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Theses/Dissertations

2013

Climate change

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Full-Text Articles in Life Sciences

Wood Decomposition In A Warmer World, Emily Elizabeth Austin Dec 2013

Wood Decomposition In A Warmer World, Emily Elizabeth Austin

Doctoral Dissertations

Climatic warming is altering species distributions and ecosystem functions across the globe. Wood is an important carbon pool and the fungal communities in wood are relatively simple compared to those in soil. These factors make decomposing wood an ideal system for exploring the influence of decomposer community on the response of decomposition to warming. My research has focused on the effects of warming wood decomposition rates and wood decomposing communities. Using field and lab- based manipulative experiments and field observations I explore the influence of tree species, wood decomposition stage, geography and warming on fungal community structure and activity. In ...


Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca Dec 2013

Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca

UNLV Theses, Dissertations, Professional Papers, and Capstones

An assessment of the growth response of key vegetative species to climatic variability is vital to identifying possible local impacts on ecosystems faced with imminent climate change. With current climate projections in Nevada predicting a shift to an even more arid climate with greater year-to-year variability, the imperative exists to identify the effects of specific climatic controls on plant growth and to research methods to assess large-scale vegetative changes, especially in more remote areas where readily available data sets may be lacking. This study utilized annual growth ring indices constructed from big sagebrush (Artemisia tridentatassp.tridentata) stems collected in Spring ...


Soil Freezing Effects On A Grass-Dominated Old Field Ecosystem Under Current And Future Rates Of Atmospheric Nitrogen Deposition, Mat Vankoughnett Nov 2013

Soil Freezing Effects On A Grass-Dominated Old Field Ecosystem Under Current And Future Rates Of Atmospheric Nitrogen Deposition, Mat Vankoughnett

Electronic Thesis and Dissertation Repository

Climate change is expected to alter the intensity and dynamics of soil freezing as a result of increased air temperatures and reduced snow cover. Soil freezing can influence ecosystem nitrogen (N) cycling by damaging plants and soil microorganisms, but little is known about how soil freezing effects on ecosystem N cycling may combine or interact with increased atmospheric N deposition, which is also expected to exert a strong influence on terrestrial ecosystems in the coming decades. The objective of my thesis was to examine the combined and possibly the interactive effects of climate induced changes in soil freezing and N ...


Thermal Adaptation Of Life History Traits In The Drosophila Melanogaster Group, Christopher James Austin Oct 2013

Thermal Adaptation Of Life History Traits In The Drosophila Melanogaster Group, Christopher James Austin

Electronic Thesis and Dissertation Repository

Thermal adaptation is typically detected by examining the tolerance to extreme temperatures in a few populations within a single life stage. However, the extent to which adaptation occurs among many different populations might depend on the tolerance of multiple life stages and the average temperature range that the population experiences. Here, I examined adaptation to local temperature conditions in four species of fruit flies, including a cosmopolitan species, Drosophila melanogaster, and three species with geographically small-sized ranges, D. nepalensis, D. sechellia, and D. mauritiana. The cosmopolitan species showed adaptation to native temperatures during the larval and adult life stages, but ...


Quantifying Crop Yield, Bioenergy Production And Greenhouse Gas Emissions From Cropland And Marginal Land Using A Model-Data Fusion Approach, Zhangcai Qin Oct 2013

Quantifying Crop Yield, Bioenergy Production And Greenhouse Gas Emissions From Cropland And Marginal Land Using A Model-Data Fusion Approach, Zhangcai Qin

Open Access Dissertations

Bioenergy is becoming increasingly attractive to many countries, but has sparked an intensive debate regarding energy, economy, society and environment. Biofuels provide alternative energy to conventional fossil fuels. However, the environmental impact of producing and using biofuel is a major concern to our society. This study is dedicated to quantifying and evaluating biofuel production and potential climate change mitigation due to potential large-scale bioenergy expansion in the conterminous United States, using model-data fusion approaches.

Biofuel made from conventional (e.g., maize (Zea mays L.)) and cellulosic crops (e.g., switchgrass (Panicum virgatum L.) and Miscanthus (Miscanthus × giganteus)) provides alternative energy ...


Local Adaptation To Climate Change In A Calcareous Grassland System, Catherine Ravenscroft Aug 2013

Local Adaptation To Climate Change In A Calcareous Grassland System, Catherine Ravenscroft

Biology - Dissertations

Annual manipulations of temperature and rainfall have been maintained in intact calcareous grassland since 1993 at the Buxton Climate Change Impacts Laboratory (BCCIL) in northern England (UK). Here I investigated the role of local adaptation as mechanism of the apparent resistance of species' to long-term climate manipulations at BCCIL using a common forb, Plantago lanceolata. Plantago lanceolata is a rosette-forming, perennial herb of wide-ranging distribution, and one of the more common forbs in calcareous grasslands, including BCCIL. In the first study I used a common garden approach to test for evidence of selection for different suites of functional traits in ...


Warming Winters And Changing Habitats: Interactive Effects On Raptor Populations And Implications For Conservation, Neil A. Paprocki Aug 2013

Warming Winters And Changing Habitats: Interactive Effects On Raptor Populations And Implications For Conservation, Neil A. Paprocki

Boise State University Theses and Dissertations

Studies across multiple spatial and temporal scales will improve understanding of the drivers of global change including habitat degradation, invasive species, and climate change. How global drivers affect the ecology of wintering raptors in western North America and the Great Basin may have important implications for changes in distribution and abundance, and consequently population persistence. I examined the winter distributions of six western North America raptor species using Christmas Bird Count data from 1975-2011 to assess range shifts over time and in relation to temperature. Also, I considered whether population patterns within Bird Conservation Regions (BCR) were best explained by ...


Assessing Physiological Thresholds For Eelgrass (Zostera Marina L.) Survival In The Face Of Climate Change, Carolyn Jane Ewers Jun 2013

Assessing Physiological Thresholds For Eelgrass (Zostera Marina L.) Survival In The Face Of Climate Change, Carolyn Jane Ewers

Master's Theses and Project Reports

Seagrasses are well known for the important ecological roles they play in coastal marine waters worldwide. However, the severe rate of decline observed in seagrasses this century is expected to accelerate with climate change. Conservation efforts can be improved by quantifying physiological thresholds of seagrasses and using these estimates in modeling to forecast changes in distribution. This study examines the response of eelgrass (Zostera marina L.) across current temperatures to look for early warning signs of vulnerability and to evaluate the ways we determine critical thresholds for survival. Whole eelgrass ramets, collected from three beds in Morro Bay, California, were ...


Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble May 2013

Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble

Doctoral Dissertations

This dissertation seeks to provide an understanding of how species coexist and, further, how climate change may alter communities by acting on the mechanisms that promote coexistence. Specifically, I examined coexistence among ant species in eastern deciduous forests and the effects that warming may have on foraging activity. Through a series of field observations, I sought evidence for the importance of four of the most commonly cited mechanisms for coexistence among ant species: the dominance – discovery tradeoff, the dominance – thermal tolerance tradeoff, spatial segregation, and niche partitioning. In this system, I did not find evidence for any of these mechanisms ...


Modeling Usa Stream Temperatures For Stream Biodiversity And Climate Change Assessments, Ryan A. Hill May 2013

Modeling Usa Stream Temperatures For Stream Biodiversity And Climate Change Assessments, Ryan A. Hill

All Graduate Theses and Dissertations

Stream temperature (ST) is a primary determinant of individual stream species distributions and community composition. Moreover, thermal modifications associated with urbanization, agriculture, reservoirs, and climate change can significantly alter stream ecosystem structure and function. Despite its importance, we lack ST measurements for the vast majority of USA streams. To effectively manage these important systems, we need to understand how STs vary geographically, what the natural (reference) thermal condition of altered streams was, and how STs will respond to climate change. Empirical ST models, if calibrated with physically meaningful predictors, could provide this information. My dissertation objectives were to: (1) develop ...


Colorado River Cutthroat Habitat Resistance And Resilience To Climate Change, Kate Olsen May 2013

Colorado River Cutthroat Habitat Resistance And Resilience To Climate Change, Kate Olsen

All Graduate Theses and Dissertations

Colorado River cutthroat trout, Oncorhyncus clarki pleuriticus , occupy less than 12% of their historic range. Restoration and conservation of this species are currently under way across the upper Colorado River basin, but guidance to inform management decisions related to the impacts of climate change on cutthroat is lacking. Shifts in the thermal distribution of freshwater fish have been documented, and will continue to occur as cold water habitat is threatened by warming water temperatures. Coupled air and water temperature data allow for an estimation of potential resistance and resilience to warming, determining the effect that local air has on stream ...


Ecology And Conservation Of The Montane Forest Avian Community In Northeastern North America, William V. Deluca Feb 2013

Ecology And Conservation Of The Montane Forest Avian Community In Northeastern North America, William V. Deluca

Open Access Dissertations

Montane forests provide habitat for unique assemblages of flora and fauna that contribute significantly to a region’s biodiversity. Previous work indicates that montane forest ecosystems are exceedingly vulnerable to a host of anthropogenic stressors including climate change, atmospheric deposition, and recreation, to name a few. Montane forests and other high elevation ecosystems are considered to be among the first and most severely impacted by climate change. It is therefore, imperative to evaluate anthropogenic impacts on montane ecosystems and maintain reliable monitoring methods that are capable of tracking potential shifts in the distribution of species dependent on these systems. I ...


Phylogeography Of Eastern Leatherwood (Dirca Palustris L.) Resolved By Chloroplast Sequencing And Microsatellite Genotyping, Bryan James Peterson Jan 2013

Phylogeography Of Eastern Leatherwood (Dirca Palustris L.) Resolved By Chloroplast Sequencing And Microsatellite Genotyping, Bryan James Peterson

Graduate Theses and Dissertations

The broad distribution of eastern leatherwood (Dirca palustris L.), from Florida to Canada, contrasted with its patchy restriction to rich, mesic forests and the paucity of vectors for dispersal of its seeds, represents a classic example of Reid's paradox of plant migration. It long has been presumed that temperate forest species of eastern North America persisted in southern glacial refugia near the Gulf Coast, after which many dispersed nearly 2000 km to contemporary northern range limits. The rates of migration necessary to account for present distributions exceed those suggested by contemporary observations of seed dispersal. I used ecological niche ...


Ecological Interactions Influencing Avicennia Germinans Propagule Dispersal And Seedling Establishment At Mangrove-Saltmarsh Boundaries, Jennifer Mcclain Peterson Jan 2013

Ecological Interactions Influencing Avicennia Germinans Propagule Dispersal And Seedling Establishment At Mangrove-Saltmarsh Boundaries, Jennifer Mcclain Peterson

Graduate Theses and Dissertations

Mangroves and saltmarshes are ecologically important coastal ecosystems; unfortunately, these low-lying coastal ecosystems are vulnerable to global climate change. As sea-levels rise, mangroves are expected to shift their distribution landward towards higher elevation sites that are occupied by other plants, including saltmarsh taxa. Therefore, mangrove recruits at the leading edge of expansion may interact with diverse assemblages of saltmarsh plants, and these interactions could influence the success of mangrove encroachment into higher tidal-elevation areas. The purpose of the research presented here was to investigate empirically the ecological interactions that may influence the recruitment of the black mangrove, Avicennia germinans, into ...


Evaluating Habitat Vulnerability And Sustainability Of Urban Seagrass Resources To Sea Level Rise, Cynthia A. Meyer Jan 2013

Evaluating Habitat Vulnerability And Sustainability Of Urban Seagrass Resources To Sea Level Rise, Cynthia A. Meyer

Graduate Theses and Dissertations

The seagrass resource provides essential ecosystem functions for many marine species. This research evaluated the vulnerability and sustainability of the seagrass resource in an urbanized area to the effects of sea level rise. The assessment required analysis of information regarding the biogeography of the seagrass resource, and developing a method to model the spatial extent of the suitable habitat for seagrass, and applying the model to predict the implications of simulated sea level rise scenarios on the seagrass resource.

Examining the biogeography of the seagrass resource required the development of a seagrass monitoring and assessment field survey and a comprehensive ...


Relating Climate Change To The Nesting Phenology And Nest Environment Of Marine Turtles, Monette Schwoerer Jan 2013

Relating Climate Change To The Nesting Phenology And Nest Environment Of Marine Turtles, Monette Schwoerer

Electronic Theses and Dissertations

Ectotherms (including marine turtles) being especially sensitive to climate, are at risk to the accelerated rate of human-driven climate change. This study addresses two concerns associated with marine turtles and climate change – the relationship between the timing of marine turtle nesting and sea surface temperature; and the concern over the feminization of marine turtle populations due to rising sand temperatures. Previous studies of loggerhead sea turtles (Caretta caretta) and green sea turtles (Chelonia mydas) have documented the relationship between sea surface temperatures and nesting phenology. Earlier nesting behaviors in both species have been associated with warmer sea surface temperatures. Also ...


Sex Ratios Of Juvenile Green Turtles (Chelonia Mydas) In Three Developmental Habitats Along The Coast Of Florida, Cheryl Sanchez Jan 2013

Sex Ratios Of Juvenile Green Turtles (Chelonia Mydas) In Three Developmental Habitats Along The Coast Of Florida, Cheryl Sanchez

Electronic Theses and Dissertations

The concept of temperature dependent sex determination (TSD) has been somewhat of an evolutionary enigma for many decades and has had increased attention with the growing predictions of a changing climate, particularly in species that are already threatened or endangered. TSD taxa of concern include marine turtles, which go through various life stages covering a range of regions. This, in turn, creates difficulties in addressing basic demographic questions. Secondary sex ratios (from life stages post-hatchling) were investigated by capturing juvenile green turtles (Chelonia mydas), 22.6-60.9 cm in straight carapace length (SCL), from three developmental areas along the east ...


Changes In Net Ecosystem Production Over The Past 40 Years In Arctic Tundra Ponds Near Barrow, Alaska: Application Of Historic And Modern Techniques, Nickole Ann Miller Jan 2013

Changes In Net Ecosystem Production Over The Past 40 Years In Arctic Tundra Ponds Near Barrow, Alaska: Application Of Historic And Modern Techniques, Nickole Ann Miller

Open Access Theses & Dissertations

Arctic environments have gained interest recently due to their sensitivity to climate change. As warming has created longer growing seasons, extended ice-free periods as well as permafrost thaw, the production in freshwater ecosystems has the potential to be greatly impacted. It is hypothesized that as climate change and warming occurs, increases in primary production will occur and ponds will become carbon sinks. Net ecosystem production (NEP) was determined using phytoplankton and periphyton samples collected weekly during the growing season (June - August) from arctic tundra ponds near Barrow, Alaska. Enrichment with 14C was used to determine both weekly photosynthetic rates and ...


Ecophysiological Responses Of Tall Fescue Genotypes To Endophyte Infection And Climate Change, Marie Bourguignon Jan 2013

Ecophysiological Responses Of Tall Fescue Genotypes To Endophyte Infection And Climate Change, Marie Bourguignon

Theses and Dissertations--Plant and Soil Sciences

Tall fescue is a widely used forage grass in the eastern USA and can form a symbiosis with a fungal endophyte, which can be beneficial for the plant but can cause livestock health issues. Little is known regarding the symbiotic response to predicted climate change. To address this knowledge gap, I analyzed tall fescue variety trial data collected throughout the U.S., exploring relationships between climate variables and yield for two different fescue cultivars that were either endophyte-free or infected. This study showed no endophyte or cultivar effect on fescue yield, but identified temperature, precipitation and location as significant predictors ...


Investigation Of Media Ingredients And Water Sources For Algae Co2 Capture At Different Scales To Demonstrate The Correlations Between Lab-Scale And Large-Scale Growth, Tabitha Graham Jan 2013

Investigation Of Media Ingredients And Water Sources For Algae Co2 Capture At Different Scales To Demonstrate The Correlations Between Lab-Scale And Large-Scale Growth, Tabitha Graham

Theses and Dissertations--Biosystems and Agricultural Engineering

As energy use increases globally the environmental burdens increase alike. Many accusations have been made that carbon dioxide is a culprit of climate change. The University of Kentucky and Duke Energy Power have partnered to test carbon capture technology in a large scale project. To this end, the objective of this thesis is to investigate potential water media sources and nutrient sources at different volume scales for algae cultivation to help create a more environmentally viable and economically feasible solution. This work will conduct a life cycle assessment of water media sources and the effects of the inputs and outputs ...


Carbon Life-Cycle And Economic Analysis Of Forest Carbon Sequestration And Woody Bioenergy Production, Prativa Shrestha Jan 2013

Carbon Life-Cycle And Economic Analysis Of Forest Carbon Sequestration And Woody Bioenergy Production, Prativa Shrestha

Theses and Dissertations--Forestry and Natural Resources

Sequestering carbon in standing biomass, using woody bioenergy, and using woody products are the three potential ways to utilize forests in reducing greenhouse gases (GHGs) and mitigating climate change. These forestry related strategies are, however, greatly influenced by the existing markets and market based policies. This study focuses on the first two forest strategies. It investigates the combined impact of carbon and woody bioenergy markets on two different types of forests in the US – oak dominated mixed hardwood forests in the Central Hardwood Forests Region and loblolly pine forests in the southeastern US. A modification of the Harman model was ...