Graduate Theses & Dissertations

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Yearly variation in fall movements of adult female American black bears (Ursus americanus) in central Ontario, Canada
I investigated site fidelity and habitat selection of American black bears (Ursus americanus) from 15 GPS-collared adult females in central Ontario, Canada over nine years. I used generalized linear mixed models to determine the factors affecting between-year variation in fall fidelity and the habitat selection in movement paths. I assessed second and third-order habitat preference by female bears moving between seasonal home ranges. I found that 66% of bears returned to the same fall area between years, expressed as range overlap, influenced negatively by whether they had cubs. When moving between seasonal ranges, bears selected for mixedwood, hardwood and wetlands cover but selected ridge tops over other habitat features at both scales. With increases in climatic uncertainty and habitat fragmentation, these results emphasize the need for wildlife management to consider annual variation in seasonal movements and habitat use by wide-ranging, opportunistic animals. Author Keywords: American black bear, Habitat Selection, Logistic Regression, Site Fidelity
Novel Aliphatic Amides from Vegetable Oils as Bio-Based Phase Change Materials
Energy storage efficiency and sustainability require advanced technologies and novel materials. Recently, bio-based phase change materials (PCMs) have received significant attention for thermal energy storage (TES) uses. Vegetable oils are versatile renewable feedstocks that are well suited for the development of sustainable, functional PCMs. PCMs derived from vegetable oil, which compares favorably with paraffin waxes, the industry standard, are currently available. However, their melting points are typically below 80 °C preventing their wider integration in TES applications, particularly those requiring higher temperatures. The present work manipulated the structural building blocks of fatty acids to advantageously affect the intermolecular forces and increase the properties relevant to TES. The polar amide functional group was incorporated into fatty moieties to take advantage of the strong hydrogen bonds that it forms to increase intermolecular attractions and hence increase the phase change temperature and enthalpy as well as to improve thermal stability and thermal conductivity. A series of carefully designed lipid-derived monoamides and four series of lipid-derived diamides were synthesized via benign and simple amidation reactions. The purity of the amides and the intermolecular hydrogen bond strength were assessed using 1H NMR and FTIR. The properties relevant to TES such as thermal transition, crystal structure and polymorphism, thermal stability and thermal conductivity were measured using DSC, XRD, TGA and a thermal conductivity analyzer, respectively. The complex roles of the PCM’s constituting molecular building blocks in the phase behavior were elucidated and correlations between structure, processing conditions and macroscopic physicochemical properties, never before elucidated, were assembled in predictive relationships, drawing a unified picture of the rules that generally govern the phase behavior of lipid-derived PCMs. Practically, the prepared amides demonstrated desirable TES properties with substantial performance improvement over current bio-based PCMs. They presented increased phase change temperatures (79 - 159 °C), enthalpies of fusion (155 - 220 J/g) and thermal stability (234 - 353 °C). More importantly, the predictive structure-function relationships established in this work will allow the straightforward engineering of lipid-derived amide PCM architectures with judicious selection of molecular building blocks to extend the range of organic PCMs and deliver thermal properties desirable for TES applications. Author Keywords: LATENT HEAT THERMAL ENERGY STORAGE, LIPID-DERIVED AMIDES, PHASE CHANGE MATERIALS, RENEWABLE, SOLID LIQUID AMIDE PCMS, THERMAL PROPERTIES
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
Impact of Agricultural Land Use on Bobolink Occurrence, Abundance, and Reproductive Success in an Alvar Landscape
Pastures and hayfields provide surrogate habitat for many declining grassland birds. Understanding agricultural land use dynamics and habitat quality can impact conservation of grassland species. I investigated 1) patterns of land use change in protected and unprotected sites in relationship to Bobolink occurrence in Carden, Ontario, Canada and 2) whether continuous grazing at lowmoderate cattle densities provided suitable breeding habitat, using both real and artificial nests. I replicated the 2001-2005 Ontario Breeding Bird Atlas to evaluate site habitat changes and Bobolink population trends. In continuously grazed pastures and late-cut hayfields, I monitored Bobolink abundance and reproductive success and modeled daily survival rate of nests using habitat management, vegetation structure, and prey availability. Results indicated that Bobolink have declined by -15.3% since 2001 in Carden; losses were explained almost entirely by changes from suitable breeding habitat (e.g. hayfields) to tilled land or by the colonization of shrubs. For pastures, stocking densities of ≤ 1Animal Units/ha did not negatively impact Bobolink. Year and caterpillar biomass, and vegetation height were the strongest predictors of nesting success in pastures and hayfields, respectively. Focus on the preservation of suitable habitat on the breeding grounds and management on small-scale beef farms can contribute to conservation action for this declining species. Author Keywords: agricultural management, avian ecology, Bobolink, continuous grazing, grassland birds, nest success
Impact of Wetland Disturbance on Phosphorus Loadings to Lakes
Total phosphorus (TP) concentrations have declined in many lakes and streams across south- central Ontario, Canada over the past three decades and changes have been most pronounced in wetland-dominated catchments. In this study, long-term (1980-2007) patterns in TP concentrations in streams were assessed at four wetland-dominated catchments that drain into Dickie Lake (DE) in south-central Ontario. Two of the sub-catchments (DE5 and DE6) have particularly large wetland components (31-34 % of catchment area), and wetlands are characterised by numerous standing dead trees and many young live trees (18 – 27 year old). These two streams exhibited large peaks in TP and potassium (K) export in the early 1980s. In contrast, TP and K export from DE8 and DE10 (wetland cover 19 – 20 %) were relatively flat over the entire record (1980-2007), and field surveys indicated negligible standing dead biomass in these wetlands, and a relatively healthy, mixed-age tree community. Furthermore, K:TP ratios in the DE5 and DE6 streams were around 5 in the early 1980s; very similar to the K:P ratio found in biomass, and as stream TP levels fell through the 1980s, K:TP ratios in DE5 and DE6 stream water increased. The coincidence of high TP and K concentrations in the DE5 and DE6 streams as well as evidence of a disturbance event in their wetlands during the early 1980s suggest that the two are related. The diameter of standing dead trees and allometric equations were used to estimate the amount of TP that would have been held in readily decomposed tree tissues in the DE5 wetland. The amount of P that would have been held in the bark, twig, root and foliage compartments of just the standing dead trees at DE5 was approximately half of the amount of excess stream TP export that occurred in the 1980s. This work suggests that disturbance events that lead to wetland tree mortality may contribute to patterns in surface water TP observed in this region. Author Keywords: Chemistry, Disurbance, Nutrients, Tree Death, Water, Wetland
Hybridization dynamics in cattails (Typha spp.,) in northeastern North America
Interspecific hybridization is an important evolutionary process which can contribute to the invasiveness of species complexes. In this dissertation I used the hybridizing species complex of cattails (Typha spp., Typhaceae) to explore some of the processes that could contribute to hybridization rates. Cattails in northeastern North America comprise the native T. latifolia, the non-native T. angustifolia, and their fertile hybrid, T. × glauca. First, I examined whether these taxa segregate by water depth as habitat segregation may be associated with lower incidence of hybridization. I found that these taxa occupy similar water depths and therefore that habitat segregation by water depth does not promote mating isolation among these taxa. I then compared pollen dispersal patterns between progenitor species as pollen dispersal can also influence rates of hybrid formation. Each progenitor exhibits localized pollen dispersal, and the maternal parent of first generation hybrids captures more conspecific than heterospecific pollen; both of which should lead to reduced hybrid formation. I then conducted controlled crosses using all three Typha taxa to quantify hybrid fertility and to parameterize a fertility model to predict how mating compatibilities should affect the composition of cattail stands. I found that highly asymmetric formation of hybrids and backcrosses and reduced hybrid fertility should favour the maintenance of T. latifolia under certain conditions. Finally, I used a population genetics approach to characterize genetic diversity and structure of Typha in northeastern North America to determine the extent to which broad-scale processes such as gene flow influence site-level processes. I concluded that hybrids are most often created within sites or introduced in small numbers rather than exhibiting broad-scale dispersal. This suggests that local processes are more important drivers of hybrid success than landscape-scale processes which would be expected to limit the spread of the hybrid. Though my findings indicate some barriers to hybridization in these Typha taxa, hybrid cattail dominates much of northeastern North America. My results therefore show that incomplete barriers to hybridization may not be sufficient to prevent the continued dominance of hybrids and that active management of invasive hybrids may be required to limit their spread. Author Keywords: fertility model, genetic structure, Hybridization, invasive species, niche segregation, pollen dispersal
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
Bio-based Polymers from Epoxidized Vegetable Oils Modified by Metathesis
The epoxides of oligomeric self-metathesized soybean oil (MSBO) and cross-metathesized palm oil (PMTAG) and canola oil (CMTAG) containing terminal double bonds were used to produce nonisocyanate polyurethanes (NIPUs) as well as anhydride, amine and thiol-cured epoxies. The synthesized NIPUs displayed metal adhesive properties for CMTAG and MSBO with MSBO being favoured probably due to its plasticizing nature as opposed to CMTAG. The relationship was reversed for the anhydride curing reaction where it was found that CMTAG, due to its lower degree of plasticizing content from the reduced dangling chains, produced higher tensile strengths than MSBO. Both MSBO and CMTAG led to fully cured amine and thiol products that were sticky gels, which prevented physical analyzses of their expected solidified products. PMTAG, due to its low number of reactive groups, was not suitable for the synthesis of these polymers. Author Keywords: Amine-cured epoxy, Anhydride-cured epoxy, Metathesis, Nonisocyanate Polyurethanes, Thiol-cured epoxy
Impacts of Cover Crops on Soil Health, Soil Nitrogen Dynamics, and Cytokinin Profiles
In Ontario, the dominant cash crop rotations consist of soybean (SB), which is a leguminous crop grown in rotation with maize (MZ) and winter wheat (WW). In addition to these crops, some farmers integrate cover crops (CC) into crop rotation, especially during the fallow period and winter seasons, to reduce nitrogen (N) losses via nitrate (NO3-) leaching and emission of N2 and the greenhouse gas nitrous oxide (N2O). This thesis focused on understanding the impact of crop phases in a MZ-(SB-WW)-CC rotation on the abundance of N-cycling bacterial communities that mediate nitrification and denitrification pathways. In addition, the influence of CCs on soil cytokinin (CK) profiles, which are plant growth-promoting hormones, were studied in a greenhouse trial to assess their potential impacts when integrating CCs into crop rotations. In particular, the relationship between traditional soil health parameters and the soil CK profiles was studied to understand how CKs might reflect biotic interactions and soil vitality. Results indicate N fertilizer application mono ammonium phosphate (MAP) and starter N:P: K (24:6:24) during WW planting in fall largely supported nitrifying bacterial communities (amoA) and potentially contributed to NO3- leaching. Management of MZ, which included spring-applied MAP resulted in larger denitrifying (nirK) bacterial communities, increasing the potential risk of N-loss via emission of dinitrogen gas (N2) and greenhouse gas N2O. However, CC soils had significantly lower nirK than MZ, reflecting the importance of strong and deep root systems of CCs, which have a higher ability to scavenge the substrates for denitrifying communities (NO3-). This highlights the importance of growing CCs in reducing the potential risk for N-loss via leaching and denitrification. Additionally, in the greenhouse trial, the ability of CCs to affect CK was detected, highlighting the importance of integrating CC in crop rotations. This is particularly noteworthy, given that total CK profiles showed strong associations with traditional soil health parameters such as labile or active carbon and soil microbial community diversity. It was concluded that total soil CK can be used as a novel and dynamic soil health measure. Future research on quantifying N2O fluxes and levels of NO3- in leachates would provide a more precise understanding of the impact of different crop rotation phases on N-dynamics in these fields. Further studies on single or combined measures of soil CKs are warranted to develop its potential as a practical and effective soil health parameter. Author Keywords: Cover crops, Crop rotations, Cytokinin hormone, Nitrogen Cycle, qPCR, Soil health
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
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
Legume species, nitrogen rate and arbuscular mycorrhizal fungi inoculation effects on crop biomass and nitrogen requirement in a corn-legume system
Interseeding legume cover crops in grain corn may improve the environmental sustainability of corn production system in Southern Ontario. This study aimed to assess the effects of legume species, nitrogen (N) fertilizer rate and arbuscular mycorrhizal fungi (AMF) inoculation on biomass and N requirement in a corn-legume system. Corn was grown with red clover (RCl), microclover (MCl), hairy vetch (HV), or beans at 10 and 80 kg N ha-1 rates with and without AMF inoculation in a greenhouse for 7 weeks. Corn dry matter (DM) and N uptake were reduced by beans and HV (average 35%) compared with control; however, the DM for beans and HV was 7 and 3 times higher than RCl and MCl, respectively. The N2 fixation ability was similar among legume species and no significant N transfer from legume was detected. Overall, species collection was critical to the success of incorporating legumes into grain corn production. Author Keywords: Arbuscular mycorrhizal fungi, corn, legume cover crop, nitrogen

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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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