Ecology and Evolutionary Biology Commons^™

Adaptation Reshapes The Distribution Of Fitness Effects, Diego Tenoch Morales Lopez

Electronic Thesis and Dissertation Repository

The process of adaptation has been of interest since the XIX century, when Darwin first proposed the idea of natural selection. Since then, there has been a myriad of theoretical and empirical works that have expanded the field. From the many evolutionary insights these works have produced, a foundational idea is that spontaneous mutations in the genome of organisms can produce changes to their reproductive success that might confer an advantage for the mutant organisms with respect to their peers. Therefore, mutations drive adaptive evolution by virtue of their heritable effects on fitness. Empirical measures of the distribution of these …

Investigating The Soil Mycobiome Of American Ginseng, Rachel Amelia Rajsp

Electronic Thesis and Dissertation Repository

American ginseng (Panax quinquefolius L.) is a perennial herbaceous plant cultivated for its medicinal properties. Growers report that when ginseng is replanted in a field previously used to cultivate ginseng, it soon succumbs to disease, known as ginseng replant disease. I examined changes in composition in the ginseng mycobiome throughout cultivation in a newly planted garden and beyond (i.e., 3–14 years post-harvest) with a third-generation metabarcoding approach (Pacific Biosciences, single-molecule real-time sequencing). Amplicons of about 600 nucleotides from the nuclear ribosomal internal transcribed spacer (ITS) region and translation elongation factor 1-α gene were chosen to help discriminate between closely …

Freezing Tolerance Of Herbaceous Legumes Within Southwestern Ontario: Evidence Of Disproportionate Freezing Sensitivity, Samuel L. Rycroft

Electronic Thesis and Dissertation Repository

Legumes (Fabaceae) represent a diverse and ecologically significant plant taxon; most described legumes form mutualisms with diazotrophic rhizobia, potentially fixing substantial quantities of nitrogen within habitats where they are well-established. Stressors causing lethal or sub-lethal impacts in legumes or rhizobial symbionts may therefore impact the nitrogen dynamics of such habitats. In recent decades, variability of winter temperatures, precipitation, and soil freeze-thaw cycling has increased in temperate regions. Without adequate snow cover to insulate roots and shoot bases, herbaceous plants will likely be exposed to more frequent or severe freezing. In southwestern Ontario, a pattern of disproportionate freezing sensitivity relative to …

The Introduction Of Nursery Seedlings And Their Fungi To A Spruce-Fir Forest In Newfoundland, Alicia G. Banwell

Electronic Thesis and Dissertation Repository

A few species of boreal trees form symbiotic relationships with many ectomycorrhizal (ECM) fungi that allow trees to thrive on nutrient poor soils in Canada. A small number of ECM species grow on tree seedlings raised in nurseries for reforestation of clearcut sites. The native ECM fungal community composition of a mixed spruce-fir forest in Newfoundland was determined through next generation sequencing. With the introduction of nursery seedlings, the transfer of native ECM fungi to seedlings and nursery-established ECM fungi to roots was investigated over 20 months. ECM community composition was found to be similar to that of other boreal …

Short-Term Versus Long-Term Effects Of Nitrogen Addition And Warming On Ecosystem N Dynamics In A Grass-Dominated Temperate Old Field, Benjamin F. A. Souriol

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Increased atmospheric nitrogen (N) deposition and climate warming are both anticipated to influence the ecosystem N dynamics of northern temperate ecosystems substantially over the next century. Nevertheless, in field experiments with N addition and warming treatments, temporal scale can play an important role in determining the extent of treatment effects on N dynamics, and it is unclear to what extent the results of short-term studies can be extrapolated to responses over longer time scales. I compared the short-term versus long-term effects of N addition and warming on net N mineralization, N leaching, and N retention in a grass-dominated old field. …

The Detectability Of Atlantic Salmon (Salmo Salar) Microsatellite And Mitochondrial Environmental Dna, Simone N. Miklosi

Electronic Thesis and Dissertation Repository

Little is known about what information can be gathered from microsatellite eDNA. It is important to gain a deeper understanding of the detectability and analysis of microsatellite eDNA because it could provide information about population size that mitochondrial eDNA cannot. Water samples were collected from tank and river experiments, and rivers known to contain Atlantic salmon (Salmo salar) and analyzed for Atlantic salmon mitochondrial and microsatellite eDNA. Mitochondrial eDNA was detected from all the tank experiments and 10 out of 15 rivers known to contain Atlantic salmon. Microsatellite eDNA was detected from all the tank experiments and none …

Evolution Of Overlapping Reading Frames In Virus Genomes, Laura Muñoz Baena

Electronic Thesis and Dissertation Repository

Viruses are formidable pathogens that represent the majority of biological entities in our planet, and their genomes are a source of interesting enigmas. One feature in which virus genomes are usually rich, is the presence of overlapping reading frames (OvRFs) — portions of the genome where the same nucleotide sequence encodes more than one protein. OvRFs are hypothesized to be used by viruses to encode proteins more compactly and to regulate transcription. In addition, OvRFs might be a source of gene novelty, facilitating the creation of new open reading frames (ORF) within the transcriptional context of existing ones.

To characterize …

The Effect Of Dietary Thiaminase On Cardiac Function And Morphology In Lake Trout (Salvelinus Namaycush), Peter Baker

Electronic Thesis and Dissertation Repository

Thiamine deficiency from the consumption of invasive, high-thiaminase prey fishes is considered to be a major barrier for lake trout restoration in the Great Lakes. In fishes, an understudied aspect of thiamine deficiency is its effect on cardiac function. I examined the effects of dietary thiaminase on cardiac function and morphology in lake trout, specifically as they relate to thermal tolerance. Two hatchery strains of lake trout (Seneca and Slate) were raised on a control or thiaminase diet for nine months. The thiaminase diet was associated with significant ventricle enlargement, impaired cardiac function, and reduced thermal tolerance; these effects were …

Addressing The Impact Of Time-Dependent Social Groupings On Animal Survival And Recapture Rates In Mark-Recapture Studies, Alexandru M. Draghici

Electronic Thesis and Dissertation Repository

Mark-recapture (MR) models typically assume that individuals under study have independent survival and recapture outcomes. One such model of interest is known as the Cormack-Jolly-Seber (CJS) model. In this dissertation, we conduct three major research projects focused on studying the impact of violating the independence assumption in MR models along with presenting extensions which relax the independence assumption. In the first project, we conduct a simulation study to address the impact of failing to account for pair-bonded animals having correlated recapture and survival fates on the CJS model. We examined the impact of correlation on the likelihood ratio test (LRT), …

Effects Of 11-Kt And Prolactin On Gene Expression, Parental Care Behaviour And Immune Response In Male Bluegill Sunfish., Adriano A P Da Cunha

Electronic Thesis and Dissertation Repository

Parental care is very critical for reproduction in species that provide it. Hormones such as prolactin and androgens play a crucial role in parenting and reproductive behaviours. In mammals and birds, prolactin’s role in parental care is well-established; it stimulates milk production and stimulates attachment to newborns by its release in the preoptic area of the hypothalamus (POA), among other functions. Androgens, on the other hand, are commonly associated with male secondary sex characteristics, territoriality, and aggressiveness in mammals and birds. There are similar reports of prolactin and androgen effects in fish, but there are fewer studies. I investigated if …

Age And Sex Differences In Stopover Behaviours And Flight Performance In Black-Throated Blue Warblers, Patricia Rokitnicki

Electronic Thesis and Dissertation Repository

Differential migration by sex and age is commonly observed in passerines. Previous studies have found differences in wing morphology between sex and age classes which could affect their movement ecology. In this thesis, I examine whether migratory stopover duration and nocturnal flight speeds differed between age and sex classes in 89 Black-throated Blue Warblers (Setophaga caerulescens) using movement data obtained by Motus Wildlife Tracking System and meteorological data from the NCEP/NCAR Reanalysis II project. Second year birds (hatched during the previous breeding season) had longer stopovers but similar post-departure movements to after second year birds (hatched before the last breeding …

From Micro To Macro: Examining Potential Microbiome Mediated Influences On Human Growth And Health Outcomes Through Breastfeeding And Antibiotic Exposures, Nicole K. Phillips

Electronic Thesis and Dissertation Repository

Human microbiome research has rapidly developed over the past two decades yet absent from most research is the composition and dynamics of microbiomes within human populations. Given the limitations in longitudinal studies which requires decades of repeated microbe taxonomic testing of a population sample, an alternative option is to examine microbiomes and their influences via proxies using pre-existing health datasets. This research demonstrates preliminary associations between presumed disrupted and supportive microbiomes dynamics proxied by antibiotic and breastmilk exposure respectively. Using health record data across the life span from approximately 500,000 U.K. participants, this research demonstrates variable altered growth and health …

Nitrogen Transfer From Cover Crops To The Subsequent Grain Crop And The Influence Of Variability In Winter Conditions, Spencer Heuchan

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Cover crops, which are used to provide ground cover after the harvest of the grain crop, can potentially improve the sustainability of agroecosystems by reducing nutrient losses. However, few data are available to document the extent to which cover crops improve both the retention of soil nitrogen (N) and the transfer of this N to the grain crop. The efficiency of this N transfer may be further influenced by variation in winter soil temperature; for example, reduced snow cover can increase the frequency and intensity of soil freezing, which can affect the survival of cover crops and the timing of …

Using Stable Isotope Techniques To Complement Existing Northern Pintail Management., Dariusz Wojtaszek

Electronic Thesis and Dissertation Repository

The Northern Pintail (Anas acuta) is a waterfowl game species with North American population levels consistently below long-term management goals. Native habitat loss to agriculture likely reduced recruitment and limits population growth. My objective was to provide a proof-of-concept approach to using stable isotope ratios (δ²H, δ¹³C, δ¹⁵N) in feathers to infer spatial origins and habitat selection to complement existing pintail management. I found 46% of all sampled pintails had likely moult origins in the boreal biome, compared to 32% estimated by breeding population survey and 55% of recruitment of young …

On The Spatial Modelling Of Biological Invasions, Tedi Ramaj

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We investigate problems of biological spatial invasion through the use of spatial modelling. We begin by examining the spread of an invasive weed plant species through a forest by developing a system of partial differential equations (PDEs) involving an invasive weed and a competing native plant species. We find that extinction of the native plant species may be achieved by increasing the carrying capacity of the forest as well as the competition coefficient between the species. We also find that the boundary conditions exert long-term control on the biomass of the invasive weed and hence should be considered when implementing …

Root-Inhabiting And Rhizosphere Mycobiomes And Crop Yield Of Corn And Wheat, Marianna E. Wallace

Electronic Thesis and Dissertation Repository

The root mycobiome plays a direct role in plant productivity, and the study of its community composition allows for identification of organisms that influence plant health. To better understand the role of fungal community composition in crop productivity, the root-associated mycobiomes of historically high and low yield sites of corn and wheat planted in rotation were characterized and analyzed along with soil physicochemical variables and crop yield. In each field studied, root and rhizosphere mycobiomes reflected significant differences in fungal species composition. Several soil variables were found to be predictors of differences in composition of sample types including soil texture …

Effects Of The Brain Nonapeptides Arginine-Vasotocin And Isotocin On Shoaling Behaviour In The Guppy (Poecilia Reticulata), Babak Ataei Mehr

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Brain nonapeptides have been suggested to regulate social behaviours. However, the contribution of Arginine-Vasotocin (AVT) and Isotocin (IT) to social behaviour in fishes is not well-characterized. Using the guppy (Poecilia reticulata), I first measured association preference for conspecifics in individuals injected with either AVT, an AVT-antagonist, or saline. The time spent associating with conspecifics did not differ significantly among the injection treatments. However, individuals injected with AVT performed more movement among areas of the tank than individuals injected with either the AVT-antagonist or saline, consistent with an effect of AVT on anxiety-related behaviours (i.e. hyperactivity). Second, I measured …

A Theoretical Perspective On Parasite-Host Coevolution With Alternative Modes Of Infection, George N. Shillcock

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We investigate how natural selection shapes the coevolution of parasitism. We discuss the antagonism fuelled by parasites’ necessity to transmit to novel hosts, and host’s desire to minimise virulence. In support, we build a mathematical model which considers the epidemiology and life-history trade-offs faced by an obligate microparasite and its host. Our model allows parasites to be transmitted to new hosts via direct contact (horizontally) or from parent to offspring during birth (vertically). We test the hypothesis that vertical transmission causes virulence to diminish in the long run, and contrary to widely accepted views, find that vertical transmission need not …

The Impact Of Long-Term Artificial Removal Experiment And Natural Local Extinctions On The Genetics Of An Alpine Butterfly, Keon Young Park

Electronic Thesis and Dissertation Repository

In the current age of widespread anthropogenic effects across the globe, organisms are vulnerable to habitat fragmentation and localized decline in population more than ever before. Therefore, insight into metapopulation-level dynamics and the genetic basis of inter-patch dispersal is key to understanding the regional persistence of a species in the face of potential localized extinction or population bottleneck. In this study I used samples from a previously conducted localized long-term population removal experiment to investigate the effects of an extended population reductions on the genetic structure of a local population, and to explore the genetic basis of dispersal and recolonization …

Using Conservation Genetics To Inform Reintroduction Of The Endangered Mottled Duskywing (Erynnis Martialis), Shayla Kroeze

Electronic Thesis and Dissertation Repository

Habitat loss and climate change have caused declines in species diversity and abundance globally, including in butterflies which are important components of many ecosystems. Reintroductions are increasingly used to reverse diversity loss but are most effective when informed using genetics. I developed 24 microsatellites and characterized genetic structure and diversity of the endangered Mottled Duskywing (Erynnis martialis) in Ontario and neighbouring provinces and states. These were used to inform a planned reintroduction in Ontario. Populations had moderate levels of genetic diversity, however all but the largest populations may be subject to appreciable levels of genetic drift. Populations more …

From Individuals To Communities: The Effect Of Climate Change On Ectothermic Predators, Matthew Lawrence Meehan

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The living components of ecological systems exist within a nested hierarchy, consisting of individuals, populations, and communities. Because of this nestedness, climate change can greatly impact ecological systems, as whole-organism metabolic and physiological demands change for ectotherms under warming, the effects of which may compound with every succeeding level. Therefore, a multi-level approach can better isolate how climate change will reshape ecological systems. In my doctoral research, I used feeding and mesocosm experiments to examine how climate change affects ectothermic predators at the individual-, population-, and community-level, using mesostigmatic mites (Arachnida: Parasitiformes) as my model predator. My research objectives were …

Connexin 43 Contributes To Phenotypic Variability Of The Mouse Skull, Elizabeth Jewlal

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The purpose of this study was to determine whether connexin 43 (Cx43) contributes to craniofacial phenotypic variability. Skull shape and variation were compared within and among two heterozygous mutant mouse models (G60S/+ and I130T/+) that exhibit different levels of Cx43 channel function when compared to their wildtype counterparts (~80% and ~50% reduction in function, respectively). Results indicated mutants have significant differences in skull shape compared to wildtype littermates. Similar patterns of shape difference were found in both mutants. Increased skull shape variation and a disruption in the covariation of skull structures were observed in G60S/+ mutants only. These results show …

Effects Of Experimental Malaria Infection On Migration Of Yellow-Rumped Warblers (Setophaga Coronata), Rebecca J. Howe

Electronic Thesis and Dissertation Repository

The potential of migratory animals to spread infectious diseases depends on how infection affects movement. If infection delays or slows the speed of travel, transmission to uninfected individuals may be reduced. Whether and how malaria (Plasmodium spp.) affects bird migration has received little experimental research. I captured 40 actively-migrating Yellow-rumped Warblers (Setophaga coronata) at a migration stopover site and held them in captivity. I inoculated 25 with P. cathemerium while 15 received sham inoculations. After 12 days the birds were released. Six P. cathemerium-inoculated birds (24%) developed P. cathemerium infections after inoculation. I radio-tagged all birds, …

Using Spatial Methods To Analyse Anthropogenic Predation Risk And Movement Ecology Of White-Tailed Deer (Odocoileus Virginianus), Rhiannon D. Kirton

Electronic Thesis and Dissertation Repository

Hunting has been used as a central tool by wildlife managers to maintain populations of game species, however, we still lack a good understanding of exactly how hunting influences deer biology. Technological advances in GPS data over the last two decades now enable us to perform more detailed analysis on the effects of human hunters on wildlife populations. This research explores the spatial ecology of hunters and White-tailed deer in the Cross Timbers ecoregion of Oklahoma. Using new statistical methodologies to analyse simultaneous GPS tracking data on deer and hunters to study their spatial interactions. The results show how new …

Fear Of The Human "Super-Predator" In African Mammals, Nikita R. Frizzelle

Electronic Thesis and Dissertation Repository

Humans’ exploitive killing of virtually every mammal species globally may result in a perception of humans as feared, ultra-lethal predators. In Africa, mammals are central to the continent’s tourism industry; however, it is largely unknown whether African mammals fear the presence of tourists. Firstly, I aimed to review how the presence of humans on the landscape affects African mammal behaviour. Of 31 studies, most authors reported that humans alter mammal behaviour in a manner that may negatively impact survival. To test if a fear of humans can pervade communities, I simulated the presence of humans, hunting, lions, and birds using …

Diversity And Drivers Of Oribatid Mites (Acari: Oribatida) In Boreal Peatlands, Carlos Rafael De Araujo Barreto

Electronic Thesis and Dissertation Repository

Boreal peatlands are important ecosystems for carbon cycling, storing 1/3 of the world’s terrestrial carbon in only ~3% of the globe, making them a key component of potential mitigation strategies in response to global climate warming. Experiments have shown that warming can affect plant and microbial communities in ways that potentially shift peatlands from carbon sinks to sources. Soil food webs, including the microarthropod community, are key in carbon cycling but are relatively understudied both in peatlands and under experimental warming. My research capitalized on a large-scale experimental field manipulation of warming in two contrasting peatland sites in Northern Ontario, …

Investigating Social Dynamics Using Automated Radiotracking Of Winter Flocks Of Black-Capped Chickadees (Poecile Atricapillus), Christopher J. Course

Electronic Thesis and Dissertation Repository

The major forces that govern social groups, namely fission-fusion dynamics, cohesion and maintenance, are nearly ubiquitous across animal groups. The field of animal collective behaviour has recently been married with automated radiotracking producing a ‘re-wilding’ of field research into sociality. The combination of this with Social Network Analysis has led to discoveries such as population wide information transfer and the flexibility of animal groups to change social connectivity based on environmental context. However, these networks are constructed, and do not include the dynamic environmental, spatio-temporal, and social contexts which directly affect sociality. I conducted the first automated radiotracking study I …

Long-Term Vs. Short-Term Plant Responses To Warming And Nitrogen Addition In A Temperate Old Field, Breanna Craig

Electronic Thesis and Dissertation Repository

Climate warming and atmospheric nitrogen (N) deposition are expected to have strong effects on plant productivity in temperate ecosystems over the next century. However, short-term experiments may not adequately address their potential effects because of lags in changes in species composition. I added new plots to a pre-existing field experiment to compare the short-term (1-2 year; new plots) vs. long-term (14-15 year; old plots) effects of warming and N addition on plant productivity, relative species abundances, plant tissue N content, and litter decomposition. In 2020, N addition increased aboveground plant productivity most in old plots and only increased belowground biomass …

Coevolution Of Hosts And Pathogens In The Presence Of Multiple Types Of Hosts, Evan J. Mitchell

Electronic Thesis and Dissertation Repository

How will hosts and pathogens coevolve in response to multiple types of hosts? I study this question from three different perspectives. First, I model a scenario in which hosts are categorized as female or male. Hosts invest resources in maintaining their immune system at a cost to their reproductive success, while pathogens face a trade-off between transmission and duration of infection. Importantly, female hosts are also able to vertically transmit an infection to their newborn offspring. The main result is that as the rate of vertical transmission increases, female hosts will have a greater incentive to pay the cost to …

Food Caching Decisions In Canada Jays (Perisoreus Canadensis), Robert J. Martin

Electronic Thesis and Dissertation Repository

Food scarce periods pose serious challenges for birds, particularly when those periods coincide with demanding life history stages such as overwintering. For resident birds in the Northern hemisphere, resource scarcity typically occurs simultaneously with winter conditions. In order to combat these compounded stressors, some species cache food to ensure a reliable supply of resources. Food caching is the storing of food items for subsequent retrieval and consumption after some delay. Canada Jays (Perisoreus canadensis) are year-round residents of the North American boreal forest and some high elevation areas in the United States, and cache food to combat resource …