Graduate Theses & Dissertations

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(Re)encountering black bears
This thesis explores the perceptions of human-bear interactions in Ontario, suggesting that they have been shaped by narratives that have roots in colonial perceptions of nonhuman animals. Further, I seek to consider how these interactions could unfold differently if we rethought our relationships and responsibilities to these beings, in particular through an embrace of Indigenous-led conservation informed by ideas of animal welfare. The methods used for this research were first empirical, through qualitative data collection via interviews. Second, it was interpretive, through the observation of bear experiences and through the analysis of circulated and conceptual themes of bear information found in media articles. What emerged was an understanding that the mitigation efforts which are used when human-bear interactions occur are deeply influenced by political, social, and cultural factors that cannot be removed from these matters, asserting that a reconceptualization of current conservation frameworks needs to be considered. Author Keywords: Compassionate conservation, Human-bear interactions, Human-wildlife relations, Indigenous conservation, Narrative inquiry, Wildlife conservation
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
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
Combining Line Transect Sampling and Photographic-Identification Surveys to Investigate the Abundance and Distribution of Cetaceans
Line transect sampling and photographic-identification (photo-ID) are common survey techniques for estimating the abundance and distribution of cetaceans. Combining these approaches in the field (‘combined LTPI’ surveys) and using data from both components has the potential for generating comprehensive ecological knowledge that can be far more valuable than when these techniques and their data are used independently. In this thesis, I evaluated the results and conclusions from these two methods, used singly and in tandem, by investigating the population dynamics of two humpback dolphin (Sousa chinensis spp.) populations: the large and widely distributed Chinese white dolphin (S. c. chinensis) of the Pearl River estuary (PRE), and the small and geographically isolated subspecies of Taiwanese white dolphin (S. c. taiwanensis) in the eastern Taiwan Strait. Data from combined LTPI surveys in Hong Kong waters, at the eastern edge of the PRE, revealed a shift in space use with individuals spending less time in these waters than at the start of surveys. Data from combined LTPI surveys in Taiwan provided further support for a subspecies restricted to the central western waters, and identified a commonly used area at the northern part of their limited range. These two case studies demonstrated an overall efficacy of combined LTPI surveys in ecological studies of cetaceans. However, a multi-criteria analysis revealed that combined LTPI surveys with a line transect focus (e.g., Hong Kong) performed better than a LTPI survey with a photo-ID focus (e.g., Taiwan) when considering ecological aspects of the study populations, labour and data requirements, and ecological output. Even so, the photo-ID focus of Taiwan’s monitoring program led to better assessments of individual space use patterns, likely helped by the Taiwanese white dolphin population’s smaller size and intensive photographic effort. In both cases, the ecological output of combined LTPI surveys could be improved by expanding the study area or extending the field season or frequency of surveys. Overall, I showed that by following a set of general guidelines, different iterations of the combined LTPI approach (i.e., photo-ID focus or LT focus) can serve as powerful tools for uncovering multi-dimensional ecological information on cetaceans. Author Keywords: abundance, cetacean, distribution, line transect sampling, multi-criteria analysis, Photo-ID
Comparative efficacy of eDNA and conventional methods for monitoring wetland anuran communities
Identifying population declines and mitigating biodiversity loss require reliable monitoring techniques, but complex life histories and cryptic characteristics of anuran species render conventional monitoring challenging and ineffective. Environmental DNA (eDNA) detection is a highly sensitive and minimally invasive alternative to conventional anuran monitoring. In this study, I conducted a field experiment in 30 natural wetlands to compare efficacy of eDNA detection via qPCR to three conventional methods (visual encounter, breeding call, and larval dipnet surveys) for nine anuran species. eDNA and visual encounter surveys detected the greatest species richness, with eDNA methods requiring the fewest sampling events. However, community composition results differed among methods, indicating that even top performing methods missed species detections. Overall, the most effective detection method varied by species, with some species requiring two to three methods to make all possible detections. Further, eDNA detection rates varied by sampling season for two species (A. americanus and H. versicolor), suggesting that species-specific ecology such as breeding and larval periods play an important role in eDNA presence. These findings suggest that optimized monitoring of complex anuran communities may require two or more monitoring methods selected based on the physiology and biology of all target species. Author Keywords: amphibian, anuran, conventional monitoring, eDNA, environmental DNA, species richness
Conservation Genetics of Woodland Caribou in the Central Boreal Forest of Canada
Maintaining functional connectivity among wildlife populations is important to ensure genetic diversity and evolutionary potential of declining populations, particularly when managing species at risk. The Boreal Designatable Unit (DU) of woodland caribou (Rangifer tarandus caribou) in Ontario, Manitoba, and Saskatchewan has declined in southern portions of the range because of increased human activities and has been identified as 'threatened' by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). In this dissertation, I used ten microsatellite DNA markers primarily from winter-collected fecal samples to delineate genetic structure of boreal caribou in declining portions of the range and increase understanding of the potential influence of the non-threatened Eastern Migratory DU of woodland caribou on genetic differentiation. Eastern migratory caribou are characterized by large home ranges compared to boreal caribou and migrate seasonally into portions of the Boreal DU range. A regional- and local-scale analysis using the spatial Bayesian clustering algorithm in program TESS delineated four regional clusters and 11 local clusters, with the majority of local clusters occurring along the southern periphery of the range. One of those clusters in Ontario corresponded spatially with the seasonal overlap of boreal and eastern migratory caribou and was characterized by substantial admixture, suggesting that the two DUs could be interbreeding. Next, I decoupled the impacts of historical and contemporary processes on genetic structure and found that historical processes were an important factor contributing to genetic differentiation, which may be a result of historical patterns of isolation by distance or different ancestry. Moreover, I found evidence of introgression from a currently unsampled population in northern Ontario, presumably barren-ground caribou (R. t. groenlandicus). Finally, because our analysis suggested recent processes were also responsible for genetic structure, I used a landscape genetics analysis to identify factors affecting contemporary genetic structure. Water bodies, anthropogenic disturbance, and mobility differences between the two DUs were important factors describing caribou genetic differentiation. This study provides insights on where conservation and management of caribou herds should be prioritized in threatened portions of the boreal caribou range and may have implications for future delineation of evolutionarily significant units. Author Keywords: boreal forest, genetic structure, landscape genetics, microsatellite DNA, Rangifer tarandus, woodland caribou
Detection of four at-risk freshwater pearly mussel species (Bivalvia
Environmental DNA (eDNA) detection uses species-specific markers to screen DNA from bulk samples, such as water, to infer species presence. This study involved the development and testing of species-specific markers for four freshwater pearly mussels (Unionidae). The markers were applied to water samples from intensively sampled mussel monitoring sites to compare species detections from eDNA with established sampling method detections. Target species were detected using eDNA at all sites where they had previously been detected by quadrat sampling. This paired design demonstrated that eDNA detection was at least as sensitive as quadrat sampling and that high species specificity can be achieved even when designing against many sympatric unionids. Detection failures can impede species conservation efforts and occupancy estimates; eDNA sampling could improve our knowledge of species distributions and site occupancy through increased sampling sensitivity and coverage. Author Keywords: conservation genetics, cytochrome oxidase subunit I (COI), environmental DNA (eDNA), quantitative PCR (qPCR), species at risk (SAR)
Disease ecology of ophidiomycosis in free-ranging snakes
Ophidiomycosis (snake fungal disease) is caused by the pathogen Ophidiomyces ophiodiicola. Infected snakes exhibit dermal lesions, occasional systemic infections, and, in some cases, mortality. We studied snakes at Rondeau Provincial Park, Ontario, Canada, to explore whether ophidiomycosis develops during brumation or year-round. Throughout their active season, we quantified the prevalence of clinical signs of the disease on snakes and conducted qPCR of skin swabs to determine the prevalence of O. ophiodiicola on snakes. Prevalence of O. ophiodiicola and disease symptoms were highest on eastern foxsnakes (Pantherophis vulpinus) and very rare on other snake species. In P. vulpinus, pathogen and clinical sign prevalence was highest, directly after emergence from overwintering, with the majority of P. vulpinus being able to resolve clinical signs of ophidiomycosis by the return of winter. When we analyzed the survivorship of P. vulpinus we determined that the likelihood of a snake dying with ophidiomycosis is similar to a snake dying without ophidiomycosis. Given that P. vulpinus were the most affected species at our study site, ophidiomycosis does not appear to pose an imminent threat to our study population of P. vulpinus under current conditions. Author Keywords: Eastern Foxsnake, Fitness, Ophidiomycosis, Pantherophis vulpinus, Seasonal trends, Snake fungal disease
Effects of Hydroelectric Corridors on the Distribution of Female Caribou (Rangifer tarandus) on the Island of Newfoundland
A species of concern is caribou (Rangifer tarandus), a species in decline across most of the circumpolar North, including the island of Newfoundland. Resource exploitation across caribou ranges is projected to accelerate in the coming decades as oil extraction, roads, forest harvesting, and mining encroach upon their habitat. Hydroelectric corridors, in particular, are anticipated to expand significantly. The effects of these linear developments on caribou habitat remain unclear. I capitalized on an existing dataset of nearly 700 radio‐tracked female caribou, 1980‐2011, to determine the long‐term effects of hydroelectric corridors on their seasonal distributions. Using an island-wide landcover map, I tested for preference or avoidance hydroelectric corridors in each of 4 seasons using the Euclidean Distance habitat selection technique at the extent of the population ranges (broad scale) for each decade (1980s, 1990s, 2000s). I also examined the distribution of caribou ≤10 km and ≤20 km from corridors (narrow scale) for five herds. At the broad scale, the response was highly variable. Female caribou were most likely to avoid corridors during the 1980s, but they often exhibited little aversion, even preference for corridors, particularly in the 1990s and 2000s. Hydroelectric corridors, therefore, did not appear to be limiting at this scale. I surmise that these long-term shifts reflect the heightened density-dependent food limitation for Newfoundland caribou. At the narrow scale, avoidance of corridors was common – typically, a 50% reduction in use within 2-5 km of the corridor. Consistent with the broad scale, caribou exhibited the strongest tendency for avoidance in the 1980s compared to subsequent decades. Understanding space-use remains central to the study of caribou ecology. Hydroelectric lines in Newfoundland tended to coincide with other anthropogenic features. Cumulative effects must be considered to understand the full range of effects by human developments on caribou. Author Keywords: Caribou, distribution, habitat, hydroelectric, Newfoundland, Rangifer tarandus
Environmental structure, morphology and spatial ecology of the five-lined skink (Plestiodon fasciatus) at high latitude range limits
Detecting relevant and meaningful patterns from the complex, interconnected network of relationships between organisms and their environment is a primary objective of ecology. Ecological patterns occur across multiple scales of space and time. In this dissertation, I examine aspects of environmental structure that influence a species’ distribution and are expressed in that species’ population dynamics. I compare the morphology of the five-lined skink (Plestiodon fasciatus) near its high latitude range limits with a lower latitude population and evaluate the economics of their behaviour in the context of its reproductive strategy. I tested the conformity of this species to biogeographical rules postulated by MacArthur, Bergmann, and Rensch. Spatial ecology was investigated in the context of the environmental potential for polygamy proposed by Emlen and Oring (1977) The five-lined skink, Plestiodon fasciatus, conformed to these biogeographic rules. Specifically, abiotic factors were the primary limiting factors affecting distribution at the high latitude range limits of the species; body size was larger in high latitude populations; and the degree of sexual size dimorphism was greater at high latitude than at low latitude. Spatial ecology at the individual scale was influenced by sites with suitable thermal conditions which facilitate the polygynandrous mating system documented in P. fasciatus in high latitude populations. My results confirm the importance of microsites with suitable thermal profiles as key habitat for ectothermic vertebrates at high latitudes. The influence of temperature as a limiting abiotic factor is expressed in population density, body size, spatial ecology, and reproductive strategy of P. fasciatus. Conservation and restoration of high latitude populations of ectothermic vertebrates should focus on ensuring thermal requirements of the species of concern are met before other factors are addressed, as temperature is likely the single most important limiting factor at high latitude range limits. Author Keywords: biogeography, lizard, Plestiodon fasciatus, range limits, sexual size dimorphism, spatial ecology
Evaluating the effects of landscape structure on genetic differentiation and diversity
The structure and composition of the landscape can facilitate or impede gene flow, which can have important consequences because genetically isolated groups of individuals may be prone to inbreeding depression and possible extinction. My dissertation examines how landscape structure influences spatial patterns of genetic differentiation and diversity of American marten (Martes americana) and Canada lynx (Lynx canadensis) in Ontario, Canada, and provides methodological advances useful for landscape geneticists. First, I identified the effects of map boundaries on estimates of landscape resistance, and proposed a solution to the bias: a buffer around the map boundary. Second, I assessed the sensitivity of a network-based estimate of genetic distance, conditional genetic distance, to incomplete sampling. I then used these landscape genetic tools in a pairwise, distance-based analysis of 653 martens genotyped at 12 microsatellite loci. I evaluated whether forest management in Ontario has influenced the genetic structure of martens. Although forest management practices had some impact, isolation by distance best described marten gene flow. Our results suggest that managed forests in Ontario are well connected for marten and do not impede marten gene flow. Finally, I used a site-based analysis of 702 lynx genotyped at 14 microsatellite loci to investigate spatial patterns of genetic diversity and differentiation at the trailing (contracting) edge of the lynx distribution in Ontario. I analyzed harvest records and found that the southern edge of lynx range has contracted by >175 km since the 1970s. I also found that neutral genetic diversity decreased towards the trailing edge, whereas genetic differentiation increased. Furthermore, I found strong correlations between gradients of lynx genetic structure and gradients of climate and land cover in Ontario. My findings suggest that increases in winter air temperature, decreases in snow depth, and loss of suitable habitat will result in further loss of genetic diversity in peripheral populations of lynx. Consequently, the adaptive potential of lynx populations on the southern range periphery could decline. In conclusion, my dissertation demonstrates the varying influences that contemporary landscape structure and climate gradients can have on genetic diversity and differentiation of different species. Author Keywords: Circuitscape, genetic network, landscape genetics, Lynx canadensis, Martes americana, range shift
Fall Migratory Behaviour and Cross-seasonal Interactions in Semipalmated Plovers (Charadrius semipalmatus) Breeding in the Hudson Bay Lowlands, Canada
I used the Motus Wildlife Tracking System to monitor the fall migration behaviour and assess the underlying drivers of migration strategy in a small shorebird, the Semipalmated Plover (Charadrius semipalmatus), breeding at two subarctic sites: Churchill, Manitoba and Burntpoint Creek, Ontario, Canada. Semipalmated Plovers from both sites departed breeding areas between mid-July and early August, with females preceding males and failed breeders preceding successful breeders. Migrants showed between and within-population variation in migration behaviour, though birds from both sites tended to follow interior or coastal routes and congregated in three major stopover regions along the mid-Atlantic coast of North America. I found that later-departing birds had initial flight tracks oriented more toward the south, faster overall ground speeds, were less likely to stopover in North America, and stopped at lower latitudes, suggesting that later-departing individuals use aspects of a time-minimizing strategy on fall migration. My findings emphasize the importance of the mid-Atlantic coast for Semipalmated Plovers and establish connectivity between sites used during breeding and migration. Author Keywords: Breeding, Migration, Motus, Semipalmated Plover, Shorebird, Stopover

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