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
Predictive Digital Mapping of Soils in Kitimat, British Columbia
Soil is an essential natural resource that supports provisioning services such as agriculture, silviculture, and mining. However, there is limited knowledge on forest soil properties across Canada. Digital soil mapping may be used to fill these data gaps, as it can predict soil properties in areas with limited observations. The focus of this study was to develop predictive maps of select soil physicochemical properties for the Kitimat Valley, British Columbia, and apply these maps to assess the potential impacts of sulphur dioxide emissions from an aluminum smelter, on soil properties in the Valley. Exchangeable [Ex.] magnesium, organic matter, pH, coarse fragment, Ex. potassium, bulk density, Ex. calcium, Ex. acidity, and Ex. sodium were all mapped with acceptable confidence. Time to depletion of base cation pools showed that ~240 km2 of the study area had a depletion time of 50 years or less. However, sources of base cations such as atmospheric deposition and mineral weathering were not considered. Author Keywords: acidification, buffering capacity, Digital soil mapping, predictive mapping, regression kriging, soil properties
In situ measurements of trace metal species in the Athabasca and Mackenzie Rivers using diffusive gradient in thin films (DGT) devices
This study assesses the bioavailable metal (Cu, Ni, Zn, Pb) species in the Athabasca-Mackenzie watersheds using diffusive gradient in thin films (DGT) devices. Metal toxicity is not only based on the concentration of metal in natural waters, but also on the nature of metal species. Four main forms in aquatic systems are: free ion, inorganic species, DOM bound (humic) species and metal colloidal species. The free ion and inorganic species and very small humic species are known as DGT-labile species and, are considered to be more bioavailable to micro-organisms due to the size and thus may be toxic to microorganisms. In this study, DGT devices were applied to (1) monitor the DGT-labile metal species in the lower Athabasca River and the Mackenzie River watershed and (2) assess the DGT-labile metal concentrations on temporal and spatial scales. In the lower Athabasca River, comparison between the DGT results and the Windermere Humic Acid Model (WHAM) calculation indicated good agreements for all metals when the precipitated iron(III) hydroxide was assumed as an active binding surface. No significant variations in labile species were found over 2003-2012 (RAMP database) despite the development of oil sands. In the Mackenzie River, no significant difference in DGT-labile metal concentrations and DOC concentrations was found in yearly basis 2012-2014. Only DOC was lower in August (6.98 and 3.85 ppm, respectively; p< 0.05) due to dilution from heavy rain events. Spatially, DGT-labile Cu and Ni in the downstream Mackenzie River were higher than upstream (1.79 and 0.58 ppb for Cu, 1.68 and 0.77 ppb for Ni, 4.06 and 6.91 ppm for DOC; p < 0.05). Overall the in situ measurements of metals constitute a benchmark for future studies in water quality and be helpful in environmental management in Alberta and the Northwest Territories in Canada. Author Keywords: Athabasca River, DGT, Mackenzie River, Speciation, Trace Metal, WHAM
Nunavik Inuit Knowledge of Beluga
Socio-ecological systems are inherently complex and marine mammals are fundamentally challenging to study. In the Arctic, marine mammals occupy a central ecological role, as nutrient cyclers and as a source of food and culture for Indigenous peoples. Inuit have developed a rich knowledge system, which has not been fully actualized in application in most Arctic research. Considering the need for the best available information in marine mammal ecology, the research question guiding this dissertation was: How can multiple methods and approaches be used to more effectively gather, understand, and represent Inuit Knowledge for an improved understanding of marine mammal ecology? The dissertation investigates this question using a case study of beluga in Nunavik (Arctic Quebec) drawing on the expertise of hunters and Elders to better understand complex questions in marine mammal ecology. The thesis uses a transdisciplinary approach to address the dissertation objective and is comprised of a general introduction, followed by four chapters formatted as journal manuscripts, and closes with an integrated discussion and conclusion. The first manuscript examines the contributions of Traditional Ecological Knowledge (TEK) of beluga to marine mammal literature. The second manuscript uses a sub-set of data gathered through participant mapping to apply a mapping method to explore how the spatial aspects of TEK could be better documented, analyzed, and represented. The third and fourth papers are based on the knowledge shared by hunters and Elders. The third explores the questions ‘why do beluga migrate?’ and ‘what factors influence beluga movement?’. The fourth investigates aspects of beluga foraging ecology. This dissertation makes methodological contributions through the application of kernel density estimators to participant maps as a method for transforming multiple mapped narratives into a quantitative database. The understandings shared by hunters and Elders make significant ecological contributions, particularly to foraging (e.g. diet composition and seasonal energy intake), and movement ecology (e.g. potential drivers of migration). Broadly these findings contribute to our collective understanding of beluga ecology and have implications for wildlife management. Author Keywords: Arctic, Beluga biology, foraging ecology, Inuit Knowledge, migration, transdisciplinary
significance of topographically-focused groundwater recharge during winter and spring on the Oak Ridges Moraine, southern Ontario
The Oak Ridges Moraine (ORM) is a key hydrogeologic feature in southern Ontario. Previous work has emphasized the importance of depression-focused recharge (DFR) for the timing and location of groundwater recharge to the ORM’s aquifers. However, the significance of DFR has not been empirically demonstrated and the relative control of land cover, topography, and surficial geology on DFR is unclear. The potential for DFR was examined for topographic depressions under forested and open, agricultural land covers with similar soils and surficial geology. Recharge (R) was estimated at the crest and base of each depression during the 2012-13 and 2013-14 winter-spring periods (~December – May) using both a 1-dimensional water balance approach and a surface-applied Br- tracer. At each depression, air temperatures, precipitation, snow depth and water equivalent, soil water contents, soil freezing, and depression surface-water levels were monitored and soil properties (texture, bulk density, porosity, and hydraulic conductivity) were measured. Both forested and agricultural land covers experienced soil freezing; however, concrete frost did not develop in the more porous and conductive forest soils. Concrete frost in agricultural depressions resulted in overland flow, episodic ponding and drainage of rain-on-snow and snowmelt inputs. Recharge was an order-of-magnitude greater at the base of open depressions. Observations of ponding (as evidence of DFR) were made at an additional 14 depressions with varying land cover, geometry, and soil type during the 2014 snowmelt period and measurements of pond depth, pond volume, land cover (i.e., percentage of agricultural vs. forested cover), depression geometry (i.e., contributing area, average slope, relief ratio) and soil texture were made. Ponding was restricted to depressions under mostly agricultural cover and a positive, non-linear relationship between pond volume and average slope was shown for sites with similar land cover and soil texture, but neither pond depth nor volume were related to any other depression characteristics. Results suggest that DFR is a significant hydrologic process during winter and spring under agricultural land cover on the ORM. Topographic depressions under agricultural land cover on the ORM crest may serve as critical recharge “hot spots” during winter and spring, and the ability of the unsaturated zone beneath these depressions to modify the chemistry of recharging water deserves further attention. Author Keywords: Concrete frost, Depression-focused groundwater recharge, Oak Ridges Moraine, Ponding, Topographic depressions, Water balance
successful invader in expansion
Researchers have shown increasing interest in biological invasions for the associated ecological and economic impacts as well as for the opportunities they offer to study the mechanisms that induce range expansion in novel environments. I investigated the strategies exhibited by invasive species that facilitate range expansion. Invasive populations exhibit shifts in life-history strategy that may enable appropriate responses to novel biotic and abiotic factors encountered during range expansion. The spatio-temporal scales at which these shifts occur are largely unexplored. Furthermore, it is not known whether the observed dynamic shifts represent a consistent biological response of a given species to range shifts, or whether the shifts are affected by the abiotic characteristics of the new systems. I examined the life-history responses of female round gobies Neogobius melanastomus across fine and coarser spatial scales behind the expansion front and investigated whether invasive populations encountering different environmental conditions (Ontario vs France) exhibited similar life-history shifts. In both study systems, I found an increase in reproductive investment at invasion fronts compared to longer established areas at coarse and fine scales. The results suggest a similar response to range shifts, or a common invasion strategy independent of environmental conditions experienced, and highlight the dynamic nature of an invasive population’s life history behind the invasion front. The second part of my research focused on the development of an appropriate eDNA method for detecting invasive species at early stages of invasion to enable early detection and rapid management response. I developed a simple, inexpensive device for collecting water samples at selected depths for eDNA analysis, including near the substrate where eDNA concentration of benthic species is likely elevated. I also developed a protocol to optimise DNA extraction from water samples that contain elevated concentration of inhibiters, in particular near-bottom samples. Paired testing of eDNA and conventional surveys was used to monitor round goby expansion along its invasion pathway. Round gobies were detected in more sites with eDNA, permitting earlier, more accurate, upstream detection of the expansion front. My study demonstrated the accuracy and the power of using eDNA survey method to locate invasion fronts. Author Keywords: Age-specific reproductive investment, DNA extraction, Energy allocation, Fecundity, Invasion front, Range expansion
Assessment of an adult lake sturgeon translocation (Acipenser fulvescens) reintroduction effort in a fragmented river system
North American freshwater fishes are declining rapidly due to habitat fragmentation, degradation, and loss. In some cases, translocations can be used to reverse local extirpations by releasing species in suitable habitats that are no longer naturally accessible. Lake sturgeon (Acipenser fulvescens) experienced historical overharvest across their distribution, leading to endangered species listings and subsequent protection and recovery efforts. Despite harvest and habitat protections, many populations do not appear to be recovering, which has been attributed to habitat alteration and fragmentation by dams. In 2002, 51 adult lake sturgeon from the Mattagami River, Ontario, Canada were translocated 340 km upstream to a fragmented 35 km stretch of the river between two hydroelectric generating stations, where sturgeon were considered extirpated. This study assessed the translocation effort using telemetry (movement), demographics and genetic data. Within the first year, a portion of the radio-tagged translocated individuals dispersed out of the release area, and released radio-tagged individuals used different areas than individuals radio-tagged ten years later. Catches of juvenile lake sturgeon have increased over time, with 150 juveniles caught within the duration of this study. The reintroduced population had similar genetic diversity as the source population, with a marked reduction in effective population size (Ne). The results indicate that the reintroduction effort was successful, with evidence of successful spawning and the presence of juvenile lake sturgeon within the reintroduction site. Overall, the results suggest adult translocations may be a useful tool for re-establishing other extirpated lake sturgeon populations. Author Keywords: conservation, endangered species, lake sturgeon, reintroduction, telemetry, translocation
Investigating Ecological Niche Differentiation Among Wild Candids Experiencing Hybridization in Eastern North America
Currently there are large areas of the North American landscape that are occupied by Canis spp. hybrids of several varieties, leading to the logical question as to the genetic structure and ecological function of Canis populations across the continent, and to what extent hybrids reflect contemporary landscapes. This study illustrated patterns of niche differentiation between parental canid species and their hybrids using individual high quality genetic profile and species distribution models to support the intermediate phenotype hypothesis. In general, hybrids demonstrated an intermediate habitat suitability compared to its parental species, across most environmental variables used. A similar trend was observed in the niche metric analysis, where we found that hybrids exhibit intermediate niche breadth, with eastern coyotes and eastern wolves exhibiting the broader and narrower niche, respectively. Our results demonstrate that the intermediate phenotype hypothesis is supported even at a large scale and when involving highly mobile large mammal species. Author Keywords: canid, ecological niche modelling, hybridization, intermediate phenotype, microsatellite genotype, niche differentiation
Fungi and Cytokinins
Cytokinin biosynthesis in organisms aside from plant species has often been viewed as a byproduct of tRNA degradation. Recent evidence suggests that these tRNA degradation products may actually have a role in the development of these organisms, particularly fungi. This thesis examines the importance of cytokinins, a group of phytohormones involved in plant cell division and differentiation as well as the phytohormone abscisic acid, involved in plant response to environmental factors, and their presence and role in fungi. An initial survey was conducted on 20 temperate forest fungi of differing nutritional modes. Using HPLC-ESI MS/MS, cytokinin and abscisic acid were detected in all fungi regardless of their mode of nutrition or phylogeny. The detection of the same seven CKs across all fungi suggested the existence of a common CK biosynthetic pathway and dominance of the tRNA pathway in fungi. Further, the corn smut fungus Ustilago maydis is capable of producing CKs separate from its host and different U. maydis strains induce disease symptoms of differing severity. To determine if CK production during infection alters disease development a disease time course was conducted on cob tissue infected with U. maydis dikaryotic and solopathogenic strains. Dramatic changes in phytohormones including an increase in ABA followed by increases in cisZCKs were detected in tumour tissue particularity in the more virulent dikaryon infection, suggesting a role for CKs in strain virulence. Mining of the U. maydis genome identified a sole tRNA-isopentenyltransferase, a key enzyme in CK biosynthesis. Targeted gene deletion mutants were created in U. maydis which halted U. maydis CK production and decreased pathogenesis and virulence in seedling and cob infections. CK and ABA profiling carried out during disease development found that key changes in these hormones were not found in deletion mutant infections and cob tumour development was severely impaired. These findings suggested that U. maydis CK production is necessary for tumour development in this pathosystem. The research presented in this thesis highlights the importance of fungal CKs, outlines the dominant CK pathway in fungi, identifies a key enzyme in U. maydis CK biosynthesis and reveals the necessity of CK production by U. maydis in the development of cob tumours. Author Keywords: abscisic acid, cytokinins, high performance liquid chromatography-electrospray ionization tandem mass spectrometry, tRNA degradation pathway, Ustilago maydis, Zea mays
Influence of Habitat on Woodland Caribou Site Fidelity
Site fidelity is the behaviour of individuals to return to the same location; for female woodland caribou it may reflect reproductive success and depend on habitat quality. I investigated the influence of landscape and disturbance conditions on fidelity among three populations in Manitoba and Ontario, Canada. Habitat classifications were based on Forest Resource Inventory (FRI) and Landsat TM landcover maps. A total of 261 sites were ground-truthed to determine mapping accuracy. An amalgamated map incorporating FRI and Landsat TM data was estimated from field measurements to have an overall accuracy of 69.0%. Site fidelity was expressed as the distance between consecutive-year locations of individuals and was investigated during five week-long periods representing calving, early and late post-calving, winter, and breeding. Site fidelity was strongest during the post-calving seasons and weakest during the winter. Habitat had little influence on site fidelity in all seasons, excepting winter, even under highly disturbed conditions, suggesting maintenance of fidelity may be a maladaptive trait. Individual variation proved a strong predictor and cursory mapping indicated that caribou may return to sites visited two or more years earlier. Conservation management and policy should recognize that site fidelity may represent an ecological trap. Author Keywords: calving, disturbance, habitat, movement, Rangifer tarandus caribou, site fidelity
Analysis and reactions of aqueous selenide and other reduced inorganic selenium compounds under anoxic conditions
Selenide is cited as a geochemically important selenium (Se) species, but it is unknown whether selenide is a stable aqueous ion in natural waters. The feasibility of using anoxic anion exchange chromatography (AEC) coupled to dynamic reaction cell-inductively coupled plasma-mass spectrometry to separate aqueous selenide was investigated with the goal of quantifying this anion to determine its importance in reducing waters. It was possible to qualitatively identify selenide using AEC, but much of the aqueous selenide oxidises to Se0 faster than the separation procedure could be completed. AEC analyses of solutions containing polyselenides produced peaks for unidentified Se compounds, which have been assigned tentative structures Se2O22-, Se2O32-, and Se2O62- based on close matches in retention time to stable S compounds. The results of this work show that aqueous selenide can be qualitatively observed in synthetic solutions using AEC, but it is unknown whether these conditions are relevant to natural waters. Author Keywords: anoxic speciation, polyselenides, selenide, selenium geochemistry, selenium speciation, selenoselenate
THE LIFE HISTORY STRATEGY, GROWTH, BODY CONDITION, AND DIET OF STOCKED AMERICAN EEL (Anguilla rostrata) IN THE UPPER ST. LAWRENCE RIVER AND LAKE ONTARIO
My study was primarily focused on the comparison of life history traits between stocked American eel and their naturally recruited conspecifics in Lake Ontario and the upper St. Lawrence River (USLR/LO). I found that stocked eels experienced faster annual growth than their naturally recruited conspecifics and were comprised of a greater proportion of males. These findings indicate that the life history patterns of American eel may be genetically predisposed. Additionally, my study served to characterize the diets of stocked American eel and examine possible associations between eel and prey size. The eels consumed a number of macroinvertebrate prey orders as well as fishes and macrocrustaceans, with the latter prey items being more prevalent in the diets of larger eel specimens. A disparity in eel growth and body condition was observed between two primary stocking locations and were likely attributable to differences in available forage and habitat. Lastly, growth, body condition, and stocked eel diet were compared between lentic and lotic habitats. Eels from lotic streams experienced slower annual growth and had reduced body condition, and their diets were comprised of smaller prey items. The results of this study suggest that the current stocking methods employed in the USLR/LO are not suitable to restore the natural recruitment of individuals that will exhibit desired life history traits. Author Keywords:

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