Thesis
Public perceptions of sagebrush ecosystem management: A longitudinal panel study of residents in the Great Basin, 2006-2010
View dissertation. The study uses data from a mail-back questionnaire sent to residents in 2006 and again in 2010. Overall, 698 respondents comprise the panel of interest. Results suggest landscape scale events such as wildfire, as well as agency management and outreach programs, had little influence on respondents’ perceptions of agencies or management options over…
Read MoreThe economic impacts of sagebrush steppe wildfires on an eastern Oregon ranch
View thesis. The purpose of this project is to determine the importance of considering specific ecological effects of cheatgrass-associated wildfires on a ranch-level economic model. This study assumes that a representative Oregon 300 cow-calf ranch possesses a Bureau of Land Management (BLM) allotment that exhibits ecological characteristics typical of sagebrush steppe sites that are vulnerable…
Read MoreSeed bank response to juniper expansion in the semi-arid lands of Oregon, USA
View thesis. Expansion of Juniperus occidentalis into the sagebrush steppe has resulted in significant changes in understory composition. A consequence of increased J. occidentalis dominance may be a depletion of the seed bank. The potential for depletion is problematic because a reduction in the amount of species available from the seed bank may compromise site…
Read MorePost-treatment hydrologic response to mechanical shredding in a juniper woodland
View thesis. Juniper woodland expansion in the western United States is thought to result in increased wildfires throughout its range and has prompted land managers to search for effective fuel control methods. Recently, mechanical shredding (Bull Hog ®) has been used to reduce juniper trees to a mulch residue on or around the juniper mound.…
Read MoreMycorrhizae in sagebrush-steppe community restoration: Mycorrhizal dependency of invasive and native grasses with intraspecific and interspecific competition
View thesis. Mycorrhizae have been used in restoration for decades. However, studies assessing the use of mycorrhizae in Bromus tectorum-invaded areas of the Great Basin are limited. Two greenhouse pot experiments were conducted to assess the role of mycorrhizae in sagebrush restoration.
Read MoreAssessing carbon and nitrogen in a central Nevada pinyon woodland with tree encroachment and prescribed fire
View dissertation. This research focuses on refining methods for estimating belowground C and N, and estimating whole ecosystem C and N associated with woodland encroachment into sagebrush ecosystems, and the effects of land management, particularly prescribed fire, on ecosystem C and N. We found that our use of a soil coring device to estimate belowground…
Read MoreDrivers of plant community dynamics in sagebrush steppe ecosystems: Cattle grazing, heat and water stress
View dissertation. Sagebrush steppe ecosystems are one of the most widespread but endangered ecosystems in North America. A diverse array of human-related stressors has gradually compromised these ecosystems’ resilience to disturbance and invasion by cheatgrass. The role of the foundational shrub Artemisia as a driver of herbaceous community structure and dynamics during this degradation process…
Read MoreSeed pool dynamics of a Great Basin sagebrush community in the context of restoration
View thesis. I determined the relationship between the compositions of the seed pool and aboveground vegetation and the effect of shrubs (microhabitat effects) and perennial bunchgrass cover (community phase effects) on the seed pool community composition, seed density, and seed pool species richness. To evaluate the relationship between the two communities and the effects of…
Read MoreThe effect of invasive annual plants on wildfire suppression costs
View thesis. Preventative fuel treatment is an effort such as thinning of brush and young trees, herbicidal treatment of invasive grasses, controlled fires to reduce fuel loads, and other actions to reduce the probability that a wildland fire will be a catastrophic wildfire that results in further expansion of invasive grasses, losses to ecological integrity,…
Read MoreSeed and seedling ecology of Artemisia tridentata in a restoration context
View dissertation. I investigated seed longevity of two A. tridentata subspecies over a 2-year period by retrieving seed bags that were placed at varying depths and sampling soil and litter fractions of the existing seed bank across six locations in the Great Basin. Artemisia tridentata ssp. wyomingensis and A. t. ssp. vaseyana exhibited patterns of…
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