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Full-Text Articles in Life Sciences
Climate Change, Increased Wildfire Frequency, And Rodent-Exclusion Create Opportunities For Exotic Grass Invasion And Alter The Timing And Availability Of Soil Water, Joshua Clark Gilman
Climate Change, Increased Wildfire Frequency, And Rodent-Exclusion Create Opportunities For Exotic Grass Invasion And Alter The Timing And Availability Of Soil Water, Joshua Clark Gilman
Theses and Dissertations
In deserts, global environmental changes, plant community structure, and soil water availability form a complex relationship characterized by direct and indirect relationships and feedbacks. Plant community structure is affected by the establishment and spread of invasive grasses, which form a positive feedback with wildfire. Plant community structure is also controlled by top-down trophic interactions by small-mammals and climate change, which alters the timing and amount of soil water. In deserts, soil water availability mediates the effects of global environmental changes and trophic interactions on plant community structure because it is the limiting resource for plant growth. In order to predict …
Of Fire, Mammals, And Rain: Mechanisms Of Plant Invasions, Tara Boyce Bishop
Of Fire, Mammals, And Rain: Mechanisms Of Plant Invasions, Tara Boyce Bishop
Theses and Dissertations
Biological invasions are driving environmental state changes on a global scale. Exotic plant species must be successful at passing several abiotic and biotic filters to establish and disrupt the native plant community assembly. Understanding where exotic plants are on a regional scale and being able to characterize how exotic plants are generally interacting with their environment is crucial information for exotic species management (chapter 1). In the western United States human-related activities are augmenting the spread of exotic plant species by increasing the ignitions of wildfire. Wildfire can lead to nutrient pulses through the removal of intact native communities and …
Plant Functional Groups And Success In A Changing Environment: Modeling Physiological Niches Of Colorado Plateau Plants, Anne Thomas
Undergraduate Honors Theses
Quantifying the environmental and physiological niches of plant species is crucial to predicting their sensitivity to global change, and aggregating plant species by functional type is fundamental both to ecological theory and to the practicality of large-scale efforts to predict the consequences of global change. However, traditional functional types are not always predictive of individual species’ responses to change. Here, an inverse species distribution modeling approach is used to identify functionally similar species based on physiological niche in order to better anticipate the consequences of climate change on the Colorado Plateau, USA. The Colorado Plateau is a semiarid region particularly …
Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum
Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum
Theses and Dissertations
The intensification of aridity due to anthropogenic climate change is likely to have a large impact on the growth and survival of plant species in the southwestern U.S. where species are already vulnerable to high temperatures and limited precipitation. Global climate change impacts plants through a rising temperature effect, CO2 effect, and land management. In order to forecast the impacts of global climate change, it is necessary to know the current conditions and create a baseline for future comparisons and to understand the factors and players that will affect what happens in the future. The objective of Chapter 1 is …
Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum
Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum
Theses and Dissertations
The intensification of aridity due to anthropogenic climate change is likely to have a large impact on the growth and survival of plant species in the southwestern U.S. where species are already vulnerable to high temperatures and limited precipitation. Global climate change impacts plants through a rising temperature effect, CO2 effect, and land management. In order to forecast the impacts of global climate change, it is necessary to know the current conditions and create a baseline for future comparisons and to understand the factors and players that will affect what happens in the future. The objective of Chapter 1 is …
Environmental And Adaptive Buffers That Mediate The Response Of Subalpine Ecosystems To Environmental Change, Lafe G. Conner
Environmental And Adaptive Buffers That Mediate The Response Of Subalpine Ecosystems To Environmental Change, Lafe G. Conner
Theses and Dissertations
This document reports the results of 4 studies of subalpine ecosystem ecology, describing ways that spatial heterogeneity in soils and plant communities mediate ecosystem responses to environmental change. Ecosystem responses to environmental change are also mediated by regional climate patterns and interannual variability in weather. In the first chapter we report the results of an experiment to test for the mediating effects of associational resistance in a forest community that experienced wide-spread beetle kill. We found that Engelmann spruce were more likely to survive a beetle outbreak when growing in low densities (host dilution) and not through other types of …
Small Mammals Matter? Linking Plant Invasion, Biotic Resistance, And Climate Change In Post-Fire Plant Communities, Rory Charles O'Connor
Small Mammals Matter? Linking Plant Invasion, Biotic Resistance, And Climate Change In Post-Fire Plant Communities, Rory Charles O'Connor
Theses and Dissertations
The introduction and establishment of exotic species can profoundly alter ecosystems. Two exotic species drastically changing the landscape of deserts in western North America are Bromus tectorum L. and Bromus rubens L. Through the buildup of biomass and slow decomposition rates in deserts these two exotic annual grasses can alter fire regimes that change the plant and animal community dynamics in the ecosystems. To better understand the ecological mechanisms that could restrict or alter the patterns of invasive plant establishment we established a replicated full factorial experiment in the Great Basin and Mojave Desert. The combinations of factors being manipulated …
Post-Den Emergence Behavior And Den Detection Of Polar Bears (Ursus Maritimus) In Northern Alaska And The Southern Beaufort Sea, Rusty Wade Robinson
Post-Den Emergence Behavior And Den Detection Of Polar Bears (Ursus Maritimus) In Northern Alaska And The Southern Beaufort Sea, Rusty Wade Robinson
Theses and Dissertations
Pregnant polar bears (Ursus maritimus) construct maternal dens out of snow in the autumn where they give birth to and raise altricial young. In recent years, there has been a decrease in polar sea ice extent and thickness, which has led to changes in denning behavior. One such change in the southern Beaufort Sea (SBS) is that polar bears are selecting maternal den sites on land, rather than on unstable sea ice. This change, coupled with expanding petroleum exploration along Alaska's North Slope, heightens the likelihood of bear-human interactions at maternal den sites. The purpose of this research …
Post-Fire Soil Water Repellency: Extent, Severity And Thickness Relative To Ecological Site Characteristics Within Piñon-Juniper Woodlands, Daniel Lewis Zvirzdin
Post-Fire Soil Water Repellency: Extent, Severity And Thickness Relative To Ecological Site Characteristics Within Piñon-Juniper Woodlands, Daniel Lewis Zvirzdin
Theses and Dissertations
Erosion and weed dominance often limit the recovery of burned piñon-juniper woodlands. Soil water repellency (SWR) is one factor that may contribute to this by increasing overland flow and impeding seedling establishment. In spite of these effects, the extent of SWR within piñon-juniper woodlands is unknown. In this study, the extent, severity and thickness of SWR were sampled across 41 1,000 m2 plots within three 2009 Utah wildfires. Predictive models of SWR were built from ecological site characteristic data collected at each site. Across the study, SWR was found at 37% of the points sampled. SWR extent was strongly related …