Global ETD Search

501	Bottom-Up Impacts of Grazing Disturbance on Ground-Nesting Bee Assemblages: Do They Dig It? Collins, Shannon Marie 12 1900 (has links) In my thesis, I examined impacts of nesting and floral resources on ground-nesting bee assemblages at nine ranch sites with differing grazing histories. Because ecological disturbances can strongly affect the availability of foraging and nesting resources over time, I also examined the impacts of grazing history on nesting and floral resources for ground-nesting bees. I sampled bee assemblages, a comprehensive array of vegetation and soil measures, and floral abundance and richness. I used these data to determine (1) the importance of different nesting habitat resources and livestock grazing history for ground-nesting bees and (2) how livestock grazing history influenced the availability of nesting and floral resources. I found that sites with sandier soils had greater abundance and richness of ground-nesting bees, and sites with less compacted soils had greater bee abundance. Contrary to many other studies, the availability of bare ground was not important for ground-nesting bee abundance or richness. Grazing history did not affect any measures of nesting or floral habitat, and had negligible effects on ground-nesting bee abundance, richness, and community composition. My results suggest that the availability of sandier or less compacted soils may be limiting for ground-nesting bee abundance or richness, especially in areas with predominately clay soil types. In this context, the availability of such nesting resources may be more limiting than floral resource availability. More research is necessary to tease apart the effects of different nesting and floral resources for bees, and how different grassland management types affect bees through those resources. My findings highlight the importance of considering nesting habitat resources in bee conservation and restoration efforts. ecology insect bee Hymenoptera grazing grassland prairie disturbance ground-nesting conservation restoration soil flowers nesting Biology, Ecology Biology, Entomology Agriculture, Range Management
502	Comparison of Soil Carbon Dynamics Between Restored Prairie and Agricultural Soils in the U.S. Midwest Ian Lucas Frantal (18514434) 07 May 2024 (has links) <p dir="ltr">Globally, soils hold more carbon than both the atmosphere and aboveground terrestrial biosphere combined. Changes in land use and land cover have the potential to alter soil carbon cycling throughout the soil profile, from the surface to meters deep, yet most studies focus only on the near surface impact (< 25 cm deep). This research bias toward shallow soil carbon cycling has ramifications for understanding the full impacts of agricultural and restoration management practices on soil organic and inorganic carbon dynamics. The primary objective of my thesis research is to evaluate the factors controlling the impact of deep-rooting perennial grass on soil carbon cycling during prairie restoration of soil following long term, row crop agriculture. Paired soil pits were established to compare the effects of restoration on soil C dynamics in a corn-soy cropping system (minimal tillage) and restored prairie sites in Nebraska and Illinois. At each site, soil organic carbon (SOC) and inorganic carbon (SIC) content, stock, and stable carbon isotope analysis were preformed to ~2 m depth to assess long term integrated C dynamics. Estimating the contribution of prairie carbon inputs to the SOC in the soil profile was examined using stable carbon isotopic signatures in the SOC in relation to the above ground vegetation changes in C<sub>3</sub> and C<sub>4</sub> photosynthetic pathway plant community composition. Comparative analysis of edaphic properties and soil carbon suggests that deep loess deposits in Nebraska permit enhanced water infiltration and SOC deposition to depths of ~100 cm in 60 years of prairie restoration. In Illinois, poorly drained, clay/lime rich soils on glacial till and a younger restored prairie age (15 years) restricted the influence of prairie restoration to the upper 30 cm. Comparing the δ<sup>13</sup>C values of SOC and SIC in each system demonstrated that SIC at each site is likely of lithogenic origin. This work indicates that the magnitude of influence of restoration management is dependent on edaphic properties inherited from geological and geomorphological controls. Future work should quantify root structures and redox properties to better understand the influence of rooting depth on soil carbon concentrations. Fast-cycling C dynamics can be assessed using continuous, in-situ CO<sub>2</sub> and O<sub>2</sub> soil gas concentration changes. The secondary objective of my thesis was to determine if manual, low temporal resolution gas sampling and analysis are a low cost and effective means of measuring soil O<sub>2</sub> and CO<sub>2</sub>, by comparing it with data from in-situ continuous (hourly) sensors. Manual analysis of soil CO<sub>2</sub> and O<sub>2</sub> from field replicates of buried gas collection cups resulted in measurement differences from the continuous sensors. Measuring CO2 concentration with manual methods often resulted in higher concentrations than hourly, continuous measurements across all sites. Additionally, O<sub>2</sub> concentrations measured by manual methods were higher than hourly values in the restored prairie and less in agricultural sites. A variety of spatial variability, pressure perturbations, calibration offsets, and system leakage influences on both analysis methods could cause the discrepancy.</p> Environmental biogeochemistry soil organic carbon inorganic carbon Land use -- Environmental aspects agriculture restored prairie
503	On the prairie lines: the earth shelter Goranov, Yavor Kamenov January 1992 (has links) The thesis of this project focuses on some possibilities for present day interpretation of the prairie style as it relates to the third dimension i.e. trying to use Frank Lloyd Wright as a departure point for my personal design explorations. I consider this thesis project to be an important step in the ongoing process of my personal development as an architect looking for some new ideas in the realm of the third dimension. / Master of Architecture LD5655.V855 1992.G672 Prairie school (Architecture)
504	Managing iron deficiency chlorosis (IDC) in soybean through a cropping system approach Waldrep, Katelin Savannah 12 May 2023 (has links) (PDF) Iron deficiency chlorosis (IDC) is a frequent problem throughout many areas of the United States where soils are high in calcium carbonate (CaCO3), including the Blackland Prairie regions of Mississippi. The main objectives of this study were to 1) determine the effects of seven different cropping systems on IDC visual symptomology and grain yield in rainfed soybeans grown in calcareous soils, and 2) evaluate the effects of soil water tension (SWT) on IDC. Rotating soybeans with corn produced significantly higher yields for both tolerant and susceptible soybean varieties. IDC symptomology was worse, and yields were lower in cropping systems with lower average SWT, or wetter soils, throughout the growing season. Last, this study evaluated the use of multispectral imagery and apparent soil electrical conductivity (ECa) to identify IDC-prone areas of a field for the site-specific implementation of management strategies that produced higher yields in the plot-scale study. iron deficiency chlorosis (IDC) Mississippi Alabama Blackland Prairie site-specific management soil water tension (SWT) soybean Agronomy and Crop Sciences Bioresource and Agricultural Engineering
505	Encountering maternal silence: writing strategies for negotiating margins of mother/ing in contemporary Canadian prairie women's poetry Hiebert, Luann E. 11 April 2016 (has links) Contemporary Canadian prairie women poets write about the mother figure to counter maternal suppression and the homogenization of maternal representations in literature. Critics, like Marianne Hirsch and Andrea O’Reilly, insist that mothers tell their own stories, yet many mothers are unable to. Daughter and mother stories, Jo Malin argues, overlap. The mother “becomes a subject, or rather an ‘intersubject’” in the text (2). Literary depictions of daughter-mother or mother-child intersubjectivities, however, are not confined to auto/biographical or fictional narratives. As a genre and potential site for representing maternal subjectivities, poetry continues to reside on the margins of motherhood studies and literary criticism. In the following chapters, I examine the writing strategies of selected poets and their representations of mothers specific to three transformative occasions: mourning mother-loss, becoming a mother, and reclaiming a maternal lineage. Several daughter-poets adapt the elegy to remember their deceased mothers and to maintain a connection with them. In accord with Tanis MacDonald and Priscila Uppal, these poets resist closure and interrogate the past. Moreover, they counter maternal absence and preserve her subjectivity in their texts. Similarly, a number of mother-poets begin constructing their mother-child (self-other) relationship prior to childbirth. Drawing on Lisa Guenther’s notions of “birth as a gift of the feminine other” and welcoming the stranger (49), as well as Emily Jeremiah’s link between “‘maternal’ mutuality” and writing and reading practices (“Trouble” 13), I investigate poetic strategies for negotiating and engaging with the “other,” the unborn/newborn and the reader. Other poets explore and interweave bits of stories, memories, dreams and inklings into their own motherlines, an identification with their matrilineage. Poetic discourse(s) reveal the limits of language, but also attest to the benefits of extra-linguistic qualities that poetry provides. The poets I study here make room for the interplay of language and what lies beyond language, engaging the reader and augmenting perceptions of the maternal subject. They offer new ways of signifying maternal subjectivities and relationships, and therefore contribute to the ongoing research into the ever-changing relations among maternal and cultural ideologies, mothering and feminisms, and regional women’s literatures. / May 2016 Elegiac poetry Motherhood Maternity poetry Canadian poetry Women authors Poetics Maternal subjectivity Maternal theory Feminist poetry Prairie poetry Pregnancy Childbirth Mourning mother loss Mourning child loss Maternal lineage Mother poets Prairie women's poetry 21st century poetry Ariel Gordon Barbara Langhorst Canadian literature (English) Charlene Diehl-Jones Claire Harris Cultural transmission Cultural violence Culture and motherhood Domestic violence Elegy Hospitality and responsibility Jennifer Still Lisa Martin-DeMoor Literary criticism Louise Bernice Halfe Maternal discourse Maternal aesthetics Maternal inheritance Maternal silence Maternal writing Méira Cook Erín Moure Melanie Dennis Unrau Mother myths Postcolonial writing Motherhood studies Motherhood and feminism Prairie women poets Regional literature Rita Bouvier Sally Ito Sarah Klassen Su Croll Subjectivity Writing and motherhood Writing the other
506	Influence du système sol – végétation – pratiques agricoles des prairies franc - comtoises sur la dynamique de population de la forme fouisseuse du campagnol terrestre (Arvicola terrestris scherman shaw, 1801). Morilhat, Céline 09 November 2005 (has links) (PDF) Les petits mammifères constituent les vertébrés responsables des dégâts les plus importants pour l'agriculture de l'Europe centrale. Dans les prairies de moyenne montagne, les populations de campagnol terrestre (Arvicola terrestris sherman) sont à l'origine de pullulations cycliques conséquentes depuis les années 70. En France, une des explications est que l'intensification de l'agriculture a conduit à l'ouverture des milieux agricoles et à la conversion de la majorité des terres en prairies toujours en herbe. Actuellement, le rôle de la structure et de la composition du paysage est établi aux échelles régionale et sectorielle mais on ne connaît pas le rôle des caractéristiques édaphiques des prairies sur les populations de A. terrestris à l'échelle parcellaire. L'objectif de ce travail de thèse était de déterminer, à l'échelle parcellaire, le rôle de la végétation des prairies, en relation avec le sol et le mode de conduite agricole, sur la dynamique des populations de A. terrestris. Dans des parcelles agricoles situées en Franche-Comté, différentes phases d'un cycle de population de A. terrestris ont été étudiées de 2001 à 2004 : basse densité, croissance, haute densité. Dans chaque parcelle d'étude, le suivi des populations de A. terrestris a été effectué par une méthode indiciaire d'estimation des densités relatives. Les populations de taupe (Talpa europaea) et de campagnol des champs (Microtus arvalis) ont également été prises en compte, en raison de leurs interactions possibles avec A. terrestris. Dans chaque parcelle, la végétation a été étudiée par ses caractéristiques structurelles (mesures de hauteur – compacité du couvert végétal) et fonctionnelles (fréquences des traits d'histoire de vie des espèces végétales). Les propriétés du sol ont été évaluées par les caractéristiques morphologiques (profondeur, texture, structure) et physico-chimiques (matière organique, pH, hydromorphie). Les données de pratiques agricoles (fauche, pâture, fertilisation, labour) ont été recueillies par le biais d'enquêtes auprès des exploitants agricoles des parcelles d'étude. Les principaux résultats montrent que les dynamiques de croissance des populations de A. terrestris sont favorisées par un régime agricole de production intensif, impliquant de nombreuses fauches et une forte fertilisation. Ce régime engendre une végétation à croissance rapide, caractérisée par une faible diversité spécifique et une forte valeur pastorale. Ponctuellement, en phase de haute densité, les populations de A. terrestris sont favorisées par un couvert végétal homogène, haut et dense et défavorisées par des pratiques telles que pâturage intensif et travail du sol. Le mode d'exploitation agricole influencerait les populations de A. terrestris en agissant sur la qualité et la disponibilité de la ressource nutritive végétale et sur la structure de l'habitat sol plante. De plus, à mode de conduite agricole constant, les caractéristiques pédologiques ne semblent pas exercer d'influence. Des résultats complémentaires indiquent que l'intensité de la colonisation des parcelles par A. terrestris est favorisée par les populations de T. europaea en phase de basse densité. En conclusion, notre étude montre qu'un seul facteur explicatif n'est pas suffisant mais que c'est bien la configuration d'un ensemble de variables qui explique la dynamique de populations de A. terrestris à l'échelle parcellaire. La prise en compte de cette régulation multifactorielle dans les programmes de contrôle des populations de A. terrestris pourra en améliorer l'efficacité à long terme. Des expérimentations à l'interface entre les domaines de la recherche et de l'application sont nécessaires pour parvenir à un compromis acceptable entre préconisation de pratiques agricoles défavorables aux pullulations de A. terrestris, remplissage des cahiers des charges des productions d'AOC et respect de l'environnement. dynamique de population micromammifères animaux fouisseurs Arvicola. terrestris Talpa europaea Microtus arvalis écologie du paysage écosystèmes tempérés agrosystèmes prairie sol végétation pratiques agricoles régulation « bottom-up »
507	Cultivating domesticity : the Homemakers' Clubs of Saskatchewan, 1911-1961. Milne, Jennifer E 22 July 2005 On January 31, 1911, the Homemakers' Clubs of Saskatchewan became an official organisation under the direction of the University of Saskatchewan. Established to provide isolated rural women with companionship, access to education, and the opportunity to carry out community service, Homemakers' Clubs appealed to thousands of farm women because they provided the means by which they could improve themselves, their farm homes, and their communities. Its appeal also lay in the fact that the organisation remained non-political and non-sectarian, focusing instead on women's primary responsibilities to their homes and their families. To that end, Homemakers' Clubs embraced a domestic ideology that institionalised notions of gender and celebrated women's roles in the home. Given that the nature of farm women's work was not restricted to the household, however, Homemakers' Clubs allowed rural women to redefine an urban domesticity to include their farming responsibilities. Moreover, in a setting where gender lines were often blurred and the division of labour was not always strictly defined, membership in an organisation that reinforced gender roles, promoted family and community life, and embraced a traditional mandate provided farm women with a level of respectability and femininity that was often lost in a farming setting. Finally, the domestic ideology under which the Homemakers' Clubs operated allowed its members to find recognition and validation in their work, and, in their goals to elevate home life, to legitimise their work, and to adjust domestic ideology to include their farming responsibilities, the organisation became a space in which its members discussed, debated, explored, and, in some cases, challenged common perceptions of women; they subtly challenged the status quo and demanded validation and recognition for their work in and contributions to their farms and communities. As such, an organisation that may outwardly appear to be a traditional women's organisation devoted strictly to the exchange of recipes and household advice, was, in actuality, quietly political and provided farm women with a sense of identity that enabled them to contribute fundamentally to their rural homes, families, and communities. women's organizations rural history Saskatchewan farm women rural life farm life women's work rural women's work farm women's work Homemakers' Clubs rural women farm women prairie agriculture western Canadian agriculture western Canada
508	Patterns and processes of exotic plant invasions in Riding Mountain National Park, Manitoba, Canada Otfinowski, Rafael 10 September 2008 (has links) Invasive exotic species threaten the biodiversity and function of native ecosystems. Existing models, attempting to predict and control successful invaders, often emphasize isolated stages of in their life history and fail to formalize interactions between exotic species and recipient environments. In order to elucidate key mechanisms in the success of select invaders, I investigated the role of dispersal, establishment, proliferation, and persistence in their threat to natural areas. Focusing on Riding Mountain National Park, Manitoba, Canada, I integrated the native climatic range and biological traits of 251 exotic vascular plants reported inside and outside the park. Based on their climatic range in Europe, 155 among 174 exotic plant species absent from the Park were predicted to establish within its boundaries; among these, 40 clonal perennials were considered the highest threat to the Park’s biodiversity. Focusing on smooth brome (Bromus inermis Leyss.), a Eurasian perennial, threatening the structure and function of native prairies throughout the Great Plains, I extended my research to investigate the role of dispersal, establishment, proliferation, and persistence in characterizing its threat to the endemic diversity of northern fescue prairies, protected within Riding Mountain National Park. Patterns of smooth brome invasions were contingent on the type of propagules dispersed. The shallow dispersal gradient of individual florets combined with the steeper gradient of panicles and spikelets suggested that smooth brome is capable of simultaneously invading along dense fronts as well as by establishing isolated foci. While low correlations between the number of dispersed seeds and their recruitment suggested post-dispersal transport, seedling establishment remained contingent on prairie diversity. Seedling biomass increased with declining plant diversity, however, its impact depended on the availability of soil nitrogen. As a result, disturbed areas, preserving the root function of native plants, resisted smooth brome establishment. Even though low nitrogen contributed to a decline in seedling biomass, physiological integration between ramets facilitated their vegetative proliferation in low resource environments. Despite its rapid establishment and proliferation, smooth brome productivity declined at the center of invading clones. Although field and greenhouse observations failed to implicate soilborne pathogens, reasons for the observed decline remain unresolved. My research demonstrates that while Riding Mountain National Park and other natural areas in western Canada will continue to be impacted by exotic plants, integrating key stages in their life history provides an important conceptual framework in predicting their threat to natural areas and prioritizing management. / October 2008 biological invasions risk analysis climate-matching model biological traits smooth brome Bromus inermis plant dispersal inverse power function spatial patterns disturbance invasion resistance community diversity clonal proliferation physiological integration soilborne pathogens negative feedback natural area northern fescue prairie
509	Restoration ecology of ecosystems invaded by Triadica sebifera (Chinese tallow tree): theory and practice Gabler, Christopher 24 July 2013 (has links) Invasive exotic species threaten biodiversity and ecosystem functions globally, creating need for and encumbering ecological restoration. When restoring exotic plant-dominated ecosystems, reinvasion pressure is the rate of new exotic recruitment following mature exotic removal. It can vary broadly among similarly invaded habitats and is crucial to restoration outcomes and costs, but is difficult to predict and poorly understood. Initial results from the experimental restoration of a wetland dominated by Triadica sebifera led us to develop the ‘outgrow the stress’ hypothesis. It holds: (1) Variation in reinvasion pressure is driven by differences in propagule abundance and spatiotemporal availability of realized recruitment windows, which are defined by abiotic conditions and biotic interactions. (2) Differences in reinvasion pressure become masked by exotic dominance when increases in niche breadth during development enable exotic persistence across sites where recruitment windows range from frequent to episodic. We validated this hypothesis. First, we used greenhouse and field experiments to quantify Triadica’s moisture niche early in development. By two months post-germination, seedling tolerances broadened to include conditions unsuitable for germination. This clearly demonstrated a rapid ontogenetic niche expansion, which could decouple mature Triadica density and average reinvasion pressure. Second, we used a greenhouse mesocosm experiment to quantify how recruitment window duration, competition and fertility impacted population-level Triadica establishment in stressful environments. As ‘outgrow the stress’ predicts, longer windows increased Triadica success and multi-factor interactions were common, with competition and fertility effects varying among environmental contexts. Third, we substantiated predictions of ‘outgrow the stress’ regarding propagule availability and soil moisture by manipulating these in a multi-site field experiment spanning eleven experimental restorations of Triadica-dominated habitats along a moisture gradient. Triadica reinvasion pressure varied broadly among sites but correlated with moisture and fertility. Propagule availability drove reinvasion in favorable environments, but availability of suitable conditions trumped propagules in extreme environments. Competition reduced Triadica performance and sometimes survival. Triadica prevalence reduced native plant prevalence. Six restorations require minimal Triadica management for success. This work advances our understanding and enables better predictions of reinvasion pressure and invasions in general. Accurate predictions enhance restoration efficiency by informing site selection and optimal management strategies. community ecology restoration invasive species Texas wetlands grasslands ontogenetic niche shifts recruitment limitation propagule availability niche abiotic conditions climate competition interspecific interactions seed addition coastal prairie Texas exotic plant management optimal control
510	Cultivating domesticity : the Homemakers' Clubs of Saskatchewan, 1911-1961. Milne, Jennifer E 22 July 2005 (has links) On January 31, 1911, the Homemakers' Clubs of Saskatchewan became an official organisation under the direction of the University of Saskatchewan. Established to provide isolated rural women with companionship, access to education, and the opportunity to carry out community service, Homemakers' Clubs appealed to thousands of farm women because they provided the means by which they could improve themselves, their farm homes, and their communities. Its appeal also lay in the fact that the organisation remained non-political and non-sectarian, focusing instead on women's primary responsibilities to their homes and their families. To that end, Homemakers' Clubs embraced a domestic ideology that institionalised notions of gender and celebrated women's roles in the home. Given that the nature of farm women's work was not restricted to the household, however, Homemakers' Clubs allowed rural women to redefine an urban domesticity to include their farming responsibilities. Moreover, in a setting where gender lines were often blurred and the division of labour was not always strictly defined, membership in an organisation that reinforced gender roles, promoted family and community life, and embraced a traditional mandate provided farm women with a level of respectability and femininity that was often lost in a farming setting. Finally, the domestic ideology under which the Homemakers' Clubs operated allowed its members to find recognition and validation in their work, and, in their goals to elevate home life, to legitimise their work, and to adjust domestic ideology to include their farming responsibilities, the organisation became a space in which its members discussed, debated, explored, and, in some cases, challenged common perceptions of women; they subtly challenged the status quo and demanded validation and recognition for their work in and contributions to their farms and communities. As such, an organisation that may outwardly appear to be a traditional women's organisation devoted strictly to the exchange of recipes and household advice, was, in actuality, quietly political and provided farm women with a sense of identity that enabled them to contribute fundamentally to their rural homes, families, and communities. women's organizations rural history Saskatchewan farm women rural life farm life women's work rural women's work farm women's work Homemakers' Clubs rural women farm women prairie agriculture western Canadian agriculture western Canada

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