Theses and Dissertations - Ecology
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Soil heterogeneity in agricultural and natural ecosystems : relationships between anaerobic activity, organic matter, nutrients, and greenhouse gases
Many soil biogeochemical processes are difficult to predict, in part, due to the spatial heterogeneity of physical, chemical, and biological components of soil. Understanding how heterogeneity forms and affects biogeochemical ... -
A social-ecological approach to managing agricultural ammonia emissions and nitrogen deposition in Rocky Mountain National Park
Atmospheric nitrogen (N) deposition is harmful to nutrient-limited mountain ecosystems. Annual wet deposition of total inorganic N in Rocky Mountain National Park (RMNP) is dominated by ammonium, which primarily comes from ... -
Climate change impacts on population dynamics in tallgrass prairie : implications for species codominance
Two grass species, Andropogon gerardii and Sorghastrum nutans, together account for the great majority of individuals, biomass, and possibly genetic diversity in plant communities of the tallgrass prairies of the Great ... -
Experimental tests of risky augmentation scenarios using Trinidadian guppies
Increased isolation of populations, and the subsequent reduction in genetic diversity, can exacerbate global biodiversity loss by contributing to inbreeding depression and reducing the ability of organisms to adapt to rapid ... -
Ultraviolet-B radiation effects on sweetpotato growth and development
In spite of the success of the implementation of Montreal Protocol, the ozone level is not expected to return to 1980's levels until this mid-century because of the remaining chloroflurocarbon (CFCS) in the atmosphere. ... -
Modeling bioenergy agroecosystems for climate change mitigation and vulnerability assessment
Agriculture is a major driver of anthropogenic climate change while also directly bearing its impacts. In addition to emissions related to farm operations and inputs, substantial greenhouse gases are released from cropland ... -
Diversity, distributions, and evolution of Rocky Mountain and Andean stream insects
Concordant with latitudinal increases in seasonality, the "climate variability hypothesis" (CVH) posits that the breadth of species' thermal tolerances should increase with latitude. Across elevations, the "mountain passes ... -
Cheatgrass (Bromus tectorum L.) management and native plant community recovery on sites selectively treated with Imazapic in Rocky Mountain National Park
Cheatgrass, a winter annual grass introduced to North America from Eurasia, has invaded much of the Western United States over the last century. Recently, cheatgrass has become a threat to the montane and subalpine plant ... -
Statistical models for animal telemetry data with applications to harbor seals in the Gulf of Alaska
Much is known about the general biology and natural history of harbor seals (Phoca vitulina), but questions remain about the aquatic and terrestrial space use of these marine mammals. This is in large part because methods ... -
Spatial ecology and conservation of tigers and their prey in the Central Terai Landscape, India
Remnant populations of the world’s ~3800 wild tigers (Panthera tigris) are generally small (< 20 adult individuals), subject to high rates of poaching, and confined to fragmented habitats with high levels of human disturbance. ... -
Mechanisms of population divergence along elevational gradients in the Tropics
Elucidating the mechanisms that give rise to population divergence and eventually initiate speciation is a key step for understanding the evolution of biodiversity. Most theories of differentiation and speciation have ... -
Greenhouse gases in arctic and alpine streams : patterns, drivers, and responses to disturbance
Streams have recently received attention as previously unaccounted for sources of greenhouse gases (GHG; CH4,CO2, and N2O) to the atmosphere. While progress has been made at incorporating streams into global estimates of ... -
Evolution and plasticity of Trinidadian guppies in the field, the laboratory, and the classroom
A fundamental question in evolutionary biology is how organisms respond to new and changing environments. This question also has conservation implications in the face of human induced rapid environmental change, including ... -
Impacts of drought on grassland productivity across the wet-dry gradient in the U.S. Great Plains in 2010-2012
Severe, prolonged droughts are predicted to occur more frequently due to global climate change. Since grasslands already grow in regions that are water limited, they are particularly vulnerable to changes in precipitation. ... -
Vulnerability of cold-water and cool-water fishes to climate change within an anthropogenic context using boosted regression trees, decision scaling, and ecosystem services
Across the globe, environmental changes are occurring in ways that are profoundly important for freshwater ecosystems with implications for the occurrence of species. Typically, ecologists have sought to understand the ... -
Impacts of climate change to breeding and migrating waterbirds in the Prairie Pothole Region
The Prairie Pothole Region (PPR) of the north-central U.S. and south-central Canada contains millions of small prairie wetlands that provide critical habitat to many migrating and breeding waterbirds. Due to their small ... -
Ivory poaching, sociality, and the role of behavior in conservation
The potential of animal behavior to contribute to conservation biology has been acknowledged for decades, but empirical work to realize this potential has been surprisingly slow (Sutherland 1998; Caro 2007; Angeloni et al. ... -
Modeling plant hotspots in New Guinea and village-scale land change dynamics in Papua New Guinea
The island of New Guinea harbors the third largest tropical forest in the world, after Amazonia and the Congo. Forest cover changes in New Guinea are occurring at a fast rate and it is vital to improve our understanding ... -
Assessing bird-mediated ecosystem services and disservices in Colorado apple orchards
Agriculture provides food, fuel and fiber to our growing human population and as the largest terrestrial biomes, crop and pastureland are major drivers of land use change. Small organic farms have the potential to provide ... -
Effects of feral horse herds on plant communities across a precipitation gradient
Feral horse herds in the western United States are managed with the goal of maintaining "a thriving natural ecological balance" with their environment. Because rangeland ecology is complex and grazers such as horses can ...
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