Ecology and Evolutionary Biology Commons^™

A Statewide Evaluation Of Fuel Treatment Effectiveness In Altering Wildfire Outcomes On Public Lands In Utah, Jamela Charmaine Thompson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fuel treatments are land management activities that reduce living and dead flammable materials on the landscape to mitigate undesirable wildfire behavior and effects. Common treatments in the western United States include mechanical methods such as thinning and mastication, prescribed burns, and chemical methods, such as herbicide application. Treatments usually have multiple objectives, including reducing fire intensity, protecting natural and cultural resources, slowing or disrupting a potential future fire’s path, supporting ecosystem health, and reestablishing low to mid severity fire cycles in ecosystems. Although treatments can potentially modify fire behavior and ecological health, they generally cannot prevent fires from igniting, eliminate …

Fishing Out Nutrients: The Spatiotemporal And Ecological Dynamics Of Fishery-Based Nutrient Extraction, Adrián A. González Ortiz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Marine fisheries are one of the most impactful human activities on the planet. Since the 1950s, marine fisheries have removed billions of metric tons of marine biomass leading to substantial declines in many fish populations. Among their impacts, we have begun to investigate the role of fisheries in disrupting marine nutrient cycles. Specifically, removing biomass can change nutrient cycles by reducing the amount of nutrients stored within animal biomass.

No studies have investigated the large-scale geographical and ecological contexts of nutrient removal by fisheries over a large timescale. For my thesis, we compiled data on fishery-targeted organisms' carbon, nitrogen, and …

Overcoming Barriers To Aquatic Plant Restoration: Addressing Gaps In Species Identification And Planting Techniques In The Intermountain West, Kate A. Sinnott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Aquatic ecosystems provide many critical and economically valuable benefits, including drinking water, food, recreational opportunities, and water supply for irrigation and agriculture. However, the health of these systems has been severely impacted by human activities such as pollution, land conversion, and introductions of harmful species. Restoring native aquatic plants can help reverse this damage and reestablish benefits, though it is not a common practice. With an objective to increase capacity for aquatic plant restoration in the Intermountain West, I identified and addressed two major barriers: 1) a lack of confidence in aquatic species identification among wetland professionals, and 2) underdeveloped …

Precipitation And Soil Properties Determine Long-Term Consequences Of Disturbance And Invasion In Drylands, Tyson Terry

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Disturbance and invasive species have dramatic effects on desert plant communities, often resulting in degradation or shifts to alternative plant communities. Climate and soil properties determine water availability to plants, and have been thought to drive patterns of recovery following disturbance and potential for invasion.

In chapter II we used a combination of natural gas pipelines and satellite imagery to understand how recovery from a uniform disturbance differs across precipitation and soil gradients. We used a recovery ratio (disturbed/undisturbed) of pipeline pixels and their undisturbed nearest neighbor pixel to quantify recovery in a comparable way across precipitation gradients. We found …

Opening The Black Box: Soil Microbial Communities In Field-Based Plant-Soil Feedback Experiments, Julia Kate Aaronson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plant-soil feedback is a process through which plants modify the properties of their associated soils, affecting their growth. PSF can play a key role in regulating plant growth and communities including altering plant invasion, rarity, and abundance. However, our understanding of the soil organisms that drive these plant growth responses is limited. Most studies treat soils as a ‘black box’ and do little to reveal which specific microbes or microbial communities may be responsible. This chapter examines two recent large PSF field experiments conducted in Minnesota, USA, and Jena, Germany. These experiments revealed that plants altered their soils, changing subsequent …

Evaluating Beaver Translocation Methods For Desert River Restoration, Christine E. Sandbach

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildlife translocation, or moving wild animals from their original home to a new location, is a common conservation practice; however, translocation programs have variable success rates. Beaver translocation is often used in stream restoration projects due to beavers’ role as ecosystem engineers—beavers enhance riparian habitat by building dams that hold water and create more diverse channels. Beaver translocation success is often limited by high mortality and long distance movement after release, and improvement in translocation methods is needed. My objective was to evaluate two methods of improving beaver translocation success in a degraded desert river in east-central Utah: beaver dam …

Mountain Lion (Puma Concolor) And Feral Horse (Equus Ferus) Interactions: Examining The Influence Of A Non-Native Ungulate On Predator Behavior In A Semi-Arid Environment, Peter C. Iacono

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A non-native is a species that evolved in one ecosystem and has established within another. Non-native species can thrive in new ecosystems as they can spread quickly, outcompete and replace native species, and disrupt food webs. Domestic horses were brought to North America by Europeans in 1493. They are now found in 11 states across the western United States. Feral horses can negatively impact vegetation, endangered species habitat, compete with native species, and be important prey for mountain lions under certain conditions. But do feral horses affect the food web? Feral horses are managed by large removals to reduce the …

Evaluating Methods For Pathogen Spillover Detection And Forecasting In Desert Bighorn Sheep (Ovis Canadensis Nelsoni), Grete E. Wilson-Henjum

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Managers mitigate the effects of disease on wildlife populations by detecting outbreaks and predicting disease transmission. Bighorn sheep (Ovis canadensis) populations face threat from the introduced pathogen Mycoplasma ovipneumoniae (M. ovipneumoniae). In the eastern Mojave Desert, managers detect pathogen outbreaks in desert bighorn (O. c. nelsoni) through aerial population surveys, which produce irregular and coarse population information. Furthermore, managers model the risk of M. ovipneumoniae transmission amongst desert bighorn populations, however these models assume that desert bighorn space use is unchanging across years. Here, I evaluate methods used by managers to detect disease outbreaks …

Local And Regional Landscape Characteristics Driving Habitat Selection By Greater Sage-Grouse Along A Fragmented Range Margin, Aidan T. Beers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In response to ongoing landscape change, wildlife species are likely to respond in varied ways. By studying habitat specialists, we are able to better understand the most likely ways in which the denizens of threatened ecosystems will react to those changes. Among the most threatened ecosystem types in North America are sagebrush ecosystems of the Intermountain West, where one of its most well-known residents, greater sage grouse (hereafter, “sage-grouse), have lost more than 50% of their habitat due to fire, invasive species, climate change, encroachment by coniferous forests and avian predators using it, and human-caused landscape conversion. Sage-grouse rely on …

Fractally Sampling Diversity-Environment Relationships To Understand Plant Assemblage Health Across Spatial Scales, Elizabeth G. Simpson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Humans influence the health of ecosystems and rely on healthy ecosystems to support their livelihoods and well-being. By looking at how the parts of ecosystems interact we can understand and improve ecosystem health. Ecosystem interactions change across spatial scales or different size patches of area. For example, individual organisms interact with each other at small spatial scales, while at large spatial scales, communities of organisms interact with weather conditions. However, many research studies do not look at how ecosystem interactions change across spatial scales. To address this gap in ecological research, I use a fractal sampling design which samples at …

The Effects Of Recent Climate Change On Spring Phenology, With A Special Focus On Patterns Of Bee Foraging, Michael Stemkovski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The date on which plants flower and on which bees begin to pollinate varies year-to-year depending on differences in weather. This seasonal timing is known as phenology, and it is already clear that climate change has pushed the spring phenology of many species earlier by increasing temperatures. This is particularly clear in flowering plants, but studying how and why the phenology of pollinators is shifting is more difficult. Most flowering plants rely on pollinators such as bees for their reproduction, and most bees rely on flowers for their sustenance, so bee and flower phenology has to overlap for the crucial …

The Barriers To Movement: The Effects Of Anthropogenic Linear Features On The Space-Use Behaviors Of Mule Deer And Pronghorn In Utah, Ronan B. Hart

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Human development of structures like roads, fences, and other linear features can make it difficult for animals to move around their environment, affecting their ability to find food and avoid danger. Animal movement and the way they use space comes about from their responses to their surroundings and their choices to balance risk and reward. Because of this, we can understand how roads and fences affect wildlife by studying the way they move around their habitats. In this thesis, I focused on two large herbivores, mule deer and pronghorn, and studied how they use the space within Utah, United States …

Regeneration Of Quaking Aspen And Understory Vegetation Change After Fire Risk Reduction Treatment, Allison M. Trudgeon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Quaking aspen (Populus tremuloides Michx.) is a keystone species that, when coexisting with conifers (i.e., seral aspen), often undergoes stand-replacing disturbances to sustain long term vigor. Historically, mixed-to-high severity fire reduced fuels and regenerated aspen, but such disturbances have become less common in recent decades. This has often led to high fuel loading, and many seral aspen stands are at now risk of an unpredictable, high-severity fire, posing a threat to development in the wildland-urban-interface. The lack of a commercial market for aspen, and the risk of conducting prescribed fire, means there are few alternate management options. This has …

Avian Species Distribution Models: Using Location Data To Inform Management Decisions, Marilyn E. Wright

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Both state and federal wildlife agencies strive to conserve and protect wildlife and their habitats as an important public resource. Applied management decisions often rely on being able to obtain data that can efficiently and effectively enhance the understanding of these systems for informing management actions. Wildlife managers often focus efforts on a small subset of species from an ecosystem, typically called focal species, who can serve as surrogates for understanding the health and function of the system. Models that consider how these focal species interact with the ecosystem are often used to better understand important aspects of their life …

Rainfall Increases Alpha And Has No Effect On The Beta Diversity Of Animal-Dispersed Shrubs In Panama, Rosemary Hopson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate patterns affect where plants can grow and survive. In tropical areas, the main form of precipitation is rain, and rainfall has been demonstrated to influence tree species distributions. For this thesis, I examined the relationship between rainfall and the diversity of animal-dispersed tropical shrubs. To do this, I used data on shrub diversity collected in the summer of 2017. Plots were established across the Isthmus of Panama, from the drier Pacific side to the wetter Atlantic side, to survey animal-dispersed shrubs. I analyzed three metrics of diversity that weigh rare and common species differently. The first weighs rare species …

Quantifying Floral Resource Availability Using Unmanned Aerial Systems And Machine Learning Classifications To Predict Bee Community Structure, Jesse Anjin Tabor

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bees are important for agricultural and non-agricultural ecosystems because they pollinate both wild plants and commercial crops. Flowers provide pollen and nectar resources that bees use to survive and reproduce. Measuring the relationship between the floral community and bee community may help apiarists and land managers to make informed decisions in managing wild and domesticated bee species. Manual methods to describe and count flowering vegetation is costly in time and personnel. Unmanned aerial vehicle (UAV) technology may be an efficient way to describe and count flowering vegetation on a large scale. UAVs with classification analysis and ground transect surveys were …

Extreme, Positive Geomorphic Change In A Historically Degraded Desert River: Implications For Imperiled Fishes, Tansy T. Remiszewski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rivers comprise some of the most unique and biodiverse ecosystems on the planet with their waters supporting both human societies as well as the organisms that make these rivers their home. Large rivers like the Colorado are often highly regulated and diverted in order to support human residence in arid regions like the desert Southwest, and these water diversions often have dramatic, negative impacts on the natural flow regime of the river. These impacts leave large reaches of the river dry, reduce the river’s capacity to transport sediment, cause channel and habitat homogenization, and significantly reduce the amount of suitable …

Seed Ecology And Regeneration Processes To Inform Seed-Based Wetland Restoration, Emily E. Tarsa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wetlands provide immense value to wildlife and humans but have been degrading rapidly around the world. One major challenge is the loss of native plant species in wetlands, which limits the ability of wetlands to function as they should. Restoring wetlands requires a combination of removing the cause of degradation (such as invasive plant species) and, in many cases, actively returning native plants to the site especially via seeding. Further, early plant life stages are the most vulnerable for plants and is often the time in which sown species die and fail to establish. Thus, understanding how and why seeds …

Pronghorn Space-Use Ecology In Utah, Veronica A. Winter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Pronghorn are viewed as a quintessential part of the landscape in the American West. Found only in western North America, pronghorn is a unique species, having historic ranges within prairie, shrubland-steppe, and desert habitat across the continental west. Even though they have been present on this landscape since the last ice age, little is known of pronghorn ecology. There has been growing concern over the impact anthropogenic features, such as development, agriculture, and roads are having on migration, seasonal range conditions, and overall population dynamics. The aim of this thesis is to investigate factors that may be important for pronghorn …

Dust Deposition Changes Production, Chlorophyll-A And Community Composition In Mountain Lakes, Jiahao Wen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Increasing quantities of dust emitted from semi-arid soils, agricultural soils, and urban regions are blown to remote mountain lakes in the American West. Remote mountain lakes lacking local nutrient inputs and presenting simple food webs that are easily affected by climate changes. Dust can carry nutrients (e.g., nitrogen and phosphorus) to mountain lakes and potentially enhance algae growth and change algal communities. However, experimental tests of this hypothesis are lacking. Using in situ experiments, we investigated the effects of dust enrichment on the production, biomass, and primary algal species in three mountain lakes in the American West. We found that …

Nest‐Site Selection, Success, And Response To Predators By Cinnamon Teal And Other Ground‐Nesting Ducks In The Wetlands Of Great Salt Lake, Utah, Mark E. Bell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The wetlands of Great Salt Lake once supported hundreds of thousands of nesting ducks each year. In recent years, the number of nesting ducks in the same area was a fraction of those historic numbers. While many species of ducks do not rely on these wetlands for primary nesting habitat, cinnamon teal (Spatula cyanoptera) do. Great Salt Lake and its associated wetlands are in the heart of the cinnamon teal breeding range, and once supported half of the continental population.

These wetlands are unique from other wetlands where waterfowl nest because they are artificially created using dams to hold …

Immunological Tradeoffs And The Impacts Of Urbanization On The Reproductive Ecology And Physiology Of The Side-Blotched Lizard (Uta Stansburiana), Emily E. Virgin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investing resources into reproduction can limit energy available to other competing demands, such as fighting off an infection; yet, both processes are necessary for organisms to survive and pass on their genes to the next generation. These strategies often follow patterns associated with lifespan, such that shorter-lived animals are more likely to invest more resources into reproduction over survival, and vice versa in long-lived animals. However, environmental change caused by urbanization can disrupt these relationships, and the within- and transgenerational costs of urbanization on females and offspring are unknown. I address these uncertainties in three research chapters to better understand …

Hidden Mechanisms Of Climate Impacts In Western Forests: Integrating Theory And Observation For Climate Adaptation, Sara J. Germain

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fire, insects, and disease are necessary components of forest ecosystems. Yet, climate change is intensifying these tree stressors and creating new interactions that threaten forest survival. This dissertation combined field observations with statistical predictions of changing disturbances in western forests to identify 1) how conventional models may underestimate future forest loss, and 2) how positive relationships between trees may be exploited by managers to prevent forest loss.

In Chapter II, I tested whether increasingly extreme weather with climate change increases Pacific yew extinction risk. I found that conventional modeling methods underestimated local extinction risk because trees were adapted to a …

Conservation Genetics Of A Declining Bumble Bee In Western North America; The Influence Of Geography, Dispersal Limitation, And Anthopogenic Activity, Ashley T. Rohde

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Conservation biology addresses the problem of species loss by identifying species in need of protection. Conservation biology has subfields to address different aspects of biodiversity loss, including genetics and sociology. I used genetic approaches to assess the conservation status of western bumble bees, a bumble bee species of conservation concern.

The western bumble bee is a bumble bee species that ranges from Alaska to New Mexico and as far east as Wyoming and Colorado. This species is disappearing in some places. It may soon be listed as endangered in the United States and is already listed as endangered in parts …

Investigating Cause-Specific Mortality Of Sheep To Determine The Impacts Of Carnivores On Domestic Livestock, Nathan Jacob Floyd

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Livestock and carnivores interact in ways that are considered conflict throughout the world. In the western United States, livestock are often grazed on public lands in close proximity to predators in their natural habitat, and can be killed as prey. Livestock losses to predators can threaten rancher’s livelihoods. Sheep and lambs are especially vulnerable to predators due to their small size and lack of defensive abilities. To reduce the impacts that predators have on livestock, it is important for ranchers and wildlife biologists to have an accurate understanding of how many livestock die and are killed by predators when grazing …

Evaluation Of Noninvasive Methods For Determining Pregnancy, Diet, Nutrition, And Stress Among Pronghorn Antelope: Implications For Population Monitoring, Cole Bleke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was conducted to increase our understanding of the influence of adult female pronghorn (Antilocapra americana) physiology on fawn summer survival. Pronghorn are a valued big game animal in Idaho, but are particularly sensitive to capture; therefore, we designed a noninvasive fecal sampling study to measure pregnancy (progesterone and estrogen), diet, nutrition (fecal nitrogen and DAPA), and stress (cortisol), during metabolically-demanding female life history stages (late gestation, early lactation, and breeding season). We also compared survey results between ground and aerial methods within mountain valley landscapes.

Pregnancy determination, via progesterone, is possible for pronghorn, but sample collection …

Characterizing The Migratory Phenology And Routes Of The Lazuli Bunting (Passerina Amoena) In Northern Utah, Kim Savides

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Migratory species time their movements to follow changes in food and environmental resources throughout the year. Despite the ubiquity of migration in birds, little is still known about how birds select routes and time migrations. Recent advancements in miniaturized tracking devices now allow tracking of small birds throughout their annual life cycle, presenting opportunities for migratory ecology research at scales immeasurable in the past. Here we investigated the migratory ecology of a northern Utah, USA breeding population of Lazuli Bunting, a common songbird in western North America for which few migratory studies have been completed. We sought to compare breeding …

Carnivoran Frugivory And Its Effect On Seed Dispersal, Plant Community Composition, Migration, And Biotic Carbon Storage, John P. Draper

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Seed dispersal by animals is important for the ecology of plants. It is particularly important to understand which animals are involved and how they move seeds differently from one another. Some seed dispersers are understudied despite ample evidence they consume fruits and seeds. This includes animals commonly referred to as carnivores in the order Carnivora. The overall goal of my dissertation was to describe the extent and quality of seed dispersal by Carnivorans, estimate important aspects of seed dispersal for a specific Carnivoran, the coyote, and estimate how differences between a coyote and songbirds affect where plants …

Quantifying The Indirect Effect Of Wolves On Aspen In Northern Yellowstone National Park: Evidence For A Trophic Cascade?, Elaine M. Brice

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Yellowstone National Park is renowned for its incredible wildlife, and perhaps the most famous of these species is the gray wolf, which was reintroduced to the Park in the mid-1990s. After reintroduction, it was highly publicized by scientists, journalists, and environmentalists that the wolf both decreased elk density and changed elk behavior in a way that reduced elk effects on plants, a process known as a “trophic cascade.” Aspen, which is eaten by elk in winter, is one species at the forefront of Yellowstone trophic cascade research because it has been in decline across the Park for over a century. …

The Effects Of Seed Mix Composition, Sowing Density, And Seedling Survival On Plant Community Reassembly In Great Salt Lake Wetlands, Rae Robinson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wetlands are known for their valuable benefits (e.g., providing habitat, improving water quality, lessening the negative impacts of drought and flooding). Invasive wetland plant species are species that cause harm to ecosystems, the economy, or human health, and replace native wetland plant communities. The revegetation of native plants may be one way to improve wetlands that have been impacted by invasive species. In Great Salt Lake (Utah, USA) wetlands, the invasive, non-native grass Phragmites australis (common reed) reduces the quality and quantity of habitat for both wildlife and humans (e.g., birdwatchers, waterfowl hunters). Even when P. australisis greatly reduced, native …