Life Sciences Commons^™

Understanding Agricultural Irrigation Practices Along Utah's Wasatch Front Through Farmer-Reported Data, Garland Ledbetter

All Graduate Theses and Dissertations, Fall 2023 to Present

Water is a growing concern in Utah, especially along the Wasatch Front, where cities, farms, and communities all rely on the same limited water supply. Agriculture uses a large portion of the state’s water, so understanding how farms manage irrigation is important for statewide water planning. Utah currently uses a dataset called Water-Related Land Use (WRLU) to estimate agricultural water use across the state. This dataset provides useful information about irrigated land and crop types. However, it does not capture many of the day-to-day decisions farmers make when managing irrigation.

To better understand irrigation practices, this study surveyed 61 farmers …

Understanding And Predicting Precipitation Characteristics In The United States Through Machine Learning, Numerical Modeling And Measurements, Cody Luther Ratterman

All Graduate Theses and Dissertations, Fall 2023 to Present

Precipitation is one of the most important yet uncertain variables in the climate system. It varies dramatically in terms of timing, accumulation, rate, and phase, depending on location, season, circulation patterns, and atmospheric conditions. Precipitation forecasts, especially snowfall, are essential to supporting drought mitigation and water management in the Intermountain West. Because rainfall and snowfall lead to opposite effects on snowpack, accurately partitioning rain and snow is important to estimate snowpack levels, winter recreation, mountain ecosystems and runoff. The research findings in this dissertation have advanced the understanding and prediction of precipitation and snowpack in the U.S. by addressing the …

Integrative Taxonomic Analysis Of Cryptic Species Diversity In The Spiny Witch-Hazel Gall Aphid, Hamamelistes Spinosus (Hemiptera: Aphididae: Hormaphidini) In Eastern North America, Gavin Andrew Powell Munson

All Graduate Theses and Dissertations, Fall 2023 to Present

Taxonomy is the practice of identifying, classifying and categorizing species, providing structure for the vast diversity of life. Aphids are an ecologically important group of soft-bodied insects, but they can be difficult to identify because of their tiny anatomical size, reduced or simplified morphological features, and morphological variation within a single species across different generations. In this study, the taxonomy of the spiny witch-hazel gall aphid, Hamamelistes spinosus, is revised. The complex multi-generational life cycle of the aphids, which alternates between witch-hazel and birch trees, has led to confusion regarding past descriptions. Scientists in the late 1800s who were …

Fibrous Protein Biomaterials: Characterization Of Solitary Bee Silk And Cocoons, And Development Of Recombinant Hagfish And Bee Silk Materials, Oran Wasserman

All Graduate Theses and Dissertations, Fall 2023 to Present

This dissertation explores two complementary aspects of fibrous protein biomaterials: the characterization of understudied naturally occurring solitary bee silk and cocoons; and recombinant expression and biomaterial formation of recombinant hagfish intermediate filaments (rHIF) and a single Osmia lignaria Say (Hymenoptera: Megachilidae) silk protein. Some solitary bee species, which make up about 75% of all bee species, spin silk to construct protective cocoons during development. Despite the importance of silk and cocoons to the solitary bees' life history, their properties remain largely unexplored. This dissertation presents a novel method for isolating and testing individual silk fibers without interfering with the development …

Bridging Animal Production And Human Nutrition: How Production Ecology Shapes The Nutritional Quality Of Terrestrial Animal Foods And Human Omega-3 Status, Joseph Vinod Varre

All Graduate Theses and Dissertations, Fall 2023 to Present

The question at the center of this dissertation is simple: does the way food is produced change the quality of the food itself in ways that matter for human health? Across a series of studies on bison meat, eggs, and human dietary intervention, the answer was yes. This work began with a broad look at the modern food system and the nutritional consequences of industrialized diets. In particular, it focused on the growing imbalance between omega-6 and omega-3 fatty acids in the Western diet. This balance matters because omega-3 fats support heart, brain, and immune health, and diets high in …

Integrating Space Use And Demography To Support Management Of An Endangered Alpine Ungulate, Danielle J. Berger

All Graduate Theses and Dissertations, Fall 2023 to Present

The places animals choose to live affect the food they find, the dangers they face, and the weather conditions they experience. These experiences influence whether individual animals survive and reproduce, which in turn affects the size and health of animal populations. Although scientists have long believed that animal movements play an important role in population trends, there has been limited real-world evidence showing this connection. Advances in GPS tracking technology now allow researchers to follow animals over long periods and better understand how movement influences survival. Using 20 years of GPS tracking data from the endangered Sierra Nevada bighorn sheep …

Carbon Cycling, Salinization, And Long-Term Water Quality Trends In Rocky Mountain Streams, Allyson J. Marrs

All Graduate Theses and Dissertations, Fall 2023 to Present

Humans have greatly affected streams and rivers worldwide through urbanization, agriculture, and water use. The purpose of my dissertation is to increase our understanding of various human impacts on rivers. In chapter two, I aim to determine whether there are differences in greenhouse gas (GHG) emissions between a natural river and manmade canals. I did this by measuring the emissions and dissolved concentrations of three of the most prevalent GHGs, carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). I found that most of the sites I studied were emitting CO₂ and CH …

Regional Occurrence And Spatiotemporal Habitat Partitioning Of The Culex Genus Mosquitoes In Salt Lake City And Uintah Basin, Utah, Katelyn Graybeal

All Graduate Theses and Dissertations, Fall 2023 to Present

West Nile virus is the most common mosquito-borne disease in North America and can cause serious illness, including inflammation of the brain and nervous system. Because there is currently no widely available vaccine for humans, preventing mosquito bites and monitoring mosquito populations remain the most effective ways to reduce disease risk. Understanding which mosquito species are present, where they occur, and how they respond to environmental change is critical for protecting public health.

This research examined the mosquito species responsible for spreading West Nile virus in Utah through two complementary studies. The first study focused on the Uinta Basin in …

Investigating Recruitment Bottlenecks Of Juvenile Native Fish In The Colorado River Basin, Utah, Anna R. Amidon

All Graduate Theses and Dissertations, Fall 2023 to Present

The first year of life is a vulnerable period for most fish species. Whether young fish survive this early stage determines how many individuals eventually survive and grow into reproductive adults, a process called recruitment. In desert rivers like the Colorado River Basin, native fish evolved alongside extreme natural conditions but now face additional pressure from drought and water storage infrastructure, which alter the shoreline habitats on which young fish depend. Long-lived, migratory native species with complex life cycles are especially vulnerable. We used four decades of monitoring data from the Upper Colorado River Basin to evaluate whether young-of-year (YOY, …

The Influence Of Habitat And Individual Specialization On Mountain Lion (Puma Concolor) Hunting Strategy In A Multi-Prey System, Hannah B. Klugman

All Graduate Theses and Dissertations, Fall 2023 to Present

There is a growing recognition that animal species considered generalists (having a broad and varied diet), are actually specialists, a collection of individuals with different preferences and strategies known as specializations. The diet of a specialist depends on the variety and quantity of available food options, and their own ability to take what they need. Mountain lions (Puma concolor) are known for their ability and tendency to hunt large prey, such as elk (Cervus canadensis) and mule deer (Odocoileus hemionus), but despite the fact they overlap with other potential large prey, like feral horses …

Drought And Diet Breadth: Does Insect Specialization Influence Herbivory When Plants Are Under Stress?, Jakob Palmer

All Graduate Theses and Dissertations, Fall 2023 to Present

Climate change will alter precipitation worldwide, causing more frequent and severe drought events worldwide. Drought affects many ecological processes, including plant-herbivore interactions, which are critical to biodiversity and ecosystem health. A variety of plant characteristics can influence herbivory – such as how hairy, nutritious, or toxic a leaf is – and drought has been shown to alter many of these traits. Unique characteristics of herbivore species are also important: herbivores can either feed on a variety of plants (generalists) or a group of closely related plants (specialists). Specialists can cope with traits of the plants they eat, while generalists are …

Behavioral And Landscape Factors Affecting The Effectiveness Of Egg-Bait Management For Common Ravens In The Great Basin, Usa, Sierra L. Pederson

All Graduate Theses and Dissertations, Fall 2023 to Present

Common Ravens have become increasingly common across the Great Basin of the western USA, largely because human activities, such as roads, agriculture, livestock operations, and human-made structures, provide them with abundant food, water, and nesting sites. As raven numbers have grown, so has their impact on vulnerable species like the greater sage-grouse. Like many other ground-nesting species, greater sage-grouse eggs and chicks are especially susceptible to predation. To help reduce raven numbers in sensitive areas, wildlife managers often place hard-boiled chicken eggs treated with a toxin (DRC-1339) on the landscape, expecting that ravens will die after eating these eggs and …

Quaking Aspen On Cedar Mountain, Utah: Status And Update, Jaycee Cappaert, Larissa L. Yocom, Paul C. Rogers, Darren J. Mcavoy, R. Justin Derose

Wildland Resources Student Research

Quaking aspen forests are important communities in the western United States where they provide preferential food and habitat for animals, limit wildfires from spreading, and have favorable aesthetics, among other things. Their putative decline is an issue for ecology and management. We remeasured the aspen population on Cedar Mountain, Utah, to assess changes to its condition since it was originally measured in 2008 and laid the groundwork for continued aspen monitoring on Cedar Mountain. Our objectives were to compare current metrics of stand structure and composition, mortality, crown dieback, bole damage, regeneration, and recruitment, to those of the original inventory. …

Divergent Belowground Strategies Of Savanna Grasses Under Varying Fire Regimes, Abigail C. Schmidt

All Graduate Theses and Dissertations, Fall 2023 to Present

Savannas are unique ecosystems, where trees and grasses live together across the landscape, not quite forming full forests or open grasslands. The ability for trees and grass to coexist is largely the result of widespread disturbances, such as fire. Fire in savannas is largely thought of in how it maintains plants above ground, however, fire also plays a key role in ecosystem and plant processes belowground. First, fire can change how soil nutrients, namely phosphorus, are cycled. Phosphorus is a key nutrient that plants need to function, and plants acquire phosphorus through their roots. Frequent fire can enhance phosphorus availability, …

Microbes In Pollination Systems: Effects On Pollinator Health, Floral Traits, Nectar Robbing, And Plant Fitness, Valerie Nicole Martin

All Graduate Theses and Dissertations, Fall 2023 to Present

Flowers produce nectar to attract pollinators, but nectar is also a habitat for yeasts and bacteria that arrive via pollinators, robbers, and other visitors. These microbes consume nectar sugars and release byproducts that change the smell and taste of nectar. Whether these changes affect how pollinators find and choose flowers, and whether they ultimately affect how many seeds a plant produces, is not well understood. In this dissertation, I studied how a common nectar yeast and a plant-associated bacterium affect the scent of wildflowers, the behavior of bumble bees and hummingbirds, and plant reproduction in montane meadows in central Colorado. …

The Role Of Individual Specialization In Migration Phenology And How Restored Habits Are Used By Native And Nonnative Fishes, Austin Garner

All Graduate Theses and Dissertations, Fall 2023 to Present

Native fish species around the world have declined due to habitat loss, habitat fragmentation, and the spread of non-native species. Because these problems often happen at the same time and interact, recovery efforts can stall unless they address all of the factors limiting a species' comeback. The June sucker (Chasmistes liorus), native only to Utah Lake, UT, has declined for many of these reasons, though its recovery effort has made significant progress due in large part to a successful hatchery program. Yet, the recovery efforts have not yet been able to establish a self-sustaining population in Utah Lake, …

'Fast' And 'Slow' Water Handling Strategies Explain Pinyon Pine Decline And Juniper Expansion, M. Faraz Rehman

All Graduate Theses and Dissertations, Fall 2023 to Present

Across the western United States, pinyon and juniper woodlands are changing with pinyon pine trees dying back while juniper becoming more abundant. Previous studies suggested that pinyon may lose more water during drier periods. But water loss is only part of the story. Water inputs, or how plants absorb water, are also likely to be important, but rarely well understood. To better understand this, we measured how pinyon and juniper absorb water from different soil depths and how actively they lose water through their leaves. Measurements were made over two years at three sites that ranged from more dry to …

The Evolution Of Hymenopteran Recombination Rates, Timothy John Delory

All Graduate Theses and Dissertations, Fall 2023 to Present

Individuals of some species mix their DNA frequently when producing sex cells, while others do so much less. Hymenopterans (ants bees and wasps) are especially useful for understanding this variation for several reasons. They show large differences in this frequency of shuffling, or rate of recombination, have well-studied genomes, and vary widely in how they live and reproduce. I capitalized on these features examines how recombination rates have evolved in this group at the trait, and gene level.

First, I revisited long-standing ideas about why recombination rates differ among these species, incorporating more than a decade of new research. This …

Stability Of The Apogee Galvanic Cell Sensors In The Utah State University Biological Oxygen Demand System, Tia Lawrence, Carson Richards, Bruce Bugbee

Techniques and Instruments

The Utah State University Crop Physiology Laboratory has developed a six-chamber biological oxygen demand (BOD) system to quantify respiration (Kusuma & Bugbee, 2020). Like all instruments, accuracy depends on the ability to get a zero in empty containers. Here we report the signal output and zero stability in empty containers over a five-day interval.

Vines In The Landscape: Japanese Wisteria, Saroj Burlakoti, Youping Sun, Shital Poudyal

All Current Publications

Japanese wisteria (Wisteria floribunda) is a vigorous, woody, deciduous climbing vine known for its spectacular, drooping (pendulous) clusters of pea-like flowers. This fact sheet provides information on planting and management guidelines, as well as its landscape performance in Utah.

Lameness In Dairy Cattle: A Practical Overview, Drew Swartz, Kalen Taylor, Jacob Hadfield, Justin Wyatt Clawson

All Current Publications

This fact sheet provides an overview of lameness in dairy cattle, including what it is, why it matters, and how to recognize and manage it. Information is geared toward producers, consultants, and educators.

Summer Research Internships In Agricultural Biotechnology For Off-Campus Undergraduate Students, Aaron J. Thomas

Funded Research Records

No abstract provided.

Three Common Hoof Problems In Dairy Cows: What To Look For And How To Prevent Them, Drew Swartz, Kalen Taylor, Jacob Hadfield, Justin Wyatt Clawson

All Current Publications

This fact sheet covers the three most common hoof lesions in dairy cows and explains why they matter and how to prevent them on your farm.

Digital Dermatitis, Sole Ulcers, And White Line Disease In Dairy Cattle: Pathogens, Diagnosis, And Treatment, Drew Swartz, Kalen Taylor, Jacob Hadfield, Justin Wyatt Clawson

All Current Publications

This fact sheet focuses on three common hoof lesions in dairy cattle: digital dermatitis, sole ulcers, and white line disease, and describes how differences in pathogenesis and risk factors influence diagnosis, prevention, and treatment.

Mechanistic Determination Of Host Environmental Impacts On Shigella Virulence, Nicholas E. Dickenson

Funded Research Records

No abstract provided.

Harmful Algal Blooms: Risks For Food In Utah, Jose Brandao, Sarah Erwin, Stephanie Vaughn, Clare Entwistle

All Current Publications

Harmful algal blooms (HABs) are a problem because they can produce toxins that make water unsafe for people, animals, and the environment. In recent years, HABs have emerged as a growing concern in freshwater systems throughout Utah, including irrigation canals, reservoirs, and livestock ponds. HABs in freshwater are caused by cyanobacteria, also called blue-green algae. These microorganisms can release dangerous toxins that can harm swimmers, pets, and the food supply. Unlike foodborne pathogens, these toxins cannot be removed by boiling, cooking, or washing the food. Therefore, regular monitoring is essential to detect HABs early and reduce exposure risks. This fact …

Tips For Growing Garden Vegetables In Utah: Soil Preparation, Gastone Makalaya, Josh Martin, Milena Oliveira

All Current Publications

To help Utah gardeners maintain healthy soils and enhance early vegetable production, this fact sheet provides practical guidance and tips on soil preparation for vegetable gardening.

Integrating Nutrition And Stress Into Life History Stages Of Wild Free-Ranging Female Pronghorn, Cole A. Bleke, Eric M. Gese, Juan J. Villalba, Shane B. Roberts, Susannah S. French

Wildland Resources Student Research

Studies addressing seasonal changes in diet quality and hormones are important for understanding the interactions between ecology and physiology. We collected fecal samples from free-ranging adult female pronghorn (Antilocapra americana) to examine the relationships between indicators of nutrition and glucocorticoid activity. This occurred during three population-level, life-history-correlated sampling periods across five subpopulations. We evaluated nutrition via fecal nitrogen, fecal 2,6-diaminopimelic acid (DAPA), and assessed glucocorticoid activity using fecal glucocorticoid metabolites (FGM). We found positive relationships between fecal nitrogen and DAPA, whereas DAPA and fecal nitrogen with FGM varied in influence and strength, depending upon life history stage. Generally, …

Tips For Growing Garden Vegetables In Utah: Soil Fertilization, Gastone Makalaya, Josh Martin, Milena Oliveira

All Current Publications

A successful vegetable garden requires precise nutrient management to achieve maximum yields. Fertilization must provide adequate nutrients to support plant growth throughout the season. Fertilizer applications should be based on soil test recommendations and crop nutrient requirements. This fact sheet provides Utah gardeners with practical guidance and tips on soil fertilization for vegetable gardening.

Topographic Control Of Forest Species Distributions In The Interior West From Forest Inventory And Analysis Data, R. Justin Derose, Matthew F. Bekker

Wildland Resources Faculty Publications

The geographic distribution of forest and woodland ecosystems in the Interior West United States is strongly influenced by topographic factors that, in part, control moisture availability through their effect on insolation, precipitation capture, and retention. Through an empirical approach, we use unique, plot-level data from the Forest Inventory and Analysis Program (n = 13,437) over eight ecoregions within eight Interior West states to characterize the distribution of the 12 most abundant tree species with respect to the effects of elevation, slope aspect, and slope steepness. Across species, elevation, and aspect, most forested plots occurred on gentle slopes and the …