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Full-Text Articles in Life Sciences
Native Plant Allelopathy: A Potential Approach To Limit Invasive Grass Encroachment In Thorn Forest Restoration, Emily A. Mullins
Native Plant Allelopathy: A Potential Approach To Limit Invasive Grass Encroachment In Thorn Forest Restoration, Emily A. Mullins
Theses and Dissertations
Less than 5% of the Tamaulipan thorn forest remains in the United States. For this reason, there have been many attempts at restoration of this ecosystem. Oftentimes these attempts are unsuccessful due to the high prevalence of invasive African grasses that outcompete the seedlings. In an effort to improve the efficacy of these restoration efforts, native plant allelopathy has been examined for its ability to exclude invasive guineagrass. Native species were surveyed and selected species were tested for allelopathy in laboratory bioassays. The species that exhibited allelopathy in the laboratory were then evaluated in pot experiments for their ability to …
Improving Rangeland Seedling Recruitment Using Fungicide Seed Coatings And Golden Eagle Reproductive Success In Relation To Explosive Military Tests And Trainings, Benjamin William Hoose
Improving Rangeland Seedling Recruitment Using Fungicide Seed Coatings And Golden Eagle Reproductive Success In Relation To Explosive Military Tests And Trainings, Benjamin William Hoose
Theses and Dissertations
The objective of the first chapter of this thesis was to determine whether fungicide seed coatings constitute an effective strategy for increasing seedling recruitment in restoration scenarios in the Intermountain West. We tested a mixture of four fungicides that address potential fungal pathogens to bluebunch wheatgrass, a dominant bunchgrass that is commonly used in restoration. Across two sites and three years, we found that the fungicide seed coating increased emergence in five of the six sites and years, with an average increase of 59.1% over the control. There was a strong interaction (P < 0.001) between the effects of fungicide treatment, the year and the site on emergence. This interaction was likely related to the effects of the hydrothermal microsite environment on disease severity. Further research is necessary to fully understand the conditions under which fungicide seed coatings are most likely to be effective. The objectives the second chapter of this thesis were to 1) estimate the effects of golden eagle nest proximity to explosive disturbances on reproductive success given other relevant habitat variables (e.g. indices of topography and vegetation), and 2) determine the relative importance of nest proximity to explosive disturbances as a predictor of golden eagle reproductive success compared to other relevant habitat variables. Reproductive success data were collected from nesting territories within and surrounding land controlled and managed by the US Department of Defense. We fit the reproductive survey data using generalized linear mixed-effects models comprised of unique, hypothesis-based sets of habitat variables. We compared the models using AICc-based model selection processes. Given the best approximating model, we found no evidence that the likelihood of reproductive success was affected by nest proximity to explosive disturbances (P = 0.460). We further found nest proximity to explosive disturbances consistently ranked in the bottom 50% of relative variable importance. These results may indicate golden eagle tolerance or habituation to explosive military tests and trainings. Although the two chapters of this thesis are disjointed, they are loosely unified by the ecological importance of disturbance, invasive species, and restoration within the Great Basin ecoregion.
Hydrologic And Biologic Responses Of Anthropogenically Altered Lentic Springs To Restoration In The Great Basin, Leah Nicole Knighton
Hydrologic And Biologic Responses Of Anthropogenically Altered Lentic Springs To Restoration In The Great Basin, Leah Nicole Knighton
Theses and Dissertations
Water is a limited and highly valued resource in the semi-arid Great Basin. Surface water sources are often small and widely spaced apart, comprising only 1-3% of the surface area of the overall landscape. Despite their small size, these springs and surrounding wet meadows have a substantial effect on the surrounding environment. Springs provide drinking water, forage and cover for livestock and wildlife, habitat for diversity of plant species and a resource for human-related activities. In recent years, many of these springs have become dewatered due to diversions of groundwater for municipal water and agriculture, and climatic shifts in precipitation …
Improving Post-Wildfire Seeding Success Using Germination Modeling And Seed Enhancement Technologies, William Charles Richardson
Improving Post-Wildfire Seeding Success Using Germination Modeling And Seed Enhancement Technologies, William Charles Richardson
Theses and Dissertations
Arid and semi-arid rangelands are important ecosystems that are consistently degraded through disturbances such as wildfires. After such disturbances, the invasion and dominance of annual grasses, like cheatgrass (Bromus tectorum L.), can lead to an overall loss of ecosystem productivity and an increase in fire frequency. To reduce weed dominance, native and introduced perennials species are typically be seeded in the fall. High mortality is seen from these seeded plant communities due to germinated seed being exposed to freezing, drought, fungal pathogens, and other biotic and abiotic stressors during winter months. We utilized wet-thermal accumulation models to first further …