Graduate Theses & Dissertations

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Moving North
Since their successful reintroduction, the eastern wild turkey (Meleagris gallopavo silvestris) has expanded its range north. Due to different and potentially more severe limiting factors, management approaches generalized from studies within the historical range may not be appropriate to apply to northern populations. To better understand northern wild turkey ecology, GPS and VHF transmitters were used to track habitat selection and survival of female turkeys at the species northern range edge in Ontario, Canada. These northern turkeys exhibited larger seasonal home range sizes relative to those in their historical range, and selected deciduous forest and pasture and fields within the study area. Supplemental food was also selected by turkeys when choosing autumn and winter ranges. The northern turkeys also suffered a low annual survival rate, and high mortality from predation. These findings underscore the challenges of maintaining turkey populations in northern environments, and will help inform management strategies. Author Keywords: Eastern Wild Turkey, Euclidean distance analysis, Habitat selection, Meleagris gallopavo silvestris, Northern range edge, Survival
Reintroducing species in the 21st century
Climate change has had numerous impacts on species' distributions by shifting suitable habitat to higher latitudes and elevations. These shifts pose new challenges to biodiversity management, in particular translocations, where suitable habitat is considered crucial for the reintroduced population. De-extinction is a new conservation tool, similar to reintroduction, except that the proposed candidates are extinct. However, this novel tool will be faced with similar problems from anthropogenic change, as are typical translocation efforts. Using ecological niche modelling, I measured suitability changes at translocation sites for several Holarctic mammal species under various climate change scenarios, and compared changes between release sites located in the southern, core, and northern regions of the species' historic range. I demonstrate that past translocations located in the southern regions of species' ranges will have a substantial decline in environmental suitability, whereas core and northern sites exhibited the reverse trend. In addition, lower percentages (< 50% in certain scenarios) of southern sites fall above the minimal suitability threshold for current and long-term species occurrence. Furthermore, I demonstrate that three popular de-extinction candidate species have experienced changes in habitat suitability in their historic range, owing to climate change and increased land conversion. Additionally, substantial increase in potentially suitable space is projected beyond the range-limits for all three species, which could raise concerns for native wildlife if de-extinct species are successfully established. In general, this thesis provides insight for how the selection of translocation sites can be more adaptable to continued climate change, and marks perhaps the first rigorous attempt to assess the potential for species de-extinction given contemporary and predicted changes in land use and climate. Author Keywords: climate change, de-extinction, ecological niche models, MaxEnt, reintroduction, translocation
Understanding Historical and Contemporary Gene Flow Patterns of Ontario Black Bears
Consequences of habitat loss and fragmentation include smaller effective population sizes and decreased genetic diversity, factors that can undermine the long-term viability of large carnivores that were historically continuously distributed. I evaluated the historical and contemporary genetic structure and diversity of American black bears (Ursus americanus) in Ontario, where bear habitat is largely contiguous, except for southern regions that experience strong anthropogenic pressures. My objectives were to understand gene flow patterns in a natural system still largely reflective of pre-European settlement to provide context for the extent of genetic diversity loss in southern populations fragmented by anthropogenic influences. Phylogeographic analyses suggested that Ontario black bears belong to a widespread "continental" genetic group that further divides into 2 subgroups, likely reflecting separate recolonization routes around the Great Lakes following the Last Glacial Maximum. Population genetic analyses based on individual genotypes showed that Ontario black bears are structured into 3 contemporary genetic clusters. Two clusters, located in the Northwest (NW) and Southeast (SE), are geographically vast and genetically diverse. The third cluster is less diverse, and spatially restricted to the Bruce Peninsula (BP). Microsatellite analyses revealed that the NW and SE clusters are weakly differentiated from each other relative to mitochondrial DNA findings, suggesting male-biased dispersal and isolation by distance across the province. I also conducted simulations to assess competing hypotheses that could explain the reduced genetic diversity on the BP, which supported a combination of low migration and recent demographic bottlenecks. I showed that management actions to increase genetic variation in BP black bears could include restoring landscape connectivity between BP and SE; however, the irreversible human footprint in the area makes regular translocations from SE individuals a more practical alternative. Overall, my work suggests that: 1) historical genetic processes in Ontario black bears were likely predominated by isolation by distance, 2) large mammalian carnivores such as black bears can become isolated and experience reduced diversity in only a few generations, and 3) maintaining connectivity in regions under increased anthropogenic pressures could prevent populations from becoming small and geographically and genetically isolated, and should be a priority for conserving healthy populations. Author Keywords: American black bear, carnivore, conservation genetics, Ontario, phylogeography, population genetics
Spatial and Temporal Variation in Peatland Geochemistry in Sudbury, Ontario, Canada
The damage to Sudbury's landscape from over a century of smelter and logging activity has been severe and impacts well documented. However, despite their abundance in the region, wetlands have received little attention. Recent studies have identified that nutrient limitation is as much a problem as metal toxicity and highlighted not only the importance of wetlands but also the need for more detailed studies examining the role of wetlands in the recovery of lakes. The objective of this work is to characterize the spatial and temporal variability in the geochemistry of 18 wetlands (poor fens) surrounding Sudbury, Ontario. Peat and water chemistry in the wetlands exhibited large spatial and temporal variability. Copper and Ni concentrations in surface peat decreased with distance from the largest smelter in the area, but water chemistry was also strongly influenced by natural factors such as climate, groundwater and peat carbon content. Redox processes contribute greatly to temporal variation in pore-water chemistry: the August and October campaigns were characterized by higher SO4, lower pH and higher concentrations of metals such as Ni, Cu and Mn compared with the May campaign. Other factors contributing to the temporal variability in pore water chemistry include DOC production, senescence and water source. Despite the large variability, soil-solution partitioning can be explained by pH alone for some metals. Modeling is significantly improved with the addition of other variables representing dissolved organic matter quality and quantity, sulphate concentration and hydrology. Author Keywords: metal contamination, metal mobility, organic matter quality, peatland geochemistry
Demography of a Breeding Population of Whimbrel (Numenius phaeopus) Near Churchill, Manitoba, Canada
I used a GIS raster layer of an area in the Churchill, Manitoba region to investigate the effect of breeding habitat on demography and density of Whimbrel from 2010 through 2013. Program MARK was used to quantify adult and daily nest survival. Apparent annual survival of 0.73 ± 0.06 SE (95% CI = 0.60-0.83) did not significantly differ between sexes or habitats and was lower than expected based on longevity records and estimates for other large-bodied shorebirds. Nest success, corrected for exposure days, was highly variable, ranging from a low of 3% (95% CI = 0-12%) in 2011 to a high of 71% (95% CI = 54-83%) in 2013. The highest rate of nest survival occurred in the spring with the warmest mean temperature. I developed a generalized linear model (GLM) with a negative-binomial distribution from random plots that were surveyed for abundance to extrapolate a local breeding population size of 410 ± 230 SE and density of 3.2 birds per square km ± 1.8 SE. The result of my study suggests that other aspects of habitat not captured by the land cover categories may be more important to population dynamics. Author Keywords: abundance, apparent survival, curlew, land cover map, nest-site fidelity, nest success
Productive Capacity of Semi-Alluvial Streams in Ontario
Changes in climate and land-use practices are leading to higher peak flows and increased transport capacity of channel substrate. Semi-alluvial streams underlain by bedrock or clay were examined to understand the potential impacts of alluvium loss on the biological community and overall productive capacity of semi-alluvial rivers. More specifically, this research investigates the productivity of gravels, bedrock, and consolidated clay, through the biomass and density of periphyton, coarse particulate organic matter, benthic invertebrates, and fish. The ecological approach undertaken demonstrates the relationships among each trophic level and linkages to productive capacity between different substrate types. Significant results were detected at the stream type level and substrate level. Bedrock-based streams were overall more productive in terms of CPOM, biomass and density of benthos in comparison to clay-based streams. Stream reaches with small to large areas of exposed bedrock or clay at the site level did not differ to areas with 100% gravel coverage in the comparison of any variable, including stream fishes. At the substrate level, gravels demonstrated the highest productive capacity in comparison to bedrock and clay substrates. CPOM biomass in gravels compared to bedrock and clay at a ratio of 30:14:1, respectively. Biomass of benthic invertebrates also demonstrated a higher productivity on gravels with a ratio of 59:19:1 in comparison to bedrock and clay, respectively. Positive relationships between CPOM and benthic invertebrate biomass were detected in both stream types. Relationships were also detected between fish biomass and benthic invertebrate biomass. Examination of benthic fishes also demonstrated positive relationships with benthic invertebrate biomass and density. Clay substrate on all accounts supported little biota. Results indicate alluvium loss in clay bed streams could reduce productive capacity. Understanding and integration of the potential impacts of alluvium loss would aid management and No Net Loss compensation plans to protect fisheries resources in semi-alluvial streams. Author Keywords:
Home range use, habitat selection, and stress physiology of eastern whip-poor-wills (Antrostomus vociferus) at the northern edge of their range
The distribution of animals is rarely random and is affected by various environmental factors. We examined space-use patterns, habitat selection and stress responses of whip-poor-wills to mining exploration activity.To the best of my knowledge, fine scale patterns such as the habitat composition within known home ranges or territories of eastern whip-poor-wills have not been investigated. Using a population at the northern edge of the distribution in an area surrounding a mining exploration site, we tested whether variations in habitat and anthropogenic disturbances influence the stress physiology of individuals. We found no effect of increased mining activity on the stress physiology of birds but found a significant scale-dependent effect of habitat on their baseline and stress-induced corticosterone levels, and we suggest that these are the result of variations in habitat quality. The importance of other factors associated with those habitat differences (e.g., insect availability, predator abundance, and microhabitat features) warrants further research. Author Keywords: anthropogenic disturbances, Antrostomus vociferus, corticosterone, eastern whip-poor-will, habitat selection, radio-­telemetry
ECTOPARASITIC INFLUENCES OF DIPTERA ON THE ACTIVITY AND BEHAVIOUR OF WOODLAND CARIBOU (RANGIFER TARANDUS) IN A MANAGED BOREAL FOREST LANDSCAPE IN NORTHERN ONTARIO
Caribou experience direct and indirect negative effects of harassment from biting flies, influencing behavior and activity on several spatial and temporal scales. I used systematic insect collection surveys during the summers of 2011 and 2012 to examine the spatial and temporal distributions of black flies (Simuliidae), mosquitoes (Culicidae), and deer flies and horse flies (Tabanidae) in a managed boreal forest in northern Ontario. Mosquitoes had a positive association with densely treed habitats, whereas black flies more often occurred in open areas, and tabanids had a strong presence in all habitat types. Habitats in proximity to large bodies of water had fewer biting flies than inland areas. Young stands supported higher abundances of tabanids despite vegetation community type. Next, I tested for seasonal effects of biting fly abundance on caribou activity by modelling the seasonal trend in abundance for each fly family for each year and compared this to an index of daily activity for 20 radio-collared female caribou in 2011 and 10 females in 2012. I modeled this index of caribou activity for each animal in each year and extracted the set of partial correlation coefficients from multiple regressions to test for effects of biting fly abundances on caribou activity. Caribou reduced their daily activity when tabanids were more numerous, and increased activity when mosquitoes were numerous. This divergent response may reflect a difference in the efficacy of moving to reduce harassment, owing to the stronger flight capabilities of tabanids. Author Keywords: Activity, Anthropogenic Disturbance, Behaviour, Insect harassment, Temporal distribution, Woodland Caribou
Tabanidae and Culicidae in the Northern Boreal Region of Ontario
I studied the abundance, distribution and diversity of horse fly and deer fly species (Diptera: Tabanidae) and mosquito species (Diptera: Culicidae) in the boreal forest region of northern Ontario in 2011 and 2012. I collected 19 mosquito species, including one species new for Ontario, Aedes pullatus (Coquillett). I documented 11 northern and one southern range extension. I also collected a total of 30 species of horse and deer flies, including one new species of horse fly for Ontario, Hybomitra osburni (Hine). Results were inconsistent with a hypothesis of colonization of dipteran species from west to east. I examined the trapping biases of Malaise and sweep sampling for horse and deer flies and found that Malaise traps collected fewer individuals than sweep netting (850 versus 1318) but more species (28 versus 22). Consequently, I determined that surveys of diversity benefit from the use of multiple trapping methods. I also examined how blood-feeding (anautogeny) requirements affect the distribution patterns of Tabanidae. Ultimately, there are likely multiple factors that affect the expression of anautogeny in Tabanidae. Author Keywords: Autogeny, Culicidae, Diversity, Hudson Bay Lowlands, Northern Ontario, Tabanidae
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
Immunogenetic Responses of Raccoons and Skunks to the Raccoon Rabies Virus
Interactions between hosts and pathogens play a crucial role in their adaptation, evolution and persistence. These interactions have been extensively studied in model organisms, yet it is unclear how well they represent mechanisms of disease response in primary vectors in natural settings. The objective of my thesis was to investigate host-pathogen interactions in natural host populations exposed to raccoon rabies virus (RRV). RRV is endemic to North America, that causes acute encephalopathies in mammals and is commonly regarded as 100% lethal if untreated; however variable immune responses have been noted in natural reservoirs. In order to further understand variable immune responses to RRV, my thesis examined (i) potential immunogenetic associations to RRV using genes intimately associated with an immune response, (ii) the nature of immune responses triggered in the host after infection, and (iii) viral expression and genetic variation, to provide insight into factors that may influence RRV virulence. Immunogenetic variation of RRV vectors was assessed using major histocompatibility complex (MHC) DRB alleles. Associations were found between specific MHC alleles, RRV status, and viral lineages. Further, similarities at functionally relevant polymorphic sites in divergent RRV vector species, raccoons and skunks, suggested that both species recognize and bind a similar suite of peptides, highlighting the adaptive significance of MHC and contemporary selective pressures. To understand mechanisms of disease spread and pathogenesis, I screened for variation and expression of genes indicative of innate immune response and patterns of viral gene expression. RRV activated components of the innate immune system, with transcript levels correlated with the presence of RRV. These data indicate that timing of the immune response is crucial in pathogenesis. Expression patterns of viral genes suggest they are tightly controlled until reaching the central nervous system (CNS), where replication increases significantly. These results suggest previous molecular mechanisms for rabies host response derived from mouse models do not strictly apply to natural vector populations. Overall my research provides a better understanding of the immunological factors that contribute to the pathogenesis of RRV in a natural system. Author Keywords: immune response, major histocompatibility complex, rabies, raccoons, skunks, virus

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