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Full-Text Articles in Life Sciences

Intraspecific Variation In Prey Susceptibility Mediates The Consumptive Effect Of Predation: A Case Study Of Yellowstone Elk And Wolves, Lacy M. Smith Dec 2021

Intraspecific Variation In Prey Susceptibility Mediates The Consumptive Effect Of Predation: A Case Study Of Yellowstone Elk And Wolves, Lacy M. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The reintroduction of wolves (Canis lupus) to Yellowstone National Park starting in 1995 is an important case study for understanding the consequences of predation on a prey population. Simulation studies conducted prior to and shortly after wolf reintroduction predicted that wolf predation of elk (Cervus canadensis) would have a modest influence on elk abundance. Predation of elk by wolves has been well documented and elk have remained the primary prey for wolves despite a decline in elk abundance. I used two quantitative approaches to estimate the influence of wolf predation on adult female elk survival and …


A Comparison Of The Ecology Of Resident And Translocated Beavers Used For Passive Restoration In Degraded Desert Rivers, Emma Doden Dec 2021

A Comparison Of The Ecology Of Resident And Translocated Beavers Used For Passive Restoration In Degraded Desert Rivers, Emma Doden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ecosystem engineers are species that create, destroy, modify, or maintain habitat. As ecosystem engineers, beavers have the potential to assist in stream restoration. Translocation is the capture and relocation of an animal to another area. Translocation of nuisance beavers has become a popular method to reduce human-wildlife conflict and restore waterways. However, few projects monitor beavers after release and compare behavior to naturally occurring resident beavers. Translocations to desert rivers are also rare. We captured, tagged, and monitored 47 beavers which we translocated to desert river restoration sites on the Price and San Rafael Rivers, Utah, USA. We compared translocated …


Host Plant Use, Phenology, And Biological Control Of The Brown Marmorated Stink Bug (Hemiptera: Pentatomidae; Halymorpha Halys) In Northern Utah, Mark Cody Holthouse Dec 2021

Host Plant Use, Phenology, And Biological Control Of The Brown Marmorated Stink Bug (Hemiptera: Pentatomidae; Halymorpha Halys) In Northern Utah, Mark Cody Holthouse

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The invasive brown marmorated stink bug, Halyomorpha halys (Stål), has become a significant agricultural and urban nuisance pest in North America, causing millions of dollars of damage to specialty fruit and vegetable crops over the past two decades. This pest uses over 170 host plant species in North America and is difficult to control with most conventional insecticides. Following the establishment of H. halys in Utah in 2012, this dissertation explores the plant host species, seasonal development, and biological control agents found in the unique climate conditions of the Intermountain West. Chapter II documents important plant species utilized by each …


Methods To Improve Our Understanding Of Aspen Regeneration And Aspen Distribution Across The Intermountain West, Robert Joseph Julius Bidner Dec 2021

Methods To Improve Our Understanding Of Aspen Regeneration And Aspen Distribution Across The Intermountain West, Robert Joseph Julius Bidner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Quaking aspen (Populus tremuloides) is the dominant broadleaf tree and an ecologically important species at upper elevations in the Intermountain West. Recent large-scale forest mortality events have raised questions about how physiological and climatic factors influence aspen’s distribution across the western U.S. Aspen is particularly well-known for reproducing asexually from its root sprouts, leading to the formation of large clonal stands. In addition, as a wind-dispersed species, aspen sexual reproduction plays an important role in how it is distributed at a landscape scale. My research focuses on questions relating to both sexual and asexual reproduction of aspen.

My …


Climate-Driven Impacts Of Warming And Grazing On Sub-Arctic Coastal Wetlands In Alaska, Ryan T. Choi Aug 2021

Climate-Driven Impacts Of Warming And Grazing On Sub-Arctic Coastal Wetlands In Alaska, Ryan T. Choi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change is rapidly warming the Arctic, especially at lower latitudes. Warmer temperatures and earlier springs are altering the timing of plants and animals, especially for long-distance migratory herbivores. Changes in the timing of both plants and herbivores have the potential to impact plant productivity and nutrient cycling, while also altering plant community diversity and composition.

In chapter 2, I conducted a field experiment to investigate how earlier growing seasons and differences in arrival times of migratory geese influence physical traits of sedge forage species. I found that both an earlier growing season and late grazing by geese had similar …


Transplanting Mature Mountain Big Sagebrush Plants Yields High First-Year Survival In Dryland Pasture Restoration, Elizabeth C. Bailey Aug 2021

Transplanting Mature Mountain Big Sagebrush Plants Yields High First-Year Survival In Dryland Pasture Restoration, Elizabeth C. Bailey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Approximately 10-20% of global dryland ecosystems are severely degraded, an amount that is expected to increase, threatening the environment and ecosystem services that 38% of the global population relies upon. Human activities such as agriculture, livestock grazing, mining and urban development have contributed to the degradation and loss of rangelands worldwide. A need for reestablishing sagebrush in disturbed landscapes across the Western United States, including dryland pastures, has been identified but traditional, primarily seeding-based, restoration methods have largely been unsuccessful. To improve restoration outcomes, there has been increased interest in the planting of containerized greenhouse “tubelings”, but transplanting of mature …


Big Fires, Big Trees, And Big Plots: Enhancing Our Ecological Understanding Of Fire With Unprecedented Field Data, Tucker J. Furniss Aug 2021

Big Fires, Big Trees, And Big Plots: Enhancing Our Ecological Understanding Of Fire With Unprecedented Field Data, Tucker J. Furniss

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildfire is an inexorable process in western landscapes, posing a major challenge to land managers: how can we use fire to restore healthy forests without jeopardizing human communities? The purpose of this dissertation is to produce research that will help guide management and support effective wildland fire use in fire-prone forests.

I utilized a longitudinal dataset from a single, large forest plot that burned under serendipitous circumstances during the 2013 Rim Fire. My research revealed that post-fire mortality models under-predict mortality of large trees, and may need to be re-calibrated to perform well under future climates. I used satellite-derived data …


Susceptibility Of High-Elevation Forests To Mountain Pine Beetle (Dendroctonus Ponderosae Hopkins) Under Climate Change, David N. Soderberg Aug 2021

Susceptibility Of High-Elevation Forests To Mountain Pine Beetle (Dendroctonus Ponderosae Hopkins) Under Climate Change, David N. Soderberg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Across western North America, pine forests are important for timber, wildlife habitat, and at high elevations are important for water retention and yield from rain and snowmelt. The mountain pine beetle (MPB) is one of the most significant disturbance agents shaping pine forests, and like all insects, temperature is a major driver of its population success and the dynamics of the landscapes that they inhabit. Changing temperature regimes can therefore directly influence MPB population persistence at a particular location, in addition to potential shifts in the range boundaries that they inhabit. MPB is currently expanding its range northward in British …


Insights On Reticulate Evolution In Ferns, With Special Emphasis On The Genus Ceratopteris, Sylvia P. Kinosian Aug 2021

Insights On Reticulate Evolution In Ferns, With Special Emphasis On The Genus Ceratopteris, Sylvia P. Kinosian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The history of life is often viewed as a evenly branching tree; however, in reality it is more like a tangled hedgerow. Many groups of organisms are known to have such a net-like or reticulate evolutionary history, but it is particularly common in ferns and lycophytes (also known as pteridophytes). This dissertation investigates how net-like evolution affects different groups of ferns, with a special emphasis on the model species C-fern (Ceratopteris richardii, also called the antler or water sprite fern). Genomic data are utilized to under-stand hybridization, cryptic species and reticulate evolution in two groups of ferns. The …


Dietary Shifts Related To Water Availability And The Demographic Response To Changing Prey Abundance Of Carnivores In The West Desert, Utah, Ashley E. Hodge Aug 2021

Dietary Shifts Related To Water Availability And The Demographic Response To Changing Prey Abundance Of Carnivores In The West Desert, Utah, Ashley E. Hodge

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The decrease in number and range of North American large carnivores, has often all owed smaller carnivores ( < 15 kg) to fill the role of the top predator. This has favored some carnivores such as coyotes (Canis latrans), who have expanded their distribution. Other small carnivores such as kit foxes (Vulpes macrotis) have experienced a range shrinkage and their population status throughout the United States is a concern. Historically, western U.S. natural resource management agencies installed artificial water sources to assist desert wildlife, but some researchers believe the access to water allowed more coyotes to live in Utah’s West Desert. In the late-1980s, research proposed that without free drinking water, coyotes would have to triple …


Predator Defense And Host Selection Behavior Of Billbugs (Coleoptera: Dryophthoridae), Desireè M. Wickwar Aug 2021

Predator Defense And Host Selection Behavior Of Billbugs (Coleoptera: Dryophthoridae), Desireè M. Wickwar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Billbugs are a complex of weevils that feed on the roots of turfgrass, causing severe damage to the plants. These pests are traditionally managed with applications of insecticides. However, there is a need for non-chemical management tools. Here I investigate billbug behavior in relation to two potential avenues for more sustainable management: using resident predators to suppress billbugs (Chapter II) and selecting specific turfgrasses that resist billbug damage (Chapter III). In Chapter II, I investigate the effects of predator presence and cues associated with their presence on billbug behavior. Though resident predators contribute very little to billbug suppression through directly …


The Fate And Cycling Of Nitrogen, Phosphorous, And Trace Heavy Metals In Beaver-Altered Headwater Streams, Desneiges S. Murray May 2021

The Fate And Cycling Of Nitrogen, Phosphorous, And Trace Heavy Metals In Beaver-Altered Headwater Streams, Desneiges S. Murray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Human land-use can increase the amount of non-point source (NPS) pollution in a stream, negatively affecting ecosystem health and beneficial services provided by an ecosystem. Unfortunately, NPS pollution remains high in many waterbodies. Beaver dams may be a passive, cost-effective strategy for removing NPS pollution in headwater streams because beaver dams slow stream flow and collect sediments. Impounded sediments can change how nutrients and pollutants are cycled in a stream through multiple pathways. In the first part of our study, we investigated whether beaver activity can reduce nitrogen, phosphorous and heavy metals from otherwise traveling downstream. Results suggest beaver ponds …


Monitoring Populations And Movement Of Bobcats (Lynx Rufus) On The Eastern Slope Of The Sierra Nevada Mountains Of California, Michael Brown May 2021

Monitoring Populations And Movement Of Bobcats (Lynx Rufus) On The Eastern Slope Of The Sierra Nevada Mountains Of California, Michael Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Monitoring the spatial ecology and population densities of carnivores is critical for effective management and conservation of these populations and the ecosystems in which they exist. However, effective monitoring of carnivore populations through estimates of space use, habitat selection and densities can be difficult due to their relatively low densities and wide ranging, elusive behaviors. Bobcats (Lynx rufus) are medium sized, top-level predators which are widely distributed across North America. Quantifying space use, habitat selection and developing effective population monitoring strategies for this species will have important implications for wildlife management.

My first objective was to use telemetry …


Short- And Long-Term Mechanisms For Increasing Inputs Of Phosphorus In Mountain Waterbodies Of Northeastern Utah, Usa, Jessica Scholz May 2021

Short- And Long-Term Mechanisms For Increasing Inputs Of Phosphorus In Mountain Waterbodies Of Northeastern Utah, Usa, Jessica Scholz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Phosphorus is an essential nutrient that allows life in water to flourish, but changes in phosphorus supplies are not well understood in remote watersheds. In mountain environments, remote watersheds contain critical high-quality water supplies and unique ecosystems, but excess phosphorus can diminish water quality by producing unfavorable aquatic species. Therefore, observed trends of increasing phosphorus concentrations in remote lakes and rivers in the US over the last two decades are a significant concern. Using the Uinta Mountains as a case study, we evaluated three different direct and indirect pathways for phosphorus increases in remote mountain watersheds that may explain observed …


Responses Of Pacific Fishers To Habitat Changes As A Result Of Forestry Practices In Southwestern Oregon, Tessa R. Smith May 2021

Responses Of Pacific Fishers To Habitat Changes As A Result Of Forestry Practices In Southwestern Oregon, Tessa R. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The fisher (Pekania pennanti) is a medium-sized carnivore found in mature forest stands across much of the northern United States. Although historically abundant in the west, fisher populations declined rapidly after fur trapping, extensive logging, and urban development reduced their numbers. Currently, biologists are concerned about the effects timber harvest practices have on fisher tolerance and adaptability when faced with changes to high-quality habitat stands. Tree removal and thinning of understory vegetation are frequently used to alleviate the spread of wildfires in previously dense forest stands with a potential for large-scale habitat loss; yet, a deficit of large …


Visitor Perceptions And Resource Conditions Of Campsites In Two Coastal Alaskan National Parks, Shannon T. Wesstrom May 2021

Visitor Perceptions And Resource Conditions Of Campsites In Two Coastal Alaskan National Parks, Shannon T. Wesstrom

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Increasing visitation in parks and protected areas presents managers with the challenge of providing quality visitor experiences while mitigating ecological impacts from recreation. Successful management strategies often suggest determining desired conditions for visitor experiences and ecological conditions to establish thresholds. These thresholds can then be compared to existing conditions in order to determine if changes in management strategies should be made. By integrating visitor survey results with ecological assessments, this research is a unique coastal Alaskan regional analysis of the three components of a management framework: 1. Establishes visitor determined thresholds of acceptability for crowding and coastal resource conditions in …


Mechanisms Of Overyielding And Coexistence In Diverse Tallgrass Prairie Communities, Leslie E. Forero May 2021

Mechanisms Of Overyielding And Coexistence In Diverse Tallgrass Prairie Communities, Leslie E. Forero

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plants compete for the same basic nutrient and water resources. According to the competitive exclusion principle, when a substantial overlap in resource pools exists, the best competitor for resources should drive all other species to extinction. The ability for plants to coexist in violation of the competitive exclusion principle is the “biodiversity paradox”. Coexistence is actually beneficial for plants: as species diversity increases, you typically see increases in plant biomass production (known as the biodiversity-productivity relationship). The mechanisms behind coexistence and the biodiversity-productivity relationship remain an ecological mystery. One hypothesis is that plants obtain water and nutrients from different places …


Range-Wide Migratory Connectivity Of Painted Buntings, Andrew J. Sharp May 2021

Range-Wide Migratory Connectivity Of Painted Buntings, Andrew J. Sharp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Painted Bunting (Passerina cirus) is a small (~16g), short/medium-distance migratory songbird that is listed as a species of conservation concern by the US Fish and Wildlife Service. Painted Buntings breed in two distinct populations, one eastern population and one interior population, separated by a 500 km gap that stretches from Mississippi to Georgia. I analyzed tracking data from 112 Painted Buntings from 11 different breeding sites to explore how individuals from different breeding sites differ in wintering location (chapter 2) and migratory timing (chapter 3). Additionally, I examined differences in migratory behavior between male and females in …


Patterns Of Post-Fire Aspen Seedling Establishment, Growth, And Mortality In The Western United States, Mark Regier Kreider May 2021

Patterns Of Post-Fire Aspen Seedling Establishment, Growth, And Mortality In The Western United States, Mark Regier Kreider

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sexual seedling establishment in aspen is increasingly recognized as an important natural regeneration pathway for the species in the western U.S. However, information on seedling abundance as well as factors influencing aspen sexual regeneration is limited and frequently anecdotal, due to historical assumptions of seedling rarity as well as difficulty identifying sexual seedlings from asexual aspen sucker regeneration. This thesis contributes to the field of aspen seedling ecology in three major ways. Chapter 1 utilizes historical aspen seedling occurrences in the western U.S. and a systematic field survey of 2018 fire footprints to explore patterns and test assumptions of aspen …


Greater Sage-Grouse And Community Responses To Strategies To Mitigate Environmental Resistance In An Anthropogenic Altered Sagebrush Landscape, Justin R. Small May 2021

Greater Sage-Grouse And Community Responses To Strategies To Mitigate Environmental Resistance In An Anthropogenic Altered Sagebrush Landscape, Justin R. Small

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sagebrush (Artemisia spp.) ecosystems are diverse habitats found throughout western North America. Anthropogenic disturbances has resulted in the loss of over half of the sagebrush ecosystems impacting sagebrush obligate species such as sage-grouse (Centrocercus spp.). Federal, state, and private land managers have implemented landscape scale mechanical pinyon (Pinus spp.) and juniper (Juniperus spp.; conifer) removal projects in an effort to restore functioning sagebrush communities to benefit sage-grouse. However, few studies have investigated the potential for using large-scale conifer treatments to mitigate factors impeding sage-grouse seasonal movements and space-use in anthropogenic altered landscapes.

To address this management need, I …


Bighorn Sheep Demographics Following Pneumonia Die-Off Events, Kylie Sinclair May 2021

Bighorn Sheep Demographics Following Pneumonia Die-Off Events, Kylie Sinclair

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bighorn sheep populations across the Intermountain West are subject to disease pressure from the respiratory bacteria Mycoplasma ovipneumoniae. Although the effects of M. ovipneumoniae-associated disease die-offs are well documented, less is known about the factors driving long-term differences in post-die-off population responses. While many herds experience years to decades in which recruitment is less than 20 lambs per 100 ewes, some herds’ lamb survival rates are able to rebound rapidly following die-off events. The reason why these herds recover quickly while others do not is currently unknown. Here, we assess the roles environmental, demographic, and pathogen-associated factors could …


Trends In Us Crop Yields & Water Use, Britta L. Schumacher May 2021

Trends In Us Crop Yields & Water Use, Britta L. Schumacher

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Over half the land in the US is dedicated to agriculture, with the vast majority of all cropland cultivated in corn, wheat, or soybean. Despite continuing advances in agricultural technologies, and consistent yield growth over the twentieth century, research suggests that environmental change is already impacting agricultural yield and future changes are sure to exacerbate challenges to agricultural production. It follows that the future of US agriculture depends on the evolution of the changing climate, the relationship between crop yields and the environment, on-farm management and adaptations, the ecosystems that support agriculture, the political and economic incentives that shape what …


Invasive Plant Occurrence Across Agency Boundaries: Two Case Studies From California, Natalie Otto May 2021

Invasive Plant Occurrence Across Agency Boundaries: Two Case Studies From California, Natalie Otto

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Non-native invasive species (NNIS) are a major concern confronting land managers in and surrounding protected areas such as national parks. These areas are managed by a variety of entities, all of which have different mandates, management priorities, and resources that are allocated to NNIS programs. These differences can result in ecological divergences at land boundaries and can create barriers to cooperative management. Through interviews and ecological data collection, this research addresses three topics; 1. It identifies disparities in NNIS and disturbance occurrence between jurisdictions and tests the strength of correlations between these variables; 2. It seeks to determine what role …


An Eulerian Perspective On Spring Migration In Mule Deer, Tatum Del Bosco May 2021

An Eulerian Perspective On Spring Migration In Mule Deer, Tatum Del Bosco

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many herbivores travel between low-elevation winter ranges and high-elevation summer sites. These seasonal movements allow them to avoid deep snow cover, ensure access to favorable habitat, and maximize food intake throughout the year. During the spring season, plants at lower elevations green up earlier at lower elevations than at higher elevations. It has been shown that individual animals will track this vegetation growth during their spring migration, which allows them to maximize forage intake coming out of the nutrient scarce winter. This phenomena has previously been studied by monitoring individual movement trajectories, but it is unknown how this pattern scales …