Life Sciences Commons^™

Comparing Multiple Approaches To Reconstructing The Phosphorus History Of Marl Lakes: A Utah Lake Case Study, Mark R. Devey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Freshwater lakes around the world have suffered from the increasing occurrence of harmful algal blooms in recent decades. One of the most pressing reasons water quality managers try to address harmful algal blooms is that some of the species that occur with them produce toxins which can affect humans, pets, and wildlife. In many lakes, the nutrient phosphorus controls whether these harmful algal and bacterial species can occur. Therefore, efforts to control harmful algal blooms often center around reducing inputs of phosphorus from a variety of sources within the watershed. Scientists and water quality managers have long been challenged by …

Identifying Optimal Stocking Strategies To Support Recovery Of An Endemic Lake Sucker, Dale R. Fonken

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Endemic fishes in the intermountain west experienced significant population declines in the 20th century due to a variety of disturbances, including habitat fragmentation, water development, and the introduction of non-native, predatory fish species. The combination of habitat degradation with increased predation risk can severely limit natural recruitment for native fish species, and in response, fisheries managers have employed a variety of recovery strategies to prevent extinction. Among the most prominent strategies is artificial propagation and subsequent release of individuals into the natural environment (i.e., stocking). Artificial propagation is an expensive endeavor, and when not coupled with a research component, can …

Latino Stepcouples’ Experiences Two Years After Stepfamily Education And A Narrative Study Regarding Changes In A Latino Stepfamily Two Years After Stepfamily Education, Sheryl Ann Goodey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There are two studies in this dissertation. Both are about couples in a stepfamily who attended stepfamily education called, Smart Steps: Embrace the Journey. The first study explored how 13 Latino stepcouples felt the concepts they learned in stepfamily education influenced their couple relationship, parenting, and their family. Participants ranged in age from 25 to 43. They were interviewed two years after participating in the course. They talked about positive changes that happened in their couple relationship, parenting relationship, and their family as a result of participating in stepfamily education. It was also found that the course helped them …

Effects Of Environmental Water Rights Purchases On Dissolved Oxygen, Stream Temperature, And Fish Habitat, Nathaniel R. Mouzon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Degraded water quality has reduced aquatic species abundance and survivability in Nevada’s Walker River. Low instream flows and increased nutrients affect native fish populations through high daily stream temperatures and low nightly dissolved oxygen concentrations. Increasing streamflow, through environmental water purchases, may improve water quality and enhance habitat for native fish species, such as Lahontan cutthroat trout. This study uses River Modeling System, a computer model, to estimate streamflows, stream temperatures, and dissolved oxygen concentrations in the Walker River. Streamflow increases are simulated to determine potential improvements to high water temperatures and low dissolved oxygen concentrations, enabling the prioritization of …

Discharge-Suspended Sediment Relations: Near-Channel Environment Controls Shape And Steepness, Land Use Controls Median And Low Flow Conditions, Angus A. Vaughan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Erosion, transport and deposition of fine sediment (clay, silt and fine sand) influence the form and function of river systems. Excess suspended sediment degrades stream ecosystems and is implicated as a leading cause of water quality and aquatic life impairment. Therefore, understanding the factors that control fine sediment transport patterns is an interesting topic for basic science and one that has important management and policy implications.

In this study, we sought to understand how attributes of the landscape and channel network might control the shape, steepness and vertical offset of the relationship between river discharge and suspended sediment. Watershed and …

Using Network Models To Predict Steelhead Abundance, Middle Fork John Day, Or, Monica R. Blanchard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It is important in the management of threatened and endangered species to have informed population estimates. Population estimates are used to gage whether or not recovery goals are being met. When assessing Pacific salmonids this assessment involves sampling a small subset of the population and then scaling up to estimate larger populations units. This is complicated by the fact that fish populations are not evenly distributed along river systems but respond to fluctuating physical and biological stream properties. We used rapid assessment survey methods and the River Styles classification to explore fish-habitat relationships. River Styles is a classification system that …

Developing A Field Indicator For Suckering Ability Of Quaking Aspen, Abbey M. Hudler Oksness

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Quaking aspen is an ecologically valuable deciduous tree species in the high elevation environment typical across many parts of western North America. It is a clonal tree species which primarily depends on vegetative regeneration by root suckering after an aboveground disturbance, e.g., wildfire, removes the stems. A flush of suckers will be stimulated after a disturbance and the resulting regeneration relies on available resources from the undamaged root system for resprouting. Due to wildfire suppression efforts of the last century, many aspen stands are considered mature, overmature, or decadent and lack regeneration to replace the overstory mortality. In the absence …

A Quantitative Approach To The Development Of Ecological Sites And State-And-Transition Models, Matthew W. Van Scoyoc

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Changes in land-use and climate can trigger changes in ecosystem conditions and may be driving ecosystems toward undesired “states” that provide inadequate ecosystem services. If these changes are drastic enough, energy intensive restoration programs are necessary to restore ecosystems to previous states. Landscape classification systems based on “ecological potential” offer a robust framework to evaluate and manage ecosystems. The ecological site concept is one such landscape classification system that has been developed by the USDA Natural Resources Conservation Service (NRCS) and describes ecosystems and ecosystem dynamics relative to “reference conditions” and response to disturbance. Ecological sites have gained popularity with …

Linking Temporal And Spatial Variability Of Millennial And Decadal-Scale Sediment Yield To Aquatic Habitat In The Columbia River Basin, Elijah Portugal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Historically the Columbia River was amongst the most productive salmonidbearing watersheds in North America. Currently, salmonid populations have collapsed and are estimated at ten percent of historic levels. Because of this, there are thirteen, Endangered Species Act (ESA) listed distinct population segments within the Columbia River Basin (CRB). The Bonneville Power Administration (BPA) operates a substantial number of hydroelectric dams within the CRB. As the dams effectively block anadromy and are thought to be extremely detrimental to the long-term persistence of salmonid populations within the CRB, the BPA funds a series of programs to mitigate the impacts of dam operation. …

Assessing Changes In Waterfowl Population And Community Dynamics, Beth E. Ross

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Studying long-term ecological studies can help ecologists understand what causes populations and communities of wildlife to change. Understanding these causes can help guide conservation efforts. Additionally, results from long-term datasets allow ecologists to predict how populations may shift with global change. Ecologists can then determine necessary management action to maintain sustainable populations in the future. However, there can be a large amount of “noise” in a long-term dataset. If ecologists fail to account for this noise, they may make incorrect management decisions. For example, samples taken in two nearby locations will likely be more similar than samples taken from two …

Common Raven Density And Greater Sage-Grouse Nesting Success In Southern Wyoming: Potential Conservation And Management Implications, Jonathan B. Dinkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Declines in the distribution and abundance of greater sage-grouse (Centrocercus urophasianus; hereafter "sage-grouse") in western North America over the past century have been severe. The goal of my research was to increase the understanding of factors influencing where sage-grouse hens placed their nests, how common ravens (Corvus corax: hereafter "raven") impacted sage-grouse nest success, and whether high raptor densities negatively impacted hen survival of sage-grouse. I compared raven and raptor densities at sage-grouse nest and brood locations to available habitat. I also assessed how sage-grouse positioned their nests and broods relative to proximity to man-made structures, …

Legacy Effects Of Habitat Degradation By Lesser Snow Geese On Ground-Nesting Savannah Sparrows Along The Hudson Bay Lowlands, Stephen L. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Little is known of the direct and indirect legacy of Lesser Snow Goose (LSGO) habitat degradation in northern Canada on the biodiversity of other avian species. It is believed that a human-induced trophic cascade caused in part by agricultural habitat modification along migratory routes and wintering grounds has contributed to the increase in LSGO numbers, which has resulted in increased foraging pressure by LSGO on northern breeding and stopover sites. This habitat degradation may lead to decreased abundance and richness of Arctic / sub-Arctic avian species across landscapes that LSGO utilize and degrade.

Here we evaluated the annual change in …

Effects Of Inorganic Nutrients And Dissolved Organic Carbon On Oxygen Demand In Select Rivers In Northern Utah, Joseph L. Crawford

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Our nation’s waterways are a valuable resource whose quality is influenced by their surroundings as well the amount of nutrients (largely nitrogen and phosphorus) in the water. Nutrients play an important role in aquatic ecosystems; however, if nutrient levels become too high, it is detrimental to water quality. Excess fertilizer that runs off of agricultural land and into the rivers and streams is a common source of nutrients in our waterways. Other sources of nitrogen and phosphorus include effluent released from wastewater facilities.

There are many negative side effects of high nutrients in the water. They can create large algal …

Greater Sage-Grouse Habitat Selection And Use Patterns In Response To Vegetation Management Practices In Northwestern Utah, Stephanie E. Graham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) are a sagebrush obligate species and an indicator of sagebrush (Artemisia spp.) habitat quality. Sage-grouse populations have declined across western North America. Fragmentation of landscapes and habitat loss have been identified as factors that negatively impact sage-grouse populations. Wildfires can increase the distribution of invasive plants and contribute to fragmentation and habitat loss across sagebrush ecosystems. Greenstripping has been identified as a technique to reduce the threat of wildfire and subsequent spread of invasive species. Forage kochia (Bassia prostrata) is a semi-shrub that contains a high moisture content year-round, high …

Mule Deer And Wildlife Crossings In Utah, Usa, Megan Schwender

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildlife-vehicle collisions (WVCs) negatively impact wildlife populations and create dangerous driving situations for motorists. In Utah, USA, mule deer (Odocoileus hemionus) encounter a variety of hazards as they attempt to cross highways and interstates, some of which are 8 lanes wide. Agencies have sought to mitigate the risks posed to drivers and mule deer by building crossing structures for wildlife. The objectives of this study were to evaluate the effectiveness of crossing structures in Utah to safely pass mule deer under highways and to determine the variables that best explain mule deer passage use. From 2008 - 2011 …

Modeling Usa Stream Temperatures For Stream Biodiversity And Climate Change Assessments, Ryan A. Hill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Stream temperature in one of the most biologically important aspects of water quality, but we lack temperature information for the vast majority of streams within the USA. Stream temperature can be influenced by several types of landscape and waterway alteration including upstream urbanization, agriculture, and reservoir releases. Stream temperatures are also expected to be affected by climate change over the next
century. We need to know how stream temperatures vary naturally, how they are influenced by human activity, and how they will respond to climate changes to effectively manage stream ecosystems. I used data from several thousand streams within the …

Importance Of Grass-Legume Choices On Cattle Grazing Behavior And Performance, Brody Todd Maughan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Livestock production systems have emphasized low diversity of high-producing forage species dependent upon costly fossil-fuel inputs. However, diversity of plants in natural systems is common, and diverse plant communities enable herbivores to meet needs for nutrition and health. Plants provide herbivores with nutrients and bioactive compounds – plant secondary compounds (SCs), which at appropriate concentrations can reduce internal parasites and greenhouse gas emissions, improve nutrient utilization and enhance meat quality in ruminants. In addition, SCs confer plants more resistance to environmental challenges such as drought or pests.

With my MS program, I sought to explore foraging behavior in cattle grazing …

Development Of Sediment Budgets At Multiple Scales, Susannah O'Brien Erwin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Channel morphology in alluvial rivers is determined by the flow of water and sediment, and the characteristics of the materials making up the channel boundary. Many modern river management problems depend upon our ability to predict channel behavior in response to changes in the delivery of water or sediment. Sediment delivery to a river may be altered by natural or human-caused changes, such as changes in land use in the watershed, construction and operations of dam, forest fires, or climate change. Understanding and predicting the effects of these alterations is important because changes in sediment supply and transport may alter …

Using Biophysical Geospatial And Remotely Sensed Data To Classify Ecological Sites And States, Carson A. Stam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Within the Intermountain West, vast expanses of big sagebrush shrubland and steppe are considered emblems of the western range. Currently, there are approximately 60 million hectares of big sagebrush within the 11 western states, four million of which are in the state of Utah. However, the historic distribution of sagebrush has been impacted by conversion to other types of land cover through juniper encroachment, urbanization, invasive weeds, and agricultural expansion. In Utah alone, big sagebrush communities have been reduced to approximately 55% of their historic extent. A primary and current example of the cumulative impact of big sagebrush loss is …

Population Dynamics And Movements Of Translocated And Resident Greater Sage-Grouse On Anthro Mountain, Utah, Natasha W. Gruber

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greater sage-grouse (Centrocercus urophasianus) populations have declined range-wide. Species translocations have been identified as a conservation strategy to augment declining populations in restored habitats. I evaluated protocols previously used to successfully translocate greater sage-grouse in Utah by comparing annual production, survival, habitat use, integration and seasonal movements of translocated birds and their chicks to the resident population. To conduct this study, I translocated 60 greater sagegrouse hens captured and radio-collared on Parker Mountain to Anthro Mountain in the spring of 2009 and 2010. I also captured and radio-collared 19 resident hens to serve as my control group. All …

The Effects Of Habitat Manipulations On Utah Prairie Dogs (Cynomys Parvidens) And Their Habitat On The Awapa Plateau Recovery Area In South-Central Utah, Gretchen Elizabeth Caudill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Utah prairie dogs have been listed, in some capacity, under the Endangered Species Act since 1972. The lack of suitable habitat, particularly cool season grass cover,
has been identified as the primary factor impeding species recovery. Due to reproduction costs, Utah prairie dogs require a large quantity of cool season grasses. Lack of recovery has also been attributed to poor juvenile survival. Increased resources have been shown to increase weights, which would increase survival through the winter.

Beneficial habitat management techniques for Utah prairie dogs have yet to be determined for the Awapa Plateau recovery area. Utah prairie dogs require …

Modeling Freshwater Mussel Distribution In Relation To Biotic And Abiotic Habitat Variables In The Middle Fork John Day River, Oregon, Ericka E. Hegeman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Freshwater mussels are the most threatened taxonomic group in North America with extinction rates that exceed those of many species found in both terrestrial and freshwater ecosystems including fish, birds, and amphibians. Part of the reason that mussels are so threatened is because their larvae are parasitic on fish, making the completion of their life cycle dependent upon healthy fish populations. The imperilment of freshwater mussels is a cause for concern because of the benefits that mussels provide to freshwater ecosystems including habitat enhancement, substratum stabilization, nutrient cycling, and water clarification. Restoration and conservation efforts targeting western freshwater mussels have …

Drivers Of Nest Success And Stochastic Population Dynamics Of The Common Eider (Somateria Mollissima), David Thomas Iles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Human-caused climate alterations to Arctic ecosystems have resulted in a constellation of impacts on the biological relationships within them, yet the consequences of these changes on the population dynamics of many species are poorly understood. Thus, an understanding of the drivers of variation in population performance is needed to inform the management and conservation of imperiled species. Here, we use a long-term dataset for the common eider, an Arctic-breeding sea duck, to examine the drivers of annual variation in nest survival, and evaluate the effects of variation in vital rates on population growth. Our chapter 2 results suggested that increased …

Genetic Diversity And Genetic Structuring At Multiple Spatial Scales Across The Range Of The Northern Leopard Frog, Rana Pipiens, Ryan P. O'Donnell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Genetic diversity is the raw material for evolution: evolution cannot happen without genetic diversity, and the ability of a population to respond to a changing environment depends directly on how diverse its genes are. Understanding the distribution of genetic diversity is important for many reasons, including predicting whether species will be able to adapt to climate change and predicting the spread of invasive species. Information about the distribution of genetic diversity across the range of the Northern Leopard Frog, a declining species, will not only help us to ensure that the species can continue to evolve in response to changing …

Avian Response To Post Wildland Fire Reseeding Treatments In Great Basin Shrubsteppe, Adam B. Brewerton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildfire is often considered a destructive force. However, we have learned that fire is a natural part of many ecosystems and can even be productive by recycling nutrients, and allowing for regrowth. A natural pattern of fire frequency allows for native plants and animals to recover from its destructiveness and capitalize on its benefits. Environmental changes, such as exotic invasive species, like cheatgrass, and livestock grazing, can make recovery less likely. Cheatgrass also promotes fire. As cheatgrass establishes, fires become more frequent and larger, making it hard or impossible for native plants to recover. Land managers often reseed to restore …

Identifying And Quantifying Sediment Sources And Sinks In The Root River, Southeastern Minnesota, Justin Collin Stout

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fine sediment, normally understood to refer to sand, silts, and clays; is a natural constituent in all rivers. When in excess this fine sediment can degrade the habitat for aquatic life in these rivers, and carry with it many pollutants and nutrients which can cause adverse effects on wildlife and human populations.

Understanding how this fine sediment moves through a river system, from erosion off of hillslopes, transport through the river, and finally export from the mouth of the system is vital part to land and river management. However, predicting how fine sediment moves through a system is a difficult …

Mapping Fire Fuels Through Detection Of Canopy Biomass Loading In Juniper, Sagebrush, And Gambel Oak Communities, Sean Laroy Hammond

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fire fuel inventory processes are customarily labor intensive endeavors. There is a growing need for an increase in accuracy of these inventories at a landscape level, due in large part to the ever increasing development of Wildland Urban Interface (WUI). More accurate inventory and mapping of wildland fuels will facilitate a more accurate simulation of wildfire behavior and analysis of fire behavior given a myriad of fuels treatments. This paper examines one approach to inventorying fire fuels at a landscape level and developing fuel model maps to be utilized in landscape level fire behavior simulations for use by land managers …

Livestock Foraging Behavior In Response To Sequence And Interactions Among Alkaloids, Tannins, And Saponins, Tiffanny L. Jensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

During the past several decades, people worldwide have expressed a growing interest in reconstructing ecosystems to enhance ecological, economic, and social values. Yet, to do so we must find ways to enhance biodiversity, environmental quality and the sustainability of grazing lands. In all these instances, plants are the glue that binds soils, water, herbivores, and people. However, monocultures or simple grass-legume mixtures are not always ideal for intensively managed pastures due to their seasonality, susceptibility to pests, and monotony of plant nutrients and toxins. All plants contain so-called “toxins,” more appropriately referred to as secondary compounds, which are crucial in …

Seasonal Transport Of Suspended Solids And Nutrients Between Bear River And Bear Lake, Cody M. Allen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I measured inflows and outflows of nutrients and suspended solid through the wetland complex, known as Dingle Marsh, at the Bear River Migratory Bird Refuge between October 2007 and September 2008. My analysis of changes throughout the year will help Dingle Marsh managers adjust the timing and volume of water movement between Bear River and Bear Lake to meet defined refuge goals, such as improving bird or other animal habitat. These results could also be used to protect Bear Lake’s water quality.

Automated samplers took readings of dissolved oxygen, turbidity, pH and water temperature every 30 minutes. These values were …

Vegetation Characteristics Of Wyoming Big Sagebrush Communities Historically Seeded With Crested Wheatgrass In Northeastern Great Basin, Usa, Justin Rodney Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) is one of the most commonly seeded grass species in the western United States and dominates thousands of hectares in the Great Basin. Although many degraded Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) plant communities have been seeded with crested wheatgrass, successional pathways, influence of soil attributes, and cultivation history on the vegetation of these communities have not been fully characterized. I sought to identify community phases, vegetative differences, and soil attributes that explain variation among 35 Wyoming big sagebrush communities historically seeded with crested wheatgrass. All communities were more than …