Life Sciences Commons^™

Assessing Stream Ecosystem Structure And Function In An Urban Canal And Logan River In Logan, Utah, Ellie Smith-Eskridge

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Humans have constructed canals to support agriculture, to mitigate flooding, and to discharge stormwater, especially in the Intermountain West. These canals are common in Cache Valley, where they receive flows from the Logan River during summer months. However, the ecological structure (e.g., water quality, freshwater invertebrates) and function (e.g., leaf decomposition) of these canals remains largely unknown. Studying ecosystem structure and function of these urban waterways is important because it can inform us of the health of these waterways.

My research had three objectives. First, I compared water chemistry, invertebrate assemblages, and leaf decomposition in an urban canal and the …

Establishment Of A Transgenic Human Angiotensin Converting Enzyme-2 Hamster Infection Model For The Evaluation Of Therapeutics Against Severe Acute Respiratory Syndrome Coronavirus 2, Scott A. Gibson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The virus SARS-CoV-2 emerged in late 2019 and has gone on to spread throughout the global population. The virus is still the cause of a healthcare crisis two years after being identified. Viral infection in humans leads to the development of the disease COVID-19. A complex disease that can result in a wide variety of outcomes for infected individuals. In the majority of individuals, COVID-19 will manifest as either an asymptomatic disease state or a mild to moderate disease state that is resolved in approximately one week. In some infected patients COVID-19 will manifest with the rapid onset of severe …

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 …

We Travel Together: Examining The Drivers And Functions Of Animal Movement In Biotic Seed Dispersal, Binod Borah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plants and frugivorous animals exist in mutually beneficial relations, as these animals feed on fruits, ingest the seeds, and carry them away from the parent trees. Such dispersion of seeds over space helps them colonize new habitats, escape high mortality rates near their parent trees, and avoid competition with conspecifics. Therefore, seed dispersing animal movement can be critical for the persistence of plant populations. Yet what drives such seed disperser movement is often less understood and how it affects seed dispersal is little explored. In my dissertation, I investigate multiple drivers of seed disperser movement, link movement to potential seed …

Effect Of Increasing Levels Of Gossypol And Fatty Acids Coming From Whole Cottonseed On Rumen Fermentation, Nutrient Digestibility And Microbial Community Composition In Continuous Culture Fermenters, Camila Castro Veloz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this study we determined the impact of increasing dietary whole cottonseed (WCS) on rumen fermentation, nutrient digestibility, and microbial community composition. This study contributes novel information to the dairy community deepening the understanding of how including different levels of WCS can affect the rumen environment. This research was conducted in continuous culture fermenters. Treatments included a control diet without WCS, or the control diet plus 5, 10, or 15% (dry matter) WCS. The control diet was a 50:50 orchardgrass hay:concentrate mixture fed twice daily. In the second experiment, soybean meal and cottonseed meal (CSM) were included, and rations were …

Evapotranspiration And Energy Balance Of Irrigated Urban Turfgrass, Matthew D. Miksch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water usage for irrigation is a big consumer of water resources in urban areas in Utah and other parts of the Intermountain Region of the Western United States. As populations continue to increase in these states, it is important to understand how much water is being used by urban landscapes in order to plan and manage future water resources. Evapotranspiration (ET), or the amount of water leaving a surface over a certain timeframe due to both transpiration from plants and evaporation from the soil, is a key variable in understanding how much water urban landscapes are really using to grow …

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 …

Student Perceptions Of Male And Female Instructors In A Post-Secondary Welding Course, S. Kjersti R. Decker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Agricultural mechanics and welding have traditionally been perceived to be careers reserved for males, yet more females have entered professions using welding such as agricultural education. This research was developed because of the lack of gender research in welding. The purpose of this study was to examine students’ perceptions of learning from a male instructor versus a female instructor in a post-secondary welding course. We examined associations and differences between students’ preference of a male and a female welding instructor as well as individual self-efficacy and perceptions towards using welding technology. The population for this study was undergraduate students and …

Practical Improvements For Pivot And Surface Irrigation, Jonathan A. Holt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Irrigation is critical to meeting global food and fiber demands. Optimizing agricultural irrigation may help sustain production levels, while reducing its demand for water. This research evaluated precision sprinklers and drip irrigation for pivots, five pivot track mitigation tools, three scientific irrigation scheduling (SIS) methods, sensors for surface irrigation cutoff, and automating surface systems to implement surge irrigation. With pivots and surface irrigation being the most common methods for irrigation in the West, small improvements from these tools could result in significant water savings.

Low energy precision application (LEPA) sprinklers and mobile drip irrigation (MDI) were tested on two pivots. …

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 …

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 …

Evaluating Quaking Aspen's Influence On Fire Behavior, Kristin A. Nesbit

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In western North America, quaking aspen (Populus tremuloides Michx.) forests have long been described as low flammability, “fireproof” forest types that are less likely to burn or burn less intensely than coniferous forests. While this assumption has been based on limited scientific research and is largely anecdotal, there is growing interest in the western U.S. to promote aspen near human developments to reduce fire risk. I investigated the available evidence for aspen forests reducing fire occurrence, behavior, and severity, and assessed possible factors that affect flammability in aspen forests to better understand when and where aspen burn, and when …

A Fine-Scale Understanding Of Sagebrush Islands To Improve Restoration Outcomes In The Intermountain West, Sofia Koutzoukis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the Intermountain West, rapid expansion of non-native grasses, primarily cheatgrass, has created a repeating cycle where cheatgrass easily ignites and after a fire, more cheatgrass establishes in the burned area, leading to more fire, and more cheatgrass. The primary method to prevent further fires is to plant grass and shrub seeds after a fire because they can deter cheatgrass from establishing and reduce the chance of fire. However, this approach does not always work. There is a need and interest in alternative ways to establish native grasses and forbs.

Sagebrush, the dominant shrub of lower-elevation regions of the Intermountain …

Status And Enhancement Of Trissolcus Japonicus (Ashmead) (Hymenoptera: Scelionidae) For Biological Control Of Halyomorpha Halys (Stål) (Hemiptera: Pentatomidae) In Northern Utah, Kate V. Richardson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The invasive brown marmorated stink bug (BMSB) is a major insect pest that invades human structures causing nuisance issues and attacks numerous fruit and vegetable crops in Northern America. As this pest threatens $23 billion worth of specialty and agricultural crops in the U.S. and is difficult to manage due to insecticide resistance, control practices such as the use of biological control through egg parasitoid wasps are critical. In its native range of Asia, BMSB populations are controlled primarily by members of the Trissolcus genus such as the samurai wasp, but U.S. native wasps have demonstrated low success of BMSB …

Consequences Of Host Life Cycles For Symbiont Genome Evolution, Ashley Elizabeth Dederich

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Aphids are small insects that feed exclusively on plant sap, a notoriously low source of nutrients due to the high sugar content and low amino acid content. To make up for these deficiencies in nutrition, aphids harbor Buchnera aphidicola, a bacterial endosymbiont that resides in a specialized organ called the bacteriome. B. aphidicola provides essential amino acids and vitamins for the aphid in exchange for a safe place to live. Over the course of the symbiosis (established 160 million years ago), B. aphidicola has lost much of its genome, including essential genes for cell envelope synthesis, DNA replication and …

Social Factors Driving Grouping Dynamics In Bighorn Sheep Ewe, Toni Proescholdt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding and predicting movement is critical for conservation planning and disease risk mitigation, and important environmental drivers of animal movement have received extensive attention in the ecological literature. Social factors surrounding group fission and fusion events also directly affect movement. However, these events are infrequently measured in the wild and rarely linked to underlying mechanisms such as relatedness, agreement in reproductive status, or shared life stage. While some social factors cannot be directly observed in the field, individual animals congregating in groups and moving about a landscape can. In animal societies, groups may merge together in a fusion event, and …

Use Of Protective Lactic Acid Bacteria Adjunct Cultures To Decrease The Incidence Of Gas Defects In Cheddar Cheese, Rhees T. Crompton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Gas production in cheese making is becoming increasingly prevalent in the dairy industry. This gas is produced by microbes that are naturally found in the cheese, and when they metabolize sugar or other sources of energy, they can produce gas. This gas causes slits and cracks in the cheese, which causes the cheese to be worth less and causes issues during slicing and shredding. There are many microbes that cause unwanted gas in cheese, this research focuses on four know gas producers and five other protective microbes that use the same energy sources or have the ability to inhibit the …

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 …

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 …

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 …

Population Ecology Of Spruce-Fir Forests Of The Interior West, Katheryn Little

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spruce-fir forest type covers nearly 10 million acres of forested land in the interior west, but there is a lack of research defining how these forests grow for future planning. Stand density index (SDI) represents the average tree size and number of trees in a stand multiplied. Each species has specific maximum number the growing space can handle known as ‘fully stocked’. If the stand is fully stocked, it must wait until trees die for individuals to grow. Spruce and fir have similar maximum stocking values, and similar growth characteristics, allowing them to be plotted together. Using current forest data, …

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 …

Bugs, Bullets And Birds: Factors Affecting The Health And Survival Of Ferruginous Hawk Nestlings In The Intermountain West, Ellis A. Juhlin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ferruginous Hawks are a bird of prey species that nest in sagebrush steppe and grassland habitat. These birds are threatened by habitat loss and fragmentation from urbanization, rural development, oil and natural gas extraction, habitat treatment projects, and wildfires, and experiencing widespread population declines across their breeding range. Because of this, Ferruginous Hawks (FEHAs) have been deemed a Species of Greatest Conservation Need by state management agencies in Utah, Idaho, Wyoming and Nevada. The health and survival of Ferruginous Hawk (FEHA) nestlings is crucial to long-term population viability. Understanding the threats these birds are facing as nestlings can provide valuable …

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 …

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 …

Functional Characterization Of The Newly Discovered Type V Crispr-Cas Protein Cas12a2, Dylan J. Keiser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Similarly to people, bacteria are under the treat of infection by viruses. To circumvent these threats, bacteria evolve complex immune systems. Our understanding of some of these immune systems has led to many advancements in the field of Biotechnology including tools that made expressing proteins for study in a lab easier, tools that revolutionized the feasibility of gene editing, and tools that could change the way we think about viral diagnostics and cancer therapeutics. A certain type of immune system that bacteria use to fight virus is called a CRISPR system. Presented here is work to understand the function of …

Insecticide Susceptibility And Resistance Detection In Phlebotomus Argentipes Sandflies (Diptera: Psychodidae: Phlebotominae), Shawna M. Hennings

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Leishmaniasis is an understudied disease found predominantly in high heat and humidity areas. The disease is transmitted by sandflies which are blood-feeding, biting insects. There is currently no known vaccine for any form of leishmaniasis and treatment imposes a significant economic impact on already poor and marginalized populations, as well as severe, lingering side effects for afflicted individuals. Annually, there are millions of people around the world afflicted with a form of Leishmaniasis that is transmitted by species of sandflies. The primary sandfly population control method for over half a century has been indoor residual spraying using insecticides. The selective …

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 …