of ionizing organic chemical contaminants in environmental systems
Ionizing organic chemicals are recognized as constituting a large fraction of the organic chemicals of commerce. Many governments internationally are engaged in the time-consuming and expensive task of chemical risk assessment for the protection of human and environmental health. There are standard models that are consistently used to supplement experimental and monitoring data in such assessments of non-ionizing organics by both government regulators and industry stakeholders. No such standard models exist for ionizing organics. Equilibrium distribution models, the foundational equations within multimedia environmental fate models for non-ionizing organics, were developed for the standard series of biphasic systems: air-water, particle-water, air-particle and organic-aqueous phases within living tissue. Multiple chemical species due to the ionization reaction were considered for each system. It was confirmed that, under select conditions, the properties of the neutral parent are sufficient to predict the overall distribution of the organic chemical. Complications due to biotransformation and paucity of identifiable equilibrium distribution data for ionizing organics limited the development of the model for living tissues. However, the equilibrium distributions of ionizing organics within this biotic system were shown to correlate with the abiotic sediment-water system. This suggests that the model developed for particle-water systems should be adaptable to the biotic system as model input and test data become available. Observational data for soil- and sediment- water systems, i.e., particle-water systems, allowed the development of a primarily non-empirical distribution equation for mono-protic acids; this model was almost entirely theoretically derived. The theoretical approach to model development allowed a quantitative assessment of the role of the neutral ion pair, resulting from the complexation of the organic anion with metal cations. To demonstrate the model's potential usefulness in governmental screening risk assessments, it was applied to a broad range of mono-protic organics including drugs and pesticides using standard property estimation software and generic inputs. The order-of-magnitude agreement between prediction and observation typical of the existing models of non-ionizing organics was generally achieved for the chemicals tested. The model was sensitive to the octanol-water partition coefficient of the most populous species. No calibration set was used in the development of any of the models presented. Author Keywords: bioconcentration, chemical equilibrium, environmental modelling, ionizing organic, sorption
New Interpretations from Old Data
Range contractions and expansions are important ecological concepts for species management decisions. These decisions relate not only to rare and endangered species but to common and invasive species as well. The development of the broad spatiotemporal extent models that are helpful in examining range fluctuations can be challenging given the lack of data expansive enough to cover the time periods and geographic extents needed to fit the models. Archival records such as museum databases and harvest data can provide the spatiotemporal extent needed but present statistical challenges given they represent presence-only location information. In this thesis, I used maximum entropy and Bayesian hierarchical occupancy algorithms fitted with archival presence-only records to develop spatiotemporal models covering broad spatial and temporal extents for snowshoe hare and Canada lynx. These two algorithm types are well suited for presence-only data records and can be adapted to include biological and physical processes, thus improving the ecological realism of the models. Using these modelling methods, I found the extent of occurrence (EOO) and area of occupancy (AOO) varied greatly over time and space for both snowshoe hare and Canada lynx, suggesting that management decisions for these species should include consideration of these variations. While the presence-only data were appropriate for model development and understanding changing values in EOO and AOO, it sometimes lacked the locational accuracy and precision needed to create fine scale ecological analyses, thus resulting in somewhat coarse but potentially relevant conclusions. Author Keywords: Area of occupancy, Bayesian hierarchical models, Canada lynx, Extent of occurrence, Presence-only data, Snowshoe hare
Assessing Brook Trout (Salvelinus fontinalis) Seasonal Occupancy in Haliburton County, ON Using Environmental DNA
Brook trout (Salvelinus fontinalis) are declining across Ontario in both numbers and distribution, prompting concern for their future. Here, conventional, emerging, and predictive tools were combined to document brook trout occupation across seasons using streams in Haliburton County, ON as model systems. By using the Ontario Ministry of Natural Resources and Forestry’s (OMNRFs) Aquatic Ecosystem Classification (AEC) system variables with environmental DNA (eDNA) sampling and backpack electrofishing, my research supports the development of species occupancy models (SOMs) and eDNA as tools to document brook trout occurrence. To do this, eDNA sampling was validated in Canadian Shield stream environments by comparison with single-pass backpack electrofishing before seasonally sampling two river systems across their main channel and tributaries to assess occupancy. Streams were classified as potential high, moderate, and low-quality brook trout habitats using indicator variables within the AEC and sampled seasonally with eDNA to quantify occupancy and relate it to habitat potential at the county scale. Results showed eDNA to be an effective tool for monitoring fish across Canadian Shield landscapes and that brook trout occupancy varied seasonally within and across watersheds, suggesting that habitat and fish management strategies need to consider seasonal movement and spatial connectivity. Using these tools will enable biologists to efficiently predict and document brook trout occurrences and habitat use across the landscape. Author Keywords: Aquatic Ecosystem Classification, brook trout, Canadian Shield, connectivity, environmental DNA, seasonal occupation
Anthropogenic particles and microplastics in headwater lake catchments in Muskoka-Haliburton, Canada
Microplastics, plastic particles less than 5 mm in diameter, are ubiquitous in the environment. This study estimated the abundance of microplastics (MP) in atmospheric deposition from four background monitoring stations in Muskoka-Haliburton, south-central Ontario, Canada and quantified the fate of microplastics to three background headwater lake catchments in Muskoka-Haliburton. Microplastics were observed across all sample media with polyethylene terephthalate and polyamide being predominant. The average atmospheric deposition of anthropogenic particles was 57 particles/m2/day with a plastic deposition rate of 7 MP/m2/day. Atmospheric deposition represented the highest daily microplastic flux rate to the three headwater lake catchments compared, 1.5 to 4 times greater than the flux rate for the inflow streams suggesting that atmospheric deposition can account for all the inflowing microplastics. A large fraction of the microplastics from atmospheric deposition (41 – 73%) were retained in the terrestrial catchment and there was a high retention of microplastics in each of the study lakes (1.44 – 7.39 million MP/day; 30 – 45%) suggesting that a large fraction of the terrestrial catchment export is retained by the lakes and that lakes are a reservoir for microplastics. Author Keywords: Atmospheric deposition, Microplastics, Ontario, Plastic pollution, Sinks, Sources
Assessing the Cost of Reproduction between Male and Female Sex Functions in Hermaphroditic Plants
The cost of reproduction refers to the use of resources for the production of offspring that decreases the availability of resources for future reproductive events and other biological processes. Models of sex-allocation provide insights into optimal patterns of resource investment in male and female sex functions and have been extended to include other components of the life history, enabling assessment of the costs of reproduction. These models have shown that, in general, costs of reproduction through female function should usually exceed costs through male function. However, those previous models only considered allocations from a single pool of shared resources. Recent studies have indicated that the type of resource currency can differ for female and male sex functions, and that this might affect costs of reproduction via effects on other components of the life history. Using multiple invasibility analysis, this study examined resource allocation to male and female sex functions, while simultaneously considering allocations to survival and growth. Allocation patterns were modelled using both shared and separate resource pools. Under shared resources, allocation patterns to male and female sex function followed the results of earlier models. When resource pools were separate, however, allocations to male function often exceeded allocations to female function, even if fitness gains increased less strongly with investment in male function than with investment in female function. These results demonstrate that the costs of reproduction are affected by (1) the types of resources needed for reproduction via female or male function and (2) via trade-offs with other components of the life history. Future studies of the costs of reproduction should examine whether allocations to reproduction via female versus male function usually entail the use of different types of resources. Author Keywords: Cost of Reproduction, Gain Curve, Life History, Resource Allocation Patterns, Resource Currencies
Historic Magnetogram Digitization
The conversion of historical analog images to time series data was performed by using deconvolution for pre-processing, followed by the use of custom built digitization algorithms. These algorithms have been developed to be user friendly with the objective of aiding in the creation of a data set from decades of mechanical observations collected from the Agincourt and Toronto geomagnetic observatories beginning in the 1840s. The created algorithms follow a structure which begins with pre-processing followed by tracing and pattern detection. Each digitized magnetogram was then visually inspected, and the algorithm performance verified to ensure accuracy, and to allow the data to later be connected to create a long-running time-series. Author Keywords: Magnetograms
Population Dynamics of Eastern Coyotes in Southeastern Ontario
The ability of animal populations to compensate for harvest mortality provides the basis for sustainable harvesting. Coyote populations are resilient to exploitation, but the underlying mechanisms of compensation and how they inter-relate are not fully understood. Moreover, deficiencies in the quality and quantity of information about eastern coyotes preclude effective management. I combined field work, laboratory work, and genetic profiling to investigate the population dynamics of eastern coyotes in southeastern Ontario. Specifically, I conducted research on coyotes during 2010–2013 in Prince Edward County where coyote hunting and trapping seasons were open all year. First, I investigated their social status dynamics and space-use patterns. Transients exhibited extensive space-use relative to residents, potentially encountering vacant territories and/or breeding positions, and some transients became residents, potentially filling vacant territories and/or breeding positions. Accordingly, the study population demonstrated the potential to compensate for harvest mortality via source-sink dynamics and/or buffering reproductive capacity. Second, I investigated their survival and cause-specific mortality. Residents exhibited greater survival than transients, probably partly because of the benefits of holding a territory, and transients seemingly exhibited greater vulnerability to harvest than residents, probably partly because their movements exposed them to greater cumulative mortality risks over time. Accordingly, harvest mortality disproportionately impacted the non-reproductive segment of the study population and thus may have failed to substantially limit reproduction, and thus recruitment. Third, I investigated their reproduction and breeding histories. Females in the study population exhibited age-specific reproductive rates and litter sizes generally typical of those in exploited coyote populations. Accordingly, increased reproductive rates and increased litter sizes may have offset losses due to harvest mortality. There was at least some breeder turnover in the study population due to harvest mortality, but many breeders survived to reproduce for multiple years and those that died were quickly replaced. My findings have important management implications for eastern coyotes and contribute significantly to better understanding of their resilience to harvest. Indiscriminate killing of coyotes through liberal harvest is unlikely to be effective in reducing their abundance. Management strategies should consider non-lethal alternatives and/or targeted lethal control for dealing with problem coyotes. Author Keywords: Canis latrans var., eastern coyotes, population dynamics, Prince Edward County, southeastern Ontario
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

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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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