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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.
231

Development of Dynamic Thermal Performance Metrics for Eco-roof Systems

Moody, Seth Sinclair 01 January 2013 (has links)
In order to obtain credit for an eco-roof in building energy load calculations the steady state and time-varying thermal properties (thermal mass with evapotranspiration) must be fully understood. The following study presents results of experimentation and modeling in an effort to develop dynamic thermal mass performance metrics for eco-roof systems. The work is focused on understanding the thermal parameters (foliage & soil) of an eco-roof, further validation of the EnergyPlus Green Roof Module and development of a standardized metric for assessing the time-varying thermal benefits of eco-roof systems that can be applied across building types and climate zones. Eco-roof foliage, soil and weather parameters were continuously collected at the Green Roof Integrated PhotoVoltaic (GRIPV) project from 01/20/2011 to 08/28/2011. The parameters were used to develop an EnergyPlus eco-roof validation model. The validated eco-roof model was then used to estimate the Dynamic Benefit for Massive System (DBMS) in 4 climate-locations: Portland Oregon, Chicago Illinois, Atlanta Georgia and Houston Texas. GRIPV30 (GRIPV soil with 30% soil organic matter) was compared to 12 previously tested eco-roof soils. GRIPV30 reduced dry soil conductivity by 50%, increased field capacity by 21% and reduced dry soil mass per unit volume by 60%. GRIPV30 soil had low conductivity at all moisture contents and high heat capacity at moderate and high moisture content. The characteristics of the GRIPV30 soil make it a good choice for moisture retention and reduction of heat flux, improved thermal mass (heat storage) when integrating an eco-roof with a building. Eco-roof model validation was performed with constant seasonal moisture driven soil properties and resulted in acceptable measured - modeled eco-roof temperature validation. LAI has a large impact on how the Green Roof Module calculates the eco-roof energy balance with a higher impact on daytime (measured - modeled) soil temperature differential and most significant during summer. DBMS modeling found the mild climates of Atlanta Georgia and Houston Texas with eco-roof annual DBMS of 1.03, 3% performance improvement above the standard building, based on cooling, heating and fan energy consumption. The Chicago Illinois climate with severe winter and mild spring/summer/fall has an annual DBMS of 1.01. The moderate Portland Oregon climate has a below standard DBMS of 0.97.
232

Short-term Effects of Nutrients on a Barrier Island Grassland Community

Moulton, Ashley 01 January 2017 (has links)
Increased nutrient availability globally has the potential to affect community functional composition of plants in nutrient limited environments, such as coastal grassland systems. Stability of these systems are threatened worldwide by urbanization, as well as effects of sea level rise and increased frequency and intensity of storms, and atmospheric N deposition, associated with climate change. Annual net primary productivity (ANPP), species composition, and functional traits (community weighted specific leaf area (CWSLA), leaf area index (LAI), growth form and photosynthetic pathway) were measured across four treatments to assess multiple resource limitation of nitrogen (N) and phosphorus (P) and functional community response in a coastal grassland on Hog Island, VA within the Virginia Coast Reserve, Long Term Ecological Research Network (LTER) applied at a rate of 10 g m-2 yr-1 Nutrient enrichment did not alter species diversity or richness. ANPP was highest in plots receiving any type of nitrogen enrichment, and was higher than expected of low nutrient systems. CWSLA was significantly higher in NP plots, and was lower than other grasslands. P treatments were not significantly different from controls. Graminoid species, specifically C4 species responded with higher ANPP than C3 forbs or graminoids within treatments. Evidence of synergistic NP effects were seen on community level resource allocation and leaf construction, but no significant species changes occurred over a 1-year time span. These results have expanded the knowledge of functional response to increased nutrient availability in an understudied, coastal grassland, which are at high risk to being lost to sea level rise and anthropogenic development and inform community assembly processes in stressful environments.
233

Estimating Heat-Related Mortality in the U.S. and In China Using Downscaled Climate Projections

Li, Ying, Zhang, Wei 07 April 2017 (has links)
Public health effects associated with rising temperatures resulted from global climate change are expected to increase significantly in this century. Projecting future heat-related mortality is challenging due to some considerable uncertainties, and national-level impacts under the latest greenhouse gas emission scenarios remain unexplored. This study investigates future excess heat-related mortality in two large countries: The United States and China in 2050s under the latest Representative Concentration Pathways (RCPs) emission scenarios. Using model-simulated future and present climate variables that were dynamically downscaled, we quantify the potential increase in heat-related mortality during the warm season. We study the entire continental U.S. and 51 largest urban areas in China, which roughly account for one third of population in China. We derive heat mortality risk estimates and adaptation assumptions from a comprehensive review of current literature of temperature-mortality relationships in both countries. We incorporate the latest population projection in both countries, and also investigate geographical variations in heat mortality risk and sources of uncertainty including population adaptation. Our findings suggest that future heat mortality risk attributable to elevated warm season temperature is likely to be significant in both countries studied, with substantial geographic variations, highlighting the significance of climate mitigation and local-level heat risk management.
234

On the Brink of Extinction: The Fate of the Pacific Northwest's Southern Resident Killer Whales

Wilk, Sabrina 01 January 2019 (has links)
The killer whales that roam the northeastern Pacific Ocean have been the objects of studies since the 1970s, making them the most well-studied population of orcas in the world. Three distinct ecotypes of killer whales (Orcinus orca), known as residents, transients, and offshores, share these waters. The ecotypes are morphologically and behaviorally distinct to the extent that some scientists consider them separate species, with residents eating salmon, transients specializing on marine mammals, and offshores preferring Pacific sleeper sharks and Pacific halibut. Resident populations have endeared themselves to the region's locals with their striking black and white markings and their tendency to frolic in waters near the shore. However, both of the two resident populations on the coast of British Columbia and Washington State are at risk, with northern residents numbering some 300 and southern residents at just 74 individuals as of December 2018. Three deaths in the span of four months in spring and summer of 2018 brought widespread attention to the southern residents' plight. Live captures of killer whales for aquaria heavily impacted the population in the 1960s and 1970s, and today they face a combination of prey shortages, pollution, and disturbance from vessel traffic. If southern resident killer whales are to persist, federal, local, and state agencies need to quickly take mitigative action.
235

CONSERVATION LIMNOGEOLOGY AND BENTHIC HABITAT MAPPING IN CENTRAL LAKE TANGANYIKA (TANZANIA)

Lucas, Joseph S. 01 January 2018 (has links)
Small scale protected zones are valuable for helping the health and productivity of fisheries at Lake Tanganyika (East Africa). Spatial placement of protected areas relies on accurate maps of benthic habitats, consisting of detailed bathymetry data and information on lake-floor substrates. This information is unknown for most of Lake Tanganyika. Fish diversity is known to correlate with rocky substrates in ≤ 30 m water depth, which provide spawning grounds for littoral and pelagic species. These benthic habitats form important targets for protected areas, if they can be precisely located. At the NMVA, echosounding defined the position of the 30-m isobath and side-scan sonar successfully discriminated among crystalline basement, CaCO3-cemented sandstones, mixed sediment, and shell bed substrates. Total area encompassed from the shoreline to 30 m water depth is ~21 km2 and the distance to the 30-m isobath varies with proximity to deltas and rift-related faults. Total benthic area defined by crystalline basement is ~1.6 km2, whereas the total area of CaCO3-cemented sandstone is 0.2 km2. Crystalline basement was present in all water depths (0-30 m), whereas CaCO3-cemented sandstones were usually encountered in water ≤ 5 m deep. Spatial organization of rocky substrates is chiefly controlled by basin structure and lake level history.
236

EVALUATION OF A SEQUENTIAL POND SYSTEM FOR DETENTION AND TREATMENT OF RUNOFF AT SKYPARK, SANTA'S VILLAGE

Caporuscio, Elizabeth 01 December 2018 (has links)
Understanding the extent to which human activities impact surface water resources has become increasingly important as both human population growth and related landscape changes impact water quality and quantity across varying geographical scales. Skypark, Santa’s Village is a 233.76-acre tourism-based outdoor recreation area located in Skyforest, California residing within the San Bernardino National Forest. The park is situated at Hooks Creek, the headwaters of the Mojave River Watershed, and is characterized by a diverse landscape that includes forest cover and human development, including impervious surfaces, a restored meadow, and recreational trails. In 2016, Hencks Meadow was considered degraded by human activity and restored by the Natural Resources Conservation Services (NRCS) using best management practices (BMPs) to manage stormwater runoff and mitigate pollutants entering recreational downstream surface water. Three BMP detention basins were constructed to store and improve water quality from stormwater runoff. The purpose of this study is to observe the extent to which the engineered BMP detention basins design were effective in mitigating stormwater pollution from entering Hooks Creek. Over a six to eight month period (January to August), ponds were tested in situ bi-weekly for temperature (ºC), dissolved oxygen (mg/L), pH, turbidity (NTU), conductivity (µS/cm), nitrate (mg/L), and ammonium (mg/L), with additional laboratory tests for total suspended solids (mg/L), total dissolved solids (mg/L), chemical oxygen demand (mg/L), total coliform (MPN/100mL), Escherichia coli (MPN/100mL), and trace metals (µg/L). The results of this study support that the BMP design is improving surface stormwater runoff from impervious surfaces before it enters Hooks Creek. Findings could also promote the design and implementation of stormwater BMP detention basins at other site locations where water degradation is evident. Furthermore, this research can be used to promote the necessary improvement of water quality and quantity on a widespread geographical scale.
237

The Resurrection of a River: The Umatilla and its Salmon

Shelley, Christopher Ward 01 March 2002 (has links)
Until the 1990s, salmon had been extinct from the Umatilla River for over 70 years. The struggle to bring salmon back to this river is a compelling story that exemplifies some of the new relationships in Columbia River Basin salmon management. The Umatilla River and the disappearance of its salmon was a local issue. Irrigation interests had used the river so thoroughly it ceased to flow during the late summer and fall months-precisely when salmon needed it for migration. The Confederated Tribes of the Umatilla Indian Reservation saw decided that they would change that: they would figure out a way to put both salmon and water back into the river. This thesis examines this process. First, it contextualizes the Umatilla River within the Columbia River Basin and Columbia Basin salmon management, and shows how a local salmon issue became a regional salmon issue. It then discusses the triangle of relationships that Indians, salmon, and hatcheries have come to form. Chapter III discusses the formation of the unique Umatilla Fish Restoration Program, which reintroduced fish into the river, and was paid for by the Bonneville Power Administration (BPA), as per the Northwest Power Act. Key elements within BPA's Fish and Wildlife Division resisted complying with the directives of the Northwest Power Planning Council to pay for the Program, setting the Program back years. I argue that this comes from two clashing ways of seeing the River: "cost-benefit analysis" versus "least cost." Chapter IV looks at the new partnerships formed in the Umatilla River Basin by the Tribes and irrigation districts in order to encourage the U.S. Bureau of Reclamation to construct a water delivery system that would satisfy irrigators while allowing most of the Umatilla to flow freely. The last Chapter suggests that these new and somewhat ironic partnerships between federal and state governments, private irrigators and landowners, nongovernmental organizations, and Indian tribes are key to restoring ecosystems in the Columbia River Basin. It further argues that without tribal nations playing an active role and exerting their treaty rights, restoring rivers like the Umatilla is impossible.
238

Preserving Nature through Film: Wilderness Alps of Stehekin and the North Cascades, 1956-1968

Bergmann, Nicolas Timothy 20 June 2013 (has links)
On March 22, 1958 David Brower's film Wilderness Alps of Stehekin premiered to an audience of conservationists in Seattle, Washington. Almost two years in the making, the thirty-one minute film advocated the preservation of nature in Washington's North Cascades through the creation of a national park. Over the next decade, Wilderness Alps of Stehekin became the most influential publicity tool in the struggle to preserve the North Cascades. Because of the region's geographic isolation, the film was the first time many people throughout the nation were exposed to the scenic grandeur of the area. Images of craggy peaks and colorful alpine meadows resonated deeply with many Americans and persuaded them to join in the campaign. It was the voice of these citizens that led Congress to pass the North Cascades Act of 1968, which placed 674,000 acres of the North Cascades under the jurisdiction of the National Park Service. In this thesis I tell the creation story of North Cascades National Park from a conservationist perspective and trace the influence of Wilderness Alps of Stehekin within this context. Although the film was never shown in movie theaters and never aired on national television, many thousands viewed it from its premiere to the signing of the North Cascades Act. The film first introduced the idea of a North Cascades National Park, and it was important in convincing conservationists to unite around a national park solution. Ultimately, Wilderness Alps of Stehekin changed the approach activists took in the North Cascades and helped to preserve a wild and scenic nature experience for future generations through the protection of old-growth forests and alpine meadows.
239

The Impact of Infrastructure on Habitat Connectivity for Wildlife

Bliss-Ketchum, Leslie Lynne 19 March 2019 (has links)
While roads can present weak to complete barriers to wildlife, depending on the animal and traffic volume, mitigations such as under-crossings and green bridges on highways at least partially increase the permeability of the landscape to some of these species. The few studies evaluating the effectiveness of these structures for at least three years typically focused on a single species. Here, we monitored the crossing structure under Boeckman Road, in Wilsonville Oregon, for wildlife activity across summer seasons for ten years, since construction of the road and subsequent opening to traffic. This long-term multi-species dataset, which includes monitoring when the road was closed to traffic has provided a unique opportunity. Wildlife activity was collected using sand track pads monitored during summer seasons from 2009 to 2018. Wildlife activity showed a significant community level response from year to year and species-specific responses to year, vegetation change, disturbance, detection area, and previous experimental additions of artificial light. Roads create barriers to animal movement through collisions and habitat fragmentation. Investigators have attempted to use traffic volume, the number of vehicles passing a point on a road segment, to predict effects to wildlife populations approximately linearly and along taxonomic lines; however, taxonomic groupings cannot provide sound predictions because closely related species often respond differently. We assess the role of wildlife behavioral responses to traffic volume as a tool to predict barrier effects from vehicle-caused mortality and avoidance, to provide an early warning system that recognizes traffic volume as a trigger for mitigation, and to better interpret roadkill data. We propose four categories of behavioral response based on the perceived danger to traffic: Nonresponders, Pausers, Speeders, and Avoiders. By considering a species' risk-avoidance response to traffic, managers can make more appropriate and timely decisions to mitigate effects before populations decline or become locally extinct. Barriers to animal movement can isolate populations, impacting their genetic diversity, susceptibility to disease, and access to resources. Barriers to movement may be caused by artificial light, but few studies have experimentally investigated the effects of artificial light on movement for a suite of terrestrial vertebrates. Therefore, we studied the effect of ecological light pollution on animal usage of a bridge under-road passage structure. On a weekly basis, sections of the structure were subjected to different light treatments including no light added, followed by a Reference period when lights were off in all the structure sections. Findings suggest that artificial light may be reducing habitat connectivity for some species though not providing a strong barrier for others. Through the work conducted herein we provide contributions to the understanding of how elements of the built environment impact wildlife communities ability to move across the landscape. Additionally, we provide new tools to support resource managers in barrier mitigation and connectivity planning. Habitat fragmentation effects are a complex set of issues that require resources and collaboration to reach meaningful solutions. The work presented here can also support decision-making, communication, and collaborative efforts that will ultimately result in on-the-ground impacts to reduce fragmentation effects and mitigate existing barriers effectively to promote the long-term viability of wildlife and the systems they depend on.
240

Cultural Politics of Community-Based Conservation in the Buffer Zone of Chitwan National Park, Nepal

Dongol, Yogesh 29 June 2018 (has links)
The dissertation research examines the socio-economic and political effects of community-based conservation initiatives within the Bagmara buffer zone community forests of Chitwan National Park, Nepal. In particular, the study investigates the role of buffer zones creation in structuring the way rural property rights have been defined, negotiated, and contested, in reinforcing or reducing patterns of ethnic dominance and exclusion, and in influencing how cultural identities are constituted and renegotiated. Using a political ecology framework with a specific focus on theoretical concepts of environmentality and territorialization, I conducted 12 months ethnographic and quantitative survey field research in the buffer zone communities of Chitwan National Park. I focused on documenting socioeconomic conditions and livelihood practices, and interpreting the meanings of residents’ lived experiences. In addition, I critically examined state and non-state conservation and development practices to understand how they work to produce identities, livelihoods, and landscapes in the park’s buffer zone. The ethnographic study documented diverse impacts of community-based conservation initiatives. One of the major effects is the distribution of costs and benefits, specifically elite capture of community forest and tourism benefits. Second is the existing conflict and potential conflict over the control of access, benefits, and territory based on social and cultural identities. Third is the reproduction of caste, ethnic, and class hierarchies. Fourth is the militarization of communities in and around the buffer zone and community forest. Fifth is the production of environmental and non-environmental subjects such as illegals and poachers. Finally, the sixth is the commodification of conservation spaces and subsequent ecological impacts. The research concludes that the discursive representation of humans and non-humans and the discourses and practices of economic development and biodiversity conservation produced and reproduced a number of negative social, political, and ecological consequences in the buffer zone of CNP. This dissertation concluded that the conservation and development practices are territorial projects to govern people and nature.

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