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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.
91

Aspects of the biology of the pink-billed lark (Spizocorys conirostris) in the Limpopo Province, South Africa

Mathonsi, Mandlenkosi Habile Thabo January 2013 (has links)
Thesis (M.Sc. ( Zoology)) --University of Limpopo, 2013 / The fieldwork for this study was carried out from October 2008 to October 2010, under the supervision of Professor D. Engelbrecht of the Department of Biodiversity at the University of Limpopo. Professor Engelbrecht kindly agreed to provide me with raw breeding data of the same population collected during 2008. This study represents original work by the author and where work of other authors has been used; they are duly acknowledged in the text and listed as references. Chapter 1 is a general introduction to the family Alaudidae in which their characteristics and taxonomy are discussed. This is followed by a brief overview of the general biology and ecology of larks of the world in general, followed by a more specific emphasis on the genus Spizocorys, and finally the Pink-billed Lark. In this section, gaps in the available knowledge of Pink-billed Larks are highlighted. This chapter culminates in the aim and objectives of this study. In Chapter 2 the various aspects of the breeding biology of the Pink-billed Lark are reported. This includes, amongst others, aspects such as breeding seasonality, clutch sizes, roles of the sexes during the breeding cycle and breeding success. Chapter 3 provides the results of a morphometric study of museum study skins from across the species range. This includes an analysis of sexual size dimorphism and geographical variation of the different subspecies. This chapter also provides a brief description of the timing and pattern of moult and the various vocalizations of the Pink-billed Lark. Chapter 4 concludes the dissertation with a summary of the results of this study and highlights avenues for future research on the species and the family. The format of Chapters 2 and 3 takes the form of research papers that can be submitted for publication with minimum editing. Chapter 2 has been published in the Journal of African Zoology (see below). Chapter 3 is in preparation for submission to a peer-reviewed journal. As such, there is some repetition in the introductory paragraphs and concluding remarks of chapters 2, 3 and 4. To give this manuscript a degree of uniformity, the literature cited in all chapters has been formatted according to the manuscript requirements of the Journal of African Zoology, and a reference list appears at the end of the dissertation. Tables and figures are arranged at the end of each chapter.
92

Análise fisiológica e comportamental de micos-leões-pretos em cativeiro : uma avaliação do nível de estresse /

Bertoli, Paula Custódio. January 2017 (has links)
Orientador: Laurence Marianne Vincianne Culot / Coorientador: Olívia de Mendonça Furtado Pimenta / Coorientador: Renata Gonçalves Ferreira / Banca: Guilherme Gomes / Banca: Patricia Izar / Resumo: O mico-leão-preto (MLP, Leontopithecus chrysopygus) é uma espécie de primata neotropical ameaçada de extinção, sendo que tanto esforços in situ, quanto ex situ devem ser feitos para sua conservação. O entendimento das condições do cativeiro que melhoram o bem-estar dos indivíduos é necessário para viabilizar o sucesso reprodutivo ex situ. No entanto, indivíduos com diferentes perfis comportamentais podem responder de formas distintas a um mesmo estímulo tendo seu bem-estar impactado de diferentes maneiras. O bem-estar animal pode ser avaliado através de variáveis comportamentais (via o estudo de comportamentos potencialmente indicativos de estresse - BPIS) e fisiológicas (via o estudo dos níveis de metabólitos fecais de glicocorticóides - MGFs). Assim, os objetivos desse trabalho foram: 1) determinar o efeito das condições de cativeiro, período do dia e estação do ano sobre o comportamento e sobre os níveis de MGFs; 2) determinar a relação entre os comportamentos e os níveis de MFGs; 3) definir os eixos que compõe o perfil de comportamento gênero-normativo e os eixos que representam as diferentes formas de reação ao estresse entre os BPIS; e 4) identificar os estilos de enfrentamento da população de MLP estudada (via a análise da relação entre os tipos comportamentais, formas de reação ao estresse e índices hormonais de MFGs). Foram observados 11 indivíduos (3 fêmeas e 8 machos) no Centro de Primatologia do Rio de Janeiro durante 15 dias em duas estações (verão e inverno), em... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The Black Lion tamarin (BLT, Leontopithecus chrysopygus) is a threatened neotropical primate species for which both in situ and ex situ efforts have to be done for its conservation. The understanding of which captive conditions improve the welfare of individuals is necessary to enable ex situ reproductive success. However, individuals with different behavioral profiles may respond differently to the same stimulus, consequently impacting their welfare in different ways. Animal welfare can be assessed through behavioral (through the study of behaviors potentially indicative of stress - BPIS) and physiological variables (through the study of fecal metabolites of glucocorticoids - MGFs). Therefore, the aims of the study were: 1) to determine the effect of the captive condition, period of the day and season on the behavior and the levels of MGFs; 2) to determine the relationship between behaviors and levels of MFGs; 3) to identify axes that make up the gender-normative behavioral profile (among normative behavioral patterns - GNBs ) and axes of the forms of stress reaction (among BPIS) and; 4) to identify coping styles (through an analysis of the relationship between behavioral types, forms of reaction to stress and hormonal indices of MFGs). We observed 11 individuals (3 females and 8 males) in the Primatology Center of Rio de Janeiro for 15 days in two different seasons (summer and winter) in 4 different treatments: 1 malefemale pair with its adult twins, 1 male-female pair, 1 m... (Complete abstract click electronic access below) / Mestre
93

Efeitos da biodiversidade sobre a estrutura e funcionamento de ecossistemas em um cenário de mudança climática /

Migliorini, Gustavo Henrique. January 2018 (has links)
Orientador: Gustavo Quevedo Romero / Banca: Aliny Patricia Flauzino Pires / Banca: Tadeu de Siqueira Barros / Banca: Victor Satoru Saito / Banca: Marcelo da Silva Moretti / Resumo: Mudanças climáticas e alterações na biodiversidade são as principais ameaças que os ecossistemas estão enfrentando na era atual. Mudanças na composição de espécies de plantas, juntamente com alterações nas suas características induzidas pelo clima, são esperados alterar a qualidade e a diversidade funcional dos detritos, o que pode gerar impactos diretos e indiretos sobre as comunidades associadas e o funcionamento ecossistêmico. Entretanto, pouco se sabe sobre como os atributos dos detritos e seus efeitos interativos com o aumento da temperatura podem afetar a estrutura de comunidades e processos ecossistêmicos. Neste estudo, nós investigamos os efeitos individuais e interativos do aquecimento e de mudanças na qualidade e diversidade funcional de detritos sobre a estrutura de comunidades de insetos aquáticos e sobre as taxas de decomposição dos detritos. Utilizando microcosmos aquáticos naturais (bromélias tanque), nós simulamos o efeito do aquecimento e manipulamos a qualidade e diversidade funcional de detritos. Nossos resultados mostram que o aquecimento pode afetar a riqueza e abundância de insetos aquáticos e mudar sua composição. Tanto a qualidade como a diversidade funcional dos detritos podem influenciar a estrutura das comunidades de insetos aquáticos. Além disso, o aquecimento e as alterações na qualidade e na diversidade funcional dos detritos podem afetar as taxas de decomposição, e esses efeitos podem ser explicados principalmente pelos conteúdos de ligninas e... / Abstract: Climate warming and biodiversity shifts are the main threats ecosystems are facing in current era. Changes in plant species composition, along with climate-induced alterations in plant traits, are expected to alter the quality and functional diversity of litter with direct or indirect impacts on the communities of consumers and ecosystem functioning. However, little is known on the importance of litter traits and how they interact with warming to affect the structuring of communities and ecosystem processes. In this study, we investigated the individual and interactive effects of warming and changes in litter quality and functional diversity on the structuring of aquatic invertebrate communities and decomposition process. Using a natural aquatic microecosystem (tank bromeliads), we simulated the effect of warming and manipulated litter quality and functional diversity. Our results shown that warming may affect richness and abundance of aquatic insects and change their composition. Both litter quality and functional diversity may affects the structure of insect communities. Moreover, warming and changes in litter quality and functional diversity may affect decomposition rates, and such changes can be explained mainly by specific traits, such as lignin contents and dissimilarities in C, N and C:N ratios. Our study highlight the importance in knowing the effects of increasing temperature and changes in plant composition on aquatic communities, in order to predict the effects of ... / Doutor
94

Ecological and phylogenetic characteristics of consumed red-backed salamanders influence antipredator behavior of conspecifics

Taylor, David A. January 2006 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Biology Department, 2006. / Includes bibliographical references.
95

Breeding Ecology Of The Egyptian Vulture (neophron Percnopterus) Population In Beypazari

Sen, Bilgecan 01 December 2012 (has links) (PDF)
The aim of this study was to determine the habitat features affecting nest site selection and breeding success of the endangered Egyptian Vultures (Neophron percnopterus) breeding around the town of Beypazari. We searched and monitored nest sites in the study area (750 km2) for the years 2010 and 2011. The differences in terms of habitat features between nest sites and random points distributed along cliffs, and between successful and failed nest sites were investigated using both parametric approaches and machine learning methods with 21 habitat variables. The size of the Beypazari population of Egyptian Vultures was estimated to be 45 pairs. Seventeen nests in 2010 and 37 nests in 2011 were found and monitored. The breeding success of the population was estimated to be 100% in 2010 and 70% in 2011. Random Forests was the modeling technique with the highest accuracy and the modeling process chose 6 and 4 variables affecting nest site selection and breeding success of the species, respectively. Results showed that human impact was a potential factor governing the distribution of nest sites in the area and increased the probability of breeding failure as vultures clearly preferred to nest away from nearby villages, towns and roads, and nests on lower cliffs and nests that are close to the dump site (therefore the town center) was prone to failure. Utilization of elevation gradient and aspect showed trends similar to other populations of the species, with probability of nesting increasing at lower altitudes and for south facing cliffs. The overall results emphasize the potential conflict between human presence and the population of Egyptian Vultures in the area. Continuous monitoring of the nest sites and conservation activities towards raising public awareness are advised.
96

Breeding Success And Reproductive Behavior In A White Stork ( Ciconia Ciconia) Colony In Ankara

Gocek, Cagri 01 September 2006 (has links) (PDF)
White Stork ( Ciconia ciconia, Linnaeus, 1758) is a summer visitor and passage migrant in Turkey. Although being widespread in summer near wetlands of Turkey, except for the eastern and western parts of the Black Sea Region, there has been no research on this species involving regular monitoring of nests. In this study, breeding success and survival of nestlings in a population in Kizilcahamam-Ankara as well as behavioral differences among nests and their probable consequences on breeding success were studied. Regular field observations throughout six-month long breeding seasons between 2003 and 2006 were carried out to determine parent and young behavior patterns at nest. Clutch size, and numbers of chicks hatched and fledged fluctuated throughout 2003-2006 for pairs that bred while fledgling success (average fledgling per successful nests with egg laid) were 2.63 in 2003, 3.82 in 2004, 1.89 in 2005 and 3.13 in 2006. These values are in good agreement with those recorded in northern Europe. The relationship between beginning date of incubation and both clutch size and brood size were found to be different for 2004 and 2005. Such a relationship may be significant in breeding seasons colder than usual. For 2004 and 2005, the amount of food brought and caring towards young by parents were compared with breeding success (proportion of hatched young that were fledged), and breeding success was found to increase with increasing amount of food provisioning. However, this result may be suggested to be related with weather conditions. In conclusion, Kizilcahamam White Stork population has been found to be not restricted by food or nest site availability and with a reproductive output above the European average, although annual climatic stochasticity was found to affect reproductive output.
97

Monitoring Of Water Clarity, And Submerged And Emergent Plant Coverages In Shallow Lake Wetlands Using Remote Sensing Techniques

Karabulut Dogan, Ozge 01 February 2007 (has links) (PDF)
Shallow lake wetlands, for which aquatic plants (macrophytes) and water clarity are the key indicators of ecological status, provide valuable services to wildlife and humanity. Conservation of these ecosystems requires development of rapid and large scale monitoring strategies, where remote sensing and Geographic Information Systems (GIS) can be advantageous. In this study, high spatial resolution Quickbird and IKONOS and medium spatial resolution Landsat and Aster images were used for monitoring the aquatic plants and water clarity in Lakes Mogan and Eymir. Classification of emergent plants with high spatial resolution data yielded overall accuracies greater than 90% for both lakes, while overall accuracies obtained from the medium spatial resolution data ranged between 80% and 93% for Lake Mogan and between 70% and 78% for Lake Eymir. It was found that there was 23ha reed bed loss in Lake Mogan between 2002 and 2005 and an additional 14ha was lost between 2005 and 2006. In Lake Eymir, no significant change in reed bed area was detected from high spatial resolution images / however medium spatial resolution images revealed 8ha of change which was attributed to the presence of mixed pixels due to low resolution. The overall accuracies for submerged plant coverage classification from Quickbird images in Lake Mogan were 83% (2005) and 79% (2006) and for classification of submerged plants species were 72% (2005) and 69% (2006). Moreover, it was found that blue band together with the ratio of red band to blue band, were the best predictors of Secchi disc depth.
98

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.
99

The Effect Of Ecotoxicants On The Aquatic Food Web And Prey-predator Relationships

Akkas, Sara Banu 01 July 2009 (has links) (PDF)
There is considerable need for higher-tier aquatic risk assessment and information on toxicant-induced molecular alterations in lower aquatic invertebrates. Thus the current study&rsquo / s priorities were two-fold: a novel approach utilizing higher-tier ecotoxicity bioassay-guided ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared) spectroscopy to better understand the impact of the presence of fish predation pressure &ndash / mimicked by predator-exuded info-chemicals &ndash / on cypermethrin or salinity toxicity to Daphnia pulex &ndash / key-stone species in lake ecosystems &ndash / and ultimately better assess toxicant-induced alterations at both organismal and molecular levels. This approach indicates that even low concentrations of cypermethrin/salinity had significant molecular and organismal effects on daphnids. Fish kairomone acted as a major factor affecting toxicant severity, interacting antagonistically below a threshold and synergistically above. Moreover, molecular ATR-FTIR spectroscopic results, clearly consistent with organismal responses, showed that both cypermethrin and salinity lead to decreased contributions of lipid and proteins to the investigated daphnid systems. It is further suggested that the action mechanism of the fish-exuded kairomone occurs via the lipid metabolism of Daphnia. Hence, infrared spectroscopic results enabled detection of early molecular alterations, whose effects might not always be observable at the organismal level. The results of this study clearly indicate that the simplistic nature of standard ecotoxicology tests hinders a precise judgment of threats imposed by chemicals of interest. Furthermore, it has been shown that ATR-FTIR spectroscopy has considerable potential for studies on daphnid responses to varying environmental conditions. Thus, this study presents a starting point for increasing the environmental realism of aquatic risk assessment.
100

Paleolimnological Assessment Of Past Aquatic Vegetation Dynamics And Ecosytem State In Turkish Shallow Lakes

Levi, Eti Ester 01 September 2009 (has links) (PDF)
Since submerged macrophytes are a key primary producer of shallow lakes and are sensitive to environmental changes, macrofossils of them can be used in investigations of past environmental conditions, to infer human introduced environmental impacts (e.g. eutrophication) and to determine past macrophyte communities. The present study includes twenty six shallow lakes, which were chosen along a latitudinal gradient ranging from the North (41&deg / 52&acute / N, 27&deg / 58&acute / E) to the South (37&deg / 06&acute / N, 29&deg / 36&acute / E) in Turkey. Sampling for environmental variables and sediment was carried out using a snap-shot sampling protocol (developed within the framework of the EU FP6 project &lsquo / Eurolimpacs&rsquo / ) during the summers of three consecutive years (2006-2008). Surface sediment, short core and long core samples were retrieved from the lakes. The aims of this study were i. to compare the surface sediment plant macrofossils with present day macrophyte taxa of the lakes, ii. to determine the environmental variables potentially influencing the temporal changes in macrophyte communities, and iii. to assess vegetation community dynamics in dated short and long cores. Comparison of plant macrofossil assemblages in surface sediment with present day macrophyte coverage revealed that approximately 41% of the modern taxa were represented among the surface sediment macrofossils. Redundancy analysis (RDA) was carried out for surface macrofossil data with corresponding environmental data. RDA revealed relation of plant species and environmental variables (e.g. Salinity and Najas marina L.). Changes in plant species assemblages in short and long cores from eight lakes chosen along a latitudinal gradient ranging from North to South Turkey is discussed in relation to the RDA results.

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