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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Spatial and temporal evolution of snow-covered sea ice, with reference to polar bear habitat

Iacozza, John 07 April 2011 (has links)
This dissertation attempts to improve the understanding of spatial distribution and evolution of snow-covered sea ice as related to polar bear habitat. This will be accomplished at both the local (i.e. 1m spatial resolution) and regional scales (i.e. 100 km spatial resolution) for various types of first-year sea ice (FYI) through four primary objectives. The first primary objective (i.e. Chapter 3) examines the observed and modeled temporal evolution of snow over smooth FYI, as well as the estimation of on-ice meteorological conditions. Results suggest that increases in observed snowdrifts and changes to the orientation of the drifts are related to snowfall and drifting events. Modeling these changes over time using a spatially distributed snow model is not able to accurately estimate the snow distribution. As well, only the on-ice temperature and humidity can be estimated from land-based station data, limiting the modeling of snow over sea ice. The second primary objective (i.e. Chapter 4) extends this research to rough FYI types, more relevant to polar bear habitat. More specifically this objective studies the spatial pattern of snow distribution over rough ice and ridges and the relationship between ice roughness and meteorological conditions. Results suggest that ice roughness influences the magnitude of snow depth, while the wind direction during periods of snow deposition and/or blowing snow events will impact the spatial pattern. The third primary objective (i.e. Chapter 5) focuses on developing a more feasible method of deriving surface roughness. This objective attempts to use satellite imagery and texture analysis to derive surface roughness for snow-covered sea ice. Results suggest that a Gamma speckle reduction filter, coupled with a grey-level co-occurrence matrix texture measure (Entropy or Angular Second Moment) is able to account for more than 88% of the variability in the surface roughness. The final primary objective (i.e. Chapter 6) examines the temporal evolution and factors controlling the changes in sea ice characteristics over regional scale for a period from 1978 to 2002. Observed anomalies in sea ice characteristics within some of the polar bear subpopulations may be explained by thermodynamic and/or dynamic factors. Results suggest that published reduction in polar bear population and condition within the subpopulations co-occur with these observed changes in sea ice characteristics.
2

Spatial and temporal evolution of snow-covered sea ice, with reference to polar bear habitat

Iacozza, John 07 April 2011 (has links)
This dissertation attempts to improve the understanding of spatial distribution and evolution of snow-covered sea ice as related to polar bear habitat. This will be accomplished at both the local (i.e. 1m spatial resolution) and regional scales (i.e. 100 km spatial resolution) for various types of first-year sea ice (FYI) through four primary objectives. The first primary objective (i.e. Chapter 3) examines the observed and modeled temporal evolution of snow over smooth FYI, as well as the estimation of on-ice meteorological conditions. Results suggest that increases in observed snowdrifts and changes to the orientation of the drifts are related to snowfall and drifting events. Modeling these changes over time using a spatially distributed snow model is not able to accurately estimate the snow distribution. As well, only the on-ice temperature and humidity can be estimated from land-based station data, limiting the modeling of snow over sea ice. The second primary objective (i.e. Chapter 4) extends this research to rough FYI types, more relevant to polar bear habitat. More specifically this objective studies the spatial pattern of snow distribution over rough ice and ridges and the relationship between ice roughness and meteorological conditions. Results suggest that ice roughness influences the magnitude of snow depth, while the wind direction during periods of snow deposition and/or blowing snow events will impact the spatial pattern. The third primary objective (i.e. Chapter 5) focuses on developing a more feasible method of deriving surface roughness. This objective attempts to use satellite imagery and texture analysis to derive surface roughness for snow-covered sea ice. Results suggest that a Gamma speckle reduction filter, coupled with a grey-level co-occurrence matrix texture measure (Entropy or Angular Second Moment) is able to account for more than 88% of the variability in the surface roughness. The final primary objective (i.e. Chapter 6) examines the temporal evolution and factors controlling the changes in sea ice characteristics over regional scale for a period from 1978 to 2002. Observed anomalies in sea ice characteristics within some of the polar bear subpopulations may be explained by thermodynamic and/or dynamic factors. Results suggest that published reduction in polar bear population and condition within the subpopulations co-occur with these observed changes in sea ice characteristics.
3

GENETIC NONINVASIVE CAPTURE-RECAPTURE TECHNIQUES TO MANAGE POLAR BEARS: A PILOT STUDY

Harris, Christopher Matthew 24 December 2010 (has links)
Global polar bear (Ursus maritimus) population numbers are expected to decline steadily over the next 50 years. A noninvasive genetic survey of polar bear numbers may be a useful addition to traditional aerial capture mark recapture (CMR) surveys undertaken throughout the Canadian polar bear population. We attempted a pilot study of noninvasive genetic survey techniques in M’Clintock Channel between May-June 2006-2009. Throughout the survey, we compared our values to the most recent (CMR) survey, conducted by Taylor et al. (2006) between March-June 1998-2000 where 133 cubs, sub-adults and adults were tagged. A total population size of 300 bears was estimated from this aerial CMR survey (Taylor et al. 2006). We found noninvasive sampling stations are sufficient for the capture of a large amount of data on individual bears in an area. Across 4 years, we collected a total of 300 hair samples, and found between 59 and 82 individual bears entered our sampling stations, depending on the stringency of our identification parameters. We estimated genotyping error from duplicated samples, and found this was low (range: 0%-6%), but large enough to not be ignored. There appeared to be a discrepancy between the capture ratio of male adult bears; the CMR survey (1998-2000) captured 25% male bears, while we estimated approximately 64% of our captured bears were male. We felt the most likely explanation of this result is that our traps have a sex bias. However, further research is required to confirm this hypothesis. On the whole, our methods are very important for the management of polar bears, but more research must be done before it can be fully implemented. / Thesis (Master, Biology) -- Queen's University, 2010-12-23 15:35:50.16
4

Mezinárodněprávní ochrana mořských savců / Protection of marine mammals under International Law

Hloušek, Michal January 2012 (has links)
The present thesis begins with a brief overview of some of the most important international, mainly global conventions relevant to the protection of biological diversity in its entierety. Subsequent chapters then deal with some species or higher taxons of marine mammals, in particular with cetaceans, polar bears and pinnipeds. The aim was not only to analyse relevant international conventions, but also to discuss some interesting and precise questions that complete and form the conservation regime.
5

Examing the Dynamic Relationship Between Climate Change and Tourism: A Case Study of Churchill's Polar Bear Viewing Industry

D'Souza, Jamie 03 October 2019 (has links)
The purpose of this thesis research was to examine the dynamic relationship between climate change and tourism, with a direct focus on Churchill, Manitoba’s polar bear viewing industry. This unique tourism industry and the polar bears it depends on, are experiencing the negative effects of climate change due to warmer temperatures and melting sea ice, which significantly impacts the health, appearance, and prevalence of polar bears on display for tourists. Not only is this tourism industry affected by climate change, it also contributes to the ongoing changes of climatic conditions. This is due to the dependence of fossil fuel energy used for transportation, accommodation, and activities which directly contributes to the release of greenhouse gas emissions and thus to global climate change. Emissions from tourism has increased by 3% over the last 10 years, largely as a result of the accessibility and affordability of air travel, the most energy intensive form of transportation (Lenzen et al., 2018; UNWTO-UNEP-WMO, 2008). It has been suggested that in response to the increase in the demand to travel, the tourism industry should take a leadership role to reduce their total greenhouse gas emissions in an effort to decrease the impact of climate change. In this study, a visitor survey was conducted during four weeks of Churchill’s 2018 polar bear viewing season (October 16 to November 16). The aim of the survey was to: 1) estimate greenhouse gas emissions from polar bear viewing tourists and the polar bear viewing industry; 2) identify tourists’ awareness of the impacts of climate change (to and from tourism activities); 3) understand tourist’s climate-related travel motivations, and 4) identify tourists’ opinions on climate change mitigation strategies. Visitor surveys were hand- distributed at the Churchill Northern Studies Centre and at the Churchill Airport to tourists who had participated on a polar bear viewing tour. Surveys were analyzed and compared with the results from similar studies (Dawson et al., 2010 and Groulx, 2015) to identify the changing trends in greenhouse gas emissions, travel motivations, tourists’ knowledge of climate change, and acceptance of climate change mitigation strategies. Similar to trends observed 10 years ago, emissions from polar bear viewing tourists are 3-34 times higher than the average global tourist experience. Tourists’ awareness about climate change has stayed relatively consistent, despite the topic of climate change having received increased attention globally. Tourists recognize that climate change is happening and that it is human induced however, there is still a lack of understanding of how air travel is a contributor to climatic change. Although briefly mentioned in some participant’s responses, the main motivation was not to see a polar bear before it disappeared from the wild. The majority of tourists identified they were traveling to Churchill simply for the opportunity to see a polar bear. Additional motivators were photography, the Northern Lights, and for the opportunity to see other Arctic animals. The climate change mitigation strategies that tourists believed to be the most effective to reduce emissions were educational programs and transportation alternatives (such as taking the train- which was not an option at the time of study due to a rail line shutdown). This research contributes to the existing knowledge about tourism and climate change and provides a current analysis of Churchill’s polar bear viewing industry, enabling a comparison between findings from another study conducted over ten years ago. This research also makes conclusions about climate change mitigation strategies that might be effective for Churchill’s tourism industry to reduce their impact on the environment.
6

Development and Fitness Consequences of Onshore Behavior Among Polar Bears in the Southern Beaufort Sea Subpopulation

Lillie, Kate M. 01 August 2018 (has links)
Polar bears (Ursus maritimus) are experiencing rapid and substantial changes to their environment due to global climate change. Polar bears of the southern Beaufort Sea (SB) have historically spent most of the year on the sea ice. However, recent reports from Alaska indicate that the proportion of the SB subpopulation observed onshore during late summer and early fall has increased considerably. Previous research suggests that the number of polar bears onshore is linked to sea ice conditions and the availability of subsistence-harvested whale carcasses, which are referred to as bone piles. My objectives were to determine the development and fitness consequences for SB polar bears that come onshore. Furthermore, I aimed to reveal the number of polar bears that come onshore and feed at whale carcasses. I used a combination of genetic and behavioral data collected on SB polar bears from 2010-2013 to determine if onshore behavior developed through genetic inheritance, asocial learning, or social learning. I found that onshore behavior was primarily transmitted via mother-offspring social learning. I used hair samples collected at bone piles near Kaktovik, Alaska from 2011-2014 and genetic capture-recapture techniques to estimate the annual number of polar bears that visited the bone piles and rates of apparent site fidelity to the bone pile. I estimated that as many as 146 (SE = 21) SB polar bears visited the bone piles near Kaktovik in 2012. Annual rates of apparent site fidelity to the bone pile for male polar bears ranged from 0.60 (SE = 0.07) to 0.61 (SE = 0.07), and female rates of apparent site fidelity was 0.69 (SE = 0.19). Lastly, I used quantitative fatty acid signature analysis to estimate the proportion of bowhead whale, ringed seal, bearded seal, and beluga whale in the diets of SB polar bears from 2004-2015. I revealed that polar bears achieved higher body condition by coming onshore and feeding at whale carcasses. Overall, my results indicated that SB polar bears are socially learning from their mother to come onshore and that this behavior is linked to increased body condition.
7

Ecophysiological studies of body composition, body size and reproduction in polar bears

Atkinson, Stephen Noel 01 January 1996 (has links)
For the polar bear (<i>Ursus maritimus</i>), a terrestrial carnivore on the highest trophic level in the Arctic marine ecosystem, periods of nutritional restriction or fasting are a characteristic feature of an annual cycle. The overall objective of my thesis was to examine some of the effects of such a 'feast-or-fast' feeding pattern on the body composition, body size and reproductive performance of this Holarctic ursid. As a reproductive strategy, pregnant polar bears occupy maternity dens for up to 6 months between late summer and spring. While in dens, maternal nutrient stores meet all maintenance energy requirements and sustain the nutritional demands of gestation and early lactation. I quantified the nutritional costs of this prolonged 'reproductive fast' in polar bears and examined the effects of variation in maternal body condition on reproductive performance. While fasting, body mass decreased by 43% and of the change in body energy content 93% was attributable to loss of fat. Bears that were fatter priorto denning produced heavier cubs, which would be more likely to survive. Much of the variation in body condition prior to denning was accounted for by age, older females being in better condition. Using an index of milk quality that was closely related to daily milk energy yield, I investigated the independent effects of maternal body condition and age on lactation. Irrespective of condition, older bears tended to produce higher quality milk. While lactation in polar bears is clearly sensitive to body condition, these results also provide strong support for an age-specific increase in reproductive effort among females. Body size is typically a strong determinant of male reproductive success in polygynous mammals such as polar bears. Consequently, theory predicts that mothers in good condition should invest more in male than female offspring in-order to produce large adult males. An underlying assumption of this theory, however, is that early differences in body size among male offspring, such as those apparent by the end of maternal care, will affect their relative adult body size. I tested the validity of this assumption in polar bears and found that, in comparison to females, variation in body size among 2-year-old males was a weak determinant of adult size. I suggest that, in comparison to females, a longer period of growth after maternal care may predispose the adult size of males to a greater degree of environmentally mediated variation. This lack of persistence in relative body size would limit the ability of mothers to affect the adult size of their male offspring, and thus reduce the effectiveness of sex-biased maternal investment as a reproductive strategy in polar bears. One of the principle physiological adaptations enabling animals to go without food for prolonged periods seems to be a heightened ability to minimize the net catabolism of body protein. I quantified changes in the body composition of free-ranging polar bears during the ice-free season. In contrast to previous studies on fasting bears, catabolism of protein appeared to meet a significant proportion of maintenance energy demands in some individuals. (Abstract shortened by UMI.)
8

Biochemical and physiological aspects of obesity, high fat diet, and prolonged fasting in free-ranging polar bears

Cattet, Marc 01 January 2000 (has links)
The principle objective of this investigation was to develop an understanding of the biochemical and physiological response of free-ranging adult polar bears (<i>Ursus maritimus</i>) to prolonged fasting. A body condition index was developed from two measures, total body mass and straight-line body length, and was used as a covariate in the analyses of all other data. Protein and amino acid catabolism and urea synthesis were significantly lower in fasting bears when compared to feeding bears, and in fat bears when compared to lean bears. The inference from these results is that the energy metabolism in both states (fasting and fat) is one in which lipid is the predominant fuel for energy and nitrogen is conserved. Nutritional state (feeding versus fasting) had no significant effect on the plasma concentrations of non-esterified fatty acid, glycerol, and ketone bodies, or on the plasma ratio of acyl-carnitine to free carnitine. Furthermore, acetoacetate concentration was below the level of detection (<196 [mu]mol/L) in all bears, and â-hydroxybutyrate concentration never exceeded 291 [mu]mol/L. These results suggest polar bears are able to regulate closely the synthesis, release, and use of lipid metabolites without significant alteration in their plasma concentrations. Fasting polar bears showed no evidence of essential fatty acid (EFA) deficiency; the proportions of the diet-derived EFA linoleic (18:2[omega]6) and á-linolenic (18:3[omega]3) acids in the plasma and adipose tissue of fasting polar bears were greater than that in feeding polar bears. Plasma triiodothyronine concentrations and rectal temperatures were lower in fasting bears captured during summer-fall than in feeding bears, which suggests metabolic rates were decreased during fasting to conserve body fuels. Liver glycogen concentrations were found to be higher in fasting polar bears than in feeding bears. Furthermore, the results from intravenous administration of glucose (glucose tolerance test) to polar bears indicated the rates of insulin secretion and clearance in polar bears were slow relative to rates reported for other mammals. The inference from these results is that polar bears are not as dependent on glucose for energy as are other mammals and, as a consequence, are more lax in regulating their body glucose stores.
9

Attitudes, trust, and wildlife co-management in Igluligaarjuk, Qamani’tuaq, and Tikirarjuaq, Nunavut, Canada

2015 January 1900 (has links)
Research has shown that trust is essential to the functioning of co-management. This is especially true in the Territory of Nunavut where wildlife is an integral part of the lifestyle and culture of Nunavummiut (the people inhabiting Nunavut). In Nunavut, wildlife is managed by a co-management board situated in between federal, territorial, regional, and community governments and organizations. This research explores Inuit attitudes and trust in managing wildlife as part of a co-management system in the Kivalliq Region of Nunavut, Canada. Interviews were conducted in the communities of Igluligaarjuk (Chesterfield Inlet), Tikirarjauq (Whale Cove), and Qamani’tuaq (Baker Lake). Even now with the 1993 settlement of the Nunavut Land Claims Agreement (NLCA) and the implementation of a public government in 1999, there is documented evidence that beneficiaries of the NLCA are dissatisfied with wildlife management decisions and do not trust the governing process of co-management. In this study, participants specifically indicated dissatisfaction with regulations and outcomes of current polar bear co-management. It has been predicted that conflicts specific to polar bear management could lead to regulations being ignored or even defied and endanger the entire system of wildlife co-management. Results from this research indicate that dissatisfaction over decisions involving polar bears is dominantly compartmentalized towards the outcomes of polar bear management and does not necessarily apply to the broader system of wildlife co-management. Therefore, in the Kivalliq Region, predicted impacts of dissatisfaction over polar bear co-management may apply directly to the polar bear co-management system but likely not the wildlife co-management system generally. This study provides a forum where Inuit trust in the wildlife co-management system is documented and I hope it will contribute to an increased understanding of Inuit goals in wildlife management and to the discourses on co-management in Nunavut.
10

Právní úprava ochrany mořských savců / Legal regulation of the protection of sea mammals

Makovec, Vojtěch January 2012 (has links)
The topic of this master thesis is the international legal regulation of the protection of marine mammals. The thesis concentrates primarily on the analysis of the species based international law instruments for the protection of the individual marine mammal species. This thesis is divided into six chapters. The first chapter addresses the main principles of the international environmental law, which have the biggest influence on the protection of marine mammals (biodiversity protection, precautionary principle and sustainable development). The second chapter describes the regulation of fisheries, which is closely related to the protection of marine mammals. This part deals with the historical beginning of the international regulation of fisheries, the UN Convention on the Law of the Sea, the division of the sea areas, regulation of individual fish species and the regulation of fisheries after the UNCLOS. The particular instruments of protection of individual species of marine mammals except Cetaceans are described in the third chapter (i.e. polar bears, Pinnipeds and Sirenidae). The protection of Cetaceans is analyzed in detail in the fourth chapter. The protection of whales on the ground of International Whaling Commission is accented. This chapter describes also the standpoint of the whaling countries...

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