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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.
371

KNOWING THE NATURAL WORLD: THE CONSTRUCTION OF KNOWLEDGE ABOUT EVOLUTION IN AND OUT OF THE CLASSROOM

Perkins, Alison Emily Havard 25 March 2010 (has links)
<p>Evolution is a central underlying concept to a significant number of discourses in civilized society, but the complexity of understanding basic tenets of this important theory is just now coming to light. Knowledge about evolution is constructed from both formal and "free-choice" opportunities, like television. Nature programs are commonly considered "educational" by definition, but research indicates the narratives often promote creationist ideas about this important process in biology. I explored how nature programs influenced knowledge construction about evolutionary theory using a combination of qualitative and quantitative approaches. Because misconceptions about evolution are common, I examined how students` conceptual ecologies changed in response to information presented in an example of a particularly poor nature film narrative. Students` held a diversity of misconceptions, proximate conceptions, and evolutionary conceptions simultaneously, and many of their responses were direct reflections of the nature program. As a result, I incorporated the same nature program into an experiment designed to examine the effects of narrative and imagery on evolution understanding. After completing an extensive pre-assessment that addressed attitudes and beliefs about science knowledge, students viewed one of four versions of the nature program that varied in the quality of science and imagery presented. The effect of watching different versions was only vaguely apparent in students with a moderate understanding of evolution. The relationship was much more complex among students with a poor understanding of evolution but suggested a negative effect that was more influenced by public discourses about this "controversial" subject than conceptual understanding. The relationships warranted examining learning from the perspective of the consumers of these programs. I surveyed audience beliefs about the educational value of nature programs and found that an overwhelming majority believed the programs were "educational" and designed to teach about nature. The results were particularly alarming because beliefs about the educational value may strongly impact learning outcomes. An informal survey of nature programs aired during a "sweeps" month indicated that poor presentation of science, and specifically evolutionary theory, was indeed the norm. Indeed, nature programs may be contributing to the "deconstruction" of knowledge about evolution both in and out of the classroom.</p>
372

RESTORATION OF NATIVE PLANT COMMUNITIES AFTER ROAD DECOMMISSIONING: EFFECT OF SEED MIX AND SOIL PROPERTIES ON VEGETATIVE ESTABLISHMENT

Grant, Ashley Stevenson 01 June 2009 (has links)
Road decommissioning is increasingly recognized as a critical first step in the restoration of terrestrial and aquatic habitats. In the past two years alone, the United States Congress has appropriated $90 million for road removal and watershed restoration. Despite this relatively large public investment, little is known about the efficacy or ecological effects of road-removal practices. One particularly important issue is the impact of post-road-removal revegetation strategies. This study evaluated 1) short-term effects of road decommissioning on plant community composition, 2) effects of seed-mix seed origin (native vs. nonnative), species diversity, and seeding density on vegetative establishment, and 3) impact of overstory canopy and coarse woody debris on revegetation success on recently decommissioned roads. Total vegetative cover declined by 60% one-year after decommissioning, with nonnative plants showing the greatest declines (ca. 90%). Although managers often justify the use of nonnative seed mixes by the need for rapid establishment of plants on disturbed sites, we did not find significant differences in percent cover of total vegetation between plots seeded with native versus nonnative species, one year after treatment. Furthermore, cover of native species was significantly higher on plots seeded with natives compared to other treatment plots (12.3% vs. 7.8%, respectively). On treatments seeded with nonnative species, 18% of total vegetative cover was due to cover of seeded species; in comparison, seeded species accounted for 43% of total vegetative cover on native treatments. These findings suggest that native seed mixes actually may outperform nonnative ones in terms of vegetative establishment after disturbance associated with road removal.
373

The Missoula Poplar Project: Utilizing Poplars to Enhance Wastewater Treatment

Carey, Heath Nicolas 11 June 2010 (has links)
Wastewater treatment plants rank second to agricultural runoff in the top ten major pollution sources to U.S. surface waters. Such nutrient-rich inputs can degrade aquatic ecosystems by accelerating eutrophication events, especially in summer months when surface water flows are low. Alternative treatment practices, modeled after natural ecosystem processes, could reduce nutrient inputs to surface waters while accumulating biomass and sequestering atmospheric carbon dioxide. I designed and implemented an alternative treatment strategy, using effluent to fertilize trees at the Missoula Wastewater Treatment Facility. The objectives of this work were to assess: 1) environmental impacts of effluent application; 2) tree survivorship; and 3) growth effects. A two acre plantation was established in May 2009 by planting 316 dormant, unrooted stem cuttings of two hybrid poplar species, Populus deltoides X Populus trichocarpa and Populus deltoides X Populus nigra, and the native Black Cottonwood, Populus balsamifera ssp. trichocarpa. The effects of effluent fertilization on poplar growth, soil and ground water nutrient contents were monitored throughout the first growing season of this pilot project. Effluent fertilization nearly doubled poplar growth, and as suspected, had no major impacts on soil or ground water nutrient concentrations. Continued research at this site is necessary to observe environmental impacts as effluent loading rates increase. Our initial results suggest that surface application of wastewater effluent offers a valuable strategy for decreasing effluent input rates to the Clark Fork River. Moreover, this project offers smaller communities a "blue print" from which to design similar projects that remediate nutrient-rich effluent in a cost-effective way.
374

RECOMMENDATIONS FOR INSTREAM FLOW RIGHTS ON NATIONAL FOREST LANDS IN MONTANA

FISCHER, ANDREW MARIAS 11 June 2010 (has links)
A unique opportunity exists to create instream water rights on national forest lands in Montana as a result of the US Forest Service Reserved Water Rights Compact between the US Forest Service (USFS) and the state of Montana, which went into law in 2007. Instream water rights on national forest lands are important because they have the potential to protect streamflows that support many vital ecosystem functions in our forests from water development pressures. Montana Trout Unlimited has an interest in advancing and accelerating this effort by providing stream recommendations to the USFS for the establishment of future water rights. The primary purposes of this paper are to offer recommendations to Montana Trout Unlimited for streams in Montana that would benefit the most from a US Forest Service instream water right and why, to develop an effective process for doing so, and to identify how Montana Trout Unlimited can help in this larger effort. Through the solicitation of stream recommendations from biologists and fisheries manager across the state and the development of a ranking worksheet to prioritize these recommendations, the final product of this research was a ranked stream list to help guide future efforts to establish USFS instream water rights. The USFS need to act on these recommendations and increase their investment in this effort before new water development pressures adjacent to national forests occur. Establishing water rights will enable the USFS to be a legal stakeholder in the water resources on national forest lands in Montana and ensure the long term health of our forests in the state.
375

MULTI-PARTNER MUTUALISMS: INTERACTIONS AMONG THE MOUNTAIN PINE BEETLE AND TWO OPHIOSTOMATOID FUNGAL ASSOCIATES

Bleiker, Katherine Patricia 07 August 2008 (has links)
I investigated interactions between the mountain pine beetle (Dendroctonus ponderosae) and its two main ophiostomatoid fungal associates,Grosmannia clavigera and Ophiostoma montium, as well as interactions between the two fungi. The main research questions were: What drives bark beetle fungal interactions? What is the nature of the interaction between the two species of fungi? I tested the hypothesis that the fungi provide nutritional benefits to the bark beetles. Evidence suggests a nutritional role of fungi in the diet of bark beetles because beetles emerging from attacked trees carrying G. clavigera were larger than beetles carrying O. montium, which in turn were larger than beetles without either fungus. Larval choice feeding experiments indicate that the two fungi may actually provide complimentary benefits. To address the second question, I tested for competition between the two fungi on artificial media. Growth of each species slowed when it encountered media occupied by the other species, indicating competition; however, both species eventually invaded media occupied by the other species. Although G. clavigera colonized unoccupied media the fastest, O. montium was more effective in colonizing media occupied by G. clavigera when their relative growth rates were considered. In another study, the relative abundances of the two fungi were sampled in beetle-attacked trees in the field over the one year life cycle of the insect. I found no evidence of interference competition, but exploitation competition was prevalent after a year when the fungi co-occurred in the phloem. Finally, I examined whether the two fungi are differentially transported in the mycangia and on the exoskeleton of the beetle using scanning electron microscopy and isolating fungi from the mycangia and elytra. I found no evidence of differential transport of G. clavigera or O. montium in the mycangia and on the exoskeleton from isolation data. There was also no evidence that one fungus was more likely to be transported on the exoskeleton than the other species using electron microscopy. The fungi appear to exist in the mycangium in an altered, yeast or yeast-like state rather than as conidia.
376

Modeling the Cumulative Effects of Forest Fire on Watershed Hydrology: A Post-fire Application of the Distributed Hydrology-Soil-Vegetation Model (DHSVM)

Stonesifer, Crystal S. 23 July 2007 (has links)
The Distributed Hydrology-Soil-Vegetation Model (DHSVM) was applied to the Eightmile Creek watershed in western Montana. The purpose of this research was primarily to assess the applicability of the model as a cumulative effects assessment tool in the post-fire landscape of a forested watershed in this region. The model was first calibrated to the pre-fire watershed conditions using six years of historic streamflow data. DHSVM was able to accurately simulate the general shape of the measured hydrograph for each of the six simulated water years, and the normalized median absolute error statistics were below the target threshold of 50% for each year simulated. This relative success of the calibration efforts is particularly surprising when one considers the significant limitations presented by the lack of any sub-daily or high-elevation meteorological data for use in driving the calibration simulations. Because the accuracy of DHSVM simulations were greatly improved through rigorous calibration, this research demonstrates the need for model calibration to a watershed of interest, prior to hydrologic simulations of different landscape scenarios. Next, two different calibrated versions of DHSVM, including DHSVM version 2.0.1 and the DHSVM fire model, were each used to simulate runoff in the Eightmile Creek watershed following a near catchment-wide stand-replacing forest fire. Due to weather anomalies and limited, discontinuous streamflow data, no decisive conclusions could be made regarding the performance of either version of the model in the validation efforts. Results do suggest, though, that the DHSVM fire model has the potential to outperform the standard model version in fire-affected landscapes. Further research utilizing the DHSVM fire model with more substantial post-fire streamflow records for model validation is warranted.
377

BLM Land Use Planning in Western Oregon: A Case Study for Integrating Public Participation in Natural Resources Planning

West, Emily Ruth 23 July 2007 (has links)
Public participation can fundamentally improve natural resources planning and decision-making. On an ad hoc basis, it has been shown that public participation improves the durability and sustainability of plans and decisions; it increases the technical, consensus-building, and decision-making capacity of the public; it increases levels of trust; and it improves relationships between agency personnel and members of the public. Despite the proliferation of these new tools and strategies and their successful implementation, innovative and inclusive public participation methods have still not become widely integrated into the natural resources planning and administrative decision-making processes of federal agencies. Utilizing the Bureau of Land Management's Western Oregon Plan Revision process as a case study, this paper considers barriers to the regular inclusion of innovative and inclusive public participation methods in agency's planning and decision-making processes and provides some prescriptions for overcoming those barriers. Through analysis of this case study, I identify eight potential roadblocks to integrating innovative forms of public participation in natural resources planning and decision-making, including: 1) political context, 2) the purpose and need of the planning effort, 3) false expectations for public involvement, 4) geographic scope of the planning area, 5) the plan timeline, 6) federal budgetary pressure, 7) agency culture and individual attitudes towards public participation, and 8) the limitations of leadership
378

HIV/AIDS AND CONSERVATION AGENCY CAPACITY IN SOUTHERN AFRICA: PERCEPTIONS OF CRITICAL IMPACTS, BARRIERS, AND INTERVENTION STRATEGIES

Cash, Jennifer Ann 23 July 2007 (has links)
The HIV/AIDS pandemic permeates all aspects of southern African civil society including the ability of organizations to practice conservation. The purpose of this research is to understand how management perceives HIV/AIDS influencing southern African conservation agencies workforce capacity to meet their missions. Research goals include: (1) identifying perceptions of the impacts of HIV/AIDS on workforce capacity; (2) elucidating barriers to addressing these impacts; and (3) exploring mitigation strategies. Data collection involved two stages: (1) semi-structured interviews of managers and scientists (n=23) to better understand impacts and barriers; and (2) a panel of key experts (n=30) within southern African conservation agencies ranked impacts according to their perceived severity, using an iterative, Delphi approach. Impacts identified include loss of experience-based knowledge, difficulty in planning for the future, and increases in human resource costs. Barriers to addressing these impacts include gender issues, lack of awareness, staff housing and stigma associated with the disease. Mitigation strategies must address impacts and barriers within a southern Africa context. This research provides perspectives from current conservation management and human resources to direct and catalyze mitigation strategies.
379

Relationships between flood frequency and riparian plant community structure in mountain streams of western Montana

Honda, Motoshi 07 August 2008 (has links)
Flooding is the dominant factor structuring riparian plant communities along large, low elevation streams, but it is less clear what role flooding plays in the structure and composition of riparian plant communities along mountain streams. In the first part of this study, I examined the influence of four environmental variables (flood frequency, microtopography, light availability, and soil texture) and spatial heterogeneity on riparian plant community structure in seven study areas along mountain streams in western Montana, USA. Multivariate and spatial statistics were used to determine the relative strength of each set of factors and their interactions in explaining riparian plant community structure. Flooding influenced vegetation characteristics by an indirect pathway through microtopography in all study areas, whereas the direct influence of flooding was found commonly only in three study areas. Other consistent direct influences included light (60%) and space (87%). Direct and indirect influences of flood frequency through microtopography, and the direct influences of light and vegetation patch structure should be included in predictive models of riparian plant community structure in mountain streams. Boundary analysis showed that microtopography was an important factor for boundary maintenance of riparian plant communities. In the second part of the study, the effective flood frequency was determined initially by partial Mantel tests between inundation extent associated with each flood frequency and plant communities, and the results were compared to floristic characteristics derived from DCA and Indicator Species Analysis. Flood frequencies ranging from one to eight years were most strongly associated with the understory and overall plant community structure, whereas overstory communities were influenced by both frequent (¡Ü 9 year) and large infrequent (¡Ý35 year) floods. Riparian plant communities in mountain streams are mostly influenced by frequent flooding but large floods are also important for maintaining spatial heterogeneity.
380

EFFECTS OF OVERSTORY RETENTION AND UNDERSTORY VEGETATION ON SMALL TREE HEIGHT GROWTH IN THE INLAND NORTHWEST

McHugh, Ryan Partrick 15 June 2009 (has links)
With the increasing use of partial retention silvicultural systems in the Inland Northwest, managers must be able to anticipate rates of growth and the degree of vegetative competition control that is necessary to recruit younger cohorts into the canopy and sustain desirable long-term growth rates. This study was designed to collect long-term understory tree growth data under a broad range of conditions, with the objective of separately evaluating the effects of site quality, overstory retention, and understory competition levels on tree height growth. After four years, mean periodic annual height growth increment (PAI) for 1,708 ponderosa pine (Pinus ponderosa) and 1,286 Douglas-fir (Pseudotsuga menziesii var. glauca) were analyzed from 21 research sites across a gradient of site productivity and stand conditions. At each research site, seven 0.2 ha plots were established under homogeneous overstory and understory conditions, with subsequent herbicide treatment of randomly selected plots to create a range of understory competition levels. Research sites were categorized into three site quality classes (Low, Medium, High) based on plant associations, with sites ranging from warm dry Douglas-fir/Pinegrass to more moist Grand fir/Twinflower. Reducing competing understory vegetation significantly improved PAI for ponderosa pine trees in Low and Medium sites (p<0.001), and for Douglas-fir in Low sites (p<0.06). PAI in untreated control plots was 42% - 59% lower for PIPO and 23% - 34% lower for Douglas-fir, relative to plots with multiple herbicide treatments. Initial size and overstory density were the most influential variables explaining growth in the linear regression analyses. Tree level analysis for initial tree size displayed more predictive value for Douglas-fir (R2 = 48%) than for pine (R2 = 29%). Plot level overstory variables explained more variation for pine (R2 =44%) than for Douglas-fir (R2 =25%). Multiple regression analyses produced models using the two prominent variables, with additional significant variables (i.e. sapling competition index, vegetation volumes, others) to explain 57%, 59%, and 60% of the variation in PAI for pine in the Low, Medium, and High sites, respectively. Models for Douglas-fir explained 50%, 82%, and 60% of the variation for PAI in the same classes. PAI rates in seedling sized conifers showed more sensitivity to increased basal area retention than larger trees, suggesting that understory tree size ought to be considered when planning silvicultural treatments. Reducing overstory to levels to between 5-10 m2-ha-1 can achieve partial retention objectives if PAI losses of 7%-26% for pine and 26% - 28% for Douglas-fir are acceptable by the landowner (compared to more full removal harvest). Results suggest that together understory vegetation and overstory density can significantly affect the rate of height growth in these species.

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