Graduate Theses & Dissertations

Pages

Early Responses of Understory Vegetation to Above Canopy Nitrogen Additions in a Jack Pine Stand in Northern Alberta
Abstract Early Responses of Understory Vegetation After One Year of Above Canopy Nitrogen Additions in a Jack Pine Stand in Northern Alberta Nicole Melong Nitrogen (N) emissions are expected to increase in western Canada due to oil and gas extraction operations. An increase in N exposure could potentially impact the surrounding boreal forest, which has adapted and thrived under traditionally low N deposition. The majority of N addition studies on forest ecosystems apply N to the forest floor and often exclude the important interaction of the tree canopy. This research consisted of aerial NH4NO3 spray applications (5, 10, 15, 20, 25 kg N ha-1yr-1) by helicopter to a jack pine (Pinus banksiana Lamb.) stand in the Athabasca Oil Sands Region (AOSR) in northern Alberta, Canada. The main objective was to assess the impacts of elevated N after one year of treatment on the chemistry of understory vegetation, which included vascular plants, terricolous lichens, epiphytic lichens and a terricolous moss species. Changes in vegetation chemistry are expected to be early signs of stress and possible N saturation. Increased N availability is also thought to decrease plant secondary compound production because of a tradeoff that exists between growth and plant defense compounds when resources become available. Approximately 60% of applied N reached the ground vegetation in throughfall (TF) and stemflow (SF). Nitrate was the dominant form of N in TF in all treated plots and organic N (ON) was the dominant form of N in SF in all plots. The terricolous non-vascular species were the only understory vegetation that responded to the N treatments as N concentration increased with increased treatment. Foliar chemistry of the measured epiphytic lichens, vascular species, and jack pine was unaffected by the N treatments. Based on biomass measurements and N concentration increases, the non-vascular terricolous species appear to be assimilating the majority of TF N after one year. Vegetation from the high treatment plot (25 kg N ha-1yr-1) was compared to a jack pine forest receiving ambient high levels of N (21 kg N ha-1yr-1) due to its proximity to Syncrude mining activities. Nitrogen concentrations in plant tissues did not differ between the two sites; however, other elements and compounds differed significantly (Ca, Mg, Al, Fe). After one year of experimental N application, there were no environmental impacts consistent with the original N saturation hypothesis. Author Keywords: Athabasca Oil Sands Region, Canopy Interactions, Jack Pine, Nitrogen, Secondary Chemistry, Understory Vegetation
Effect of Water Surface Simulated Rain Drop Impacts on Water to Air Chemical Transfers of Perfluorinated Carboxylic Acids (PFCAs)
Perfluorinated carboxylic acids (PFCAs) are anthropogenic environmentally ubiquitous surfactants that tend to concentrate on water surfaces. This investigation looked at the effect of simulated rain on the atmospheric concentration of a suite of PFCAs (C2 - C12) above the bulk water system. Increased air concentrations of all PFCAs were detected during simulated rain events. Long chain PFCAs (>C8) were found to be much more concentrated in the air above the bulk water system than their short chain counter parts (
Habitat use and community structure of grassland birds in southern Ontario agro-ecosystems.
Most grassland bird populations are in decline, so it is becoming increasingly important to understand how they use agricultural field types and form their communities. I performed point counts in cultural meadow, intensive agriculture, and non-intensive agriculture areas in 2011 and 2012. Generalized linear models were used to determine the habitat relationships of six focal species. I found that non-intensive agriculture was used most often and intensive agriculture was often avoided, but there were exceptions which indicate habitat use can be species-specific. I determined in which habitats competition was likely occurring and which species pairs were competing in 2011. In 2012, I experimentally tested these relationships by introducing artificial competitors onto sites. By comparing presence-absence data from 2011 to 2012, I found evidence of habitat-mediated interspecific and conspecific attraction involving Bobolink and Grasshopper Sparrow. This research contributes to the current understanding of grassland bird community ecology and conservation. Author Keywords: agriculture, BACI, community ecology, habitat use, species at risk, species interactions
Why do landowners restore wetlands? A case study from east central Ontario
Wetlands were once widespread in southern Ontario, but many have been drained through land use changes. Using a case study of twelve landowners in the Kawartha region, I explored motivations for restoring wetlands. Psychological research suggests that people who are more connected to nature and attached to place are more likely to behave sustainably. Results showed that having land available and receiving funding were necessary preconditions. Connectedness to nature and place attachment were motivations, as were personal benefits and having a supportive social community. Challenges included: the Permit to Take Water, paperwork and bureaucracy, delays and timing, and economic restrictions. Positive outcomes were: increased property value and crop productivity; personal enjoyment of wetlands; and improved wildlife habitat and water quality. Negative outcomes were: `nuisance' wildlife, trespassing, and a lack or excess of water. This is a novel study exploring nature connectedness, place attachment and wetland restoration qualitatively in southern Ontario. Author Keywords: agriculture, connection to nature, motivation, southern Ontario, stewardship, wetland restoration
"TOUGH BUT NECESSARY"? AN ANALYSIS OF NEOLIBERAL AND ANTI-FEMINIST DISCOURSES USED IN THE ELIMINATION OF THE NEW BRUNSWICK ADVISORY COUNCIL ON THE STATUS OF WOMEN
This study demonstrates that the New Brunswick government rationalized the 2011 elimination of the New Brunswick Advisory Council on the Status of Women (NBACSW) by discursively framing it as a duplication of services and as a non-essential service. The study relies on interviews with women who had been involved with the NBACSW, as well as literature about the use of neoliberal and anti-feminist discourses at the national level. I argue that the two rationalizations offered by the New Brunswick government rely on similar neoliberal and anti-feminist discourses to those used at the national level to eliminate women's institutional machinery and thus diminish women's capacities for advocacy and political representation. I argue that this discursive move positioned the province's largest women's advocacy group as an impediment to the common good of the province and as a threat to "Ordinary New Brunswickers," signalling a negative step for women in the province. Author Keywords: Anti-feminist backlash, Canadian Feminism, Canadian Women's Movements, Discourse Analysis, Neoliberalism, New Brunswick
Pausing Encounters with Autism and Its Unruly Representation
This dissertation seeks to explore and understand how autism, asperger and the autistic spectrum is represented in Canadian culture. Acknowledging the role of films, television, literature and print media in the construction of autism in the consciousness of the Canadian public, this project seeks to critique representations of autism on the grounds that these representations have an ethical responsibility to autistic individuals and those who share their lives. This project raises questions about how autism is constructed in formal and popular texts; explores retrospective diagnosis and labelling in biography and fiction; questions the use of autism and Asperger's as metaphor for contemporary technology culture; examines autistic characterization in fiction; and argues that representations of autism need to be hospitable to autistic culture and difference. In carrying out this critique this project proposes and enacts a new interdisciplinary methodology for academic disability study that brings the academic researcher in contact with the perspectives of non-academic audiences working in the same subject area, and practices this approach through an unconventional focus group collaboration. Acknowledging the contribution of disability studies approaches to representation, this project will also challenge these methodologies on the grounds that the diverse voices of audiences are, at times, absent from discourse focused research. Chapter One offers an explanation of disability studies scholarship and the history of autism as a category of disability and difference. Chapter Two looks at how disability and specifically autistic representations have been understood academically and introduces the rationale and experiences of the focus group project. Chapter Three explores retrospective, biographical diagnosis, the role of autism as technological metaphor, and contemporary biography. Chapter Four looks at the construction of autistic characters in Canadian literature and film. Chapter Five interrogates documentary and news media responses to autism and the construction of autism as Canadian health crisis, and also explores how discourses that surround autism are implicated in interventions and therapeutic approaches to autistic individuals. Key Terms Autism; Autistic Spectrum; Asperger; Disability; Representation; Media; Interdisciplinary Research; Focus Group; Retrospective Diagnosis; Biography; Academic Method; Academic and Representational Responsibility; Literature; Film; Diagnosis; Disability Studies; Therapy Author Keywords: Academic Method, Autism Spectrum, Biography, Disability, Interdisciplinary Research, Representation
Sinaakssin (writing/picture)
Assimilative policies limit and disrupt the inclusion of Aboriginal values in most Aboriginal services today. This art-based, qualitative research study approaches that issue, and using symbolism and story a sample scenario was created to demonstrate the impact of assimilative policy on Aboriginal service delivery in a storyboard format. The storyboard was then presented to four traditional thinkers who contemplated the issues therein, and as they deconstructed, considered, and conferred they resolved the matter and produced four distinct models. Imagery is relied on as a traditional means of communication to capture and convey the research issue as a painted story. This research tested the viability of using imagery as a storyboard methodology for solving social issues. By using this approach this dissertation sought to answer the question, does Indigenous knowledge have the power to change the systemic structures that surround our services. For the analysis, did the three Indigenous knowledge paradigms effectively assist in determining the nature of the Indigenous knowledge applied? Author Keywords: collective community subjectivity, Indigenous methodology, paradigms, story, symbolic communication, symbolic representation
USE OF SALIVARY CORTISOL TO EVALUATE THE INFLUENCE OF RIDES ON THE STRESS PHYSIOLOGY OF DROMEDARY CAMELS (CAMELUS DROMEDARIUS)
Many facilities attempt to alleviate the risk of chronic stress in captivity by providing environmental enrichment shown to minimize behavioural disorders and stress in several species. One potential form of enrichment used in zoos is training animals to perform rides for guests, however, the effect of this activity on the welfare of individual animals has never been examined. I validated the use of saliva for assessing stress in dromedary camels (Camelus dromedarius) an animal commonly used for rides. I then measured variation in salivary cortisol in four male camels during animal rides for guests at the Toronto Zoo. The camels were sampled during the ride season (from June to August) using four treatments: 1) in their pasture, 2) at the ride area not performing rides, 3) performing a low number of rides (n=50/day) and 4) performing a high number of rides (n=150/day). Furthermore, samples were taken before and after the ride season for comparison. There was a significant difference between the post-ride season treatment and the three treatments involving guest presence during the ride season (ride area, low rides, high rides. This indicates that performing rides is not a stressful experience based on the stress metrics I used, and suggests that rides may be a form of enrichment for dromedary camels. Author Keywords: ACTH challenge, animal welfare, camels, environmental enrichment, salivary cortisol, stress
THE EFFECTS OF ROTATIONAL GRAZING AND HAY MANAGEMENT ON THE REPRODUCTIVE SUCCESS OF BOBOLINK AND EASTERN MEADOWLARK IN EASTERN ONTARIO
I investigated the impact of beef-cattle farm management on the reproductive success of Bobolink (Dolichonyx oryzivorus) and Eastern Meadowlark (Sturnella magna) within Eastern Ontario. I monitored rotational grazing management regimes and hay cut dates while assessing breeding phenology and reproductive success of Bobolinks and Eastern Meadowlarks. In pasture paddocks the major factor determining Bobolink reproductive success was the date that cattle entered a paddock to graze, with earlier entries resulting in lower reproductive success. On a landscape scale, within a series of paddocks grazed by a single herd, as the number of paddocks grazed during the nesting season increased, the number of Bobolinks that reproduced successfully decreased. Experimental quantification of trampling showed that cattle exposure to clay pigeon targets, regardless of stocking rates, resulted in the majority of targets being trampled. In hayfields associated with beef- cattle operations, grassland birds had a higher likelihood of success when cutting occurred after 4 July. The best method to improve the reproductive success of Bobolinks and Eastern Meadowlarks is to leave some hayfields and pasture paddocks undisturbed until nesting is complete. Author Keywords: Bobolink, Dolichonyx oryzivorus, farm management, hayfield, pasture, rotational grazing
Spatial dynamics of pollination in dioecious Shepherdia canadensis in Yukon, Canada
Sexual reproduction in flowering plants depends on investment in reproduction, the mode of pollen transfer, the availabilities of nutrient resources and potential mates, and the spatial scales over which these processes take place. In this thesis, I studied the general reproductive biology of Shepherdia canadensis (L.) Nutt. (Elaeagnaceae) and the suite of pollinators that visit the plants in Ivvavik National Park, Yukon, Canada. Across ten sites, I found that S. canadensis females were larger than males, but males produced more flowers than females at most sites. Males typically occurred at higher frequencies than females with the average male to female sex ratio being 1.19 ± 0.08 (mean ± SE, n = 10 sites). Both shrub size and flower production were significantly influenced by interactions between soil nitrogen and sex. Insect visitors to S. canadensis flowers were primarily ants and flower flies (Syrphidae), but exclusion experiments indicated that visitation by flying insects yielded greater fruit production than visitation by crawling insects. I found that fruit set was limited by the density of males within populations, but only over small distances (4-6 m). This is the first study to demonstrate that female reproductive success of a generalist-pollinated dioecious plant is limited by the density of males over small spatial scales. Author Keywords: dioecy, pollinators, sex ratio, sexual dimorphism, Shepherdia canadensis
Songs We Share (and the Records We Steal)
This thesis explores the rhetoric of theft imposed on online music by comparing file sharing to shoplifting. Since the litigation between the music industry and Napster, file sharing has been perceived, both by the entertainment industry and by a music listening public, as a criminal act. However, file sharing has more in common with home taping and music archives than it does with music shoplifting. It differs from theft in terms of law, motivation and publicness. In reviewing three histories -- a history of petty theft, a history of policing online music, and a history of shoplifting narratives in popular music culture -- the implications for the cultural production of popular music and popular music identity become apparent. In the end, file sharing links itself more to parody and the concept of fairness than it does to youth rebellion and therefore is unsuitable for sustaining a traditional music industry and the values it has formed with its public. Author Keywords: copyright, cultural production, file sharing, mp3, popular music, shoplifting
Longitudinal trends of benthic invertebrates in regulated rivers
The Serial Discontinuity Concept describes the downstream recovery of key biophysical variables below an impoundment. With the proliferation of hydropower dams to meet increasing societal demands, further refinement and understanding of the Serial Discontinuity Concept is needed to accurately predict downstream impacts and ensure the proper management of rivers. In this study, I examine SDC predictions on physical, chemical and biological recovery in regulated rivers providing evidence from 1) a comprehensive literature review and 2) a formal test using two regulated rivers in Northern Ontario. I specifically address how these changes are reflected in benthic invertebrate abundance, diversity, and community composition. The literature review and case studies support the predicted recovery of temperature, periphyton, substrate, and drift. In addition, the study suggests that two recovery gradients exist in regulated rivers: 1) a longer, thermal gradient taking up to hundreds of kilometres downstream; and 2) a shorter, resource subsidy gradient recovering within 1-4 km downstream of an impoundment. Total benthic invertebrate abundance varies considerably and depends on the degree of flow alteration and resource subsidies from the upstream reservoir. In contrast, benthic diversity is reduced below dams irrespective of dam location and operation with little recovery observed downstream. Contrary to SDC predictions, the longitudinal gradient in regulated rivers is not a compaction of functional changes seen over several stream orders in natural rivers but a response to dam design and reservoir conditions. Stoneflies and dragonflies are particularly sensitive to regulation while filter feeding invertebrates are enhanced. Ward and Stanford's (1983) Serial Discontinuity Concept is still a useful framework for testing hypotheses. Future studies should further expand the SDC through empirical estimation within the context of the landscape to gain a better scientific understanding of regulated river ecology. Author Keywords: benthic invertebrates, dams, longitudinal, recovery, River Continuum Concept, Serial Discontinuity Concept

Pages

Search Our Digital Collections

Query

Enabled Filters

  • (-) ≠ History

Filter Results

Date

1973 - 2033
(decades)
Specify date range: Show
Format: 2023/01/28