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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.
11

Maternal Denning Phenology and Substrate Selection of Polar Bears (<em>Ursus maritimus</em>) in the Southern Beaufort and Chukchi Seas

Olson, Jay Wesley 01 December 2015 (has links)
Loss of sea ice due to global warming may affect the phenology and distribution of polar bear (Ursus maritimus) denning by altering access to denning habitats. We examined trends in the selection of maternal denning substrate (land versus sea-ice denning) in the southern Beaufort Sea (SB), addressing the potential influence of summer land-use and fall sea-ice conditions on substrate selection. We developed an algorithm based on statistical process control methods to remotely identify denning bears and estimate denning phenology from temperature sensor data collected on collars deployed 1985–2013 in the SB and Chukchi Sea (CS). We evaluated cub survival relative to den entrance, emergence, and duration, and examined differences in the phenology of land and sea-ice dens. Land denning in the SB was more common during years when ice retreated farther from the coast and off of the continental shelf in September. All SB bears that occupied land prior to denning subsequently denned on land; however, only 29% of denning bears that summered on sea ice denned on land. Den entrance and duration in the SB and CS were similar, although CS bears emerged later. Land dens were occupied longer than those on ice. Bears later observed with cubs remained in dens 23 days longer and emerged from denning 17 days later on average than bears that denned but were subsequently observed without cubs, suggesting that den exit dates are related to cub survival. The increase in land-based denning in the SB when sea ice retreated farther from shore, along with the positive correlation between fall land-use and land denning, suggest that further sea-ice declines may result in continued increases of onshore denning. Growing numbers of denning females along the coast may increase the potential for human-bear interactions.
12

Bioaccumulation and toxicokinetics of brominated and chlorinated contaminants in East Greenland polar bears (Ursus maritimus) /

Gebbink, Wouter A. January 1900 (has links)
Thesis (M.Sc.) - Carleton University, 2006. / Includes bibliographical references. Also available in electronic format on the Internet.
13

Arktisk turism och skyddet av isbjörnen : En miljörättslig analys av skyddet av Svalbards isbjörnar i en tid av ökad sjöburen turism

Szanto, Imola January 2020 (has links)
One of the main attractions for tourists visiting Svalbard, Norway, are polar bears. The polar bear is a vulnerable species, dependent on sea ice to survive as this is where they hunt, wander and raise their cubs. Ship-based tourism poses a number of threats mainly due to the disturbances caused by the presence of ships, damage of critical habitats and the increasing interactions and deadly conflicts between humans and polar bears. Appropriate and effective legislation based on scientific knowledge of the impacts of ship-based tourism on polar bears is necessary to ensure sustainable tourism and environmental protection. Species protection and habitat conservation is not an issue isolated to Svalbard or the polar bears but rather just one part of the pressing global issue concerning loss of biodiversity, which is one of the greatest threats to humankind. The Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) aims to ensure the conservation of wild flora and fauna species and their habitats. At the time of signing, the Norwegian Government excluded Svalbard from the application of the Bern Convention, ensuring that national conservation policies for Svalbard would be promoted. The Svalbard Environmental Protection Act is the main act regulating environmental protection on Svalbard, including both general principles and specific provisions regarding species and habitat protection. This paper explores the various needs of the polar bear population in Svalbard and the impacts caused by ship-based tourism. The Bern Convention’s provisions relating to the identified threats posed by ship-based tourism are examined and compared with the corresponding provisions in the Svalbard Environmental Protection Act. Moreover, this paper analyses the potential benefits that could arise from the application of the Bern Convention to the Svalbard territory. This paper concludes that the protection of the polar bears could, de jure, be strengthened by the Bern Convention, mainly due to the extensive interpretation of the types of activities that should be prohibited by signatory states. However, the Bern Convention can only be enforced by non-binding mechanisms and it is therefore unlikely that the application of the convention would lead to stronger protection of the polar bears than that which is provided by national legislation. The protection of the polar bear from threats caused by ship-based tourism would therefore, de facto, most likely not be strengthened by the application of the Bern Convention.
14

Post-Den Emergence Behavior and Den Detection of Polar Bears (<em>Ursus maritimus</em>) in Northern Alaska and the Southern Beaufort Sea

Robinson, Rusty Wade 01 March 2014 (has links) (PDF)
Pregnant polar bears (Ursus maritimus) construct maternal dens out of snow in the autumn where they give birth to and raise altricial young. In recent years, there has been a decrease in polar sea ice extent and thickness, which has led to changes in denning behavior. One such change in the southern Beaufort Sea (SBS) is that polar bears are selecting maternal den sites on land, rather than on unstable sea ice. This change, coupled with expanding petroleum exploration along Alaska's North Slope, heightens the likelihood of bear-human interactions at maternal den sites. The purpose of this research was to 1) describe polar bears' post-den emergence behavior, establishing a benchmark for comparison to identify behavioral changes associated with climate change and disturbance, and 2) explore factors influencing the efficacy of a currently used den detection method, forward-looking infrared (FLIR). Maternal den sites were observed along Alaska's North Slope from March to April of 2009 and 2010. The mean length of stay at den sites post-emergence was 11.3 ± 7.5 d. The mean date of den emergence was 14 March; abandonment 26 March. Adult females were generally inactive (58.4% out-of-den time) with standing being the most prevalent activity (49.9%). Cubs were generally active (76.7%), playing more than any other activity (45.3%). Bears spent the majority of their time in the den (97.3% for adult females and 99% for cubs) with short bouts of intermittent activity (× = 7 min 42 s). We documented the death of one member of a triplet polar bear litter at its den site. All three cubs showed low activity levels relative to other cubs observed, and one died within one week of den emergence. Necropsy confirmed that the dead cub had a low body weight and was malnourished. Capture later confirmed that the two surviving cubs were also undersized. Triplet litters are often smaller and suffer higher mortality rates than singletons and twins. This cub was not only a triplet but also born following 2 y of record minimum sea ice extent, both of which may have played a role in this cub's death. Concurrent with the den emergence portion of this work, we conducted a separate study to identify limitations and optimal conditions for locating dens using FLIR. We took handheld FLIR images of three artificial dens under varied conditions. We tested variables hypothesized to influence detectability with linear models using a zero-inflated negative binomial distribution. Solar radiation, wind speed, and den wall thickness reduced the likelihood of detecting dens. The negative effect of wind speed on detectability increased with increasing distance. To maximize the efficacy of hand-held FLIR, den surveys should be conducted when solar radiation is <16 w/m2 (night) and when wind speed is <10 km/h (6 mph). Adherence to these guidelines will maximize the protection FLIR can afford to denning bears.
15

A Dissection of Pacing in Zoo-Housed Polar Bears: How Details of the Behavior Can Suggest Motivational and Causal Factors

Cless, Isabelle T. 02 September 2015 (has links)
No description available.
16

Managing nature, producing cultures : Inuit participation, science and policy in wildlife governance in the Nunavut Territory, Canada

Henri, Dominique January 2012 (has links)
In this thesis, a critical analysis is proposed of the relationships between Inuit participation, science and policy in wildlife governance in the Nunavut Territory, Canada. This analysis situates the emergence of a participatory regime for the governance of wildlife in Nunavut, explores its performance and examines the relations between the ways in which wildlife governance arrangements are currently represented in policy and how they are played out in practice across the territory. To pursue these objectives, this research draws upon a number of theoretical perspectives and methodological strategies poised at a crossroads between environmental geography, science and technology studies, political ecology and ecological anthropology. It combines participant observation, semi-directed interviews and literature-based searches with approaches to the study of actor-networks, hybrid forums and scientific practices associated with Latour and Callon, as well as with Foucauldian and post-Foucauldian analyses of power, governmentality and subjectivity. This analysis suggests that the overall rationale within which wildlife governance operates in Nunavut remains largely based on a scientific and bureaucratic framework of resource management that poses significant barriers to the meaningful inclusion of Inuit views. In spite of their participation in wildlife governance through a range of institutional arrangements, consultation practices and research initiatives, the Inuit of Nunavut remain critical of the power relations embedded within existing schemes, where significant decision-making authority remains under the control of the territorial (or federal) government, and where asymmetries persist with regard to the capacity of various actors to produce and mediate their claims. In addition, while the use of Inuit knowledge, or Inuit Qaujimajatuqangit, in wildlife governance in Nunavut has produced some collaborative research and management endeavours, it has also crystallised a divide between ‘Inuit’ and ‘scientific’ knowledge, generated unresolved conflicts, fuelled mistrust among wildlife co-management partners and led to an overall limited inclusion of Inuit observations, values and beliefs in decision-making.
17

An evaluation of hair cortisol concentration as a potential biomarker of long-term stress in free-ranging grizzly bears (Ursus arctos), polar bears (Ursus maritimus), and caribou (Rangifer tarandus sp.)

2013 October 1900 (has links)
Human-caused ecological change negatively affects the sustainability of many wildlife populations but may be especially challenging for large carnivores and ungulates. Long-term physiological stress may be an important mechanism linking ecological change with impaired health and reduced population performance in these groups. The determination of hair cortisol concentration (HCC) has recently demonstrated potential as a biomarker of long-term stress in humans and domestic animals, and may also represent a practical technique for use in free-ranging wildlife. The objectives of this research program were to: 1) develop and apply an accurate and reliable method for measuring cortisol levels in hair collected opportunistically or remotely from free-ranging grizzly bears (Ursus arctos), polar bears (Ursus maritimus), and caribou (Rangifer tarandus sp.), and 2) to evaluate the utility of HCC as a biomarker of long-term stress (and thus potentially useful conservation tool) in these threatened species. An enzyme-immunoassay (EIA) based technique for measuring HCC in non-human primates was successfully modified for use with small quantities (5-100 mg) of hair representative of samples which may be obtained through opportunistic (e.g. hunting, research captures, archives) or remote (e.g. barb wire snagging) methods in each species. HCC was determined in 151 free-ranging grizzly bears from Alberta, Canada (mean 2.84 pg/mg, range 0.62-43.33 pg/mg); 185 free-ranging polar bears from southern Hudson Bay, Canada (mean 0.48 pg/mg range, 0.16-2.26 pg/mg); in 12 captive Alaskan caribou (R. t. granti) (mean 2.31 pg/mg, range, 1.57-3.86 pg/mg) and 12 captive reindeer (R .t. tarandus) (mean 2.88 pg/mg, range 2.21-3.40 pg/mg) injected either with adrenocorticotropic hormone (ACTH) or saline; and in 94 free-ranging caribou (R. t. groenlandicus) from West Greenland (mean 2.21 pg/mg, range 0.60-6.90 pg/mg). Factors influencing HCC in each species were then explored including: 1) technical considerations for the prudent use of HCC analysis and 2) potential relationships between HCC, biological traits, health, and prevailing environmental conditions. Evidence revealed in this study suggests that, with further research, this technique may show potential as a practical conservation tool for use in free-ranging grizzly bear, polar bear, and caribou populations.

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