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Plasticité comportementale de l’ours grizzli (Ursus arctos horribilis) dans un contexte de changements climatiquesPigeon, Karine 23 April 2018 (has links)
L’étude de la plasticité comportementale s’attarde aux réponses physiologiques et comportementales des individus face aux contraintes de leur environnement. Les changements climatiques modifient les conditions du milieu et ont le potentiel d’influencer les composantes biodémographiques des individus. L’étude des liens mécanistiques entre le comportement animal et les conditions du milieu est donc utile à la compréhension des impacts potentiels des changements climatiques sur les individus. Le premier volet de ma thèse s’attarde aux liens entre les conditions du milieu, le comportement d’hibernation et la sélection de tanière de l’ours grizzli, une espèce menacée en Alberta. Ce volet révèle que l’abondance de nourriture à l’automne ainsi que le statut reproducteur des individus sont liés aux variations observées dans les dates d’entrée en tanière tandis que les conditions météorologiques à large échelle et le statut reproducteur des individus expliquent bien les dates de sorties de tanières. Ce volet démontre aussi que les caractéristiques physiques des tanières ne diffèrent pas entre les sexes et que pour creuser leurs tanières, les mâles et les femelles sélectionnent des attributs du paysage similaire. À large échelle, l’ours grizzli évite les zones humides et choisi des peuplements de conifères en haute altitude associés à une grande disponibilité de nourriture de haute qualité au printemps. À l’échelle du domaine vital et à l’échelle locale, l’ours grizzli choisi des peuplements de conifères associés à un fort couvert latéral et vertical, à une faible disponibilité de nourriture de haute qualité à l’automne, à une forte abondance d’Hedysarum spp. ainsi qu’à une faible densité de routes. Le second volet s’attarde à la sélection de l’habitat et à la thermorégulation durant la période active et mets en évidence les contraintes thermiques associées à une augmentation de la température ambiante sur les patrons de sélection de l’habitat. La sélection de l’habitat de l’ours grizzli selon les saisons et durant la journée dépendait de la température ambiante et ce, davantage pour les mâles que pour les femelles. Plus la température ambiante était élevée, plus la sélection de peuplements ouverts qui abondent en nourriture de haute qualité augmentait durant les périodes les plus fraîches de la journée et plus la sélection de ces mêmes peuplements diminuait durant les périodes les plus chaudes de la journée. Ma thèse approfondie les connaissances concernant les facteurs intrinsèques et extrinsèques influençant le comportement d’hibernation et met en évidence l’influence de la thermorégulation sur la sélection de l’habitat chez l’ours. Mes résultats contribuent à une meilleure compréhension des facteurs déterminant la distribution des individus et améliore notre capacité à prédire l’effet des changements climatiques globaux sur les grands mammifères. / The study of behavioural plasticity aims at understanding the physiological and behavioural responses of individuals to limiting factors. Climate change has the potential to influence the life history of individuals by altering environmental conditions. Thus, studying the mechanistic links between animal behaviour and environmental conditions is necessary to understand the potential impacts of climate change on individuals. The first part of my thesis focuses on the links between environmental conditions, hibernation behaviour, and habitat selection of grizzly bears, a threatened species in Alberta, Canada. The phenology of den entry and exit was driven by sex and reproductive status, food availability in autumn, winter precipitation, and spring temperature. There was no difference in the dimensions and characteristics of dens excavated by male and female grizzly bears, and males and females selected similar landscape attributes to dig their dens. At the broadest scale investigated, grizzly bears avoided wetlands and selected high-elevation dry conifer stands with abundant high-quality spring foods. At the home-range scale and within the den vicinity, grizzly bears selected dense conifer stands associated with little high-quality autumn food and abundant Hedysarum spp. in areas with low road densities. The second part of my thesis focuses on the links between habitat selection and thermoregulation during the active season, and highlights the thermal constraints associated with increasing ambient temperatures on habitat selection patterns. Grizzly bear habitat selection followed a daily and seasonal pattern that was influenced by ambient temperature, with adult males showing a stronger response than females to warm temperatures. With increasing ambient temperatures, male and female grizzly bears increased their selection for open stands with abundant food resources during the coolest periods of the day, and concurrently decreased their selection for these open stands during the warmest periods of the day. My thesis increases our understanding of the role of intrinsic and extrinsic factors on hibernation behaviour, habitat selection, and thermoregulation constraints of grizzly bears. Ultimately, my results enhance our understanding of the factors regulating the distribution of individuals in time and space; improving our ability to predict the potential impacts of climate change on large mammals.
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Spatial and dietary niche variation associated with diverse resource availability, competitive environment, and landscape heterogeneity; ecology and conservation of bear-salmon systems in coastal British ColumbiaService, Christina Nicole 24 April 2019 (has links)
The niche concept provides a tractable measure of the ecological roles and requirements of organisms, which can inform our understanding of the patterns of biodiversity, and subsequently, direct conservation policy. Although niche is most commonly considered for species, variation nested within lower hierarchies of biological organization (i.e., phenotypes, genotypes) also contributes to maintaining biodiversity. Herein I examine spatial and dietary niche variation among and within species in a consumer–resource system where resources and competition are structured by a heterogeneous environment. An underlying theme of this dissertation was developing research through a community-engaged approach that not only contributed to conceptual advancements in niche theory but also to applied conservation priorities.
The marine archipelago of the central coast of British Columbia, Canada structures salmon (Oncorhynchus spp.) resources and the inter- and intraspecific competitive context for coastal grizzly (Ursus arctos) and black bears (Ursus americanus). This assembly of ursids represents nested levels of biological organization (i.e., species, phenotypes (white vs black-coated morphs of black bears) and genotypes (dominant homozygote black-coated black bears, heterozygote black-coated black bears, recessive homozygote white-coated ‘Spirit’ black bears)), which allows for investigation into niche variation across and within species.
I investigated niche variation using a suite of non-invasive methods. Local and Traditional Ecological Knowledge (LEK/TEK) provided complementary information to genetic and stable isotope (13C and 15N) data from hair samples. First, I investigated changes in the spatial niche of coastal grizzly bears. By combining western scientific approaches with TEK/LEK interviews I found the range of coastal grizzly bears has expanded westward onto several coastal islands. The economic, cultural, and ecological impacts of this shift in spatial niche are not yet understood. Second, I tested hypotheses related to variation in the foraging niche of black bears in response to the competitive environment and salmon resource availability. I found that grizzly bear presence reduced the proportion of salmon in black bear diets by ~40%. I also found that salmon species diversity, and not biomass abundance, was positively correlated to salmon in black bear diets. This highlights the importance of resource diversity to consumers beyond the consideration of abundance. Third, I explored spatial niche patterns of Spirt bears in relation to protected areas. I found that landscape-level Spirit bear allele frequency and population estimates were lower than previously reported. Approximately ~50% of Spirit bear allele hotspots corresponded to protected areas. This finding suggests Spirit bears are rarer and less protected than previously assumed. Finally, I tested hypotheses related to niche variation between phenotype and genotypes of Spirit bear populations. I found both phenotypes and genotypes diverged in foraging niche, with Spirit bears and black-coated heterozygotes having elevated stable isotope signatures compared to black-coated homozygotes. This result supports the role of ‘multi-niche’ mechanisms in maintaining this rare polymorphism.
Results from all chapters contributed to land- and marine-use stewardship efforts of collaborating First Nations. Collectively, this dissertation offers novel contributions towards understanding how niche variation at multiple levels of biological organization can contribute to conservation planning. / Graduate / 2020-04-04
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Habitat linkages and highway mitigation using spatially-explicit GIS-based modelsJones, Andrew Charles 13 December 2012 (has links)
I identified suitable locations for highway wildlife crossing mitigations across the TransCanada Highway (TCH) in the area of Mount Revelstoke and Glacier National Park (MRGNP), British Columbia. Highways fragment natural landscapes leading to habitat loss, reduced ecosystem connectivity and direct wildlife mortality though motor vehicle collisions. Grizzly bears (Ursus arctos) are vulnerable to the effects of habitat and population fragmentation. Highway wildlife crossing mitigations improve ecosystem connectivity by increasing the permeability of transportation corridors to wildlife. I identified high-quality habitat patches using a resource selection function (RSF) based on 1,703 radio telemetry locations from 59 grizzly bears. Least-cost path analysis (LCP) among habitat patches identified 6 linkage zones across the TCH. Electric circuit theory was used to generate current maps that classify linkage zones as high-volume crossing areas or tenuous linkages. Linkage zones occurred where high-quality habitat aligned with physical features conducive to cross-valley wildlife dispersal.
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Coexistence : the human/grizzly bear interface in a rural community of British ColumbiaSanders, Gillian 13 June 2013 (has links)
Environmental Education is becoming increasingly important as human populations expand into wildlife habitat, often resulting in human/wildlife conflicts. Meadow Creek British Columbia has experienced a long history of conflicts with grizzly bears resulting in significant bear mortalities. This qualitative research investigates human attitudes and behaviours relating to human/grizzly bear coexistence in this area. Twenty eight participants with diverse values contributed to in-depth interviews and a focus group that revealed perceived barriers and potential solutions to human/grizzly bear coexistence. Results show increased attitudes of tolerance since mid-2000s and that on-going support is needed to enable bears and humans to coexist. This research suggests coexisting with grizzly bears in Meadow Creek may serve to improve the linkage function of this area, making coexistence important to local grizzly populations. This work may be a useful study for communities in areas of high human/bear conflicts or in linkage areas between threatened populations of wildlife.
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Grizzly bears, roads, and human-bear conflicts in southwestern AlbertaJoseph, Northrup Unknown Date
No description available.
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PRAGMATISM AND THE POLITICS OF REWILDING NATURE: THE CASE OF GRIZZLY BEAR REINTRODUCTION IN IDAHOHintz, John G. 01 January 2005 (has links)
In 1975, the US Fish and Wildlife Service listed the grizzly bear as a threatened species under the Endangered Species Act. Following the listing, a recovery plan was drafted in which the Bitterroot Ecosystem of central Idaho and extreme western Montana was one of six proposed grizzly bear recovery areas. It was the only one of the six, however, which did not contain a resident population of grizzlies. The Fish and Wildlife Service eventually accepted a proposal submitted by a coalition of environmental and timber industry groups. The coalition proposed to reestablish a population of grizzlies in the Bitterroot by translocating 25 bears over five years from existing populations in the US and Canada. The proposal, however, included significant concessions, including reduced protection for the reintroduced grizzlies and management of the grizzly population by a Citizen Management Committee. A large contingent of regional and national environmental groups quickly rose up in vociferous objection to the proposal exposing a significant rift within the environmental movement. These environmentalists objected to the very idea of Citizen Management and also claimed that the proposed recovery area was too small to ensure recovery. Drawing on interviews and document analyses, this dissertation employs an environmental pragmatist approach to examine the intra-environmentalist disputes that flared up throughout the Bitterroot grizzly recovery debates. The dissertation focuses on the relationship between environmental ideologies, science, and conservation advocacy, with an eye toward examining how environmentalists crafted and defended rival proposals for grizzly recovery. Through this interpretive lens, the dissertation aims to explain the existence and persistence of this intra-environmentalism rift as well as explore its ramifications for environmentalism in the region. While no wholly unified environmental movement can ever be possible or is even necessarily desirable unwavering commitments to unreachable ideals on the part of many environmentalists are hindering the growth, flexibility and efficacy of conservation in the region. The main contribution of this dissertation will be to provide an empirical case study that defends the environmental pragmatist assertion that hostile and unnecessary divisiveness within the environmental movement ultimately obstructs the development of a more successful environmentalism.
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Spatial-temporal analysis of grizzly bear habitat useSmulders, Mary Catherine Alexandra 27 August 2009 (has links)
This research develops spatial-explicit methods to characterize the relationship between wildlife and habitat use and selection. Both home range analysis and resource selection function (RSF) models, two common methods of representing wildlife-habitat associations, are often summarized aspatially. I apply a novel method to home range analysis which quantifies the spatial-temporal patterns of site fidelity and range drift. As a result, the spatial structure of home ranges is described, thus building on current methods which summarize ranges as aspatial metrics, often mean area. Furthermore, I develop a new method to spatially assess the ability of RSF models to predict wildlife occurrence using conditional randomization. As opposed to summarizing RSF model accuracy as a single value, I produce spatially-explicit and mappable outputs. I also demonstrate how this spatial method may be used to improve RSF model results. I apply these two spatial-temporal methods to a case study on adult female grizzly bears (Ursus arctos) in the Northeastern slopes of the Canadian Rockies. Through describing the spatial-temporal pattern of grizzly bear home range change, I determine that offspring status and season impact the size and spatial configuration of a bear’s home range. By spatially evaluating the predictive success of a RSF model, I locate and quantify the spatial pattern of areas where the model is under-predicting bear occurrence using Local Moran’s I. Further, I evaluate landscape characteristics at these locations and suggest additions to the model which may increase accuracy. Both home range analysis methods and RSF evaluation techniques could assist in conservation by aiding in the delineation of critical grizzly bear habitat areas in both space and time.
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Grizzly bears, roads, and human-bear conflicts in southwestern AlbertaJoseph, Northrup 11 1900 (has links)
Because most grizzly bear mortalities occur near roads, the Province of Alberta plans to implement gated access management. Little is known about how grizzly bears will respond to road closures because the effects of roads are confounded by habitat and human use. I examined mechanisms underlying grizzly bear habitat selection near roads on private and public lands of southwestern Alberta. I incorporated habitat selection models into an analysis of conflict risk. Grizzly bears selected areas near roads with low traffic and were most active at night on private lands, where human use was low. However, habitat selection varied among individuals, and roads were not a consistent predictor of overall habitat selection across individual bears. Patterns of habitat selection led to the emergence of ecological traps on private land. Access and attractant management should be implemented to reduce bear-human conflicts, and decrease displacement of bears from high-quality habitats. / Ecology
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Evaluating the role of movement behaviour and habitat familiarity on translocated grizzly bear success using an agent-based modelling approachZubiria Perez, Alejandra 10 September 2020 (has links)
In North America, the grizzly bear (Ursus arcos) is one of many species increasingly threatened by the consequences of human-wildlife conflict, with human-bear encounters on the rise due to increased human activity near or in bear habitat. As a result, a growing number of bears are subjected to management measures such as translocations in which animals are moved to areas with lower risk of human conflict, although these measures are not always successful. Previous research has attempted to understand factors associated with translocation success, but new methods are needed to address the continuous and complex nature of issues related to how animals move and learn about their surroundings as well as how they adapt to novel environments. The objective of my MSc thesis is to develop and employ a novel agent-based computer simulation model to analyze how grizzly bears learn and respond following a translocation event. This modelling effort attempts to capture how bears make decisions based on multiple factors, and represent how grizzly bears interact with their environment and make movement decisions based on learned behaviours.
First, an agent-based movement model was developed for female grizzly bears using GPS-location data for bears within a region in west-central Alberta, Canada. The model, which incorporates multi-scale decision-making and machine learning, generated movement patterns similar to those observed in radio-collared females in the study area. Home range sizes and movement metrics produced by the model were consistent with those observed in female grizzly bears in the area. The model was then used to simulate translocation events in which bears with varying “exploration” propensities were translocated to habitats with familiar or novel landscape characteristics. In general, bears translocated to habitats with similar landscape features to their original habitat were more likely to use high-quality habitat than bears moved to areas with very different landscape features. However, while increased exploration led to greater use of high-quality habitat in the long run, exploratory behaviour was found to be mostly detrimental during the first years following a translocation, the period considered critical for translocation success. Model results were found to be scale-dependent with results varying both in time and space, highlighting the need for a multi-scale approach to animal movement studies. The findings presented here also emphasize the need to account for behavioural traits of wildlife and habitat characteristics of the capture and release sites when selecting suitable translocation locations. This work highlights the potential for agent-based modelling as a tool to study animal movement as a continuous and complex process and evaluate conservation policies. / Graduate / 2021-08-24
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Sensitivity of high-resolution satellite sensor imagery to regenerating forest age and site preparation for wildlife habitat analysisWunderle, Ame Leontina 11 April 2006
In west-central Alberta increased landscape fragmentation has lead to increased human use, having negative effects on wildlife such as the grizzly bear (<i>Ursus arctos</i> L.). Recently, grizzly bears in the Foothills Model Forest were found to select clear cuts of different age ranges as habitat and selected or avoided certain clear cuts depending on the site preparation process employed. Satellite remote sensing offers a practical and cost-effective method by which cut areas, their age, and site preparation activities can be quantified. This thesis examines the utility of spectral reflectance of SPOT-5 pansharpened imagery (2.5m spatial resolution) to identify and map 44 regenerating stands sampled in August 2005. Using object based classification with the Normalized Difference Moisture Index (NDMI), green, and short wave infrared (SWIR) bands, 90% accuracy can be achieved in the detection of forest disturbance. Forest structural parameters were used to calculate the structural complexity index (SCI), the first loading of a principal components analysis. The NDMI, first-order standard deviation and second-order correlation texture measures were better able to explain differences in SCI among the 44 forest stands (R2=0.74). The best window size for the texture measures was 5x5, indicating that this is a measure only detectable at a very high spatial resolution. Age classes of these cut blocks were analysed using linear discriminant analysis and best separated (82.5%) with the SWIR and green spectral bands, second order correlation under a 25x25 window, and the predicted SCI. Site preparation was best classified (90.9%) using the NDMI and homogeneity texture under a 5x5 window. Future applications from this research include the selection of high probability grizzly habitat for high spatial resolution imagery acquisition for detailed mapping initiatives.
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