Life Sciences Commons^™

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

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

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

Assessing Post-Fire Revegetation Efforts In Box Elder County, Utah, Using The Rangeland Analysis Platform, Rayce Bryan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

After fires occur in western rangelands, land management agencies commonly perform vegetation treatments and reseeding projects. The West Box Elder Coordinated Resource Management Group expressed concern regarding the difficult process of determining outcomes from the many post-fire revegetation projects undertaken on rangeland of Box Elder County, Utah. This research attempted to compile and clarify the fire and treatment history of the county and produce an assessment of the outcomes from each unique post-fire treatment in West Box Elder County. Also produced was a database of post-fire revegetation outcomes in published literature.

Unique treatment polygons were identified and then subset according …

Quantification Of Hydrologic Response To Forest Disturbance In Western U.S. Watersheds, Sara A. Goeking

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forested watersheds produce more than half of the water supply in the United States. Forests affect how precipitation is partitioned into available water versus evapotranspiration. This dissertation investigated how water yield and snowpack responded to forest disturbance following recent disturbances in western U.S. forests during the period 2000-2019.

Chapter 2 systematically reviewed 78 recent studies that examined how water yield or snowpack changed after forest disturbances. Water yield and snowpack often increased after disturbance, but decreased in some circumstances. Decreased water yield was most likely to occur following disturbances that did not remove the entire forest canopy. It was also …

Interactions Between Fire Severity And Forest Biota In The Central Sierra Nevada: Formation And Impact Of Small-Scale Fire Refugia And The Effect Of Fire On Forest Structure Predictive Of Fisher (Pekania Pennanti) Den Habitat, Erika M. Blomdahl

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fire is a natural and essential component of forests in western North America. Fire maintains biodiversity through the creation of different habitat types, and regular fire rotations reduce the accumulation of woody fuels and thick understory plant densities that give rise to catastrophic fire. The practice of fire exclusion has altered western forests and increased the risk of widespread change under rising temperatures projected for the 21^st century. To manage for the reintroduction of fire it is critical that we understand the interactions between fire and forest biota in recently fire-suppressed forests.

In Chapter 2, I studied the formation …

Land Cover And Use Change In Utah: A Comparison Of Field- Vs. Aerial Image-Based Observations, Jennifer Lynn Bakken

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Image-based Change Estimation program (ICE) was developed by the US Forest Service Forest Inventory & Analysis (FIA) program and the Geospatial Technology Applications Center in response to the 2014 Farm Bill calling for more timely and accurate estimates of land cover and use change. ICE monitors change throughout the US on a state by state basis by assessing each FIA plot using high resolution imagery from two dates in time. In the western US, FIA measures 10% of the plots each year to report on status, trends, and sustainability of our Nation’s forests. However, this 10 year cycle misses …

Managing For Multiple Objectives In Southwestern Forests: Evaluating The Trade-Offs Between Enhancing Mexican Spotted Owl Nest Habitat And Mitigating Potential Crown Fire, Daniel C. Deane Mckenna

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Forest Inventory and Analysis (FIA), the United States’ forest census, measured sixty-six Mexican spotted owl nest stands in order gain insight into the structure and composition of the nest habitat of this threatened species. I used these data, along with the greater FIA database and the Forest Vegetation Simulator to explore questions surrounding the management of Mexican spotted owl habitat, specifically how to balance the objective of sustaining and enhancing nest habitat in face of increasing forest fire size and severity in the Southwest. My research consisted of three studies. The first study quantified the structure and composition of …

The Influence Of Aspen Chemistry And The Nutritional Context On Aspen Herbivory, Kristen Y. Heroy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Consumption of aspen by herbivores is one major force causing aspen decline in North America. In this Dissertation, I aimed to determine why herbivores prefer browsing on certain aspen stands over others, and why they prefer consuming aspen that contains chemical defenses over understory forages like grasses, forbs, and shrubs. I explored the influence of nutrients and chemical defenses within aspen on aspen intake and preference by lambs in pen experiments. I also explored drivers of aspen preference on the landscape by looking at relationships between aspen herbivory, indicators of aspen health, amount of nutrients available in the understory, and …

Effect Of Foliage And Root Carbon Quantity, Quality, And Fluxes On Soil Organic Carbon Stabilization In Montane Aspen And Conifer Stands In Utah, Antra Boča

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soil organic carbon (SOC) positively affects many soil properties (e.g., fertility and water holding capacity), and the amount of carbon (C) in soil exceeds the amount in the atmosphere by about three times. Forest soils store as much C as is found in trees. Tree species differ in their effect on SOC pools. Quaking aspen forests in the Western US often store more stable SOC in the mineral soil than nearby conifers. During the last decades a decline in aspen cover, often followed by conifer encroachment, has been documented. A shift from aspen to conifer overstories may negatively affect the …

Impact Of Climate Variability On The Frequency And Severity Of Ecological Disturbances In Great Basin Bristlecone Pine Sky Island Ecosystems, Curtis A. Gray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many high elevation conifer species, including high elevation five needle pines, are declining throughout western North America. Warming temperatures, mountain pine beetle, white pine blister rust and alteration of naturally occurring fire regimes represent an interactive set of circumstances leading to greater risk. The loss of these treeline pines can detrimentally impact biodiversity and valuable ecosystem services including wildlife habitat, watershed and soil protection, aesthetics and recreation. Great Basin bristlecone pine ecosystems are naturally highly fragmented because of their elevational requirements. However, they may become even more fragmented due to combined impacts of warming temperature, insects and diseases listed above. …

Comparing Conventional And Noninvasive Monitoring Techniques For Assessing Cougar Population Size In The Southern Greater Yellowstone Ecosystem, Peter D. Alexander

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Determining the abundance or density of wildlife populations is needed for informed decision-making by wildlife biologists. Cougars (Puma concolor), however, are a highly secretive species occurring at very low densities across the landscape, and thus their populations are difficult for biologists to accurately assess. The conventional, and most trusted, method entails physically trapping and radio-collaring as many cougars as possible in a population, and then performing a simple count to determine a minimum population size. While accurate, this method is prohibitively expensive, logistically challenging, and behaviorally disruptive to the study animal. Many noninvasive surveying techniques, such as camera …

Fire Environment Analysis At Army Garrison Camp Williams In Relation To Fire Behavior Potential For Gauging Fuel Modification Needs, Scott M. Frost

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Large fires (400 ha +) occur about every seven to ten years in the vegetation types located at US Army Garrison Camp Williams (AGCW) practice range located near South Jordan, Utah. In 2010 and 2012, wildfires burned beyond the Camp’s boundaries into the wildland-urban interface. The political and public reaction to these fire escapes was intense. Researchers at Utah State University were asked if a spatially organized system of fuel treatments could be developed to prevent future escapes. The first step of evaluation was to spatially predict fuel model types derived from a random forests classification approach. Fuel types were …

Bark Beetle-Induced Changes To Crown Fuel Flammability And Crown Fire Potential, Wesley G. Page

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent outbreaks of aggressive tree-killing bark beetles, including mountain pine beetle in lodgepole pine forests and spruce beetle in Engelmann spruce forests, have recently affected vast areas across western North America. The high levels of tree mortality associated with these outbreaks have raised concerns amongst fire managers and wildland firefighters about the possible effects on fire behavior potential, particularly crown fire potential, as crown fires (fires that consume part or all of tree crowns) hinder the ability of firefighters to conduct safe and effective fire suppression operations. The purpose of this research was to measure and characterize the changes in …

Influence Of Mountain Pine Beetle On Fuels, Foliar Fuel Moisture Content, And Litter And Volatile Terpenes In Whitebark Pine, Chelsea Toone

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mountain pine beetle (Dendroctonus ponderosae Hopkins) has caused extensive tree mortality in whitebark pine (Pinus albicaulis Engelm) forests. Previous studies conducted in various conifer forests have shown that fine surface fuels are significantly altered during a bark beetle outbreak. Bark beetle activity in conifer stands has also been shown to alter foliar fuel moisture content and chemistry over the course of the bark beetle rotation.

The objective of this study was to evaluate changes to fine surface fuels, foliar fuel moisture and chemistry and litter chemistry in and under whitebark pine trees infested by mountain pine beetle. Fuels …

Forest Recovery, Nutrient Cycling And Carbon Sequestration In A Southern Appalachian Spruce-Fir Forest, Patrick T. Moore

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Our forests provide us with a variety of services from clean water, forest products and wildlife habitat to the lesser known functions of nutrient cycling and carbon
sequestration. This research helps to demonstrate the extent of some of these services in a heavily disturbed southern Appalachian spruce-fir forest within Great Smoky Mountain National Park, the most heavily visited National Park in the United States. Following a catastrophic infestation of the non-native balsam wooly adelgid, the future of this forest was unknown, causing some to speculate about the future of this sensitive forest type. Though predictions about this forest’s future varied …

Analysis Of Food Web Effects Of Non-Native Fishes And Evaluation Of Stream Restoration Potential For The San Rafael River, Utah, Timothy E. Walsworth

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Native fishes of the Colorado River Basin have experienced dramatic reductions in range and abundance as a result of extensive human alterations to the basin’s waterways. Many of these native fishes are federally listed under the Endangered Species Act, while several others are subject to range-wide conservation agreements between state and federal management agencies. Three of the native species subject to range-wide conservation agreements are the flannelmouth sucker, bluehead sucker, and roundtail chub (hereafter, the “three species”). Each of the “three species” is still found in the San Rafael River of southeastern Utah, which has experienced habitat degradation and non-native …

Reducing Reliance On Supplemental Winter Feeding In Elk (Cervus Canadensis): An Applied Management Experiment At Deseret Land And Livestock Ranch, Utah, Dax L. Mangus

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wildlife managers have fed elk in North America for nearly 100 years. Giving winter feed to elk can compensate for a shortage of natural winter range and may boost elk populations while also helping prevent commingling with livestock and depredation of winter feed intended for livestock. In contrast to these benefits of supplemental feeding, there are economic and environmental costs associated with feeding, and elk herds that winter on feeding grounds have a higher risk of contracting and transmitting disease. Brucellosis is of primary concern now, and Chronic Wasting Disease may be in the future. Many see the discontinuation of …

Spatiotemporal Modeling Of Threats To Big Sagebrush Ecological Sites In Northern Utah, Alexander J. Hernandez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study tested the performance of classification, regression, and ordination techniques to evaluate the spatiotemporal dynamics of threats to big sagebrush ecological sites. The research was focused on invasion by annual exotic grasses and encroachment by woodlands.

We sought to identify those areas that have had a persistent coverage of cheatgrass (Bromus tectorum) in big sagebrush ecological sites. We took advantage of the contrast in greenness between multi-temporal (within one year) remotely sensed vegetation indices captured in the spring and summer to find a distinct phenological signature that allowed mapping cheatgrass. We utilized support vector machines (SVM) to classify three …

Invertebrate Community Changes Along Coqui Invasion Fronts In Hawaii, Ryan T. Choi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Puerto Rican coqui frog, Eleutherodactylus coqui, was introduced to Hawaii in the late 1980s via the commercial horticulture trade. Previous research has shown that coquis can change invertebrate communities, but these studies were conducted at small scales using controlled, manipulative experiments. The objective of this research was to determine whether coqui invasions change invertebrate communities at the landscape scale across the island of Hawaii. At each invasion front, we measured environmental variability on either side of the front and removed sites that were too variable across the front to ensure that the impacts we measured were the result …

Object-Based Segmentation And Classification Of One Meter Imagery For Use In Forest Management Plans, W. Kevin Wells

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research developed an ArcGIS Python model that extracts polygons from aerial imagery and assigns each polygon a vegetation type based on a modified set of landcover classes from the Southwest Regional Gap Analysis Project. The model showed an ability to generate polygons that accurately represent vegetation community boundaries across a large landscape. The model is for use by the Utah Division of Forestry, Fire, and State Lands to assist in the preparation of forest management plans. The model was judged useful because it was easy to use, it met a designated 50% threshold of useable polygons, and it met …

Identifying And Understanding The Spatial Distribution Of Bobcat And Coyote Behavior, Ryan Radford Wilson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A common observation in animal space use studies is that animals do not use space uniformly, but rather use some areas of their home ranges and territories with much higher intensity than others. Numerous methods have been developed to estimate these "core areas"; however, all of the current methods available are based on arbitrary rules. Additionally, most studies do not attempt to understand what behavioral processes lead to the observed patterns of non-uniform space use. This study has four main objectives: 1) to develop an objective and more precise method for estimating core areas, 2) to understand the processes leading …

Terrestrial Ecosystem Classification In The Rocky Mountains, Northern Utah, Antonin Kusbach

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Currently, there is no comprehensive terrestrial ecosystem classification for the central Rocky Mountains of the United States. A comprehensive classification of terrestrial ecosystems in a mountainous study area in northern Utah was developed incorporating direct gradient analysis, spatial hierarchy theory, the zonal concept, and concepts of diagnostic species and fidelity, together with the biogeoclimatic ecosystem classification approach used in British Columbia, Canada.

This classification was derived from vegetation and environmental sampling of both forest and non-forest ecosystems. The SNOwpack TELemetry (SNOTEL) and The National Weather Service (NWS) Cooperative Observer Program (COOP) weather station network were used to approximate climate of …

Disturbance Ecology And Vegetation Dynamics At Varying Spatial And Temporal Scales In Southern Rocky Mountain Engelmann Spruce Forests, R. Justin Derose

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

High-severity disturbances are the primary drivers of Engelmann spruce-subalpine fir ecosystems in the southern Rocky Mountain. Recently, an unprecedented, landscape-wide (at least 250 km2) spruce beetle outbreak killed virtually all the Engelmann spruce on the Markagunt Plateau in southwestern Utah, USA. Results from dendroecological analyses suggested the combination of antecedent disturbance history and drought-driven stand development was responsible for creating suitable host conditions prior to the recent outbreak. Multiple and consistent lines of evidence suggested mixed- and high-severity fires shaped the development of the Markagunt Plateau. Subsequent stand development, influenced by species-specific differential tree-ring response to drought, resulted in the …

Sustaining The Allideghi Grassland Of Ethiopia: Influences Of Pastoralism And Vegetation Change, Almaz Tadesse Kebede

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Allideghi Wildlife Reserve in the Amibara District of Afar Regional State, Ethiopia, has international significance for harboring endangered Grevy's Zebra and other wildlife dependent on grasslands. The reserve is increasingly used by pastoral people and their herds. Impacts of livestock on native vegetation include direct effects of grazing and indirect effects from livestock-facilitated dispersal of an invasive plant, Prosopis juliflora. The main research objective was to determine effects of pastoralism and vegetation change on prospects for sustaining the Allideghi Wildlife Reserve as grassland habitat for Grevy's Zebra. Methods included use of driving surveys to quantify resource use by …

Effects Of Olfactory And Visual Predators On Nest Success And Nest-Site Selection Of Waterfowl In North Dakota., Jennifer S. Borgo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Selecting a nest site is an important decision for waterfowl. Because most nest failure is due to depredation, the primary selective pressure in choosing a nest site should be to reduce depredation risk. This task is difficult because predators use differing tactics to locate nests, such as olfactory or visual cues. I investigated several components of waterfowl nest-site selection and success on sites with shelterbelts (planted tree-rows) in North Dakota, during the 2006 and 2007 nesting seasons.

I found that meteorological conditions impacted nest depredation; artificial nests were more likely to be depredated when either temperature or dew point was …

Livestock Mortality At Beef Farms With Chronic Wolf (Canis Lupus) Depredation In The Western Great Lakes Region (Wglr), Arion Vandergon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Gray wolf (Canis lupus) depredation on beef calves has been studied extensively in recent years. As wolf populations increase throughout the United States there is a corresponding increase in wolf/livestock interactions. Most research concentrates on summaries of reported depredations and surveys of producers affected by depredations. The objective of this study was to present data on the fate of beef calves on 3 farms in Minnesota and Wisconsin over a 2-year period. Predator presence/absence was studied as an indicator of potential depredations. Also, data are presented comparing 2 techniques that may aid researchers and livestock producers with monitoring …

Granivores And Restoration: Implications Of Invasion And Considerations Of Context-Dependent Seed Removal, Steven M. Ostoja

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Granivores are important components of sagebrush communities in western North America. These same regions are being altered by the invasion of the exotic annual Bromus tectorum (cheatgrass) that alters physical and biological dynamics in ways that appear to promote its persistence. This research directly relates to the restoration of B. tectorum-dominated systems in two inter-related ways. First, because these landscapes have large quantities of seeds applied during restoration, it is important to determine the major granivore communities in intact sagebrush communities and in nearby cheatgrass-dominated communities. Second, it is important to develop an understanding of patterns of seed harvest …

Ponderosa Pine Mortality And Bark Beetle-Host Dynamics Following Prescribed And Wildland Fires In The Northern Rocky Mountains, Usa, Ryan Stephen Davis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ponderosa pine delayed mortality, and bark beetle attacks and emergence were monitored on 459 trees for 3 years following one prescribed fire in Idaho and one wildland fire in Montana. Resin flow volume (ml) was measured on 145 fire-injured ponderosa pine 2 and 3 years post-fire. Logistic regression was used to construct two predictive ponderosa pine mortality models, and two predictive bark beetle-attack models. Post-fire delayed tree mortality was greater with the presence of primary bark beetles independent of diameter at breast height (DBH) (cm), and was greater in smaller diameter trees most likely due to direct effects of fire-caused …

Comparison Of Water Dynamics In Aspen And Conifer: Implications For Ecology Water Yield Augmentation, Eric Martin Lamalfa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Differences in water dynamics between deciduous aspen (Populus tremuloides) and co-occurring evergreen conifer species in the Northern Rocky Mountains result from complex physical and biological interactions. A comprehensive evaluation of individual water transfer mechanisms was used to elucidate the relative importance of several components of the hydro logic cycles of aspen and conifer, and determine which water transfer mechanisms have potential to cause differences in net water yield.

Adjacent aspen and conifer stands were monitored to determine snow accumulation and ablation (snow survey), soil moisture recharge (capacitance probes), snowpack sublimation (sublimation pan), transpiration period (thermal dissipation probes), and …

Quantifying Losses Of Understory Forage In Aspen Stands On The Dixie And Fishlake National Forests, Barton R. Stam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The West has lost up to 60% of its historic aspen stands over the last century, probably as a result of the successional tendency of aspen to be replaced by coniferous species in the absence of periodic fires. One of several major impacts of this change is the loss of understory forage as conifer canopy cover increases. I measured understory biomass in aspen stands ranging from 0% to 81 % absolute conifer cover in the canopy and found that understory production declines exponentially as conifers replace aspen. I also did an economic analysis to determine the value of the forage …

Greenstrip Establishment And Management In The Intermountain West, Brenda Kristine Younkin-Kury

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greenstrips were established at two sites in Utah to determine if seeded, grazed cool-season, perennial grasses would change fire behavior characteristics in areas currently dominated by Bromus tectorum. Frequency data were collected for both grazed and ungrazed seeded species and resident weed species. Moderate spring grazing did not negatively impact the establishment of seeded species at Camp Williams. Grazing at Promontory Point decreased Agropyron desertorum frequency and increased the frequency of Pascopyrum smithii. Biomass data collected for grazed and ungrazed treatments in both years indicated that moderate spring or winter grazing the first two years of establishment did …