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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

Algal preferences in the masking behaviour of the spider crab, Notomithrax ursus : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Ecology, University of Canterbury /

Ertel, Catherine M. January 2008 (has links)
Thesis (M. Sc.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 85-86). Also available via the World Wide.
2

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
3

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.
4

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.
5

Data v obchodní databázi CITES a jejich interpretace / Data in the CITES trade database and their interpretation

VRŠECKÁ, Lucie January 2016 (has links)
An international trade in endangered species of plants and animals is regulated by CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). Information on trades are available in CITES Trade Database. However, there are a lot of mistakes and discrepancies in this database that lead to inaccurate interpretation of data. The aim of this thesis was to: (1) identify mistakes in the database, record types and their possible ways of interpretation and (2) quantify the volumes of trade based on different ways of data interpretations in selected species of the family Ursidae. There were found 19 different combinations of missing data, except by unlisted unit and traded quantity specified only by one state of the trade and 5 types of record interpretation. Data were compared with the CITES annual records reported by the Ministry of the Environment of the Czech Republic. This thesis contains also recommendations for evaluation of international trade.
6

Algal Preferences in the Masking Behaviour of the Spider Crab, Notomithrax ursus

Ertel, Catherine Monica January 2008 (has links)
The purpose of this study was to examine the masking preferences of the spider crab, Notomithrax ursus. The algal composition of the mask in the natural habitat at Kaikoura was examined to determine the general rules the crab follows when decorating itself. The effects of size and sex on the mask composition were examined, as well as determining how the composition of the mask varies by body part. The preference of the crabs was further examined through the use of choice and background change experiments in the laboratory. It was determined that the preference of certain types of algae for mask material is not entirely dependent on their relative abundance in the environment. Possible explanations for this behaviour are given.
7

Scaling Patterns and Ecological Correlates of Postcranial Skeletal Robusticity in Canis and Ursus: Implications for Human Evolution

Doyle, Sara Kathleen January 2009 (has links)
<p>There has been a trend toward decreasing skeletal robusticity in the genus Homo throughout the Pleistocene, culminating in the gracile postcrania of living modern humans. This change is typically attributed to changing tool technologies and subsistence patterns among human groups. However, other mammalian groups also experience a similar change in their postcranial strength over the same time period. It is proposed in this dissertation that ecological variables are correlated with measures of postcranial strength and may be a better explanation for Holocene skeletal gracilization in humans, as well as in other mammalian genera. This hypothesis is investigated through a close examination of the scaling patterns in two extant genera, Canis and Ursus, and a comparison of scaling patterns and relative strength of different species of Canis, including a fossil species that provides information about temporal change. Measurements of limb length, joint surface area, bone diameter, and strength measurements derived from radiographic images of long bone midshafts of North American specimens of Canis, (including the fossil Canis dirus) and Ursus were collected. Scaling patterns of the cross-sectional variables on limb length and joint surfaces were analyzed for the interspecific and intraspecific samples. </p><p>The first hypothesis tested was that Canis scales with geometric similarity of cross-sectional variables on bone length and body mass, and the Ursus scales with elastic similarity. Larger Canis have relatively stronger postcrania than smaller Canis. The primary way in which this strength is achieved in larger individuals is through a relatively shortening of the bone length. The second hypothesis tested was that postcranial strength is correlated with ecological variables. To investigate this hypothesis, scaling patterns of different species of Canis were compared, including the fossil dire wolf. The results show that the dire wolf is relatively stronger than its living congenerics. There is also a strong relationship between the ratio of prey body mass to predator body mass and relative strength for these species. Carnivores that are hunting animals much larger than themselves must have postcranial skeletons that are strong enough to withstand the loading of the skeleton that occurs during hunting, taking down, and processing large herbivores.</p> / Dissertation
8

THE EFFECTS OF ROADS ON SPACE USE AND MOVEMENTS OF BLACK BEARS IN EASTERN KENTUCKY

Jensen, Rebekah A. 01 January 2009 (has links)
Kentucky, USA, is the site of recent natural recolonization by the American black bear (Ursus americanus); however, bears are rarely observed outside the Cumberland Mountains along the state‘s southeastern border. I examined the influence of roads in constraining the distribution of this population by altering animal space use and movement. I identified patterns of road avoidance and road crossing using data from Global Positioning System collars worn by 28 adult bears (16M, 12F), and described road mortality trends using 27 roadkill events. Bears avoided roads at the home range and landscape scale, primarily crossed low-traffic roads, and crossed in sites that minimized detection by humans. Males displayed more evidence of road avoidance than females, but females crossed roads more selectively than males. Bears were most often killed on high to moderate traffic roads, and in areas less forested than expected. Roadkill and road crossing sites bore different attributes. The results of my study support previous findings that space use near roads and road crossing reflect a tradeoff between the risks of road mortality and human harassment, and the benefits of access to habitat, mates, and anthropogenic food. Road-mediated restriction of black bear space use and movement is indicated.
9

Analyses Of Human-bear Conflict In Yusufeli, Artvin, Turkey

Ambarli, Huseyin 01 February 2006 (has links) (PDF)
Increasing levels of conflict between brown bears and rural people have been reported for Yusufeli (Artvin, Turkey). This study aimed to document the conflict, understand human attitudes and responses, determine local habitat use and daily activity patterns of bears, and evaluate available damage prevention techniques. The study was conducted within landscapes at different scales, ranging from a core area defined by a large valley system to the whole of Artvin Province. Data on close encounters, injuries and damages caused were collected through government records, published literature and open-ended interviews with the locals. Bear presence and activity were monitored through various techniques, including the capture and radio-collaring of one individual. Population density was found to range between 11-27 adult bears/100 km2. Bear activity increased during hyperphagia, with many daytime observations. Interviews (n=67) showed that almost all (95%) locals believed that bears have become more of a problem lately. Only 6% supported full protection while 38% conditionally accepted it. On more than two-thirds of close encounters, the bear and person(s) involved departed without any harm. Rare bear attacks on humans, usually provoked, sometimes caused non-fatal injuries. Several bears were found to be shot and killed within the study area in 2002-2005. Damages were mostly in late summer on field crops and orchards, and in spring on beehives. Precautions taken by villagers differed in effectiveness against bears. Bears caused a minimum of US$21,500 worth damages annually at Yusufeli County. Implementation of modern techniques of exclusion and scaring would reduce human-bear conflict in the region.
10

Algal Preferences in the Masking Behaviour of the Spider Crab, Notomithrax ursus

Ertel, Catherine Monica January 2008 (has links)
The purpose of this study was to examine the masking preferences of the spider crab, Notomithrax ursus. The algal composition of the mask in the natural habitat at Kaikoura was examined to determine the general rules the crab follows when decorating itself. The effects of size and sex on the mask composition were examined, as well as determining how the composition of the mask varies by body part. The preference of the crabs was further examined through the use of choice and background change experiments in the laboratory. It was determined that the preference of certain types of algae for mask material is not entirely dependent on their relative abundance in the environment. Possible explanations for this behaviour are given.

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