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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

Life history tradeoffs, incubation behavior and conservation of horned larks (Eremophila alpestris)

Camfield, Alaine Francine 11 1900 (has links)
Nearly 30 percent of the earth’s terrestrial surface is mountainous and despite representing a large proportion of the planet’s protected areas, the ecology of vertebrates in high elevation areas have received little attention from researchers and managers. I studied two subspecies of horned larks (Eremophila alpestris articola and E. a. strigata) that breed at high elevation and latitude in British Columbia, Canada and at low elevation and latitude in Washington, USA, respectively. I addressed the question of how the life history of alpine breeding songbirds differs from their low elevation conspecifics and showed that life history variation can be found among closely related groups. My results were consistent with other comparative demographic studies which suggest that alpine vertebrate populations tend to show survivor life history strategies when compared to their low elevation counterparts. In addition, population growth rates were stable for E. a. articola suggesting that this subspecies is well adapted to the challenges of breeding in alpine environments. E. a. strigata, however, is declining rapidly and the remaining breeding habitats in Washington do not support stable populations. I used demographic models to show that within reasonable ranges for each vital rate (fecundity, adult and juvenile survival), management actions that target a single rate independently are unlikely to result in stable or recovering populations and management actions that target multiple vital rates should be prioritized. Finally, to further investigate adaptations of E. a. articola to alpine environments I examined how they modify their incubation behavior in response to changes in ambient temperatures which were generally well outside the optimal temperature range for normal embryonic development. Females adjusted the amount of time spent incubating by varying the frequency rather than the duration of recesses. At low ambient temperatures they appeared to shift their investment toward the survival of their eggs by increasing the total time spent on the nest instead of taking longer or more frequent foraging bouts. Overall, the results of my study indicate that alpine populations of horned larks have life history traits and breeding behaviors that allow them to persist in these areas despite the challenging breeding conditions.
12

The value of stormwater wetlands for supporting multiple life-history stages of the wood frog (Lithobates sylvaticus) in the City of Edmonton, Alberta, Canada

Scheffers, Brett Unknown Date
No description available.
13

The value of stormwater wetlands for supporting multiple life-history stages of the wood frog (Lithobates sylvaticus) in the City of Edmonton, Alberta, Canada

Scheffers, Brett 11 1900 (has links)
I reviewed 32 urban amphibian studies from North America and found most amphibians respond negatively to urbanization (69 negative responses, 6 positive and 35 no effect). Additionally, I conducted amphibian surveys (adult, egg, larvae, and metamorphs) at 75 wetlands located throughout the City of Edmonton, Alberta, Canada, with a focus on the wood frog (Lithobates sylvaticus). Wetlands consisted of natural river valley and upland sites, and constructed stormwater wetlands. Breeding male wood frogs occured at 50% of stormwater wetlands versus 93% of natural wetlands. The presence of breeding males was best predicted by the proportion of native vegetation within 100 m of a wetland. Wood frogs successfullly reproduced on stormwater wetlands but relative abundances of eggs, tadpoles and metamorphs were lower than at natural sites. However, stormwater metamorphs were significantly larger which may contribute to higher survivorship and subsequent reproductive success. Stormwater wetlands are required to control flooding and run-off, therefore, future amphibian conservation efforts should focus on preserving native terrestrial habitat surrounding urban wetlands. / Ecology
14

Life history tradeoffs, incubation behavior and conservation of horned larks (Eremophila alpestris)

Camfield, Alaine Francine 11 1900 (has links)
Nearly 30 percent of the earth’s terrestrial surface is mountainous and despite representing a large proportion of the planet’s protected areas, the ecology of vertebrates in high elevation areas have received little attention from researchers and managers. I studied two subspecies of horned larks (Eremophila alpestris articola and E. a. strigata) that breed at high elevation and latitude in British Columbia, Canada and at low elevation and latitude in Washington, USA, respectively. I addressed the question of how the life history of alpine breeding songbirds differs from their low elevation conspecifics and showed that life history variation can be found among closely related groups. My results were consistent with other comparative demographic studies which suggest that alpine vertebrate populations tend to show survivor life history strategies when compared to their low elevation counterparts. In addition, population growth rates were stable for E. a. articola suggesting that this subspecies is well adapted to the challenges of breeding in alpine environments. E. a. strigata, however, is declining rapidly and the remaining breeding habitats in Washington do not support stable populations. I used demographic models to show that within reasonable ranges for each vital rate (fecundity, adult and juvenile survival), management actions that target a single rate independently are unlikely to result in stable or recovering populations and management actions that target multiple vital rates should be prioritized. Finally, to further investigate adaptations of E. a. articola to alpine environments I examined how they modify their incubation behavior in response to changes in ambient temperatures which were generally well outside the optimal temperature range for normal embryonic development. Females adjusted the amount of time spent incubating by varying the frequency rather than the duration of recesses. At low ambient temperatures they appeared to shift their investment toward the survival of their eggs by increasing the total time spent on the nest instead of taking longer or more frequent foraging bouts. Overall, the results of my study indicate that alpine populations of horned larks have life history traits and breeding behaviors that allow them to persist in these areas despite the challenging breeding conditions.
15

Sex, subjectivity and agency: A life history study of women's sexual relations and practices with men

Bryant, Joanne January 2004 (has links)
This study explores women’s experiences of sex with men. It is based on qualitative data collected from eighteen life history interviews. Such an approach provides means for examining women’s sexual experiences over time. The study finds that women give meaning to their sexual experiences through two main discursive representations: the passive, “proper” and sexually obliging girlfriend or wife, and the active and “sexually equal” woman. However, these representations do not capture the entirety of women’s sexual experiences. The life history analysis demonstrates that women are not simply inscribed by discourse. Rather, they are embodied beings actively engaged in pursuing sexual identities. Central to the process is a relationship between the practice of sex and self-reflexivity over time. Finally, the study demonstrates how the process of gaining sexual subjectivity is shaped by the material conditions of women’s lives. For instance, the praxeological circumstances of women’s class or race are powerful in recasting discourses of feminine sexuality, the meanings women ascribe to them, their access to broader sexual experiences, and the kinds of relationships they have with their male partners.
16

A sinfonia da vida: narrativa sobre a constituição do habitus docente musical

Silva, Marco Antonio January 2017 (has links)
SILVA, Marco Antonio. A sinfonia da vida: narrativa sobre a constituição do habitus docente musical. 2017. 138f. –Tese (Doutorado) – Universidade Federal do Ceará, Programa de Pós-Graduação em Educação Brasileira, Fortaleza (CE), 2017. / Submitted by Gustavo Daher (gdaherufc@hotmail.com) on 2017-09-13T13:12:52Z No. of bitstreams: 1 2017_tese_masilva.pdf: 3904908 bytes, checksum: 4a8a6996e600225528aa4e0f2bfaf9ed (MD5) / Approved for entry into archive by Márcia Araújo (marcia_m_bezerra@yahoo.com.br) on 2017-09-13T13:55:14Z (GMT) No. of bitstreams: 1 2017_tese_masilva.pdf: 3904908 bytes, checksum: 4a8a6996e600225528aa4e0f2bfaf9ed (MD5) / Made available in DSpace on 2017-09-13T13:55:14Z (GMT). No. of bitstreams: 1 2017_tese_masilva.pdf: 3904908 bytes, checksum: 4a8a6996e600225528aa4e0f2bfaf9ed (MD5) Previous issue date: 2017 / This study is a self-analysis of the aspects that outlined my teaching training in music at Federal Teaching Institution. The research aims to analyze the trajectory of the agent seeking to unveil such aspects. It is an autobiographical procedure that seeks to describe the transformations that occurred in my career, considering familiar, social, cultural and musical aspects that influenced to a great extent, the decisions that directed me in the role of violin teacher at the Federal University of Cariri. In this sense, the objective of the research is to understand the constitution of the teaching staff habitus of a degree course in music. Thus, looking at the past of formation, the concepts of the praxisology of the sociologist Pierre Bourdieu about the habitus, field, social, cultural and financial capital as a tool to illuminate this analysis are considered. Life History and Praxiology are two research traditions that help to understand this research. In this way, my trajectory demonstrates the process of acquiring a habitus that extrapolates the idea of reproduction of the existence conditions; at the same time, that this context denies my probable destiny allows me to postulate the following thesis: “the inadaptation of the primary habitus, combined with strategies and the contact with key elements in the musical field led me as agent to occupy a prominent position in this field”. / O presente estudo é uma autoanálise dos aspectos que delinearam minha formação docente em Música em uma instituição federal de ensino. A pesquisa tem como objetivo analisar a trajetória do agente procurando desvelar tais aspectos. Trata-se de um procedimento autobiográfico que descreve as transformações ocorridas em minha trajetória, considerando aspectos familiares, sociais, culturais e musicais que influenciaram, em grande medida, as decisões que me direcionaram na função de professor de violino da Universidade Federal do Cariri (UFCA). Nesse sentido, a pesquisa dedica-se a compreender a constituição do habitus docente do professor de um curso de licenciatura em Música. Assim, ao olhar para o passado de formação, são considerados os conceitos da praxiologia do sociólogo Pierre Bourdieu acerca do habitus, campo e capital social, cultural e financeiro como ferramenta para iluminar esta análise. História de vida e praxiologia são duas tradições de pesquisa que ajudam a compreender esta investigação. Desse modo, a trajetória aqui presentada demonstra o processo de aquisição de um habitus que extrapola a ideia de reprodução das condições de existência. Ao mesmo tempo que esse contexto nega meu destino provável, permite-me postular a seguinte tese: “a inadaptação do habitus primário, aliado a estratégias, e o contato com elementos-chaves no campo musical me conduziram, enquanto agente, a ocupar uma posição de destaque no referido campo”.
17

FORAGING BEHAVIOR OF DUCKS DURING SPRING MIGRATION IN THE WABASH RIVER REGION, ILLINOIS

Behney, Adam Christopher 01 December 2014 (has links)
Strategies animals use to find and consume food in the face of conflicting forces such as competition and predation are central questions in the fields of ecological theory and management. Whereas theoretical models abound, proper empirical tests of these theories are less abundant. In studying the relationship between food abundance, predation risk, and competition there exists an array of confounding factors, which need to be accounted for by manipulating some aspect of the system. I used a guild of spring migratory ducks as a model system and manipulated food abundance in areas differing in presumed risk to assess the relative effects of food abundance, predation risk, competition, and life history characteristics on foraging strategies used by ducks. Using a randomized block design, I established a pair of 0.4 ha plots (block) in emergent, open water, and forested wetlands in the Wabash River Floodplain in eastern Illinois. I randomly selected one plot within each block to supplement with 2000 kg/ha of corn (Zea mays), creating an area of very high duck food abundance next to a control area with no added food. I conducted instantaneous focal animal samples and used video recorders to estimate the proportion of time mallard (Anas platyrhynchos), blue-winged teal (Anas discors), wood duck (Aix sponsa), ring-necked duck (Aythya collaris), and lesser scaup (Aythya affinis) devoted to feeding, identify the specific behaviors used, and estimate feeding stint lengths and frequencies. I used these metrics as an index of risk that ducks were willing to engage in for a known food reward. I predicted that species with a faster life history strategy, factors that increase perceived predation risk (cover, water depth, group size), and increase energetic demand (due to nesting or temperature), would elicit more risk-taking behaviors in ducks. This would be realized by an increase in the proportion of time spent feeding, longer feeding durations, and deeper feeding behaviors in treatment plots compared with control plots. Consistent with my life history prediction, species with a faster life history strategy were willing to engage in more risky behavior (feeding more) for a greater food reward (food treatment). Mallards, lesser scaup, and wood ducks exhibited risk-taking behavior consistent with perceived predation risk. Mallards devoted more time to feeding and used longer feeding stints when in areas with less cover. Alternatively, lesser scaup devoted more time to feeding when in areas of more cover. Wood ducks devoted more time to feeding in treatment plots, when in shallow areas, and larger flocks. When blue-winged teal fed on the surface (eyes above water), they devoted more overall time to feeding indicating that surface feeding is less risky than deeper feeding. Wood ducks and lesser scaup exhibited behavior consistent with an increase in energetic demand as observed by an increase in the proportion of time devoted to feeding later in the spring. I also examined how food abundance influenced aspects of ducks' foraging niches. I found that dabbling ducks used a greater variety of behaviors (behavior niche breadth) when in treatment plots compared to control plots and also shifted to slightly deeper feeding behaviors in treatment plots. This greater breadth when food was more abundant was due to individuals of the same species diverging from one another, rather than each individual using a broader array of behaviors. Overall, I found substantial variability among and within species in how they manage risk while foraging, although this was partially explained by life history theory, and what types of conditions they perceive as risky. I document the importance of taking the state of the forager (life history, perceived risk, energetic demand) into account when examining patterns of risk-taking.
18

Life-history patterns of terrestrial mammals in the southern African subregion

Smit, Anne-Marie 07 April 2011 (has links)
Life-history features of terrestrial mammals in the southern African subregion were explored in an attempt to identify the factor(s) that may influence the evolution of common mammalian life-history patterns within this subregion. Allometry and phylogeny were found to underly most of the variation observed in life-history features. Residual variation was considered and age at maturity, gestation period and litter size emerged as additional features influencing life-history patterns. Southern African mammals could generally be arranged along a theoretical r-K continuum with small mammals having relatively short developmental periods and relatively large litter sizes represented at one extreme and large mammals having relatively long developmental periods with relatively small litter sizes at the opposite extreme. However, the carnivores did not conform to this expected general gradient suggesting that they may be an exceptional order as far as their life-histories are concerned. / Dissertation (MSc)--University of Pretoria, 2011. / Zoology and Entomology / unrestricted
19

Life history tradeoffs, incubation behavior and conservation of horned larks (Eremophila alpestris)

Camfield, Alaine Francine 11 1900 (has links)
Nearly 30 percent of the earth’s terrestrial surface is mountainous and despite representing a large proportion of the planet’s protected areas, the ecology of vertebrates in high elevation areas have received little attention from researchers and managers. I studied two subspecies of horned larks (Eremophila alpestris articola and E. a. strigata) that breed at high elevation and latitude in British Columbia, Canada and at low elevation and latitude in Washington, USA, respectively. I addressed the question of how the life history of alpine breeding songbirds differs from their low elevation conspecifics and showed that life history variation can be found among closely related groups. My results were consistent with other comparative demographic studies which suggest that alpine vertebrate populations tend to show survivor life history strategies when compared to their low elevation counterparts. In addition, population growth rates were stable for E. a. articola suggesting that this subspecies is well adapted to the challenges of breeding in alpine environments. E. a. strigata, however, is declining rapidly and the remaining breeding habitats in Washington do not support stable populations. I used demographic models to show that within reasonable ranges for each vital rate (fecundity, adult and juvenile survival), management actions that target a single rate independently are unlikely to result in stable or recovering populations and management actions that target multiple vital rates should be prioritized. Finally, to further investigate adaptations of E. a. articola to alpine environments I examined how they modify their incubation behavior in response to changes in ambient temperatures which were generally well outside the optimal temperature range for normal embryonic development. Females adjusted the amount of time spent incubating by varying the frequency rather than the duration of recesses. At low ambient temperatures they appeared to shift their investment toward the survival of their eggs by increasing the total time spent on the nest instead of taking longer or more frequent foraging bouts. Overall, the results of my study indicate that alpine populations of horned larks have life history traits and breeding behaviors that allow them to persist in these areas despite the challenging breeding conditions. / Forestry, Faculty of / Graduate
20

Plasticity of Senescence in the Antler Fly (Protopiophila litigata)

Angell, Christopher 18 May 2021 (has links)
As most multicellular organisms age, they undergo senescence: a progressive physiological deterioration that leads to declines in survival, reproduction, and performance in late life. Although senescence was once thought to be a phenomenon peculiar to captive animals and humans, field data have demonstrated age-related performance declines in a variety of taxa. Nevertheless, the ecology and evolution of senescence is not fully understood. The bulk of our knowledge about senescence in wild populations comes from studies of long-lived vertebrates, while short-lived invertebrates are often studied in the lab. Male antler flies (Protopiophila litigata; Diptera: Piophilidae) are an emerging insect model for studying senescence in nature, as they have short lifespans and high site-fidelity, facilitating collection of longitudinal data, and they can be easily reared and manipulated in the lab. This species is an ideal model to connect our lab-invertebrate- and field-vertebrate-based insights into aging biology. The developmental environment can have an especially large impact on life-history plasticity, including plasticity in senescence. This is because a developing organism makes “decisions” affecting phenotypes such as body size, sexual investment, metabolic rate, etc., which in turn can influence longevity and senescence. In my dissertation, I investigate how the early life environment, including larval diet and parental effects, plastically alters longevity and senescence in antler flies, primarily in the field in Algonquin Provincial Park. First, I quantified the effect of experimentally manipulated larval nutrient concentration on both early-life (growth and development) and late-life traits (reproduction, survival, senescence). Rich larval diet decreased development time, and although fast developers grew large and had low initial mortality in the field (and high average lifespan), they aged rapidly and had low mating rate. Due to these contrasting effects, diet and development time did not predict lifetime mating success, suggesting trade-offs among fitness components and alternative strategies in low condition males. Only male antler flies can be tracked in the field, so nothing is known about aging in females. In my second study, I compared longevity and aging of female and male antler flies in the lab. Theory suggests that males may age faster and die sooner than females, but empirical data are highly variable. Furthermore, the sexes may respond differently to variation in nutrition, so I reared flies on different larval diets based on the design of my first chapter. The sexes did not differ in senescence or longevity in the lab, and diet had a negligible effect. Large-bodied flies of both sexes senesced slower, in contrast to previous field data, highlighting plastic differences in senescence between wild and captive populations. In my third study, I quantified parental age effects on male antler flies. Offspring quality often changes with parental age, due to accumulation of germline mutations and/or changes in nongenetic maternal or paternal effects. To investigate whether and how parental age influences performance in wild insects, I mated lab-reared young and old females and males to one another in all combinations, and tracked their male offspring’s performance in the wild. Old fathers had long-lived sons, while maternal age had no effect on offspring survival in the field. Parental age did not affect mating success. Thus, the one parental age effect I observed was in fact positive, not negative. In my final study, I looked at how natural differences in larval diet, rather than artificial lab diets, influenced survival, mating, and senescence in wild male antler flies. Antlers become depleted of resources from year to year, as multiple generations of larvae feed within them. I collected larvae that grew inside nine different shed moose antlers, and tracked them in the field as adults. Males from high quality antlers (those that were more attractive to adult flies) completed metamorphosis more quickly, but did not differ in body size, longevity or lifetime mating success. However, large flies tended to live longer and have higher mating success. In conclusion, my dissertation research expands our understanding of plasticity in life history and senescence, particularly in insects, which are enormously abundant but understudied in this area. I quantified, for the first time to my knowledge, the effects of juvenile diet and parental age on longevity, mating success, and senescence in a wild insect.

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