Some Characteristics of Polar Bears Killed during Conflicts with Humans in the Northwest Territories, 1976-86

We examined 265 cases where polar bears were killed in the Northwest Territories as a result of bear-human encounters between 1 July 1976 and 30 June 1986. Age and sex of the bears, time of year and general circumstances of the cases were characterized. Subadult animals constituted 53% of the aged sample, and males accounted for 70% of the sexed bears. Subadult males represented 40% of known age and sex bears. Problem kills occurred throughout the year but were most frequent in the ice-free season (August-November). In 222 cases where circumstances surrounding the death were known, 63% were associated with Inuit on the land, 18% with settlements, 15% were industrial sites and 4% with research activities. Most problem kills (87%) were not included in the quota harvest. This mortality in excess of the quota may adversely affect some populations. Therefore, wherever possible we encourage the inclusion of problem bears on community quotas.Key words: polar bear (Ursus maritimus), problem bears, bear-human encounters, Arctic, Northwest TerritoriesMots clés: ours polaire (Ursus maririmus), ours-problèmes, rencontres entre l’homme et l’ours, Arctique, Territoires du Nord-Oues

Productivity, Survival, and Movements of Female Moose in a Low-density Population, Northwest Territories, Canada

Moose (Alces alces andersoni) occur at low density (140-160 moose/1000 sq km) and are the most important game animal in much of the Mackenzie Valley, western Northwest Territories. Productivity and survival of 30 female moose (>=1.5 yr.) were studied from November 1985 through November 1988. Twenty-nine of these moose were radio-tracked for a total of 1039 relocations. Pregnancy rates were 96% for adult and 40% for yearling females. Most females returned to the same restricted area to calve each year. Mean newborn calf:female ratio and twinning rates were 1.2:1 and 31%, respectively. Mean annual female survival rate was 85%. Annual calf survival was high and stable (44±0.02%). Individual total home range size varied from 40 sq km to 942 sq km. Mean home range size for 29 moose was 174±31 sq km and 202±59 sq km for the 14 moose radio-tracked the entire three years of study. Fall home ranges were twice the size of winter and summer home ranges; seasonal ranges overlapped widely, indicating that these moose were non-migratory.Key words: moose, low density, productivity, movements, Mackenzie Valley, Northwest TerritoriesL'orignal (Alces alces andersoni) est présent à faible densité (140-160 orignaux/1000 km²) et constitue le gibier le plus important dans la plupart de la vallée du Mackenzie, à l'ouest des Territoires du Nord-Ouest. On a étudié la productivité et le taux de survie de 30 orignaux femelles (<= 1,5 ans) de novembre 1985 à novembre 1988. Vingt-neuf de ces orignaux ont été suivis par radio sur un total de 1039 déplacements. Les taux de gestation étaient de 96 p. cent pour les adultes et de 40 p. cent pour les femelles d'un an. La plupart des femelles retournaient chaque année mettre bas dans la même zone restreinte. Le rapport moyen mâle/femelle parmi les nouveau-nés était de 1,2 pour 1, et le pourcentage de jumeaux était de 30 p. cent. Le taux de survie annuel moyen des femelles était de 85 p. cent. Le taux de survie annuel des veaux était élevé et stable (44 ± 0,02 p. cent). Le territoire individuel total variait de 40 à 942 km². Le territoire moyen mesurait 174 ± 31 km² pour l'ensemble des 29 orignaux, et 202 ± 59 km² pour les 14 orignaux suivis par radio du début à la fin de la période triennale d'étude. Les territoires étaient deux fois plus étendus en automne qu'en hiver ou en été; les territoires saisonniers se recoupaient largement, ce qui indique que ces orignaux n'étaient pas migratoires.Mots clés: orignal, faible densité, productivité, mouvements, vallée du Mackenzie, Territoires du Nord-Ouest&nbsp

Ecological effects of mine reclamation on grizzly bears

The grizzly bear (Ursus arctos) is a threatened species in Alberta and although we have studied grizzly bear response to forest seral stage change, little is known about the response to coal mine reclamation by bears. We addressed basic ecological questions to describe landscape change effects on grizzly bears, focusing on Luscar and Gregg River reclaimed coal mines in west-central Alberta as case studies. We summarize bear use of mine mineral disturbance limits in relation to season, habitat, diet, and designated human access trails. Eight adult bears were monitored intensively during 2008-2010 using GPS radiocollars that allowed tracking of their movement and distribution on the landscape and facilitated collection of scats for diet analysis. Bears were present on reclaimed mines mostly during summer and fed primarily on vegetative matter. Although habitats were similar on the two mines under study, on Luscar mine bears had higher use of undisturbed forested areas and were closer to forest edge than on Gregg River mine. We attribute these differences primarily to higher presence of humans on Luscar mine, but bears responded differently to motorized and non-motorized trails. While reclaimed mines can provide habitat and forage for grizzly bears during summer, maintaining undisturbed forest patches and access management are necessary to ensure persistence of grizzly bears on reclaimed mining areas.Non UBCUnreviewedOthe

Land-use planning following resource extraction : lessons from grizzly bears at reclaimed and active open-pit mines

Gauging the success of industrial reclamation requires targets to be set for restoring ecosystem structure and function. An indication of reclamation success is if wildlife recolonize, forage, rest, reproduce and survive on reclaimed areas. The grizzly bear is a threatened species that exists at low densities in Alberta, Canada and facilitates a variety of ecosystem processes. To make suggestions for mitigating the effects of open pit mining on this species, we collected and analysed biological data for grizzly bears on and around Cheviot, Luscar and Gregg River coal mines in west-central Alberta. During 2008-2010, we captured and attached GPS radiocollars on 12 adult bears on and around mines which allowed us to intensively track their movements. We visited bear used GPS locations in the field to assess bear activity and microhabitat characteristics. Bears selected reclaimed mines and areas near mines extensively in late spring and early summer to forage on forbs sown as part of mine reclamation and to depredate ungulate calves and lambs. In the fall, bears moved primarily in areas outside mines to forage on berries in preparation for winter denning. Bears often bedded in dense tree cover which underlines the importance of maintaining original vegetation patches in planning mine operations. The animals sometimes crossed the major active mine haul road and moved on and near trails designated for human access on mine leases. High mortality risk associated with expansion of human access into previously remote areas is a major threat to long-term persistence of the grizzly bear population. Defensive driving and potentially enforcement of speed restrictions on mine haul roads in areas with high frequency of bear crossings, provisioning for ecological movement corridors and proper waste management practices will help prevent human-bear conflict during the active mining phase. Following closure of mines, access management along designated trails will reduce the risk of conflicts. Imposing access restrictions, along with preserving undisturbed habitat patches and restoring the original vegetation cover will enable coexistence of people and bears on a shared landscape.Non UBCUnreviewedOthe

Assessing den selection and den characteristics of grizzly bears

Hibernation has evolved as an adaptive strategy to avoid harsh environmental conditions associated with a lack of resources, and the choice of hibernacula can affect the fitness of individuals. Most habitat selection studies, including investigations of overwintering sites, are based on data collected from land inventories or remote sensing databases used in a geographic information system (GIS). Although rarely used, forest stand ecological data gathered at fine spatial scales may enhance our understanding of selection processes. Our objectives were to enhance previous GIS-based investigations of den use by grizzly bears (Ursus arctos) with field-based investigations and determine whether males and females selected dens in response to food availability, within-stand characteristics related to concealment cover, or factors affecting the structural stability of dens. We studied den selection for 10 male and 21 female grizzly bears at the home-range scale and within the den vicinity using data collected at 42 den sites, 168 adjacent sites, and 345 random locations within the Rocky Mountains and boreal forest of Alberta, Canada between 2001 and 2012. Within their autumn home range, male and female grizzly bears selected sites with greater concealment cover, greater canopy cover, and more abundant sweet-vetch (Hedysarum spp.) compared to availability. Poor model performance when comparing den sites to adjacent sites within the den vicinity suggests that male and female grizzly bears select sites at scales larger than 0.1 km. We found no difference in the dimensions and characteristics of dens excavated by males and females, nor in the structural stability of dens dug under a mature tree or in open areas, and no selection for a specific type of mineral soil or percentage of boulders and cobbles. Our results corroborate previous resource selection functions using remote sensing and land inventory data but show that home-range scale analyses can fail to assess selection of potentially influential, ecologically important within-stand characteristics such as food abundance and lateral cover. Within-stand data are typically unavailable through current habitat maps and field data can enhance our understanding of fine-scale selection. To minimize human-bear interactions and disturbances at dens, we recommend integrating field-based investigations to high-priority denning areas identified from resource selection functions, and to further improve conservation efforts, we recommend taking into account within-stand data to describe behaviors occurring during the active and inactive periods

Remote sensing derived edge location, magnitude, and class transitions for ecological studies

Regionally intensive human activities related to resource extraction (i.e., harvesting, oil and gas extraction) are increasing the occurrence of edges found in some forested landscapes. Edges between different land cover types represent important transition zones for abiotic and biotic processes. However, boundary detection methods often identify edges solely in areas of high contrast, such as transitions between forest and non-forest areas, and are insensitive to the relative contrast and orientation of different transitions. Edge contrast and orientation can determine the magnitude and even the occurrence of ecological edge effects and should be measured to provide information on landscape condition and habitat potential. Wombling was applied to the wetness component of a tasselled cap transformation (TCT) of a Landsat scene acquired over a portion of the eastern slopes of the Rocky Mountains in Alberta, Canada. By incorporating wombled edge contrast and orientation, and edge class transition type obtained from a land cover dataset, the nature of all transitions between land cover classes within the image was characterized and quantified. The consistency between edges identified by wombling and other common methods of edge delineation (such as spatial clustering) and methods of edge quantification (such as landscape pattern indices, or LPIs) was also assessed. Land cover transitions showed a broad range of edge contrast. Comparisons of edge contrast and the LPI edge density showed a positive correlation (r2 = 0.33); however, the strength of this relationship varied with the dominant land cover type (e.g., r2 = 0.016 for broadleaf open forest to r2 = 0.48 for dense coniferous forest). Stratifying edge contrast to higher values (i.e., >1 standard deviation) increased agreement with edge density, indicating that the LPI is preferentially relating high contrast edges. This study demonstrates how unique edge characteristics may be generated from a remotely sensed continuous variable (TCT wetness). This knowledge of the location, magnitude, and class transitions found at edges provides insights into the nature of the edge effects and enables the development and testing of hypotheses informing wildlife habitat use and selection

Staying cool in a changing landscape: the influence of maximum daily ambient temperature on grizzly bear habitat selection

To fulfill their needs, animals are constantly making trade-offs among limiting factors. Although there is growing evidence about the impact of ambient temperature on habitat selection in mammals, the role of environmental conditions and thermoregulation on apex predators is poorly understood. Our objective was to investigate the influence of ambient temperature on habitat selection patterns of grizzly bears in the managed landscape of Alberta, Canada. Grizzly bear habitat selection followed a daily and seasonal pattern that was influenced by ambient temperature, with adult males showing stronger responses than females to warm temperatures. Cutblocks aged 0–20 years provided an abundance of forage but were on average 6 °C warmer than mature conifer stands and 21- to 40-year-old cutblocks. When ambient temperatures increased, the relative change (odds ratio) in the probability of selection for 0- to 20-year-old cutblocks decreased during the hottest part of the day and increased during cooler periods, especially for males. Concurrently, the probability of selection for 21- to 40-year-old cutblocks increased on warmer days. Following plant phenology, the odds of selecting 0- to 20-year-old cutblocks also increased from early to late summer while the odds of selecting 21- to 40-year-old cutblocks decreased. Our results demonstrate that ambient temperatures, and therefore thermal requirements, play a significant role in habitat selection patterns and behaviour of grizzly bears. In a changing climate, large mammals may increasingly need to adjust spatial and temporal selection patterns in response to thermal constraints

An approach for determining relationships between disturbance and habitat selection using bi-weekly synthetic images and telemetry data

Ecological studies can be limited by the mismatch in spatial-temporal scales between wildlife GPS telemetry data, collected sub-hourly, and the large-area maps used to identify disturbances, generally updated annually. Recent advancements in remote sensing, data fusion modeling, mapping, and change detection approaches offer environmental data products representing every 16-day period through the growing season. Here we highlight opportunities and challenges for integrating wildlife location data with high spatial and temporal resolution landscape disturbance data sets, availab