Thesis (D. Min.)--Southwestern Baptist Theological Seminary, 1995. / Includes bibliographical references (leaves 270-280).

Thesis (M.S.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 31-35)

Thesis (M.S.)--Evergreen State College, 2005. / Includes bibliographical references: p. 77-99.

Fire, a natural disturbance, regulates species composition in Fescue Prairie. However, little is known about the contribution of different regeneration strategies in altering species composition after burning in Fescue Prairie. The present study was conducted to determine if and how fire and associated fire cues regulate species composition in Fescue Prairie through their effects on seedling recruitment. The effects of fire and various fire cues, including smoke, ash, and smoke plus ash on seedlings emerging in the field and/or from litter, 0-1 cm, and 1-5 cm layers of the soil seed banks were therefore examined. These studies were complimented by a study of testing effects of smoke originated from different plant materials on seed germination and seedling growth of species from Fescue Prairie. Chemical analyses were also conducted to determine whether different active compounds existed in smoke made from different materials, which in turn affect germination and seedling growth differently. Burning increased densities, richness, and diversity of seedlings emerging in the field. This was possibly attributed to direct fire cues of burning. Seedling densities of native forbs and non-native graminoids emerging from the soil seed bank were increased and decreased by burning, respectively. Ash and smoke plus ash increased density of forbs emerging from the soil seed bank. Species composition of seedlings emerging in the field and from the soil seed bank was altered by burning. Complex responses were observed for the effects of smoke on seedling establishment, which depended on the type and dilution of smoke solutions, as well as germination conditions. Smoke solutions partly substituted light requirement for germination of Artemisia ludoviciana. Germination of Cirsium arvense and Conyza canadensis only responded to smoke solutions at 25/15°C, but not at 10/0 °C. Diluted smoke solutions increased radical length of Artemisia ludoviciana. Karrikinolide (KAR1) was in the smoke made from prairie hay and wheat straw, but not in that made from alfalfa. This is the first report that different active compounds existed in smoke made from different materials. Highly concentrated smoke solutions made from alfalfa increased germination and radical length of Conyza canadensis, while the same concentrated smoke solutions made from prairie hay and wheat straw reduced germination of Conyza canadensis at 25/15 °C in darkness. Priming in KAR1 solutions and active fractions obtained from prairie hay and/or wheat straw increased germination of Artemisia frigida, Artemisia ludoviciana, and Conyza canadensis at certain germination conditions. In summary, fire and direct fire cues, smoke and ash specifically, stimulated recruitment of some species, especially early seral species and native forbs, contributing to potential changes in species composition of the Fescue Prairie. Different compounds existed in smoke solutions made from alfalfa as compared with those from prairie hay and wheat straw, showing different effects on seed germination and seedling growth. KAR1, the most important active compound discovered in smoke, was present in the smoke made from prairie hay and wheat straw, but was not in that made from alfalfa.

As more and more critics now write about postmodernism in the past tense, the 'New Sincerity' of a group of late twentieth-century American writers, led by David Foster Wallace, Jonathan Franzen, and Richard Powers, has been championed as one of its successors. In response to these increasingly widespread views, this dissertation argues that much more can be learned about these three writers when we stop thinking of their work within this 'end of postmodernism' discourse. Instead of attempting to make claims about its novelty, this thesis conducts a literary-historical inquiry into the New Sincerity, arguing that its roots extend across postmodernism and reach back to regionalism, in particular from the midwestern provinces that all three authors grew up in and that occupy a central place in their work. Though regionalism's subject matter, small-town America, is commonly believed to have died in the postwar period, it is this 'death of the prairie town' and its symbolic afterlife that have opened up new literary possibilities outside the realm of conventional regionalism. The powerful feelings of loss and nostalgia that its death has engendered are precisely those of which Wallace, Franzen, Powers, and the New Sincerity in general make creative use. The thesis examines how they do so in a series of three extended chapters, each of which focuses on one author. The first chapter pays careful attention to Wallace's re-imagining of the Midwest over the course of his career and reveals how he constantly deviated from the literary trajectory he had outlined in his essay 'E Unibus Pluram,' a key text in the 'end of postmodernism' discourse. The second chapter explores what role the Midwest plays in Franzen's authorial self-presentation and his contradictory attempts to balance 'high-art' status with an anti-elitist image. The third and final chapter gets to the root of Powers's problems with flat characters by examining how he all too readily relies on the Midwest and its stereotypical associations with all-American goodness in his attempts to create endearing characters. Here, as well as in the other two chapters, it is the construction of a symbolic 'heartland' that plays a central role in the creative process behind the author's New Sincerity writing.

Invasive species are cited as a major threat to native community composition and biodiversity throughout the world. Some recent studies have focused on whether invasive species are the drivers or passengers of change in degraded systems. A strongly-interactive community is supposed to resist invasion by all but the most strong invasive competitors (`drivers') which can establish there without the aid of disturbance and actively reduce the abundance of natives. A weakly-interactive community, impaired by some anthropogenic disruption, is invasible by weaker exotics which are merely `passengers' of the habitat degradation that is more constraining to natives. Though competitive and disturbance-adapted species fit into this model, there is no correlate for species with superior toleration of stress. Systems with high degrees of natural abiotic stress are weakly-interactive and as a result may be invasible by an exotic `tolerator' in the same way that anthropogenically-weak systems are invasible by passengers. Dolomite prairie, differentiated from typic tallgrass prairie by its shallow soils, represents a relatively stressful system. A study of its plant community composition and relationships to environmental variables was done to get a better understanding of the natural abiotic drivers of composition. Compositional patterns were most closely associated with the soil depth gradient. Exotic Poa species were by far the most frequent invaders, a finding more typical of Great Lakes alvars than of typic tallgrass prairie of which the dolomite prairie is a subset. I hypothesized that Poa species dominated dolomite prairie via the tolerator model. In a series of removal treatments, I determined that Poa is neither a driver nor a tolerator, but a passenger of environmental degradation. My results suggest that historic anthropogenic degradation rather than specific competitive ability is a common explanation for exotic dominance on the landscape today. More empirical work needs to be conducted in other stressful (particularly relatively undisturbed) systems to further investigate the tolerator model.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work, the Lagrangian stochastic particle model LAMBDA is utilized to simulate the dispersion and the transport of contaminants under different atmospheric conditions. The analysis employs three different field experiments of atmospheric diffusion: the Copenhagen experiment, which was accomplished in unstable conditions, the Prairie Grass experiment in which was considered only neutral stability cases (mean wind velocity higher than 6ms-1) and the INEL experiment occurring in low wind stable conditions and presenting wind meandering phenomenon. LAMBDA is a tridimensional model to simulate the pollutants dispersion over flat terrain. The model solves the generalized form the Langevin Equation and it can use the higher moments of Eulerian probability density function of the wind velocity fluctuations. The main aim of this work is to test a new parameterization for the parameters p and q which represent the frequency associated to the meandering phenomenon. The new parameterization is expressed in terms of m , a non-dimensional quantity that controls the meandering oscillation frequency, and T , a time scale associated to the coherent structures in a fully developed turbulence. The simulations show that the LAMBDA model incorporating this new parameterization reproduces correctly the enhanced diffusion of passive scalars in a low wind speed stable atmospheric boundary layer. / Neste trabalho é utilizado o modelo de partículas estocástico Lagrangeano LAMBDA para simular a dispersão e o transporte de contaminantes sob diferentes condições atmosféricas. A análise emprega três diferentes experimentos de difusão atmosférica: o experimento de Copenhagen, que foi realizado sob condições convectivas, o experimento de Prairie Grass, em que foram considerados somente os casos de estabilidade neutra (velocidades do vento médio maiores que 6m/s) e o experimento de INEL realizado em condições estáveis com velocidade do vento fraco e apresentando o fenômeno de meandro do vento. LAMBDA é um modelo tridimensional para simular a dispersão de poluentes sobre terreno plano. O modelo resolve a forma generalizada da Equação de Langevin e pode usar os momentos de ordem superior da função densidade de probabilidade Euleriana das flutuações da velocidade do vento. O principal objetivo deste trabalho é testar uma nova parametrização dos parâmetros p e q que representam as frequências associadas ao fenômeno de meandro do vento. Esta nova parametrização é descrita em termos de m , uma quantidade adimensional que controla a frequência de oscilação do meandro e T , uma escala de tempo associada às estruturas coerentes em uma turbulência bem desenvolvida. As simulações demonstram que o modelo LAMBDA incorporando esta nova parametrização reproduz corretamente a difusão de escalares passivos em uma camada limite atmosférica estável com velocidade do vento fraco.

Master of Science / Department of Animal Sciences and Industry / K C Olson / We evaluated effects of annual, prescribed burning on vigor of the noxious weed, sericea lespedeza (Lespedeza cuneata; SL) in native tallgrass prairie over a 4-yr period. We hypothesized that annual prescribed burning conducted during the growing season would selectively pressure SL, whereas locally-conventional, dormant-season prescribed burning would have no effect on SL. A 50-ha native tallgrass pasture infested with SL (initial basal frequency = 2 ± 1.3%, initial aerial frequency = 36 ± 3.4%) was used for our study. It was divided along watershed boundaries into 9 fire-management units (5 ± 2.6 ha) for this experiment. Burn units were assigned randomly to 1 of 3 prescribed-burning times (n = 3 / treatment): early spring (1 April; EARLY), mid-summer (1 August; MID), or late summer (1 September; LATE). Forage biomass, SL aerial frequency, SL stem length, SL seed production, soil cover, and plant species composition were measured along single, permanent 100-m transects in each burn unit. Treatment and measurement date influenced forage biomass and SL stem length (treatment × time). Forage biomass was not different (P ≥ 0.43) between treatments on 17 July; however, forage biomass was greater (P < 0.01) in EARLY than MID and greater in MID than LATE on 10 October. Maximum stem length of SL was less (P ≤ 0.02) in MID and LATE than in EARLY on 17 July and on 10 October. Aerial frequency of SL was least (main effect – P < 0.01) in LATE, intermediate in MID, and greatest in EARLY, whereas basal frequency of SL was less (P < 0.01) in MID and LATE compared with EARLY. Whole-plant dry weight and seed production of SL at dormancy were greatly diminished (P ≤ 0.02) in MID and LATE compared with EARLY. Occurrence of bare soil, litter cover, and total basal plant cover were not different (P ≥ 0.21) between treatments. Similarly, basal cover of grasses, forbs, and shrubs were not different (P ≥ 0.24) between treatments. We interpreted these data to indicate that annual prescribed burning during the growing season had strong suppressive effects on SL compared to locally-conventional, early-season prescribed burning and produced no apparent detrimental effects on soil cover or non-target plant species. Post-fire regrowth was sufficient to prevent erosion and soil-moisture loss during the subsequent dormant season and would have allowed light to moderate grazing during the ensuing winter. Key words: Lespedeza cuneata, prescribed fire, range improvement

Master of Science / Department of Geology / Matthew Kirk / Groundwater from the High Plains aquifer is vital for food production and a growing human population in the Great Plains region of the United States. Understanding how groundwater quality is changing in response to anthropogenic and natural processes is critical to effectively managing this resource. Our study considers variation in groundwater geochemistry in the Great Bend Prairie aquifer, a portion of the High Plains aquifer in southcentral Kansas. We collected samples during summer 2016 from 24 monitoring wells and compared our results to data collected previously from the same wells from 1979 to 1987. We sampled 13 wells screened in the upper portion of the aquifer (avg. depth 72 ft), 10 wells screened near the aquifer base (avg. depth 141 ft), and one well screened in underlying bedrock. Compared to initial samples, samples we collected tended to have higher total dissolved solids (TDS) and nitrate content, particularly those we collected from the upper aquifer. Compared to initial samples, TDS was 78 mg/L higher in samples we collected from the upper aquifer and 373 mg/L lower in samples we collected from the aquifer base on average. Nitrate exceeded the U.S. standard for public supplies of drinking water (10 mg/L as N) in seven of the samples we collected, compared to only two samples collected previously. Compared to previous samples, nitrate concentrations were 9.5 and 3.9 mg/L as N higher on average in samples collected from the upper aquifer and aquifer base, respectively. Based on a mixing analysis, variation in the salinity of our samples primarily reflects the dilution of natural Permian brines by freshwater recharge throughout the area. However, salinity decreases observed in four samples reflects flushing of initial oil brine contamination over time, salinity increases in two samples may be due to evapotranspiration, and salinity increases in two samples may reflect migration of oil-brine contamination towards the site. Stable nitrogen (15N/14N) and oxygen (18O/16O) isotope ratios in our samples primarily fall within the range typical of nitrification of ammonium-based fertilizers with potential contributions from manure or sewage. In our analysis of the microbial community, we observed groups capable of denitrification, including genera within Nitrospirae, Firmicutes, and Proteobacteria. Despite their presence, our results demonstrate that water quality in the aquifer has degraded over the past 30 to 40 years due to nitrate accumulation.

Master of Science / Department of Biology / Brett K. Sandercock / Grassland birds are declining throughout their native range. The Flint Hills of eastern Kansas and Oklahoma contain large tracts of tallgrass prairie, but intensification of agricultural practices may be contributing to ongoing population declines. Common rangeland management practices include annual burning coupled with heavy grazing by cattle. This system, known as intensive early stocking and burning, promotes homogeneous utilization of forage by cattle but may not provide habitat for some grassland bird species. Patch-burn grazing is an alternative management system that aims to restore heterogeneity on rangelands by recreating the fire-grazing interaction that would have historically occurred throughout the Great Plains. From 2011-2013, we examined responses of grassland birds to traditional rangeland management and patch-burn grazing by conducting vegetation surveys, line transect surveys, and nest monitoring on privately-owned pastures in Chase County and Greenwood County, Kansas. Vegetative heterogeneity was higher on patch-burned pastures, with unburned patches having higher visual obstruction and less bare ground. Densities of grassland birds differed by species and among habitat strata. Unburned patches on patch-burned pastures were associated with increased densities of Dickcissels (Spiza americana), Eastern Meadowlarks (Sturnella magna) and Grasshopper Sparrows (Ammodramus savannarum). Henslow’s Sparrows (A. henslowii) were only detected on patch-burned pastures. Nest survival of grassland songbirds was similar among management systems but varied by year. Probability of nest parasitism by Brown-headed Cowbirds (Molothrus ater) varied among years and between treatments for Dickcissels and Grasshopper Sparrows, with overall lower rates on burned areas and during drought years. For Dickcissels and Grasshopper Sparrows, there was a significant reduction in host clutch size between parasitized versus unparasitized nests. Overall, nest survival of grassland songbirds in managed rangelands was low. Patch-burn grazing improved rangeland conditions and provided habitat for more species of birds, but did not increase nest survival. Drought conditions in 2012 and 2013 may have influenced the results of this study, as many landowners were unable to burn as planned. Further study is needed to determine underlying factors driving variation in nest success and parasitism rates for grassland birds, particularly on private lands which make up the vast majority of remnant tallgrass prairies.