Graduate Theses & Dissertations

Pages

Making eDNA count
Environmental DNA (eDNA) is rapidly becoming an established method for the detection of species in aquatic systems and has been suggested as a promising tool to estimate species abundance. However, the strength of the relationship between eDNA concentrations and taxon abundance (density/biomass) can vary widely between species. I investigated the relationship between eDNA concentration and species abundance using two common and closely-related amphibians in eastern North America, the wood frog (Rana sylvatica) and northern leopard frog (Rana pipiens). I manipulated tadpole density in 80 L mesocosms and documented the relationship between tadpole density, biomass, and eDNA concentration. Species were comparable in biomass but differed in the amount of detectible genetic material produced; density and biomass were the superior abundance metric correlated with eDNA concentration for wood frogs and leopard frogs, respectively. However, increases in eDNA concentration reflected increasing tadpole biomass, therefore biomass is likely a better metric of abundance than density. Overall my findings support that eDNA concentration can be used as an index of species abundance, but that species-specific calibration may be needed before eDNA concentration can be effectively translated to an abundance metric. Future research should refine our understanding of how biotic and abiotic factors influence eDNA production, degradation, and recovery across species, before the method can receive widespread use as a monitoring tool in natural settings. Author Keywords: abundance estimates, environmental DNA, mesocosm, Rana pipiens, Rana sylvatica
Research and development of synthetic materials for presumptive testing in bloodstain pattern analysis
Chemical presumptive tests are used as the primary detection method for latent bloodstain evidence. This work focuses on developing a forensic blood substitute which mimics whole blood reactivity to a luminol solution commonly used in presumptive testing. Designing safe and accessible materials that mimic relevant properties of blood is a recognized research need in forensic science. Understanding the whole blood dynamics related to reactivity with presumptive testing chemicals is important for developing accurate analogues. Provided in this thesis is a quantitative and qualitative characterization of photoemission from the reaction of a luminol solution to ovine blood. Luminol reactivity of a horseradish peroxidase encapsulated sol-gel polymer was validated against this ovine blood standard. This material, the luminol-reactive forensic blood substitute, is a key deliverable of this research. An optimized protocol for implementing this technology as a reagent control test, and as a secondary school chemistry experiment are presented. This thesis outlines the research and development of a forensic blood substitute as it relates to presumptive testing in bloodstain pattern analysis. Author Keywords: bloodstain pattern analysis, forensic science, luminol, presumptive testing, secondary school education, sol-gel chemistry
Frog Virus 3
Understanding the maintenance and spread of invasive diseases is critical in evaluating threats to biodiversity and how to best minimize their impact, which can by done by monitoring disease occurrences across time and space. I sought to apply existing and upcoming molecular tools to assess fluctuations in both presence and strain variation of frog virus 3 (FV3), a species of Ranavirus, across Canadian waterbodies. I explored the temporal patterns and spatial distribution of ranavirus presence across multiple months and seasons using environmental DNA techniques. Results indicate that ranavirus was present in approximately 72.5% of waterbodies sampled on a fine geographical scale (<10km between sites, 7,150 km2), with higher detection rates in later summer months than earlier. I then explored the sequence variability at the major capsid protein gene (MCP) and putative virulence gene (vIF-2α) of FV3 samples from Ontario, Alberta, and the Northwest Territories, with the premise of understanding pathogen movement across the landscape. However, a lack of genetic diversity was found across regions, likely due to a lack of informative variation at the chosen genetic markers or lack of mutation. Instead, I found a novel FV3-like ranavirus and evidence for a recombinant between FV3 and a ranavirus of another lineage. This thesis provides a deeper understanding into the spatio-temporal distribution of FV3, with an idea of how widespread and threatening ranaviruses are to amphibian diversity. Keywords: ranavirus, frog virus 3, amphibians, environmental DNA, phylogenetics, wildlife disease, disease surveillance, major capsid protein, vIF-2α Author Keywords: amphibians, environmental DNA, frog virus 3, phylogenetics, ranavirus, wildlife disease
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
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
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
Social discrimination by female polar bears (Ursus maritimus) when accompanied by dependent offspring during the ice-free season in southern and western Hudson Bay and James Bay
Polar bears are generally described as solitary, but features of their life cycles and habitats regularly necessitate interaction. Effective conspecific assessment, including accurate recognition and discrimination, likely confers benefits, especially to females accompanied by dependent young. Individuals in the Southern (SH) and Western (WH) Hudson Bay subpopulations are ideal for studying polar bear social behaviours because of the prolonged high densities of the ice-free season. First, I looked outside family groups to model their fine scale sociospatial organization on land. Capture locations were more likely to correspond to family groups when there were fewer neighbouring bears, when a greater proportion of neighbours were female, and when the focal individual and neighbours were significantly related. Second, I looked within the family group to assess offspring recognition. Of 288 offspring in 207 family groups captured in the SH subpopulation from 1999 through 2013, only one case of adoption (of a singleton) was observed. Author Keywords: Adoption, Kin Recognition, Logistic Regression, Maternity Analysis, Social Discrimination, Sociospatial
Temperature effects on the routine metabolic rates of brook trout (Salvelinus fontinalis) eggs, alevin and fry
Early developmental stages of cold-adapted ectotherms such as brook trout (Salvelinus fontinalis) are at risk of mortality with increasing water temperatures because of their sensitivity to changes in their environment. I studied the mass and routine metabolic rate (RMR) of wild-origin brook trout eggs, alevin and young fry reared at normal (5°C) and elevated (9°C) temperatures for the duration of the study or at mismatched temperatures. This setup determined if preconditioning acclimation for one temperature benefits or hinders the organism later in life. Three levels of biological organization (ancestry, population, family) were studied using Akaike’s Information Criterion (AIC) to identify models that best accounted for variation in the data. Family, mass and temperature were most important in predicting body mass and mass-adjusted RMR, although population and ancestral-level differences were also detected at some life stages. Strong variation in body mass and mass-adjusted RMR among families may indicate adaptive potential within brook trout populations to respond to increases in water temperature with climate change. Author Keywords: Acclimation, AIC, Brook trout (Salvelinus fontinalis), Environmental matching, Routine metabolic rate, Temperature
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
Reproductive Fitness of Smallmouth Bass (Micropterus dolomieu) Under Heterogeneous Environmental Conditions
Identifying the biotic and abiotic factors that influence individual reproductive fitness under natural conditions is essential for understanding important aspects of a species’ evolutionary biology and ecology, population dynamics, and life-history evolution. Using next generation sequencing technology, I developed five microsatellite multiplex reactions suitable for conducting large scale parentage analysis of smallmouth bass, Micropterus dolomieu, and used molecular pedigree reconstruction techniques to characterize the genetic mating system and mate selection in adult smallmouth bass nesting in Lake Opeongo, Ontario, Canada. I used multivariate spatial autocorrelation analysis to indirectly infer the occurrence and extent of natal philopatry among spawning adults, to assess the strength and direction of sex-bias in natal dispersal patterns, and to evaluate the degree of nest site fidelity and breeding dispersal of spawning adults. I also evaluated how differences in littoral zone water temperature caused by wind-induced seiche events influence the relative reproductive success of spawning adults. Lastly, I provide a synopsis of potential future research aimed at further exploring factors that influence the reproductive fitness of smallmouth bass in Lake Opeongo. This information will contribute to our understanding of the factors regulating smallmouth bass populations, and provide insight into the factors controlling the variance in individual reproductive success and thus recruitment dynamics in this species. Author Keywords: Dispersal, Fitness, Mate selection, Mating systems, Philopatry
Stress Axis Function and Regulation in New World Flying Squirrels
Across vertebrate taxa, the hypothalamic-pituitary-adrenal axis (or the stress axis) is highly conserved, and is central to vertebrate survival because it allows appropriate responses to psychological stressors. Habitat shapes successful physiological and ecological strategies, and to appreciate how individual species respond to stressors in their environment, it is essential to have a thorough knowledge of the basic stress physiology of each species. In this dissertation, I studied the functioning and evolution of the stress physiology of New World flying squirrels. I showed that baseline, circulating cortisol levels in northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels are some of the highest ever reported for mammals, indicating that their stress axes operate at a higher set point than most other species. I also assessed other aspects of their acute stress response, including free fatty acid and blood glucose levels, and indices of immune function, and showed that the flying squirrels’ physiological reaction to stressors may differ from that of other mammals. Using immunoblotting, I found that corticosteroid-binding globulin (CBG) expression levels in flying squirrels appeared to be higher than previously reported using alternative methods. I also concluded however, that these levels did not appear to be high enough to provide their tissues with the protective CBG-bound buffer from their high circulating cortisol concentrations experienced by the majority of vertebrates. Thus, this arm of cortisol regulation within the flying squirrel stress axes may be weak or non-existent. Following this, I focused on southern flying squirrels and showed evidence that the second arm of cortisol regulation — the negative feedback mechanism at the level of the brain — functions effectively, but that this species is glucocorticoid resistant. Their tissue receptors appear to have a reduced affinity for cortisol, and this affinity may change seasonally to allow for the onset of other biological processes required for survival and reproduction. Due to their distinctive stress physiology, northern and southern flying squirrels may provide comparative physiologists with model systems for further probing of the function and evolution of the stress axis among vertebrates. Author Keywords: corticosteroid-binding globulin, flying squirrel, Glaucomys, glucocorticoids, physiological ecology, stress physiology
Habitat Preferences and Feeding Ecology of Blackfin Cisco (Coregonus nigripinnis) in Northern Algonquin Provincial Park
Blackfin Cisco (Coregonus nigripinnis), a deepwater cisco species once endemic to the Laurentian Great Lakes, was discovered in Algonquin Provincial Park in four lakes situated within a drainage outflow of glacial Lake Algonquin. Blackfin habitat preference was examined by analyzing which covariates best described their depth distribution using hurdle models in a multi-model approach. Although depth best described their distribution, the nearly isothermal hypolimnion in which Blackfin reside indicated a preference for cold-water habitat. Feeding structure differentiation separated Blackfin from other coregonines, with Blackfin possessing the most numerous (50-66) gill rakers, and, via allometric regression, the longest gill rakers and lower gill arches. Selection for feeding efficiency may be a result of Mysis diluviana affecting planktonic size structure in lakes containing Blackfin Cisco, an effect also discovered in Lake Whitefish (Coregonus clupeaformis). This thesis provides insight into the habitat preferences and feeding ecology of Blackfin and provides a basis for future study. Author Keywords: allometric regression, blackfin cisco, habitat, hurdle models, lake whitefish, mysis

Pages

Search Our Digital Collections

Query

Enabled Filters

  • (-) = Environmental and Life Sciences
  • (-) = Wilson
  • (-) ≠ Freeland

Filter Results

Date

2009 - 2029
(decades)
Specify date range: Show
Format: 2019/12/15

Author Last Name

Show more

Last Name (Other)

Show more

Subject (Topic)