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Full-Text Articles in Life Sciences
Cheatgrass Die-Off Phenomena: What Are The Short And Long Term Recovery Factors Of Bromus Tectorum Stand Failure?, Joshua Alan Nicholson
Cheatgrass Die-Off Phenomena: What Are The Short And Long Term Recovery Factors Of Bromus Tectorum Stand Failure?, Joshua Alan Nicholson
Theses and Dissertations
Observations of Bromus tectorum L. (cheatgrass or downy brome) monocultures have shown that populations are susceptible to stand die-off or replacement failures. Die-offs, where the seed bank from the previous year fails to emerge, occurs in cheatgrass stands and it is unclear the trigger or cause. The fungus Fusarium has been identified in plant and seed samples from die-offs and may drive die-off activity through pathogenicity. Die-off recovery may take several years but cheatgrass populations eventually reestablish. The purpose of our study was to determine whether Fusarium is a potential player in a die-off, and understand how die-offs recover after …
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 …
Plant Establishment And Soil Microenvironments In Utah Juniper Masticated Woodlands, Kert R. Young
Plant Establishment And Soil Microenvironments In Utah Juniper Masticated Woodlands, Kert R. Young
Theses and Dissertations
Juniper (Juniperus spp.) encroachment into sagebrush (Artemisia spp.) and bunchgrass communities has reduced understory plant cover and allowed juniper trees to dominate millions of hectares of semiarid rangelands. Trees are mechanically masticated or shredded to decrease wildfire potential and increase desirable understory plant cover. When trees are masticated after a major increase in tree population density and associated decrease in perennial understory cover, there is a risk that invasive annual grasses will dominate because they are highly responsive to the increased resource availability that commonly follows removal of the main resource user. To determine if tree mastication increases …
Scarification And Cultural Practice Of Four Lupine Species Native To The Great Basin, Covy Dennis Jones
Scarification And Cultural Practice Of Four Lupine Species Native To The Great Basin, Covy Dennis Jones
Theses and Dissertations
The Great Basin is North America's largest desert, encompassing 135 million acres. Grazing and other anthropogenic activities in the Great Basin have put heavy demands on the landscape over the last 150 years. Heavily grazed areas lack diversity which allows the spread of exotic weed species. Cheatgrass (Bromus tectorum L [Poaceae]) has invaded and shortened fire frequency intervals from historic 30—100 years to as few as three to five years. Post-fire reseeding of native species is requisite for restoration of highly invaded ecosystems thus, preventing complete conversion to exotic weeds. Most native shrubs and grasses are available for restoration …
Predictive Modeling Of Sulfur Flower Buckwheat (Erigonum Umbellatum Torrey) Using Non-Parametric Multiplicative Regression Analysis, David B. Davis
Predictive Modeling Of Sulfur Flower Buckwheat (Erigonum Umbellatum Torrey) Using Non-Parametric Multiplicative Regression Analysis, David B. Davis
Theses and Dissertations
Impacts of humans on ecosystems in western United States have necessitated ecological restoration, which includes the development of native seed that can be used for revegetation efforts. Development of such seed sources are costly and time consuming. This study describes the use of non-parametric multiplicative regression analysis (NPMR) to develop a predictive model for occurrence of sulfur-flower buckwheat (Eriogonum umbellatum Torrey) population seed collection. This perennial forb species is of interest for seed source development in the western United States. Presence and absence data for E. umbellatum was taken from the Utah Division of Wildlife Resources Big Game Range …