Graduate Theses & Dissertations

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Comparative Evaluation of Effective Population Size Genetic Estimation Methods in Wild Brook Trout (Salvelinus fontinalis) Populations
Effective population size (Ne) is a key concept in population genetics, evolutionary biology and conservation biology that describes an important facet of genetic diversity and the capacity of populations to respond to future evolutionary pressures. The importance of Ne in management and conservation of wild populations encouraged the development of numerous genetic estimators which rely on a variety of methods. Despite the number and diversity of available Ne methods, however, tests of estimator performance have largely relied on simulations, with relatively few tests based on empirical data. I used well-studied wild populations of brook trout (Salvelinus fontinalis) in Algonquin Park, Ontario as a model system to assess the comparative performance of multiple Ne estimation methods and programs, comparing the resultant Ne estimates against demographic population size estimates. As a first step, the genetic diversity and ancestry of wild brook trout populations was determined using 14 microsatellite loci. Genetic structure of brook trout populations showed variable contributions from historical supplemental stocking and also identified localized gene pools within and between watersheds, reflecting variable levels of connectivity and gene flow. Once the genetic ancestry and connectivity of populations had been resolved, single sample (point) and two samples (temporal) genetic estimators were used to estimate Ne of populations with pure native ancestry. Values obtained from genetic estimators utilizing both methods were variable within as well as among populations. Single sample (point) estimators were variable within individual populations, but substantially less than was observed among the temporal methods. The ratios of Ne to the estimated demographic population size (N) in small populations were substantially higher than in larger populations. Variation among estimates obtained from the different methods reflects varying assumptions that underlay the estimation algorithms. This research further investigated the effect of sampling effort and number of microsatellite loci used on Ne values obtained using the linkage disequilibrium (LD) estimation method. Ne estimates varied substantially among values generated from subsets of loci and genotyped individuals, highlighting the necessity for proper sampling design for efforts aiming to measure Ne. Despite the variation observed among and within estimation methods, the Ne concept is a valuable for the conservation and management of both exploited and endangered species. Author Keywords: Brook Trout, Effective population size, Genetic Diversity, Genetic Structure
Demography and habitat selection of Newfoundland caribou
The objective of this thesis is to better understand the demography and habitat selection of Newfoundland caribou. Chapter 1 provides a general introduction of elements of population ecology and behavioural ecology discussed in the thesis. In Chapter 2, I examine the causes of long-term fluctuations among caribou herds. My findings indicate that winter severity and density-dependent degradation of summer range quality offer partial explanations for the observed patterns of population change. In Chapter 3, I investigate the influence of climate, predation and density-dependence on cause-specific neonate survival. I found that when caribou populations are in a period of increase, predation from coyotes and bears is most strongly influenced by the abiotic conditions that precede calving. However, when populations begin to decline, weather conditions during calving also influenced survival. I build on this analysis in Chapter 4 by determining the influence of climate change on the interplay between predation risk and neonate survival. I found that the relative equilibrium between bears and coyotes may not persist in the future as risk from coyotes could increase due to climate change. In Chapter 5, I investigate the relationships in niche overlap between caribou and their predators and how this may influence differential predation risk by affecting encounter rates. For coyotes, seasonal changes in niche overlap mirrored variation in caribou calf risk, but had less association with the rate of encounter with calves. In contrast, changes in niche overlap during the calving season for black bears had little association with these parameters. In Chapter 6, I examine broad-level habitat selection of caribou to study trade-offs between predator avoidance and foraging during the calving season. The results suggest that caribou movements are oriented towards increased access to foraging and the reduction of encounter risk with bears, and to a lesser extent, coyotes. Finally, I synthesize the major findings from this thesis and their relevance to caribou conservation in Chapter 7, to infer that Newfoundland caribou decline is ultimately driven by extrinsic and intrinsic elements related to density-dependence. Reduction in neonate survival emerged from nutritionally-stressed caribou females producing calves with lower survival. Author Keywords: Behavioural ecology, Black bear (Ursus americanus), Coyote (Canis latrans), Population ecology, Predator-prey interactions, Woodland caribou (Rangifer tarandus)
Constraints on phenotypic plasticity in response to predation risk
Inducible defenses are plastic responses by an organism to the perception of predation risk. This dissertation focuses on three experiments designed to test the hypothesis that plastic ability is limited by energetic constraints. Chapter 1 provides a general introduction to phenotypic plasticity research and the theoretical costs and limitations affecting the expression of plastic traits. In Chapter 2, I tested the hypothesis that costs of early plasticity may be manifested by a reduced response to risk in later life stages. I found that amphibian embryos are able to detect and respond to larval predators, but that the energetic cost of those plastic responses are not equivalent among behavioural, growth, and morphological traits, and their expression differs between closely-related species. Chapter 3 explicitly examines the relationship between food resource availability and plasticity in response to perceived predation risk during larval development. Food-restricted tadpoles showed limited responses to predation risk; larvae at food saturation altered behaviour, development, and growth in response to predation risk. Responses to risk varied through time, suggesting ontogeny may affect the deployment of particular defensive traits. Chapter 4 examines the influence of maternal investment into propagule size on the magnitude of the plastic responses to predation risk in resulting offspring. I found that females in better body condition laid larger eggs and that these eggs, in turn, hatched into larvae that showed greater morphological plasticity in response to predation risk. Maternal investment can therefore affect the ability of offspring to mount morphological defenses to predation risk. Last, Chapter 5 provides a synthesis of my research findings, identifying specific factors constraining the plastic responses of prey to perceived predation risk. Overall, I found constraints on plastic responses imposed by the current environment experienced by the organism (resource availability), the prior experience of the organism (predator cues in the embryonic environment), and even the condition of the previous generation (maternal body condition and reproductive investment). Together, these findings both provide new knowledge and create novel research questions regarding constraints limiting phenotypic variation in natural populations. Author Keywords: behaviour, inducible defense, Lithobates pipiens, morphometrics, phenotypic plasticity, predation risk
Hybridization Dynamics between Wolves and Coyotes in Central Ontario
Eastern wolves (Canis lycaon) have hybridized extensively with coyotes (C. latrans) and gray wolves (C. lupus) and are listed as a `species of special concern' in Canada. Previous studies have not linked genetic analysis with field data to investigate the mechanisms underlying Canis hybridization. Accordingly, I studied genetics, morphology, mortality, and behavior of wolves, coyotes, and hybrids in and adjacent to Algonquin Provincial Park (APP), Ontario. I documented 3 genetically distinct Canis types within the APP region that also differed morphologically, corresponding to putative gray wolves, eastern wolves, and coyotes. I also documented a substantial number of hybrids (36%) that exhibited intermediate morphology relative to parental types. I found that individuals with greater wolf ancestry occupied areas of higher moose density and fewer roads. Next, I studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of canids in the hybrid zone. I found that survival was poor and harvest mortality was high for eastern wolves in areas adjacent to APP compared with other sympatric Canis types outside of APP and eastern wolves within APP. Contrary to previous studies of wolves and coyotes elsewhere, I hypothesized that all Canis types exhibit a high degree of spatial segregation in the Ontario hybrid zone. My hypothesis was supported as home range overlap and shared space use between neighboring Canis packs of all ancestry classes were low. Territoriality among Canis may increase the likelihood of eastern wolves joining coyote and hybrid packs and exacerbate hybridization. Canids outside APP modified their use of roads between night and day strongly at high road densities (selecting roads more at night), whereas they responded weakly at lower road densities (generally no selection). Individuals that survived exhibited a highly significant relationship between the difference in their night and day selection of roads and availability of roads, whereas those that died showed a weaker, non-significant response. My results suggest that canids in the unprotected landscape outside APP must balance trade-offs between exploiting benefits associated with secondary roads while mitigating risk of human-caused mortality. Overall, my results suggest that the distinct eastern wolf population of APP is unlikely to expand numerically and/or geographically under current environmental conditions and management regulations. If expansion of the APP eastern wolf population (numerically and in terms of its geographic distribution) is a conservation priority for Canada and Ontario, additional harvest protection in areas outside of APP may be required. If additional harvest protection is enacted, a detailed study within the new areas of protection would be important to document specific effects on eastern wolf population growth. Author Keywords: Canis, coyotes, eastern wolves, hybridization, resource selection, survival
Dynamics and Mechanisms of Community Assembly in a Mined Carolinian Peatland
Theoretical work on community recovery, development, stability, and resistance to species invasions has outpaced experimental field research. There is also a need for better integration between ecological theory and the practice of ecological restoration. This thesis investigates the dynamics of community assembly following peat mining and subsequent restoration efforts at Canada's most southerly raised bog. It examines mechanisms underlying plant community changes and tests predictions arising from the Dynamic Environmental Filter Model (DEFM) and the Fluctuating Resource Hypothesis (FRH). Abiotic, biotic and dispersal filters were modified to test a conceptual model of assembly for Wainfleet Bog. Hydrology was manipulated at the plot scale across multiple nutrient gradients, and at the whole bog scale using peat dams. Trends in time series of hydrological variables were related to restoration actions and uncontrolled variables including precipitation, evapotranspiration and arrival of beaver. Impacts of a changing hydrology on the developing plant community were compared with those from cutting the invasive Betula pendula. Transplanting experiments were used to examine species interactions within primary and secondary successional communities. Seedlings of B. pendula and the native Betula papyrifera were planted together across a peat volumetric water content (VWC) gradient. Impacts of beaver dams were greater than those of peat dams and their relative importance was greatest during periods of drought. Cutting of B.pendula had little effect on the secondary successional plant community developing parallel to blocked drains. Phosphorus was the main limiting nutrient with optimum levels varying substantially between species. Primary colonisers formed a highly stable, novel plant community. Stability was due to direct and indirect facilitative interactions between all species. Reduction in frost heaving was the major mechanism behind this facilitation. Interactions within the secondary successional community were mostly competitive, driven by light and space availability. However, restricted dispersal rather than competition limited further species recruitment. Predictions based on the DEFM were partially correct. A splitting of this model's biotic filter into competition and facilitation components is proposed. There was little support for the FRH based on nutrient levels and VWC. B. pendula had higher germination and growth rates, tolerance to a wider range of peat VWCs and a greater resistance to deer browsing than native birch. Peat mining, combined with restoration actions and the arrival of beaver has moved much of the bog back to an earlier successional stage circa 350+ years BP. Evidence points to B. pendula being a "back-seat driver" in the ecosystem recovery process. Indirect facilitation of a native by an exotic congener, mediated through herbivory, has not been described previously. Shifts in relative contributions of facilitation, competition and dispersal limitations to community assembly may be useful process-oriented measures for gauging progress in restoration. Author Keywords: Betula pendula, community assembly, competition, facilitation, peatland, restoration
Hydroclimatic and spatial controls on stream nutrient export from forested catchments
Winter nutrient export from forested catchments is extremely variable from year-to-year and across the landscape of south-central Ontario. Understanding the controls on this variability is critical, as what happens during the winter sets up the timing and nature of the spring snowmelt, the major period of export for water and nutrients from seasonally snow-covered forests. Furthermore, winter processes are especially vulnerable to changes in climate, particularly to shifts in precipitation from snow to rain as air temperatures rise. The objective of this thesis was to assess climatic and topographic controls on variability in stream nutrient export from a series of forested catchments in south-central Ontario. The impacts of climate on the timing and magnitude of winter stream nutrient export, with particular focus on the impact of winter rain-on-snow (ROS) events was investigated through a) analysis of long-term hydrological, chemical and meteorological records and b) high frequency chemical and isotopic measurements of stream and snow samples over two winters. The relationship between topography and variability in stream chemistry among catchments was investigated through a) a series of field and laboratory incubations to measure rates and discern controls on nitrogen mineralization and nitrification and b) analysis of high resolution spatial data to assess relationships between topographic metrics and seasonal stream chemistry. Warmer winters with more ROS events were shown to shift the bulk of nitrate (NO3-N) export earlier in the winter at the expense of spring export; this pattern was not observed in other nutrients [i.e. dissolved organic carbon (DOC), total phosphorus (TP), sulphate (SO4), calcium (Ca)]. Hydrograph separation revealed the majority of ROS flow came from baseflow, but the NO3-N concentrations in rainfall and melting snow were so high that the majority of NO3-N export was due to these two sources. Other nutrient concentrations did not show such a great separation between sources, and thus event export of these nutrients was not as great. Proportionally, catchments with varying topography responded similarly to ROS events, but the absolute magnitude of export varied substantially, due to differences in baseflow NO3-N concentrations. Field and laboratory incubations revealed differences in rates of net NO3-N production between wetland soils and upland soils, suggesting that topographic differences amongst catchments may be responsible for differences in baseflow NO3-N. Spatial analysis of digital elevation models revealed strong relationships between wetland coverage and DOC and dissolved organic nitrogen (DON) concentrations in all seasons, but relationships between topography and NO3-N were often improved by considering only the area within 50 or 100m of the stream channel. This suggests nutrient cycling processes occurring near the stream channel may exert a stronger control over NO3-N stream outflow chemistry. Overall, topography and climate exert strong controls over spatial and temporal variability in stream chemistry at forested catchments; it is important to consider the interaction of these two factors when predicting the effects of future changes in climate or deposition. Author Keywords: biogeochemistry, forest, nitrate, south-central Ontario, stream chemistry, winter
Canadian Refugee Policy
This dissertation is an inquiry into the politics of the frame in Canadian refugee policy. It is focused on "framing," thereby taking up the stance of critical policy studies while pressing the contribution of Donald Schön and Martin Rein in a critical and politically inflected direction. The dissertation unfolds as a political history of Canadian refugee policy that provides a "contextual mapping," relevant to both inquiry and action in regard to the framing of refugees. The main argument is that twentieth- and twenty-first- century refugee policy in Canada is a story of three shifting meta-frames: beginning with humanitarianism (in the inter-War years and the post-World War II period); shifting to neo-humanitarianism (beginning in the late 1970s, in connection with the rise of neoliberalism); then shifting again (beginning in the 1990s) to securitization. The concept of a meta-frame here is analogous to that of a "metacultural frame" in Schön and Rein, but accents political rather than cultural dimensions. This concept is developed in a manner suitable to a political history by illustrating how meta-frames both become stable and change. With humanitarianism, the refugee was typically portrayed in ambivalent terms - both deserving of and entitled to protection, while also posing a burden for the national interest. In the context of neo-humanitarianism, this ambivalence began to wane, and the refugee was more typically portrayed as a potential criminal. With securitization, especially as it has become entrenched and intensified, the refugee has been more typically portrayed as a potential terrorist. The analysis includes a focus on the particular importance of ambivalence and contingency in the politics of the frame. Securitization has become so deeply entrenched since September 11, 2001 that it appears virtually fixed in place. However, it may still become possible in moments of contingency for refugee advocates to destabilize the securitization meta-frame and help shift the framing of refugees into a more hospitable register. Author Keywords: ambivalence, contingency, humanitarianism, neo-humanitarianism, refugees, securitization
Genome annotation, gene characterization, and the functional analysis of natural antisense transcripts in the fungal plant pathogen Ustilago maydis
Ustilago maydis (DC) Corda is the causal agent of 'common smut of corn'. Completion of the U. maydis lifecycle is dependent on development inside its host, Zea mays. Symptoms of U. maydis infection include chlorosis and the formation of tumours on all aerial corn tissues. Within the tumours, thick-walled diploid teliospores form; these are the reproductive and dispersal agent for the fungus. U. maydis is the model to study basidiomycete biotrophic plant-pathogen interactions. It holds this status in part because of the completely sequenced 20.5 Mb genome; however, thorough genome annotation is required to fully realize the value of this resource. The research presented here improved U. maydis genome annotation through the analysis of cDNA library sequences and comparative genomics. These analyses identified and characterized pathogenesis-related genes, and identified putative meiosis genes. This enabled the use of U. maydis as a model for investigating 'host-induced' meiosis. Further, the cDNA library analyses identified non-coding RNAs (ncRNAs) and natural antisense transcripts (NATs). NATs are endogenous RNA molecules with regions complementary to a protein-coding transcript. Although NATs have been identified in a wide variety of mammals, plants, and fungi, very few have been functionally characterized. Over 200 U. maydis NATs were annotated by analyzing full-length cDNA sequences. NAT structural features were characterized. Strand-specific RT-PCR was used to detect NATs in U. maydis and in a related smut fungus, U. hordei. The data supported a common role for NATs in smut teliospore development, independent of the RNA interference pathway. Analysis of the expression of one U. maydis NAT, as-um02151, in haploid cells, led to a model for NAT function in U. maydis during teliospore dormancy. This model proposed NATs facilitate the maintenance of stored mRNAs through the formation of double-stranded RNA. In testing this model, it was determined that the deletion of two separate upstream regulatory regions, one of which contained a ncRNA (ncRNA1), altered NAT levels and decreased pathogenesis. These studies strengthened U. maydis as a model organism, and began the functional investigation of NATs in U. maydis, which identified a new class of fungal pathogenesis genes. Author Keywords: cDNA library analysis, genome annotation, mRNA stability, natural antisense transcripts, pathogenesis, Ustilago maydis
Abject Utopianism and Psychic Space
This dissertation utilizes the psychoanalytic theories of French psychoanalyst Julia Kristeva as a lens through which to read the novels of American author Samuel R. Delany. I argue that concepts proper to Kristeva's work--namely abjection and/or the abject--can provide a way to think what it might mean to be utopian in the 21st century. Delany's novels are received historically, which is to say his work speaks from a certain historical and cultural viewpoint that is not that of today; however, I claim that his novels are exceptional for their attempts to portray other ways of being in the world. Delany's novels, though, contain bodies, psychologies, and sexualities that are considered abject with respect to contemporary morality. Nonetheless, this dissertation argues that such manifestations of abject lived experience provide the groundwork for the possibility of thinking utopianism differently today. Throughout, what I am working toward is a notion that I call Abject Utopianism: Rather than direct attention toward those sites that closely, yet imperfectly, approximate the ideal, one should commit one's attention to those sights that others avoid, abscond, or turn their nose up at in disgust, for those are the sites of hope for a better world today. Author Keywords: Abject, Delany, Kristeva, Literary Criticism, Psychoanalysis, Utopia
gi-mi-ni-go-wi-ni-nan o-gi-ma-wi-win zhigo o-gi-ma-win (The gifts of traditional leadership and governance)
ni' o-nah-ko-nah ah-di-so-kah-nahg zhigo di-bah-ji-mo-wi-nan g'dah mi-kwe-ni-mah-nahn obwandiacbun (nigig), tecumthabun (mizhibizhi), miinwaa shingwaukbun (ah-ji-jawk) (I ceremonially call upon the stories, the sacred and spiritual narratives and stories of personal experience... In the spirit of obwandiac, tecumtha and shingwauk) gi-mi-ni-go-wi-ni-nan o-gi-ma-wi-win zhigo o-gi-ma-win (The gifts of traditional leadership and traditional governance) explores anishinabe o-gi-ma-wi-win (traditional leadership and to be esteemed) from the point of view of obwandiac (nigig) in 1763, tecumtha (mizhibizhi) and shingwauk (ah-ji-hawk) in 1812 and 1850 respectively. It also examines the political and social significance of anishinabe o-gi-ma-win (traditional governance) and the n'swi-ish-ko-day-kawn anishinabeg o'dish-ko-day-kawn (Three Fires Confederacy) during the time of these esteemed leaders. The use of our ah-di-so-kah-nahg (sacred and spiritual stories), di-bah-ji-mo-wi-nan (stories of personal experience and reminiscences) and ah-way-chi-gay-wi-nan (moral stories) provides the opportunity to show how anishinabe people used different narratives to ah-way-chi-gay-win (teach by telling stories). In listening to these personal and intimate stories we have an opportunity to understand and explore these concepts of o-gi-ma-wi-win (traditional leadership and to be esteemed) and o-gi-ma-win (traditional governance). The first layer to this distinct way of knowing embodies anishinabe nah-nah-gah-dah-wayn-ji-gay-win (how we come to think this way about our reality and epistemology) and is expressed to us within our gah-wi-zi-maw-ji-say-muh-guhk (creation and stories of origin) and miskew ah-zha-way-chi-win (blood memory and the act of flowing). It states explicitly that we have always known where we came from, who we are, and how we fit into this world. anishinabe i-nah-di-zi-win (our way of being and way of life and ontology) lends voice to the second layer of anishinabe kayn-daw-so-win (traditional knowledge), which defines the responsibilities and expectations of anishinabe society, leadership and governance. Our ni-zhwa-sho gi-ki-nah-mah-gay-wi-nan (seven teachings), ni-zhwa-sho o-na-sho-way-wi-nan (seven sacred laws) and the relationship of the do-daim-mahg (clan system) are described within anishinabemowin, the language of our ceremonies and of the jeeskahn (shake tent). Harry Bone (2011)1, an elder from Keeseekoowenin First Nation suggests that ah-zhi-kay-ni-mo-nahd-a-di-sid bay-mah-di-sid (how we use our way of doing, thinking, ceremony and spirituality to find answers and methodology) represents a third layer that provides us with the ways and means to help us understand the essence of anishinabe nah-nah-gah-dah-wayn-ji-gay-win (how we come to think this way about our reality and epistemology and i-nah-di-zi-win (our way of being and way of life and ontology). This represents the literal and metaphoric o-dah-bah-ji-gahn (sacred bundle) and traditional approach that provides this narrative with the means to explore the ideas of leadership and governance from within a traditional construct. He adds that our spirituality and manitou kay-wi-nan (ceremonies) will be clearly defined and shared within this o-dah-bah-ji-ji-gahn (sacred bundle). It helps establish the spiritual core for this narrative. These anishinabe approaches to methodology (intimate conversations, family history and ceremony) are used to tell a story that mirrors the academic construct of interviews and document analysis. Therefore, the o-dah-bah-ji-gahn (sacred bundle) provides the nay-nahn-do-jee-kayn-chi-gayd (to dig around and research) tools to have this discussion exploring the traditional construct of anishinabe o-gi-ma-wi-win (traditional leadership and to be esteemed) and o-gi-ma-win (traditional governance). Lastly, it is important to understand that this traditional approach shows how these narratives are in-and-of-themselves powerful strategies in understanding anishinabe ah-yah-win (way of being and existence) and gah-gi-bi-i-zhi-say-mah-guhk (history). mii i'i-way anishinabe i-zhi-chi-gay-win (This is the anishinabe way) zhigo mii'iw eta-go o-way neen-gi-kayn-dahn zhigo ni-gi-noon-dah-wah (This is as much as I know and have heard) 1 Bone, Harry (Personal Communication) 2011. Author Keywords:
Not In Their Classrooms
This dissertation examines the rise of teachers' union militancy in Ontario through a case study of the Federation of Women Teachers' Associations of Ontario (FWTAO) and the Ontario Public School Teachers' Federation (OPSTF) between 1970 and their amalgamation into the Elementary Teachers' Federation of Ontario (ETFO) in 1998. It uses the archival records of the two unions, relevant legislation, media records, personal collections, and interviews to explore how these two professional organizations became politicized, militant labour unions able to engage with the state and the trustees of boards of education. The Introduction situates the public education project within nation building in a capitalist-democracy and outlines the theoretical influences informing the dissertation. Chapter 1 follows the two unions during the 1970s as they developed into labour unions. The 18 December 1973 one-day, province-wide, political strike achieved the right to strike and established a unique labour regime for teachers. Chapter 2 examines the advance of the unions during the 1980s as they developed labour militancy. At the same time, neo-liberalism was ascending and the post-war social accord was coming to an end resulting in attacks on unions and cuts to social programs. How gender affected the elementary teachers' unions between 1970 and 1990 is developed in Chapter 3. The FWTAO campaigned for women's equality on a platform of liberal feminism while the OPSTF followed a unionist path in an effort to convince women teachers to join them. Chapter 4 scrutinizes the effect of neo-liberal ideology on education during the 1990-1995 Bob Rae NDP government and the impact the Social Contract had on teachers. The development of teacher resistance to the neo-liberal state is explored in Chapter 5. Alliances with other labour organizations during the Days of Action campaign culminated in a two-week, province-wide strike in the fall of 1997 against the Mike Harris Conservative government. The Conclusion brings together the findings of the dissertation and suggests future research exploring teacher union strength in the Canadian context. Author Keywords: Federation of Women Teachers' Associations of Ontario; FWTAO, neoliberalism, Ontario Public School Teachers' Federation; OPSTF, teachers' strikes, teachers' unions, women's union
Evaluating the Effects of Habitat Loss and Fragmentation on Canada Lynx
Current major issues in conservation biology include habitat loss, fragmentation and population over-exploitation. Animals can respond to landscape change through behavioural flexibility, allowing individuals to persist in disturbed landscapes. Individual behaviour has only recently been explicitly included in population models. Carnivores may be sensitive to changing landscapes due to their wide-ranging behaviour, low densities and reproductive rates. Canada lynx (Lynx canadensis) is a primary predator of snowshoe hares (Lepus americanus). Both species range throughout the boreal forests of North America, however lynx are declining in the southern range periphery. In this dissertation, I developed new insights into the effects of habitat loss and fragmentation on lynx. In Chapter 2, I created a habitat suitability model for lynx in Ontario and examined occurrence patterns across 2 regions to determine if habitat selection is flexible when different amounts of habitat are available. Although lynx avoided areas with <30% suitable habitat where suitable land cover is abundant, I found that they have flexible habitat selection patterns where suitable land cover is rare and occurred in low habitat areas. In Chapter 3, I investigated the effects of dispersal plasticity on occupancy patterns using a spatially explicit individual-based model. I showed that flexible dispersers, capable of crossing inhospitable matrix, had higher densities and a lower risk of patch extinction. In contrast, inflexible dispersers (unable to cross inhospitable matrix), were most limited by landscape connectivity, resulting in a high extinction risk in isolated patches. I developed three predictions to be explored with empirical data; (1) dispersal plasticity affects estimates of functional connectivity; (2) variation in dispersal behaviour increases the resilience of patchy populations; and (3) dispersal behaviour promotes non-random distribution of phenotypes. Finally, in Chapter 4, I examined the consequences of anthropogenic harvest on naturally cycling populations. I found that harvest mortality can exacerbate the effects of habitat fragmentation, especially when lynx densities are low. Dynamic harvest regimes maintained lynx densities and cycle dynamics while reducing the risk of population extinction. These results suggest that lynx display some flexibility to changing landscapes and that the metapopulation structure is more resilient to increasing habitat loss and fragmentation than previously understood. Future studies should focus on determining a threshold of connectivity necessary for population persistence and examining the effects of habitat loss on the fecundity of lynx. Author Keywords: Fluctuating Populations, Habitat Fragmentation, Landscape Ecology, Occupancy Dynamics, Population Ecology, Spatially Explicit Population Models

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