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.

North American black bears and brown bears can be difficult to distinguish in the fossil record due to similar dental and skeletal morphologies. Challenges identifying ursid material from Oregon Caves National Monument (ORCA) called for an accurate tool to distinguish the species. This study utilized a large database of lower tooth lengths and ratios in an attempt to differentiate black and brown bears in North America. Further, this project examined how these linear measurements differ geographically. Analysis of variance (ANOVA) found significant differences between black and brown bears from across North America for every variable studied. Stepwise discriminant analyses (DA) found lengths separated species better than ratios. When sexes were analyzed, ANOVA only found significant differences for lengths while DA found lengths and ratios could not accurately distinguish between sexes. Fossil specimens from North America, including ORCA specimens, demonstrated the utility of this study, supporting several identifications and questioning others.

Le maintien des populations de grands carnivores est un élément clé dans le maintien des écosystèmes. L'étude de la dynamique des populations permet de comprendre et d'anticiper les fluctuations en taille de population et est donc un outil essentiel dans la gestion et la conservation des espèces. En Suède, la population d'ours bruns (Ursus arctos) a connu une forte croissance depuis le début du 20e siècle. Conséquemment, les quotas de chasse ont augmenté de façon fulgurante depuis le début des années 2000. Or, les effets de la chasse sur la dynamique de la population restent encore méconnus et donc, les conséquences de cette augmentation sur le taux de croissance de la population sont inconnues. La chasse devrait avoir des impacts particulièrement importants dans cette population, puisque plusieurs études suggèrent qu'une augmentation de la chasse mènerait non seulement à une augmentation de la mortalité des classes d'âge exploitées, mais aussi à une augmentation de la mortalité des oursons à travers une augmentation de l'infanticide sexuellement sélectionné (où les mâles tuent les jeunes qui ne sont pas les leurs pendant la saison de reproduction pour augmenter leurs opportunités de reproduction). Mon projet avait donc pour but de quantifier les effets directs ainsi que l'effet potentiellement indirect de la chasse à travers l'infanticide sexuellement sélectionné sur la dynamique de la population d'ours brun en Suède. Les objectifs spécifiques de mon projet étaient de : i) quantifier comment les taux démographiques et le taux de croissance de la population varient sous faible et forte pression de chasse; et de ii) déterminer l'importance des différents taux démographiques, dont la survie des oursons, sur le taux de croissance de la population. Pour ce faire, j’ai collaboré au suivi individuel à long terme d’ours bruns dans le centre-sud de la Suède effectué par le Scandinavian Brown Bear Research Project. À l'aide de ces données, j'ai construit des modèles matriciels de la population qui permettent de calculer son taux de croissance ainsi que l'importance relative des différents taux démographiques pour la croissance de la population. J'ai élaboré un modèle pour l'ensemble de ma période d'étude (1990-2011) ainsi que des modèles distincts pour deux périodes qui diffèrent par la pression de chasse : de 1990 à 2005 avec une pression de chasse relativement faible, et de 2006 à 2011 avec une forte pression de chasse. J'ai trouvé que la grande majorité des taux démographiques étaient plus faibles sous une forte pression de chasse : ceci se reflétait par un taux de croissance asymptotique légèrement en deçà de 1, indiquant ainsi un déclin de la population. La survie des oursons était plus faible sous forte pression de chasse, probablement en raison d'une augmentation de l'infanticide sexuellement sélectionné. D'ailleurs, la survie des oursons avait une influence relativement forte sur le taux de croissance de la population. Finalement, j'ai aussi pu quantifier l'impact de l'infanticide sexuellement sélectionné sur le taux de croissance de la population. J'ai trouvé que le comportement était très important, puisque s’il n'y avait pas d'infanticide sexuellement sélectionné dans la population, celle-ci aurait été en croissance même sous forte pression de chasse. Ainsi, mon projet de recherche a mis en évidence l'importance du comportement individuel et des effets indirects de la chasse pour la dynamique d'une population sauvage. Les effets indirects de l'exploitation sont bien souvent méconnus et doivent être étudiés davantage afin que nous comprenions l'impact réel sur les populations exploitées.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

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

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.

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.

Because of increasing frequency of bear sightings, vehicle collisions, and nuisance incidents in coastal South Carolina, the South Carolina Department of Natural Resources is developing a comprehensive black bear management plan. However, no reliable estimates of population abundance or density are available. I used genotypes of black bears determined from hair samples collected in Lewis Ocean Bay and Carvers Bay to estimate population abundance and density. I obtained hair samples from snares during 8 weekly sampling periods in 2008 and 2009. I used Huggins closed population models to estimate abundance and spatially explicit capture- recapture models to estimate density. Based on model averaging, black bear abundance was 30 (SE = 9.3) on Carvers Bay and 42 (SE = 5.4) on Lewis Ocean Bay. Model-averaged density was 0.037 bears/km2 (SE = 0.003) for Carvers Bay. For Lewis Ocean Bay, population densities were much higher: 0.307 bears/km2 (SE = 0.025). I extrapolated the density estimates to the upper coastal region of South Carolina, using logistic regression to weight density based on similarity of the regional landscape with the 2 study areas. Predicted bear densities were low throughout the coastal region but several areas centered on more productive habitats (e.g., Carolina Bays, pocosin) and public lands (e.g., Francis Marion National Forest, Lewis Ocean Bay) had high densities. I also sampled an area in North Carolina and assessed genetic structure among the 3 areas. Based on heterozygosity, genetic distance, and genetic assignment, I found no evidence of historic or recent barriers to gene exchange among the 3 sampled populations. However, demographic connectivity may be a concern for areas such as Lewis Ocean Bay, which is surrounded by highways and development. If the goal is to maintain current black bear densities in those areas, maintaining connectivity with other habitat areas and mitigating impacts of highways would be important. The regional map of potential black bear density may be useful to identify areas that should be surveyed for occupancy or where additional studies may be conducted (e.g., Francis Marion National Forest).

In 1992, the Louisiana black bear (Ursus americanus luteolus) was granted threatened status under the Endangered Species Act primarily because of extensive habitat loss and fragmentation. Currently, the Louisiana black bear is restricted to 3 relatively small, disjunct breeding subpopulations located in the Tensas River Basin of northeast Louisiana, the upper Atchafalaya River Basin (ARB) of south-central Louisiana, and coastal Louisiana. The 1995 Recovery Plan mandates research to determine the viability of the remaining subpopulations. I conducted a capture-mark-recapture study during 2007–2009 to estimate population parameters for the ARB bear subpopulation by collecting hair samples (n = 2,977) from 115 barbed-wire hair traps during 8 1-week periods each summer. DNA was extracted from those hair samples and microsatellite genotypes were used to identify individuals. I analyzed encounter histories using the Huggins full heterogeneity estimator in a robust design framework in Program MARK. I compared candidate models incorporating heterogeneity, behavior, and time effects on capture using information-theoretic methods. I directly estimated apparent survival, temporary emigration, probability of capture and recapture, and probability of belonging to 1 of 2 mixtures; population abundance was a derived parameter. Apparent survival was 0.91 (SE = 0.06) and did not vary by gender or year. There was some evidence of temporary emigration for males only (0.10, 95% CI = 0.001–0.900). I modeled capture probabilities with a 2-mixture distribution for both male and females. Overall mean weekly capture probability was 0.12 (SE = 0.03) and 0.25 (SE = 0.04) for males and females, respectively. Recapture rates indicated a positive behavioral response to capture. Model-averaged mean annual abundance was 56 (SE = 4.5, 95% CI = 49–68). I calculated population density using spatially-explicit maximum-likelihood methods; model-averaged density was 0.15 bears/km2 (SE = 0.03). My results updated previous abundance estimates for the ARB bear subpopulation and will be used in a population viability analysis to determine if recovery criteria for the Louisiana black bear have been met.

The persistence of grizzly bears (<i>Ursus arctos</i>) in western Alberta is threatened by increasing human activities on the landscape. The Foothills Research Institute Grizzly Bear Program (FRIGBP) hypothesizes human-caused landscape change in Alberta causes long-term stress in individual bears, resulting in impaired biological functions and, when many bears are affected, decreased population performance. To facilitate the evaluation of individual grizzly bear health within the FRIGBP, the objective of my research was to develop and assess the usefulness of a health function score system for grizzly bears. From a large set of complex biological data collected from grizzly bears from 1999 to 2007, I merged 14 � constituent� variables into four health functions; growth, immunity, movement, and stress. For each health function, I calculated individual scores by adding ranked and weighted variable percentiles. I found that health function scores corresponded well with health status of individual bears based on values for multiple constituent variables. The score system facilitated quick screening of health in individual bears, identification of bears with reduced health, and comparison of health profiles between bears. I examined the usefulness of the score system by evaluating relationships presumed to exist under the working hypothesis of the FRIGBP. Results generated from health function scores were compared with those from constituent variable values using statistical and graphical techniques. I concluded that scores likely provided clearer depiction of wildlife health relationships than did constituent variables because they were not influenced by capture method, sex, or outlying observations. By using the score system, I found support for the proposed positive relationship between human-affected landscape condition and stress, but not for inverse relationships between stress and other health functions. The usefulness of the score system could be increased by minimizing use of redundant constituent variables, e.g., in growth and immunity, and removing the influence of potential confounding factors, e.g., capture.