Environmental and Life Sciences

Assessments of the adaptive potential of natural populations are essential for understanding and predicting responses to environmental stressors like climate change and infectious disease. The range of stressors species face in a human-dominated landscape, often have contrasting effects. White-tailed deer (Odocoileus virginianus, deer) are expanding in the northern part of their range following decreasing winter severity and increasing forage availability, caused by climate change. Chronic wasting disease (CWD), a prion disease affecting cervids, is likewise expanding and represents a major threat to deer and other cervids We obtained tissue samples from free-ranging deer across their native range in Ontario, Canada which has yet to detect CWD in wild populations of cervids. High throughput sequencing was used to assess neutral genomic variation and variation in the gene responsible for the protein that misfolds into prions when deer contract CWD, known as the PRNP gene. Neutral variation revealed a high number of rare alleles and no population structure, consistent with an expanding population of deer. Functional genetic variation revealed that the frequencies of variants associated to CWD susceptibility and disease progression were evenly distributed across the landscape and the frequencies were consistent with deer populations not infected with CWD. These findings suggest that an observable shift in PRNP allele frequencies likely coincides with the start of a novel CWD epidemic. Sustained surveillance of genomic and genetic variation can be a useful tool for CWD-free regions where deer are managed for ecological and economic benefits.

Author Keywords: Canadian wildlife, population genetics, prion, PRNP, RADseq, ungulate

This thesis uses three approaches to assess the potential of permaculture in Central Ontario. This was done using a vegetable field trial and modelling programs to determine the effectiveness of permaculture to decrease negative impacts of climate change based on projected climate values derived from regional circulation models. The first approach showed no statistical difference (P<0.05) of applying varied volumes and combinations of organic amendments on crop yields. The second approach indicated permaculture may be a sustainable production system with respect to soil erosion when compared to traditional agricultural practices. The third approach was inconclusive due to the lack of quantitative literature on permaculture management impacts on biomass yields, soil carbon or nutrient retention, which were missing from basic and scientific literature searches. The models used within this thesis include USLE, RUSLE2, AgriSuite, RothC and Holos.

Author Keywords: Agriculture, Climate Change, Computer Modelling, Permaculture, Soil Erosion and Assessment

Basic biogeographic information is lacking for many species, such as where species are found, and how they dispersed there. Using ground beetles collected during 2008-2015 from across northern Ontario and Akimiski Island, Nunavut, I present new information on ground beetle distribution in this eastern Nearctic boreal forest, including 2 first Canadian records, 9 first provincial and 48 first territorial records, as well as 74 new records that extend the known range of many large and common ground beetles several hundred kilometres. I used these distributions to redress the knowledge gap that includes fundamental distribution data, i.e. the Wallacean shortfall, and to inform later chapters in my thesis.In Chapter 3, I examine the range expansion pattern of Carabus granulatus, a non-native species, as it spread across northeastern North America and I provide a new range record. Northern Ontario is already under threat from non-native species entering the region and it is important to conduct studies in the region before more disturbance associated with development occurs. In Chapter 4, I examine the hypothesis that northern Ontario effectively acts as a climate plateau for poikilotherms, using the predictions from Bergmann's rule as my metric. The body length of ground beetles does not appear to change over the small temperature gradient that exists across northern Ontario latitudes, supporting the climate plateau hypothesis. In Chapter 5, I test hypotheses about dispersal mechanisms that contributed to post glacial re-establishment of ground beetles using predictions of geographic distribution patterns as metrics. I found that ground beetles were likely carried downstream by rivers which aided their dispersal northward from southern refugia. I infer from the current geographic distributions that flightless ground beetle species are still expanding their range in this boreal region. Finally, I argue that there is an urgent need for more basic research on species distributions while it is still possible in regions like northern Ontario, before increased industrial and agricultural development, and expanding resource extraction projects obliterate evidence of historic ecological processes.

Author Keywords: Boreal forest, Carabidae, Coleoptera, Passive dispersal, Post-glacial distribution, Range extension

Opioid drugs are among the microcontaminants that are discharged with domestic wastewater into the aquatic environment with the potential to affect the development and reproductive capacity of aquatic organisms. To study the effects of exposure of fish to opioid drugs, Japanese medaka (Oryzias latipes) were exposed over a full life cycle to environmentally relevant (i.e. ng/L) concentrations of two opioids, codeine and fentanyl. Acute exposure of early life stage (ELS) of medaka to codeine resulted in slightly extended times to hatch, but no increase in embryo mortalities or reduced hatching success. Chronic exposure to codeine at a nominal concentration of 25,000 ng/L over a full life cycle interfered with growth, reducing the weight of the fish at maturity. Life cycle treatments with codeine at all test concentrations resulted in a significant reduction in the number of eggs produced in reproductive trials, as well as a reduction in the numbers of mature oocytes in adult females. High treatments with codeine also increased the percentage of immature sperm cells in adult males. Life cycle exposures to codeine also resulted in reduced whole-body concentrations of several hypothalamic-pituitary-gonadal (HPG) axis hormones, including reduced levels of luteinizing hormone in male and female fish and a reduction in 11-ketotestosterone in males and 17β-estradiol in females. Fentanyl did not affect reproduction or HPG hormones at the exposure concentrations tested, but high fentanyl exposures increased the mortality rate among ELS's of the F1 generation offspring from life cycle exposed adults. The results of this thesis contribute to the literature on the environmental impacts of microcontaminants of wastewater origin and, the potential for effects in fish exposed to opioids.Keywords: Opioids, microcontaminants, fentanyl, codeine, sexual development, reproduction.

Author Keywords: codeine, fentanyl, microcontaminants, opioids, reproduction, sexual development

Road runoff is a vector for the transport of potentially toxic chemicals into receiving waters. In this study, selected tire-derived chemicals were monitored in surface waters of rivers adjacent to two high traffic highways in the Greater Toronto Area in Ontario, Canada. Composite samples were collected from the Don River and Highland Creek in the GTA during 5 hydrological events that occurred in the period between early October 2019 and late March 2020, as well as an event in August 2020. Grab samples were collected from these rivers during a period of low flow in August 2020, as well as during a storm event in July of 2020. Analysis was performed using ultra-high pressure liquid chromatography with high resolution mass spectrometric detection (UHPLC-HRMS). Hexamethoxymethylmelamine (HMMM), a cross-linker of tire material, was detected at elevated concentrations (> 1 µg/L) during rain events in the fall and winter of 2019-20 and during a period of rapid snow melt in early March of 2020. These samples were also analyzed for the tire additive, 6PPD, and its oxidation by-product, 6PPD-quinone, as well as 1,3-diphenylguanidine (DPG). In many samples collected from the Don River and Highland Creek during storm events, the estimated concentrations of 6PPD-quinone exceeded the reported LC50 of 0.8 µg/L for Coho salmon exposed to this compound. Temporal samples collected at 3-hour intervals throughout rain event the October 2020 showed that there was a delay of several hours after the start of the event before these compounds reached their peak concentrations. In addition, 26 candidate transformation products and precursor compounds of HMMM were monitored; 15 of these compounds were detected in surface waters in the GTA. The maximum total concentration of this class of methoxymethylmelamine compounds in surface water samples was estimated to be 18 µg/L. There is limited knowledge about the properties of HMMM, its precursor contaminants, and its transformation compounds, as well as their fate in the environment. COSMO-RS solvation theory was used to estimate the physico-chemical properties of HMMM and its derivatives. Using the estimated values for these properties (e.g., solubility, vapour pressure, log Kow) as inputs to the Equilibrium Criterion (EQC) fugacity-based multimedia model, the compounds were predicted to readily partition into aqueous media, with mobility in water increasing with the extent of loss of methoxymethyl groups from HMMM. Overall, this study contributes to the growing literature indicating that potentially toxic tire-wear compounds are transported via road runoff into urban surface waters. In addition, this study provides insight into the environmental behaviour of HMMM and its transformation products.

Author Keywords: 6PPD-quinone, COSMOtherm, Fugacity, Hexamethoxymethylmelamine, Road runoff, Tire wear

The oyster mushroom, Pleurotus ostreatus, is one of the most widely cultivated edible basidiomycetes. It has gained increased attention for its economic, environmental, and medicinal properties. While a lot is known about cytokinins (CKs) and their actions at the molecular and cellular levels in plants, much less is known about the function of CKs in other kingdoms. Cytokinins, which have been detected in several fungal species, play a role in pathogenic attack against plants or during plant growth promotion by plant beneficial microbes; however, the role of CKs in fungal physiology, separate from plant associations remains largely unknown. This thesis focuses on the occurrence of fungal-derived CKs in P. ostreatus when grown in vitro as submerged or aerial mycelium. Cytokinin profiling by UHPLC-HRMS/MS revealed that P. ostreatus produces CKs and that the tRNA degradation pathway is the main source of these molecules. CK dynamics within fungal growth supported previous evidence, which suggested that tRNA degradation products have a role in the physiological development of fungi for which CKs act as fungal growth regulators. A second component of the thesis demonstrated that P. ostreatus responds to exogenous applications of aromatic and isoprenoid CKs and their effects were dependent on the dose and CK type. N6-Benzyladenine (BAP), Kinetin (KIN), N6-isopentenyladenine (iP), and trans-zeatin (tZ) bioassays revealed hormone-type responses (hormesis: biphasic response). At low doses, mycelium growth could be stimulated, whereas, at high doses only inhibitory effects were observed. This stimulation/inhibition was observed whether the measured response was an increase/decrease of aerial mycelium colony diameter, biomass accumulation or a change in mycelium morphology as compared to the controls. Results indicated there is potential to alter mycelium growth and development of P. ostreatus; thus, CKs may play the role of a "mycohormone" and may be specifically helpful for medicinal fungi by increasing growth and efficiency to produce many biologically active substances with valuable medical and environmental applications.

Author Keywords: cytokinins, fungal-derived CKs, hormesis, mycelium, mycohormone, Pleurotus ostreatus

Peatlands can be found widely across all latitudes and play a significant role in global cycles within the earth's biosphere. The anoxic conditions in peatlands promotes the accumulation of organic matter through decreased rates of decomposition and the storage of certain elements, which have received contaminant loading over the course of human existence, with significant increases occurring during the period of industrialization. We assessed global patterns of metal enrichment in peatlands in 439 cores distributed across 5 continents and 21 countries and measured 35 elements by depth increments and by peatland type. Global patterns in enrichment factors (EF's) were determined for all metals with the majority of metals being found to have a median EF < 2 indicating relatively minor enrichment. Principal component analysis indicated EF's of 6 metals (Cd, Co, Cu, Ni, Pb, and Zn), 2 metalloids (As and Sb) and Se in the upper peat horizon had similar spatial patterns among peatlands and these elements had generally the highest EF's with many cores exceeding EF >10 and some having EF values >100. Significant differences in EF's were found for these 9 "pollution" elements by peatland type and to a greater extent by geographic region, with higher EF values typically occurring in Europe and North America. Enrichment factors for most elements exhibited weak but significant positive correlations with modelled [1850 – present] S deposition. Estimated pools for the "pollution metals" within the 0 - 40 cm depth varied considerably, with median global pools in peat ranging from 12.9 mg m-2 (Sb) to 439 mg m-2 (Zn) for these 9 metals. Climate changes presents a significant risk to global peatland geochemistry due to expected changes in hydrologic regimes, resulting in potentially increased metal mobility though drought-induced peatland acidification, with historic areas previously impacted by industrial activities presenting the greatest risk of metal release to downstream receiving environments. Using a case study, we examined the impact of simulated 30-day drought on pore water chemistry at six sites in a peatland complex in Elliot Lake Ontario that were historically impacted by uranium (U) mining activities. All sites responded similarly to simulated drought with pore water pH significantly declining. The decline in pore water pH was likely due to increasing sulphate (SO42-) concentrations, which accompanied large increases in Al, Ni, Cu, Pb, Zn, and U. Dissolved organic carbon (DOC) increased, which may further enhance Al, Cu, and U mobility as these metals are strongly complexed by organic acids. Metal partitioning (Kd) values could be significantly predicted by pH and DOC although the strength of the relationship varied considerably among sites. Multiple linear regression and the inclusion of SO4-2 improved predictions, indicating that declines in pH as a result of SO4-2 and H+ production primarily governs metals and U partitioning in peatland soils. The results from both studies show that metal enrichment in global peatlands is highly variable, with northern peatlands in industrialized areas presenting the greatest risk of metal release to downstream surface waters based on expected hydrologic impacts from climate change due to historical and on-going metal and S deposition.

Author Keywords: Acidification, Climate Change, Drought, Enrichment Factors, Global, Peatlands

Fisheries assessment and management approaches have historically focused on individual species over relatively short timeframes. These approaches are being improved upon by considering the potential effects of both broader ecological and evolutionary processes. However, only recently has the question been raised of how ecological and evolutionary processes might interact to further influence fisheries yield and sustainability. My dissertation addresses this gap in our knowledge by investigating the role of eco-evolutionary dynamics in a commercially important lake whitefish fishery in the Laurentian Great Lakes, a system that has undergone substantial ecosystem change. First, I link the timing of large-scale ecological change associated with a species invasion with shifts in key density-dependent relationships that likely reflect declines in the population carrying capacity using a model selection approach. Then, using an individual-based model developed for lake whitefish in the southern main basin of Lake Huron, I demonstrate how ecosystem changes that lower growth and recruitment potential are predicted to reduce population productivity and sustainable harvest rates through demographic and plastic mechanisms. By further incorporating an evolutionary component within an eco-genetic model, I show that ecological conditions also affect evolutionary responses in maturation to harvest by altering selective pressures. Finally, using the same eco-genetic model, I provide a much-needed validation of the robustness of the probabilistic maturation reaction norm (PMRN) approach, an approach that is widely used to assess maturation and infer its evolution, to ecological and evolutionary processes experienced by exploited stocks in the wild. These findings together highlight the important role that ecological conditions play, not only in determining fishery yield and sustainability, but also in shaping evolutionary responses to harvest. Future studies evaluating the relative effects of ecological and evolutionary change and how these processes interact in harvested populations, especially with respect to freshwater versus marine ecosystems, could be especially valuable.

Author Keywords: Coregonus clupeaformis, density-dependent growth, fisheries-induced evolution, individual-based eco-genetic model, Lake Huron, stock-recruitment

Cis-isomers of the cytokinin plant hormone family are thought to have low activity or impact on plant growth and development. Mutants with independent silencing of the pathway leading to cis-CK (cis-cytokinin) were investigated at the phenotype and metabolite levels. Phenotypic deviations were noted in trichome development, fresh weight, rosette diameter, number of non-rosette leaves, shoot height, delayed flowering, flower number, and carotenoids. Exploratory metabolomic analysis detected a number of metabolite features that have been associated with CK, auxin, and ABA (abscisic acid) activity. Evidence from both phenotype and metabolomic analysis support the hypothesis that cis-CK production is biologically important for plant growth and development.

Author Keywords: arabidopsis, cytokinin, IPT, metabolmics

This thesis focused on expanding knowledge of Hybomitra, Chrysops and Tabanus (Diptera: Tabanidae) distributions north of Lake Nipigon, Ontario, in a managed boreal forest. As land use and climate changes accelerate, there is increased pressure to increase knowledge from which to monitor changes. In 2011 and 2012, 8928 individuals representing, 44 species were captured using sweep netting. Major northward range extensions were observed for Chrysops shermani, C. aberrans and Tabanus fairchildi. Smaller range extensions and in-fills were observed for another 15 species. 23 species had exntensions to their previously known seasonal range. C. carbonarius was the only species that showed an extension to both sides of its season. In general, harvested stands had 50% more individuals and 30% greater species richness than younger stands. A possible link between stand age and interspecific competition was identified. Information has been provided to build baseline of species richness, relative abundance and distribution of Tabanid flies.

Author Keywords: diptera, distribution, natural history, northern Ontario, species range, tabanid