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Full-Text Articles in Life Sciences

Effect Of Predator Removal On Greater Sage-Grouse (Centrocercus Urophasianus) Ecology In The Bighorn Basin Conservation Area Of Wyoming, Elizabeth Kari Orning Dec 2013

Effect Of Predator Removal On Greater Sage-Grouse (Centrocercus Urophasianus) Ecology In The Bighorn Basin Conservation Area Of Wyoming, Elizabeth Kari Orning

All Graduate Theses and Dissertations

The decline of greater sage-grouse (Centrocercus urophasianus) populations across western North America has intensified conservation, research, and management efforts. Predator-prey interactions have been the focus of widespread scientific study, but little research has been conducted on the effects of predation and predator removal on sage-grouse ecology. This study had three main objectives: 1) identify the types of predators impacting hen survival and nest success, 2) compare the effect of predator removal on vital rates, and 3) evaluate habitat selection and movement. Over two years (2011-2012), an observational study and field experiment were used to test the effects of predation and ...


Presence And Function Of Tetrodotoxin In Terrestrial Vertebrates And Invertebrates, Amber N. Stokes Aug 2013

Presence And Function Of Tetrodotoxin In Terrestrial Vertebrates And Invertebrates, Amber N. Stokes

All Graduate Theses and Dissertations

Tetrodotoxin (TTX) is a potent neurotoxin that acts by blocking the pore region of voltage-gated sodium channels in nerve and muscle tissue. This causes paralysis, and often death due to asphyxiation. Interestingly, TTX is found in an array of organisms ranging from bacterial species to vertebrates. Further, TTX is found in both aquatic and terrestrial environments. This range of taxa and environments has led to three common lines of study for ecological research on this toxin: production, predation, and identification of novel TTX bearing taxa. I began my research by also refining a Competitive Inhibition Enzymatic Immunoassay technique for fast ...


The Ecology And Genetics Of Schoenoplectus Maritimus, An Important Emergent Macrophyte, Across Diverse Hydrologic Conditions--Implications For Restoration, Amanda Clare Sweetman Aug 2013

The Ecology And Genetics Of Schoenoplectus Maritimus, An Important Emergent Macrophyte, Across Diverse Hydrologic Conditions--Implications For Restoration, Amanda Clare Sweetman

All Graduate Theses and Dissertations

Revegetation projects in wetlands are challenging due to questions surrounding where to obtain plant materials and how hydrologic conditions, which are often unpredictable at restoration sites, may impact restoration success. We used a two-pronged approach to inform decisions on seed sourcing. Our study species, Schoenoplectus maritimus (alkali bulrush), is a widely distributed wetland plant. First, we investigated how genetic diversity was partitioned within and among populations of S. maritimus. We found five weakly differentiated populations and one distinct population. We found high levels of genetic diversity with the majority (92%) of diversity found within rather than among sites (8%). Also ...


Climate Change And Plant Demography In The Sagebrush Steppe, Aldo Compagnoni Aug 2013

Climate Change And Plant Demography In The Sagebrush Steppe, Aldo Compagnoni

All Graduate Theses and Dissertations

We used demographic methods to address one of the main challenges facing ecological science: forecasting the effect of climate change on plant communities. Ecological forecasts will be crucial to inform long-term planning in wildland management and demographic methods are ideal to quantify changes in plant abundance. We carried out our research in the sagebrush steppe, one of the most extensive plant ecosystems of Western North America. Our research intended to inform ecological forecasts on an exotic invader, cheatgrass (Bromus tectorum). Moreover, we investigated the general question asking: to what degree competition among plants influences the outcome of ecological forecasts on ...


Modeling Habitat Use Of A Fringe Greater Sage-Grouse Population At Multiple Spatial Scales, Anya Cheyenne Burnett Aug 2013

Modeling Habitat Use Of A Fringe Greater Sage-Grouse Population At Multiple Spatial Scales, Anya Cheyenne Burnett

All Graduate Theses and Dissertations

While range-wide population declines have prompted extensive research on greater sage-grouse (Centrocercus urophasianus), basic information about southern periphery populations, such as the Bald Hills population in southern Utah, has not been documented. The objective of this research was to determine habitat preferences and space use patterns of the Bald Hills sage-grouse population which occurs in an area of high potential for renewable energy development. I tracked 66 birds via VHF telemetry in 2011 and 2012 and surveyed vegetation plots throughout the study area. I found that the population was primarily one-stage migratory with seasonal distributions that did not correspond well ...


Effects Of Non-Surface-Disturbing Restoration Treatments On Native Grass Revegetation And Soil Seed Bank Composition In Cheatgrass-Invaded Sagebrush-Steppe Ecosystems, Alexandra D. Reinwald May 2013

Effects Of Non-Surface-Disturbing Restoration Treatments On Native Grass Revegetation And Soil Seed Bank Composition In Cheatgrass-Invaded Sagebrush-Steppe Ecosystems, Alexandra D. Reinwald

All Graduate Theses and Dissertations

The conversion of sagebrush-steppe communities of the Great Basin into cheatgrass-dominated communities is one of the most dramatic ongoing land conversions in North America. Although restoration of these communities is a high priority to landowners and land management agencies, restoration of native vegetation is difficult. Several restoration treatments intended to increase the success of aerially‐seeded perennial grasses in cheatgrass-invaded sagebrush ecosystems were assessed to determine their effects on perennial seedling emergence and soil seed bank density and composition. Assessed restoration treatments were: 1) vegetation manipulation (sagebrush thinning and prescribed burning); 2) imazapic herbicide application; 3) seedbed amendments (aerial seeding ...


Self-Limitation As An Explanation For Species' Relative Abundances And The Long-Term Persistence Of Rare Species, Glenda Marie Yenni May 2013

Self-Limitation As An Explanation For Species' Relative Abundances And The Long-Term Persistence Of Rare Species, Glenda Marie Yenni

All Graduate Theses and Dissertations

Much of ecological theory describes species interactions. These interactions often play an important theoretical role in facilitating coexistence. In particular, rarity in ecological communities, though often observed, provides a significant challenge to theoretical and empirical ecologists alike. I use a plant community model to simulate the effect of stronger negative frequency dependence on the long-term persistence of the rare species in a simulated community. This strong self-limitation produces long persistence times for the rare competitor, which otherwise succumb quickly to stochastic extinction. The results suggest that the mechanism causing species to be rare in this case is the same mechanism ...


Causes And Consequences Of Local Variability In Aroga Websteri Clarke Abundance Over Space And Time, Virginia L.J. Bolshakova May 2013

Causes And Consequences Of Local Variability In Aroga Websteri Clarke Abundance Over Space And Time, Virginia L.J. Bolshakova

All Graduate Theses and Dissertations

With increasing pressures on sagebrush steppe ecosystems, the sagebrush defoliating Aroga moth, Aroga websteri Clarke (Lepidoptera: Gelechiidae) has become a critical organism of concern. Despite the cyclic nature of A. websteri outbreaks throughout the Great Basin, there is limited information on the moth’s population dynamics. The goal of this dissertation was to develop effective means of assessing and describing population trends of the Aroga moth across space and time, and potentially promoting biological control of the moth to prevent unnaturally large, prolonged and destructive outbreaks. Field studies were conducted to: 1) monitor and quantify activity of the Aroga moth ...


Interspecific Interactions Between Penstemon Palmeri And Shrubs In The Arid Shrublands Of The Spring Mountains, Nevada, Jesse M. Poulos May 2013

Interspecific Interactions Between Penstemon Palmeri And Shrubs In The Arid Shrublands Of The Spring Mountains, Nevada, Jesse M. Poulos

All Graduate Theses and Dissertations

A project involving shrub removal was undertaken by the United States Forest Service in the Spring Mountains National Recreation Area (SMNRA) to reduce accumulated woody fuels, which can pose risks to human communities. This research focuses on the interactions between shrubs and the perennial forb Palmer's penstemon (Penstemon palmeri), one of many nectar sources for the endemic Spring Mountains Acastus Checkerspot Butterfly (Chlosyne acastus ssp robusta). Initial observations revealed that P. palmeri (`penstemon') seemed to grow almost exclusively under shrubs. Such spatial associations are often indicative of a history of positive interactions between plants, and led to the research ...


Forest Recovery, Nutrient Cycling And Carbon Sequestration In A Southern Appalachian Spruce-Fir Forest, Patrick T. Moore May 2013

Forest Recovery, Nutrient Cycling And Carbon Sequestration In A Southern Appalachian Spruce-Fir Forest, Patrick T. Moore

All Graduate Theses and Dissertations

In order to fully understand the magnitude of the benefits that forests provide, it is crucial to understand the full suite of ecosystem services that they offer. A southern Appalachian red spruce-Fraser fir forest was intensively analyzed using a variety of methodologies to determine the nature and quantity of some of these services. Many hypotheses exist regarding the future of these spruce-fir forests, which were heavily disturbed by the non-native balsam wooly adelgid during the 1980s. Direct measurements over the course of a decade assessed these hypotheses and indicate that this forest is recovering structure and function. The forest is ...


A Multi-Scale Investigation Of Factors Limiting Bull Trout Viability, Tracy Bowerman May 2013

A Multi-Scale Investigation Of Factors Limiting Bull Trout Viability, Tracy Bowerman

All Graduate Theses and Dissertations

Effective conservation strategies for imperiled species require an understanding of processes that influence fitness throughout the organism's life cycle and across the range of habitats needed to complete that cycle. I evaluated factors that affect population viability of bull trout Salvelinus confluentus, a threatened freshwater char species, throughout individual life stages and over the entire life cycle. I assessed the relationship between bull trout egg incubation success and environmental variables. Egg survival was negatively related to the percent of fine sediment in redds and positively related to hydraulic conductivity and the strength of downwelling. Next, I quantified juvenile bull ...