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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

Prostorová aktivita medvěda hnědého (Ursus arctos Linnaeus, 1758) v zoologické zahradě / Home range activity of the Brown Bear (Ursus arctos) in ZOO

Vojáčková, Jana January 2012 (has links)
This dissertation deals with monitoring of European brown bears behavior (Ursus arctos arctos), namely of males Pišta, Miky and Honzík and of female Eliška in zoological garden in Plzen in spring 2012. Behaviour of all European brown bears is for better clarity presented in the form of tables and graphs. The dissertation includes overview of all kinds of ursine (size, environment, food and reproduction). Key words: bear, hibernation, bears activity
2

Skillnader i födoval mellan brunbjörnshonor (Ursus arctos) med och utan årsungar / Differences in choises of food items between female brown bears (Ursus arctos) with and without cubs of the year

Virmaja, Tommy January 2017 (has links)
Inom födosöksteori söker och konsumerar djur föda på ett sätt som maximerar deras förmåga att reproducera sig och få sina gener representerade i kommande generationer. För att åstadkomma detta måste individer ibland anpassa sina beteenden. Brunbjörnhonor (Ursus arctos) med årsungar måste bland annat dela den föda de hittar med ungarna. För att inte riskera att ungarna dödas av hannar så har honor med årsungar under parningsperioden mindre hemområden och rör sig mindre under ett dygn än vuxna honor utan årsungar. Med bakgrund av dessa olikheter undersöks ifall honor med årsungar konsumerar annan föda jämfört med honor i andra reproduktiva kategorier. En spillningsinsamling från GPS-märkta björnar gjordes i västra Hälsingland och norra Dalarna under 2015 från 25:e maj till 11:e oktober. Inför dataanalysen delades säsongen upp i två perioder vid den 15:e juli på grund av olikheter i födotillgång samt att parningssäsongen slutar. En frekvensanalys gjordes av individernas spillningar som resulterade i en icke signifikant skillnad mellan honor med och honor utan årsungars födoval. En undersökande dataanalys av volymprocent antyder dock att det kan finnas skillnader i mängd av vissa födoämnen under parningsperioden. Dessa skillnader fanns i kategorierna ben, älghår samt övriga växtmaterial. Även om studien lider av liten provstorlek med endast fyra honor med årsungar i var och en av de båda perioderna tycks undersökningen originell med en upplösning på individnivå. Tidigare skandinaviska födovalsanalyser hos brunbjörnen har gjorts med spillning som minsta enhet. / According to foraging theory, animals seek and consume food in ways that maximize their ability to reproduce and have their genes represented in future generations. In order to achieve this, individuals must sometimes adapt their behaviors. Females of the brown bear (Ursus arctos) with cubs of the year must share the food they find with their cubs. To protect the cubs from being killed by males in the mating period, females with young have smaller home ranges than other adult females and move less on a daily basis than other females. In view of these differences my hypothesis is that females with yearlings consume different food items than other females. A fecal collection from GPS-marked brown bears was made in 2015 in the northern Dalarna county and northwestern county of Gävleborg in Sweden from 25 May to 11 October. Prior to the data analysis, the season was divided into two periods, 25 May to 15 July and 16 July to 11 October, based on differences in food availability and season (mating vs non-mating season). A frequency analysis detected no significant differences in food items consumed for either period. However, an exploratory data analysis of percent volume of different food items suggests that there may be differences in the amount of certain foods during the mating period. These differences were found for the food categories, bone, moose hair and other plant material. Although the study suffers from a small sample size with only four females with cubs of the year in each of the two periods, this study is relatively novel with a resolution at the individual level. Previous food item analyzes of the brown bear in Scandinavia have been done with fecal samples as the smallest unit.
3

Effects of Dietary Plasticity and Landscape Heterogeneity on Brown Bears

Stutzman, Lindsey 06 May 2017 (has links)
The brown bear (Ursus arctos) is a generalist omnivore that occupies diverse habitats and displays high levels of behavioral plasticity. Plasticity in foraging behavior can result in variable diets across a population, and allow individuals to use a greater variety of resources. The distribution of food in space and time may also be an important factor in determining brown bear resource selection as it can greatly influence foraging efficiency. Our objectives were to determine if seasonal brown bear home ranges were influenced by temporal availability and spatial distribution of resources and if deviation from an optimal diet influenced brown bear body condition. Understanding how the spatial and temporal distribution of food influences brown bear space use and the relationships between behavioral plasticity and the ability of populations to persist in dynamic environments could provide additional insights into the eco-evolutionary advantages of variable foraging behavior and ultimately population resilience.
4

Approche intégrative de la gestion des conflits homme-nature : le cas de l'ours brun en France / An integrative approach in the management of human-wildlife conflicts : the case of the French brown bear

Piédallu, Blaise 12 December 2016 (has links)
La conservation des populations animales autour desquelles existe une controverse passe entre autres par une compréhension de l’écologie de l’espèce, mais également par une analyse des attitudes humaines vis-à-vis de sa présence. Cependant, ces deux aspects sont rarement mobilisés ensemble au sein de travaux combinant sciences de l’environnement et sociologie. Nous proposons ici une étude portant sur la population d’ours brun (Ursus arctos) résidant dans les Pyrénées, intégrant à la fois dynamique de la population et de sa distribution, et une analyse de l’attitude des Pyrénéens vis-à-vis des plantigrades. Nous conduisons également une réflexion sur les méthodes à employer afin d’intégrer ces résultats au sein d’une approche socio-écologique. Nos modèles écologiques, qui utilisent des données de suivi obtenues dans le cadre d’un partenariat transfrontalier entre France, Andorre et Espagne, mettent en évidence une augmentation des effectifs et une réduction de la distribution de la population entre 2008 et 2014. Si ces conclusions ne semblent pas aller dans le sens d’une dégradation rapide de leur état de conservation, les ours pyrénéens restent menacés du fait de leurs faibles effectifs et du fort taux de consanguinité au sein de la population. Notre enquête sociologique, réalisée dans les communes sur lesquelles l’ours est ou a été présent entre 2008 et 2013, a mis en évidence une hétérogénéité spatiale dans l’attitude des habitants des Pyrénées sur la question de l’ours, avec notamment des variations significatives en fonction de leurs lieux de naissance et de résidence. Nous discutons ensuite d’une approche intégrant résultats de sociologie et d’écologie avec le but de créer un modèle pouvant servir d’outil à un responsable chargé de la gestion ou de la résolution du conflit, en analysant les méthodes à notre disposition, leurs avantages et leurs limites. Nous concluons sur l’intérêt des approches pluridisciplinaire dans la gestion des controverses autour de la conservation de populations animales. / The conservation of controversial animal populations requires an understanding of the species’ ecology, but also an analysis of the human attitudes towards its presence. However, those two aspects are rarely studied together through a combination of environmental sciences and sociology. Here we study the brown bear (Ursus arctos) population residing in the Pyrenees mountains, analyzing both population dynamics and distribution, and the attitudes of Pyrenean people towards the species. We also ponder on the methods to use to combine these results in a socio-ecological approach. Our ecological models, which use monitoring data obtained through a crossborder partnership between France, Andorra and Spain, highlight an increase of population size and a reduction of its distribution between 2008 and 2014. If those conclusions do not seem to indicate a quick degradation of their conservation status, Pyrenean brown bears remain threatened by low numbers and high inbreeding in the population. A sociological study was performed in the municipalities where bear was or had been present between 2008 and 2013. We found spatial heterogeneity in the attitudes of Pyrenean people regarding bears, with significant variations depending on where they were born and where they currently live. We follow by discussing an approach that combines sociological and ecological results, with the goal of building a model that can be used as a tool for someone responsible for managing or solving the conflict; to do this, we analyze the methods available, their strengths and limits. We conclude on the importance of interdisciplinary approaches when managing controversies over wildlife conservation.
5

Att arbeta där brunbjörnen lever : Påverkan vid ensamarbete i skogen / To work where the brown bear lives : Impact of working alone in forestry

Granström Sundgren, Johanna January 2021 (has links)
De som arbetar där brunbjörnen (Ursus arctos L.) lever riskerar att påverkas genom olycksfall och ohälsa, vilket kan leda till ett arbetsmiljöproblem. Björnpopulationen har efter upp- och nedgångar ökat senaste årtiondena vilket har ökat incidenterna. Syftet med studien var att kartlägga hur anställda som arbetar ensam till fots i fält inom skogsnäringen påverkas av björnens närvaro i skogen och att utreda vad som skulle kunna göra skogen till en säkrare arbetsplats genom att motverka ohälsa och olycksfall kopplat till björnens närvaro. En litteraturstudie och en enkätstudie gjordes för att uppfylla syftet. Resultatet av enkätstudien blev tvetydigt eftersom respondenterna var positivt inställda till björn trots att majoriteten kände sig illa till mods på grund av den. En kollega ansågs vara en trygghet trots att väldigt få var emot ensamarbete. Av respondenterna hade majoriteten varit med om minst ett björnmöte. Som slutsats; utbilda, förekom och försvara.
6

Influence de la chasse et de l'infanticide sur la dynamique de la population de l'ours brun scandinave (Ursus arctos)

Gosselin, Jacinthe January 2014 (has links)
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.
7

Cranial Morphological Distinctiveness Between Ursus arctos and U. americanus

Hillesheim, Benjamin James 01 May 2017 (has links)
Despite being separated by millions of years of evolution, black bears (Ursus americanus) and brown bears (Ursus arctos) can be difficult to distinguish based on skeletal and dental material alone. Complicating matters, some Late Pleistocene U. americanus are significantly larger in size than their modern relatives, obscuring the identification of the two bears. In the past, fossil bears have been identified based on differences in dental morphology or size. This study used geometric morphometrics to look at overall differences in cranial shape and used step-wise discriminant analysis to identify specific characters that distinguish cranial morphology between black and brown bears. Such differences could prove important in identifying fossil bears when crania are present but teeth are missing. Furthermore, being able to properly identify U. arctos and U. americanus crania is important in understanding evolutionary and ecological distinctions among both fossil and modern bears. Principal components, discriminant, and thin plate spline analyses indicated a clear morphological separation between the crania of U. americanus and U. arctos and highlighted key identifying features including a more convex forehead and a narrower, more elongate rostrum in U. arctos than U. americanus.
8

Development and application of a health function score system for grizzly bears (<i>Ursus arctos</i>) in western Alberta

Lindsjö, Hans Johan Anders 09 March 2009
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.
9

Development and application of a health function score system for grizzly bears (<i>Ursus arctos</i>) in western Alberta

Lindsjö, Hans Johan Anders 09 March 2009 (has links)
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.
10

Study Of Effects Of Selective Hunting On A Bear Population Through Pva Simulation

Agzitemiz, Mehmet Melih 01 October 2008 (has links) (PDF)
Management of big wildlife such as bears can be a difficult task, especially in the face of human-wildlife conflict and demands of the hunting industry. The Brown Bear (Ursus arctos) population at Yusufeli County (Artvin, northeastern Turkey) has recently been the focus of scientific, social and economic concerns. This study population of c. 140 individuals occurs within 800 km2 of forested and alpine land. Legal hunting of male bears was allowed in 2007 after an interval of four years. This study aims to find out through a population viability analysis the level and frequency of trophy hunting this population can tolerate for the next 50 years. A matrix model with six age-classes for each sex was constructed using observed and literature-based parameter values. RAMAS Metapop was used to simulate four different scenarios where numbers of hunted bears and hunting frequency changes. The model was highly sensitive to maximum growth rate and adult survival. Interval extinction probabilities for the next 50 years ranged between 0% and 26% depending on the scenario. Viable scenarios (with an extinction probability &lt / 0.05) were only possible with either no trophy hunting or hunting of 4 subadult/adult males and 1 adult female every other year. Legal and illegal hunting jointly impact the bear population in a strong way, and when they occur simultaneously every year, they lead to extinction in the long run. Avoidance of illegal killing and a close supervision of trophy hunting are crucial in the management of this bear population.

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