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Full-Text Articles in Life Sciences
Mountain Big Sagebrush (Artemisia Tridentata Ssp Vaseyana) Seed Production, Melissa L. Landeen
Mountain Big Sagebrush (Artemisia Tridentata Ssp Vaseyana) Seed Production, Melissa L. Landeen
Theses and Dissertations
Big sagebrush (Artemisia tridentata Nutt.) is the most widespread and common shrub in the sagebrush biome of western North America. Of the three most common subspecies of big sagebrush (Artemisia tridentata), mountain big sagebrush (ssp. vaseyana; MBS) is the most resilient to disturbance, but still requires favorable climactic conditions and a viable post-fire seedbank for successful unassisted recovery. This study was designed to assess MBS seed production throughout post-fire recovery. We performed 2 pilot studies to develop methods for estimating seed production and plant age. The results of the pilot studies and a space-for-time substitution strategy were used to measure …
Fire And Ungulate Herbivory Differentially Affect The Sexual Reproduction Of Generalist And Specialist Pollinated Plants, Andrew Hollis Lybbert
Fire And Ungulate Herbivory Differentially Affect The Sexual Reproduction Of Generalist And Specialist Pollinated Plants, Andrew Hollis Lybbert
Theses and Dissertations
Currently the size and frequency of wildfires are increasing at a global scale, including arid ecosystems that exhibit great sensitivity to disturbance. Fire effects on plant pollination and reproductive success in deserts are largely unknown. Plant dependence on animal pollinators for reproduction can increase the risk of reproductive failure if pollination services are hindered or lost. Species that depend on few taxonomically related pollinator species are expected to be most negatively affected by disturbances that disrupt pollination interactions. To assess fire and isolation effects on reproductive success in desert plant communities, and how wildfire influences the pollination success of generalist …
Fuel Response To Mechanical Mastication Of Pinyon-Juniper Woodlands In Utah, Alan Wyatt Shakespear
Fuel Response To Mechanical Mastication Of Pinyon-Juniper Woodlands In Utah, Alan Wyatt Shakespear
Theses and Dissertations
Pinyon-juniper woodland encroachment threatens ecosystem function and diversity on sagebrush steppe. Decreased fire frequency likely favors proliferation of pinyon-juniper woodlands and subsequent decline in desirable understory species. Increased tree cover produces hazardous canopy fuel loads that contribute to severe crown fires and threaten life and property at the wildland-urban-interface. Mechanical mastication converts large canopy fuels into small woody debris, altering wildfire dynamics from a potential crown fire to a more controllable surface fire. We measured fuel loading and cover on untreated, masticated, and masticated + burned treatments on 30-m transects within 30 X 33-m subplots, representing 45 different sites throughout …
Fire Severity And Size Alter Quaking Aspen (Populus Tremuloides) Regeneration And Defense Against Ungulate Herbivory, Ho Yi Wan
Theses and Dissertations
Human activities and rapid global climate change are altering fire regimes with potential threat to the stability of aspen ecosystems in North America. Aspen is an early successional species that plays an important role in post-fire forest reestablishment, but chronic browsing on juvenile aspen by large ungulate herbivores after fire can be detrimental and lead to regeneration failure. Although larger and more severe fires are expected to become more prominent, whether and how this may influence aspen and ungulate communities remains unclear. The objective of this research was to examine how the relationship between aspen and ungulate communities might be …
Exploring Post-Fire Recovery Of Biocrusts And Desert Ecosystem Services, Jason R. Bahr
Exploring Post-Fire Recovery Of Biocrusts And Desert Ecosystem Services, Jason R. Bahr
Theses and Dissertations
Biocrusts and the ecosystem services they provide are becoming more susceptible to fire as exotic annual grass invasions facilitate the spread of desert wildfires. Further, precipitation patterns across the western United States are predicted to change over the next century, and have the potential to dramatically influence fire regimes and the recovery of burned biocrusts. Despite these changes to desert fire and precipitation cycles, our understanding of post-fire biocrust recovery is limited, especially regarding the first two years after fire. To investigate biocrust recovery, we created burn manipulations (i.e., unburned and burned) and tracked crust form and function over two …
Factors Underlying Invasive Grass Fire Regimes In The Mojave Desert And Its Consequences On Plant And Animal Communities, Kevin J. Horn
Factors Underlying Invasive Grass Fire Regimes In The Mojave Desert And Its Consequences On Plant And Animal Communities, Kevin J. Horn
Theses and Dissertations
Climate change and exotic plant invasions are significant anthropogenic threats to desert community structure and resilience . In the Mojave Desert, the invasive grass red brome (Bromusrubens L) is increasing fire frequency and extent in response to climatic factors. The resilience of this ecosystem will be affected by how plant and animal communities respond to fire. To better understand these dynamics, we studied the environmental factors underlying changes in invasive grass fire regimes in the Mojave Desert and its structural and functional effects on plant and animal communities. Following fire, reestablishment of native vegetation can be preempted by repeated burning …
Forage Adaptability Trials For Forage And Seed Production In Bolivia; Effect Of 5 Herbicides On 7 Native Utah Forbs, Joshua C. Voss
Forage Adaptability Trials For Forage And Seed Production In Bolivia; Effect Of 5 Herbicides On 7 Native Utah Forbs, Joshua C. Voss
Theses and Dissertations
The harsh environmental and poor economic conditions of the Bolivian Altiplano require intervention to assist many of those that live there to become economically self-sufficient. We attempted to find introduced dry season reserve forage grasses that could produce enough biomass to be useful as feed for livestock, and that could also produce enough seed to distribute to farmers. While some of the grasses produced reasonable amounts of biomass, none produced seed in quantities that would be even close to being economically viable. The most likely cause of this is that the timing of resources that the grasses need to flower …