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Consequences Of Vegetation Change On The Dynamics Of Labile Organic Matter And Soil Nitrogen Cycling In A Semiarid Ecosystem, Toby D. Hooker
Consequences Of Vegetation Change On The Dynamics Of Labile Organic Matter And Soil Nitrogen Cycling In A Semiarid Ecosystem, Toby D. Hooker
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Sagebrush-dominated ecosystems are being transformed by wildfire, rangeland improvement techniques, and exotic plant invasions. These disturbances have substantial effects on the composition and structure of native vegetation, but the effects on ecosystem C and N dynamics are poorly understood. To examine whether differences in dominant vegetation affect the quantity and quality of plant organic matter inputs to soil, ecosystem C and N pools and rates of plant turnover were compared among historically grazed Wyoming big sagebrush, introduced perennial crested wheatgrass, and invasive annual cheatgrass communities. Since low soil moisture during the summer may inhibit the microbial colonization of plant detrital …
Evolutionary Consequences Of The Introduction Of Eleutherodactylus Coqui To Hawaii, Eric Michael O'Neill
Evolutionary Consequences Of The Introduction Of Eleutherodactylus Coqui To Hawaii, Eric Michael O'Neill
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The introduction of a species to areas outside its native range can result in ecological and genetic changes of evolutionary significance. The frog Eleutherodactylus coqui was introduced to Hawaii, from Puerto Rico, in the late 1980s and has lost genetic variation in mitochondrial DNA. The extent to which founder effects have influenced phenotypic variation in the introduced range is unknown. In this study I compared phenotypic variation in life-history traits, advertisement calls, and stripe patterns among introduced and native populations of the frog Eleutherodactylus coqui. I also conducted laboratory experiments to determine the influence of genetics and temperature on …
Sustaining The Allideghi Grassland Of Ethiopia: Influences Of Pastoralism And Vegetation Change, Almaz Tadesse Kebede
Sustaining The Allideghi Grassland Of Ethiopia: Influences Of Pastoralism And Vegetation Change, Almaz Tadesse Kebede
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Allideghi Wildlife Reserve in the Amibara District of Afar Regional State, Ethiopia, has international significance for harboring endangered Grevy's Zebra and other wildlife dependent on grasslands. The reserve is increasingly used by pastoral people and their herds. Impacts of livestock on native vegetation include direct effects of grazing and indirect effects from livestock-facilitated dispersal of an invasive plant, Prosopis juliflora. The main research objective was to determine effects of pastoralism and vegetation change on prospects for sustaining the Allideghi Wildlife Reserve as grassland habitat for Grevy's Zebra. Methods included use of driving surveys to quantify resource use by …
Potential For Introduced-Range Expansion Of Chinese Tallow Tree (Triadica Sebifera) In The Southeastern United States, Isaac Park
All Theses
The potential for populations of invasive plants to differ in their response to stressful environmental conditions or in their invasiveness is an underexplored issue in determining introduced species' range limits. Introduced genotypes might differ in their response to freezing temperatures, soil type, or differing biotic factors within their introduced range. We examined the potential of Chinese tallow tree seeds (Triadica sebifera (L.) Small) collected from two genetically distinct areas of its introduced range in the United States (North Carolina and South Carolina) as well as from the northern and southern portions of its native range in China to germinate and …
Characterization Of Antibiotic Resistance In Vibrio Cholerae Isolated From Ships' Ballast And Other Environmental Sources, Frank Kornegay Thomson Iii
Characterization Of Antibiotic Resistance In Vibrio Cholerae Isolated From Ships' Ballast And Other Environmental Sources, Frank Kornegay Thomson Iii
OES Theses and Dissertations
Ships' ballast has been implicated as a vector in the dispersal of invasive species into new environments. Numerous cases have been documented for the introduction of macroorganisms via ballasting operations, but what is less known is the role of ballast water and residuals in the spread of potentially harmful microbes, especially with reference to novel genotypes. Of particular interest are the genes encoding for various forms of antibiotic resistance, many of which are carried on mobile genetic elements. A four-year sampling effort has yielded over 300 putative isolates of Vibrio cholerae from ships' ballast tanks and various environmental sources, of …
Soil Nutrient Changes Following A Typha X Glauca Invasion In A Great Lakes Coastal Wetland, Lane Marie Vail
Soil Nutrient Changes Following A Typha X Glauca Invasion In A Great Lakes Coastal Wetland, Lane Marie Vail
Master's Theses
Invasive species are one of the major threats to the integrity and health of Great Lakes coastal wetlands. Plant invaders, such as the hybrid cattail Typha x glauca, threaten wetlands, as they can cause shifts in ecosystem structure and function and modify biogeochemical cycles and nutrient availability. Cheboygan Marsh on the coast of Lake Huron is currently undergoing invasion by T. x glauca, and soils in T. x glauca-dominated areas of the marsh have greater soil carbon and nitrogen concentrations than in areas dominated by native vegetation. This study investigated whether T. x glauca is affecting the accumulation of carbon …