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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

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
12

Maternal Phylogeography Of Brown Bears (ursus Arctos) And Testing The Utility Of Non-invasive Genetic Samples

Cilingir, Fatma Gozde 01 October 2012 (has links) (PDF)
The genetic diversity and phylogeography of brown bear maternal lineages have been studied extensively over the last two decades. In this study the genetic diversity and maternal phylogeography of non-invasively sampled 35 brown bears, including 5 captive individuals were reported from Turkey. In addition to the optimization of DNA extraction from hair, faeces and old skin samples and their PCRs, Bayesian phylogenetic analyses based on a 269 bp long piece of bear mitochondrial DNA were conducted and 14 novel haplotypes belonging to three major lineages were revealed. The most widespread lineage was found to be the &ldquo / Eastern&rdquo / clade 3a, while geographically more restricted &ldquo / Western&rdquo / and &ldquo / Middle Eastern&rdquo / lineages were reported for the country for the first time. A specimen from the Taurus range (southern Turkey) was shown to be closely related to the presumably extinct bears in Lebanon. Moreover, a unique novel lineage that appears to have split early within the Middle Eastern clade was defined. Despite limited sampling, this study demonstrates a high level of mitochondrial diversity in Turkish brown bears, extends the ranges of both European and Middle Eastern clades into Turkey, and identifies a new divergent lineage of possibly wider historical occurrence while demonstrating the significance of non-invasive genetic sampling for such analysis.
13

Spatio-temporal Ecology, Habitat Use And Population Size Of Brown Bears (ursus Arctos) In Yusufeli, Turkey

Ambarli, Huseyin 01 September 2012 (has links) (PDF)
Brown bear is the largest mammal in Turkey and its main distribution lies in the Black Sea and Eastern Anatolia Regions. Its basic ecology is almost unknown in Turkey, except for a limited number of studies. This study aims to determine the spatio-temporal ecology and habitat use of brown bears in the Ka&ccedil / kar Mountains, and to estimate their population size in the &Ouml / zg&uuml / ven Valley and Yusufeli, both firsts for Turkey. The study area is primarily covered with conifer and oak stands, but sparse mixed shrubland occurs in the Mediterranean climate influenced lower parts. GPS-GSM telemetry on seven captured bears (5 males and 2 females) was the main field technique used in this study. Other methods include monitoring via camera trapping, visual direct observations, and counting cubs of the year. Bears were fitted with GPS-GSM collars and tracked for 3 to 603 days. Mean home range size (HRS) was calculated by 95% kernel and MCP estimators for three different samples sizes.95% MCP for all positions produced a home range size of 19.91 &plusmn / 8.89 sq. km. for females, and 130.68 &plusmn / 102.95 sq.km. for males. On average, males and females move at rates of 199 m/h and 129 m/h, respectively. Males hibernate around 140 days whereas females around 150 days and at lower elevations than males. According to camera trapping results, bears are generally active at twilight whereas activity data loggers produced disparate results for tracked bears. Resting patterns showed that bears may also rest at midnight. Estimated population density per 100 km2. is 24.50 &plusmn / 1.74 individual using the Fcub method and 23.85 &plusmn / 2.51 using the mark&ndash / resight method. Captured bears indicated nonrandom distribution on habitat use and selected productive croplands and shrublands than other types of vegetation. Brown bear HRS in the Ka&ccedil / kars is smaller than reported from most countries. The large female-male HRS difference is probably due to polygamous mating system, sexual dimorphism, hard mast availability, high population density, and female&rsquo / s habitat exclusivity as a result of high tolerance by the local people in contrast with most northern countries. Although primary productivity is used to explain high population density and small HRS in other countries, the low productivity in the study area cannot explain the observed density and HRS difference. These findings will construct a scientific basis for brown bear management and conservation in Turkey.
14

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.
15

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.
16

Spatio-temporal changes of salmon consumption by brown bears: An example of human-induced alterations in marine-terrestrial linkage / ヒグマによるサケ利用の時空間的変化:人の活動が、海と陸のつながりに及ぼす影響の一例として

Matsubayashi, Jun 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18828号 / 理博第4086号 / 新制||理||1587(附属図書館) / 31779 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 中野 伸一, 准教授 谷内 茂雄, 教授 高橋 淑子 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
17

Evolutionary and Ecological Causes and Consequences of Trophic Niche Variation in Ursids

Raper Lafferty, Diana Jean 14 August 2015 (has links)
Individual variation and fitness are the cornerstones of evolution by natural selection. The trophic niche represents an important source of phenotypic variation on which natural selection can act. Although individual variation is fundamental to species-level ecological and evolutionary change, individual variation is often ignored in population-level approaches to wildlife ecology, conservation and management. Failing to link individual resource use to fitness or to biological outcomes related to fitness limits us to managing for the average resource needs of a population, which may be insufficient for protecting the diversity of resource use within populations and the underlying eco-evolutionary processes that generate that diversity. My goals were to provide insights into the mechanisms that generate and constrain intrapopulation trophic niche variation, evaluate whether linkages exist between individual biological outcomes and variation in food habits across the range of resources consumed within generalist consumer populations and examine how that variation manifests in population-level responses. I investigated the causes and physiological consequences of intrapopulation trophic niche variation in two generalist consumers, the American black bear (Ursus americanus) and brown bear (U. arctos) across three sites in British Columbia, CAN and at one site in Alaska, USA. My primary tools included stable isotope analysis to estimate diet, enzyme-linked immunoassay of hair to quantify the hormone cortisol for indexing physiological stress, and genetic analyses to identify individuals, species, and sex and to estimate ancestry. I found that individual differences in resource use can result in similar biological outcomes and that similar resource use can result in different biological outcomes. Intra- and interspecific competition, sex-based differences in nutritional and social constraints and annual variation in food availability all influenced trophic niche variation and the resultant biological outcomes. I also found evidence of a link between intrapopulation trophic niche variation and population genetic structure. My results highlight the diverse ecological drivers and diverse consequences of trophic niche variation, which further illuminates why the trophic niche is a nexus for eco-evolutionary dynamics.
18

Using Multi-criteria analysis and GIS to determine the brown bear denning habitat : a case study in Sånfjället National Park, Sweden

Jia, Yanjing, Liu, Zihan January 2011 (has links)
Human disturbance as the main factor influencing the habitat of brown bear (Ursus arctos) has occurred frequently with the development of human society. How to reduce and prevent the conflict between human and brown bears is considered as an important question for brown bear conservation, management and public safety. Sånfjället National Park has one of the densest bear populations in Sweden. Many tourists are attracted to visit bears each year. Through this study, the most possibility brown bear denning habitat in Sånfjället National Park was determined by using Multi-Criteria Analysis. A customized habitat distribution map generator was programmed within the Microsoft Visual Basic® for Applications (VBA) in ArcGIS. Three themes were designed in the map generator, i.e., the human impact emphasis weighted, neutral weighted themes and customized weighted theme. Customized weighted theme was produced for user discovering denning habitat results with user-defined weights. Comparing the final maps generated from the human impact emphasis weighted and neutral weighted themes, human influence concentrated in the south area of the National Park. The trails near Sveduterget should be changed to avoid human disturbance in the bear denning period.
19

Foraging ecology of brown bears in the Mackenzie Delta region, NWT

Barker, Oliver Unknown Date
No description available.
20

Foraging ecology of brown bears in the Mackenzie Delta region, NWT

Barker, Oliver 06 1900 (has links)
The Mackenzie Delta region, NWT, has a short growing season and highly seasonal climate, and brown bears (Ursus arctos) there face many challenges obtaining their nutritional requirements. Consumption of meat by brown bears is linked to increases in population density, fecundity, growth and body size. I examined the use of Arctic ground squirrels (Urocitellus parryii), and broad whitefish (Coregonus nasus) as meat sources by Mackenzie Delta brown bears. As a preliminary step, I built an Arctic ground squirrel habitat model, using field-surveyed ground squirrel burrow locations. Using this model, I examined bears selection for Arctic ground squirrel habitat as a population, by sex and as individuals, and linked this to results of stable isotope analysis and site investigations. Bears showed little evidence of Arctic ground squirrel use at the population and sex level, but some individual bears appeared to prey heavily on ground squirrels, particularly during hyperphagia. I also described observations of a brown bear using broad whitefish in autumn, and used telemetry locations to show that other bears may also feed heavily on broad whitefish during hyperphagia. My research provides prey-specific evidence for intrapopulation niche variation among Mackenzie Delta brown bears. / Ecology

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