Life Sciences Commons^™

Revegetation Strategies For Native Wetland Plant Restoration In The Face Of Phragmites Australis Reinvasion And Hydrologic Extremes, Maddie Houde

All Graduate Theses and Dissertations, Fall 2023 to Present

Reestablishing native plant communities in degraded habitats through seeding or planting ("revegetation") is a necessary step to restore ecosystems and their functions (e.g., supporting biodiversity, nutrient cycling, etc.). Globally, wetlands have suffered high rates of degradation and also experience numerous invasions. Invasive species are those that cause environmental, economic, or societal harm. Phragmites australis is a widespread invasive species that outcompetes native plants and reduces habitat diversity. Reestablishing native plant communities can limit P. australis invasion, yet effective methods to do so remain somewhat untested in wetlands. Additionally, stressful environmental conditions can increase plant mortality in revegetation efforts. In semi-arid …

Spatiotemporal Dynamics Of Disease: Social And Environmental Drivers Of Movement, Connectivity, And Disease Transmission In Bighorn Sheep, Lauren E. Ricci

All Graduate Theses and Dissertations, Fall 2023 to Present

Movement is a fundamental component of animal ecology. Animals move in order to access resources and avoid risk. Movement decisions aggregated across time determine how individuals use space, contact dynamics between individuals within a population, and connectivity across a species range. These patterns that emerge from movement decisions have downstream implications for many ecological processes and a mechanistic understanding of movement can help answer broader questions about ecology.

Disease dynamics are intrinsically tied to movement. Understanding the mechanisms that drive movement can elucidate how disease will spread and impact host populations. In this vein, I employed a suite of movement …

Experimental Nonnative Wood Addition Enhances Instream Habitat For Native Fishes And Investigating Dryland River Alterations, Benjamin J. Miller

All Graduate Theses and Dissertations, Fall 2023 to Present

The rivers of the Colorado River Basin (CRB) have been degraded by human activities such flow regulation, water overallocation, and the introduction of invasive riparian vegetation (primarily tamarisk tamarix spp. and Russian olive Elaeagnus angustifolia). These stressors have resulted in widespread habitat loss and simplification, which is a major contributor to the endangerment of native fishes in the CRB.

The objectives of this study were to 1) assess the effectiveness of enhancing native fish habitat by experimentally adding cut wood from nonnative Russian olive to the San Juan River, a highly degraded dryland river, and 2) determine the …

Top-Down Vs Bottom-Up Effects On Predator-Prey Interactions In Aquatic Communities, Catherine Mary Mcclure

All Graduate Theses and Dissertations, Fall 2023 to Present

Ecology is studied at multiple scales to better understand how small changes at the individual level scale up to affect our ecosystems and global systems. These ecological scales include individuals (single organism), populations (group of organisms of the same species), communities (populations of different species interacting with each other), and ecosystems (species interacting with other species and their local environment). The research in this document is focused on the individual, population, and community scale. In particular, this research addresses questions regarding how changes in environmental conditions (i.e., predation and resources) affect species interactions which ultimately affects the composition of ecological …

Causes And Consequences Of Space-Use Behavior Under Predation Risk In A Free-Living System, Brian J. Smith

All Graduate Theses and Dissertations, Fall 2023 to Present

Predators can have important ecological effects through killing and eating their prey, the so-called consumptive effect, but predators can also have a nonconsumptive effect (NCE) on their prey – this happens when the risk of predation itself causes prey to alter their behaviors or other traits and these alterations ultimately reduce prey survival, reproduction, or population size. While scientists understand the consumptive effects of predators well, we are still unsure whether NCEs are important in free-living systems. In this dissertation, I sought to better understand the potential NCEs of predators (wolves and cougars) on elk in northern Yellowstone National Park …

Movement Behavior And Habitat Selection Of Juvenile Mountain Lions (Puma Concolor) During Three Behavioral States Of Dispersal, John F. Randolph

All Graduate Theses and Dissertations, Fall 2023 to Present

Juvenile dispersal, the act of moving from their natal range to the place where they eventually reproduce and establish an adult home range is hazardous. Juveniles must travel and find food across unfamiliar landscapes, where they must also cross roads, avoid harvest, and navigate developed landscapes. Despite the inherent dangers of dispersal, this demographic process is important for finding suitable mates and reducing inbreeding depression. Wildlife conservation concerns arise when individuals are unable to disperse due to a loss of connectivity, as this can negatively impact population demographics and genetic diversity. We explored the effects of hunting and human-developed landscapes …

The Effects Of Aboveground Herbivory On Root Traits And Root Decomposition, Emily A. Chavez

All Graduate Theses and Dissertations, Fall 2023 to Present

Soil holds more carbon (C) than the Earth's atmosphere and vegetation combined. Soil loses carbon through soil respiration and releases CO₂ from the soil. The soil respiration rate can vary based on the chemistry of the plant litter inputs and physical factors, such as soil temperature and nutrient content. In Alaska's Yukon-Kuskokwim (YK) Delta, grazing by geese affects the chemistry of plants and the soil's physical qualities, thus altering the rate of soil respiration. Although we know that goose herbivory leads to changes in the rate of soil respiration, we know very little about how goose herbivory affects the …

Evaluating Aspen Seedling Outplanting Success Following High Severity Wildfire In The Southwest, Sarah M. Kapel

All Graduate Theses and Dissertations, Fall 2023 to Present

Quaking aspen (Populus tremuloides Michx.) is an ecologically important forest species in the western U.S. Aspen forests host a variety of understory species, are critical wildlife habitat, and are considered a "natural fuel break" since they are less likely to support crown fires than conifers. Because of climate change and altered disturbance regimes, populations are declining, and innovative strategies are needed to restore aspen. Planting aspen seedlings is a solution, though not a common practice in the West and has been met with high mortality in past experiments. For aspen planting to be more broadly implemented, managers need guidance …

Dusky Grouse Population Ecology And Thermal Landscape Ecology In The Great Basin Ecosystem, Stephanie M. Landry

All Graduate Theses and Dissertations, Fall 2023 to Present

Dusky Grouse are a mountainous forest grouse found throughout the western, inland mountain ranges of the United States and Canada. While a few studies have looked at Dusky Grouse in the Rocky Mountain Ecosystem of their range, there have been no prior studies of the Dusky Grouse in the Great Basin Ecosystem aside from a brief survey by Zwickel and Bendell in 2004 in the Duck Creek Range of Nevada. With the available habitats differing in both species diversity and availability on the landscape between the two Ecosystems, I wanted to assess characteristics about the Dusky Grouse populations at the …

Balsam Woolly Adelgid And Host Forest Characteristics: Impacts And Interactions In Recently Invaded Areas Of Northern Utah And Southeastern Idaho, Grayson B. Jordan

All Graduate Theses and Dissertations, Fall 2023 to Present

The balsam woolly adelgid (BWA), is an invasive forest insect native to central and southern Europe. In 2017, it was detected in Utah for the first time. While BWA had limited impact as a pest in its native European range, it has caused considerable damage to true fir populations in North America. In the Intermountain region, subalpine fir has been identified as the tree species most at risk of BWA infestation. Subalpine fir provides a variety of ecosystem services and is a critical component of the spruce-fir alpine forests of the area. With an expected increase in the severity and …

Edaphic And Climatic Regulation Of Microbial Carbon-Use Efficiency In Managed Semi-Arid Systems, Kirsten R. Butcher

All Graduate Theses and Dissertations, Fall 2023 to Present

In agricultural systems, an increasingly prevalent goal is to promote carbon sequestration into stable, mineral-associated soil organic matter, as increases in soil organic matter have been linked to increases in soil water-holding capacity and increases in nutrient availability. Because microbially-produced compounds are the foundation of soil organic matter, understanding interactions between management strategies and abiotic controls on microbial activity can prove invaluable for producers and ranchers interested in building soil organic matter and safeguarding production systems under a changing climate. The ability of microorganisms to contribute to growing soil organic matter stocks is dictated by their carbon-use efficiency, which is …

Specialized Recreation, Spatial Behavior, And Ecological Implications In The Nature Reserve Of Orange County, Ca, Jake Van Deursen

All Graduate Theses and Dissertations, Fall 2023 to Present

A widespread surge in park and protected area (PPA) visitation strikes managers with the imminent challenge of preserving ecological conditions and maintaining accessibility in the open spaces that are a fundamental component to the health and wellness needs of society. In the field of recreation resource management, recreation specialization, the selective channeling of interests and abilities into a specific recreational activity, has contributed to comprehensive understandings of recreation behavior, site preference, management perceptions and conservation support. Contributing to historical understandings of specialization can inform recreation planning on the diversity of uses occurring in urban-proximate PPAs. Survey data providing information on …

Restoration Strategies For Wetlands In The Arid West: Seeding And Planting Approaches For Lakeshore Ecosystems, Jes Braun

All Graduate Theses and Dissertations, Fall 2023 to Present

Wetlands are widely recognized for their valuable benefits such as providing habitat, improving water quality, and reducing the impacts of flooding. However, wetlands face threats from development, drought, and invasive species. This is particularly apparent in the arid west, where upstream water use and drought make water scarcer and contribute to dramatically changing water levels. Here, I investigated revegetation techniques for lakeshore wetlands, using Utah Lake as a case study. Although recent management efforts have minimized invasive Phragmites cover, the desired plant communities are not returning as quickly as needed, highlighting the need to research restoration techniques. Through my research, …

Metapopulation Genomics Of American Goshawks In The Intermountain West, Megan M. Sidran

All Graduate Theses and Dissertations, Fall 2023 to Present

Understanding a species dispersal ecology and population dynamics is essential to effectively manage and conserve a species. As advancing technology improves our knowledge of species movements, it is becoming clear that many species form metapopulations to some extent. A metapopulation is a network of interconnected subpopulations that exchange reproductive individuals with subpopulations occupying nearby patches. Metapopulations have been observed in a variety of species, ranging from plants to vertebrates, and can vary greatly in their dynamics (level of connectivity and gene flow) based on the species behavior and life history strategy.

Forming a metapopulation can add much resilience to the …

Reducing Inputs And Adding Value To Turfgrass Systems Through Clover Inclusion And Plant Growth-Promoting Rhizobacteria Applications, Paige E. Boyle

All Graduate Theses and Dissertations, Fall 2023 to Present

Recently, the US has seen an expansion in the amount of turfgrass land cover (lawns, parks, roadsides, sports fields, and golf courses), as well as an interest in reducing fertilizer, water, and pesticide use in these grass systems. To help maintain quality and function while reducing resource inputs, two promising approaches have emerged: planting clover into lawns and applying plant growth-promoting rhizobacteria.

White clover and grass mixtures have been studied for their ability to cut down on fertilizer usage and provide a uniform, dark green lawn, but other clover types have not been as widely studied and may provide similar …

Developing Empirical Predictive Models To Support Conservation Planning For Threatened Frogs, Toads, And Turtles In South-Coastal California, Umarfarooq Adavudi Abdulwahab

All Graduate Theses and Dissertations, Fall 2023 to Present

Amphibians and reptiles (i.e., herptiles) are among the most threatened groups of species on Earth. The major threats to these species include the direct, indirect, and synergistic effects of habitat loss and fragmentation, invasive species, disease, overexploitation, and pollution. To protect and restore species, natural resource managers need effective, data-driven conservation plans that are grounded in sound knowledge of species distributions and habitat requirements. Species distribution models (SDMs) are popular tools used to assess species-habitat relationships. However, SDMs are sensitive to the choice and quality of input data, both of which can affect model accuracy and precision and lead to …

Ecology And Management Of Dyer's Woad (Isatis Tinctoria) In Northern Utah, Erin Marie Hettinger

All Graduate Theses and Dissertations, Fall 2023 to Present

Dyer’s woad (Isatis tinctoria L.) is a non-native forb that continues to threaten natural areas throughout Northern Utah and much of the Intermountain West. Once introduced, dyer’s woad can become extremely invasive, decreasing forage quality, and displacing native species. While dyer’s woad is found throughout much of Northern Utah, its range in other states remains limited. If promptly managed, control success in these areas will be much higher and populations may be kept at bay before ecological damage becomes severe.

This project tested the ability of dyer’s woad seedlings to compete with common rangeland grasslands at varied densities as …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 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 …

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 …