Digital Commons Network^™

Consequences Of Host Life Cycles For Symbiont Genome Evolution, Ashley Elizabeth Dederich

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Aphids are small insects that feed exclusively on plant sap, a notoriously low source of nutrients due to the high sugar content and low amino acid content. To make up for these deficiencies in nutrition, aphids harbor Buchnera aphidicola, a bacterial endosymbiont that resides in a specialized organ called the bacteriome. B. aphidicola provides essential amino acids and vitamins for the aphid in exchange for a safe place to live. Over the course of the symbiosis (established 160 million years ago), B. aphidicola has lost much of its genome, including essential genes for cell envelope synthesis, DNA replication and …

Analyzing The Von Neumann Entropy Of Contact Networks, Thomas J. Brower

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

When modeling the spread of disease, ecologists use ecological or contact networks to model how species interact with their environment and one another. The structure of these networks can vary widely depending on the study, where the nodes of a network can be defined as individuals, groups, or locations among other things. With this wide range of definition and with the difficulty of collecting samples, it is difficult to capture every factor of every population. Thus ecologists are limited to creating smaller networks that both fit their budget as well as what is reasonable within the population of interest. With …

Subsistence Strategy Tradeoffs In Long-Term Population Stability Over The Past 6,000 Years, Darcy A. Bird

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I conduct the first comparative analysis of long term human population stability in North America. Questions regarding population stability among animals and plants are fundamental to population ecology, yet no anthropological research has addressed human population stability. This is an important knowledge gap, because a species’ population stability can have implications for its risk of extinction and for the stability of the ecological community in which it lives. I use archaeological and paleoclimatological data to compare long term population stability with subsistence strategy and climate stability over 6,000 years. I conduct my analysis on a large scale to better understand …

Urban Bobcat (Lynx Rufus) Ecology In The Dallas-Fort Worth, Texas Metroplex, Julie M. Golla

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Urban landscapes are quickly replacing native habitat around the world. As wildlife and people increasingly overlap in their shared space and resources, so does the potential for human-wildlife conflict, especially with predators. Bobcats (Lynx rufus) are a top predator in several urban areas across the United States and a potential contributor to human-carnivore conflicts. This study evaluated the movements and habitat use of bobcats in the Dallas-Fort Worth (DFW), Texas metroplex. Spatial data were collected from 10 bobcats via Global Positioning Satellite (GPS) for approximately one year. Average home range size was 4.60 km² (n=9, SE=0.99 km …

The Behavior And Ecology Of Cursorial Predators And Dangerous Prey: Integrating Behavioral Mechanisms With Population-Level Patterns In Large Mammal Systems, Aimee Tallian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Driving into Yellowstone National Park for the first time is a moving experience. Gazing over the sweeping landscapes, seeing a geyser erupt 80 feet into the air, and having your first ‘wildlife encounter’, whether that be a 2 ton bull bison aggressively wallowing on his dirt mound, snorting and kicking up dust, or watching a pack of 6 wolves move through a valley off in the distance, pausing to howl in search of their companions. Yellowstone staff wishes to manage our park in a way that preserves these remarkable experiences. In order to effectively manage this dynamic ecosystem, it is …

Ecology, Behavior And Taxonomy Of Anurans From Brazil's Atlantic Forest, Rodrigio Barbosa Ferreira

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Anura is a diverse group with more than 7382 species described, which represents 88% of the species belonging to the Class Amphibia. Anurans are among the first organisms to be affected by environmental stressors, so when they show decline in the wild, it is a warning to other species, including humans. It is alarming that one-third of the world’s anurans are facing extinction. Following the same trend, a substantive portion of the 988 recognized species of the Atlantic Forest have suffered population declines and local extinctions, attributed primarily to habitat changes.

Despite the unique life history characteristics that make amphibians …

Ecology And Behavior Of Coyotes In Urban Environments At Varying Spatial Scales, Sharon A. Poessel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As urban development continues to increase throughout the world, wildlife species, including carnivores, will be affected either positively or negatively. Coyotes (Canis latrans) have learned to efficiently adapt to highly developed areas, and conflicts between humans and coyotes, such as attacks on humans and pets, are increasing. We conducted three studies of urban coyotes to understand the factors affecting habitat use by coyotes so that wildlife managers can reduce human-coyote conflicts. Each study was conducted at progressively larger scales, with the first study at a fine scale using captive coyotes, the second study at a local scale in the …

Factors Contributing To The Conservation Of Phacelia Submutica (Boraginaceae), A Threatened Species In Western Colorado: Reproductive Biology And Seed Ecology, Alicia M. Langton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Conservation and recovery plans for rare species require biological and ecological information to discern how they may be susceptible to human disturbances. Phacelia submutica is a threatened annual species in western Colorado. Human activities including energy development, recreation, and livestock grazing are occurring within the species’ range. To provide conservation practitioners with a scientific basis for management, this research aimed to elucidate elements of the species’ ecology. Chapter 2 describes the reproductive biology of P. submutica. Potential insect pollinators were not observed during two years of observations. Floral traits and development ensure self-pollination and reduce the likelihood that insects …

Factors Influencing The Ecology Of Greater Sage-Grouse Inhabiting The Bear Lake Plateau And Valley, Idaho And Utah, Casey J. Cardinal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) are a sagebrush obligate species and as such an indicator of sagebrush (Artemisia spp.) habitat quality and quantity. Sage-grouse populations have declined across western North America. This decline has been attributed to habitat loss and degradation of the sagebrush ecosystem. To determine factors that may cause localized declines in sage-grouse populations, managers may need site-specific information on the ecology and habitat use patterns of meta-populations. This information is currently lacking for sage-grouse populations that inhabit the Bear Lake Plateau and Valley (BLPV), encompassing parts of Idaho, Utah and Wyoming. I captured, radio-marked …

Foraging Ecology Of Cougars In The Pryor Mountains Of Wyoming And Montana, Linsey Blake

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We conducted this study to better understand the impact of cougar (Puma concolor) predation in the Pryor Mountains of Wyoming and Montana. Managers of the Bighorn Canyon National Recreation Area and the Pryor Mountain Wild Horse Range were concerned that cougars were having a negative impact upon a small, isolated Rocky Mountain bighorn sheep (Ovis canadensis canadensis) population and were hoping predation might be limiting a feral horse population (Equus caballus) that was in excess of the Appropriate Management Level set by the Bureau of Land Management. Wildlife tourism brings revenue to the park …

Synthesizing Research And Education: Ecology And Genetics Of Independent Fern Gametophytes And Teaching Science Inquiry And Content Through Simulations, Aaron M. Duffy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The mission statements of Utah State University and the Department of Biology, as well as the requirements of funding agencies like the National Science Foundation encourage an integration of teaching and research. I have attempted to achieve that in my dissertation work by using tools I originally created to support and inform my biological research projects to teach science content and inquiry to middle school and undergraduate students.

Chapter 2 of this dissertation reports the results of surveys for Hymenophyllum wrightii, a fern with independent gametophyte populations in the Pacific Northwest, which improved our understanding of the range, distribution, …

Winter Waterbird Ecology On The Great Salt Lake, Utah, And Interactions With Commercial Harvest Of Brine Shrimp Cysts, Anthony J. Roberts

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Interactions among commercial fisheries and birds have been studied in open ocean ecosystems and at aquaculture facilities. On the Great Salt Lake (GSL), Utah, USA, a commercial harvest of brine shrimp (Artemia franciscana) eggs (i.e. cysts) occurs annually during fall and winter. Coinciding with commercial harvest is the use of the GSL by millions of waterbirds which has the potential to result in conflict among industry and birds. The objectives of my research were to examine fall and winter ecology of birds using the GSL and interactions with the brine shrimp cyst harvest. I examined the influence of temperature and …

Roads And The Reproductive Ecology Of Hesperidanthus Suffrutescens, An Endangered Shrub, Matthew B. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We studied the pollination ecology of the endangered Utah desert shrub, shrubby reed-mustard (Hesperidanthus suffrutescens). We also studied the impacts that dust from unpaved roads has on successful reproduction. In addition, we looked at the relationship between the total number of plants, the spacing of plants, and reproduction. We found that shrubby reed-mustard requires pollinators for successful pollination. Pollinators include many small native bees from the genera Andrena, Dialictus, and Halictus. Additionally, we found that reproduction of shrubby reed-mustard is limited, possibly due to scarcity of these bees. We found that dust from the road …

Dot Product Graphs And Their Applications To Ecology, Sean Bailey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We will introduce a new tool to visualize the comparison between different birds. This tool will allow users to use any number of measurable traits to see relationships between different birds, both individually and collectively.

Ecology Of Coyotes On The Valles Caldera National Preserve, New Mexico: Implications For Elk Calf Recruitment, Suzanne J. Gifford

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Valles Caldera National Preserve (VCNP) managers were concerned about low elk recruitment observed at the same time as an apparent increase in sightings of coyotes and observations of coyote predation on elk calves. The goal of this study was to describe coyotes’ ecological interactions with elk, particularly coyote diet and movements on the Valle Grande, a large grassland meadow in the southeastern portion of the VCNP.

We examined coyote diet by quantifying undigested remains of food items in coyote scats (feces). The most frequent taxa were rodents (montane voles and pocket gophers), elk (adult and calf), insects (grasshoppers and beetles), …

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 …

Homogenization Of Large-Scale Movement Models In Ecology With Application To The Spread Of Chronic Wasting Disease In Mule Deer, Martha J. Garlick

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) that affects deer, elk, and moose. TSEs are prion diseases which include mad cow disease and scrapie in sheep and goats. The disease agent is a misshapen protein called a prion, which causes lesions in the brain, and to date, there is no cure. CWD is a slow-developing, fatal disease, which is rare in the free-ranging mule deer population of Utah. Infected deer shed prions into the environment through saliva, feces, and decaying carcasses. These prions remain infective in soils for many years and healthy deer may contract CWD by …

Ecology Of Isolated Greater Sage-Grouse Populations Inhabiting The Wildcat Knolls And Horn Mountain, Southcentral Utah, Christopher J. Perkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greater sage-grouse (Centrocercus urophasianus) currently inhabit about 56% of pre-settlement distribution of potential habitat. In 2005, the Castle Country Adaptive Resources Management Local Working Group (CaCoARM) was formed to address concerns regarding local sage-grouse populations in Carbon and Emery counties. In 2006-2007, CaCoARM identified the Wildcat Knolls and Horn Mountain as areas of special concern for greater sage-grouse conservation. Both sites selected by the group were inhabited by what appeared to be small isolated sage-grouse populations. Factors limiting small isolated greater sage-grouse populations throughout its range are diverse and largely site-specific.

During 2008-2009, I captured, radio-collared, and monitored …

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 …

Hydrological Characterization Of A Riparian Vegetation Zone Using High Resolution Multi-Spectral Airborne Imagery, Osama Zaki Akasheh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. Located in an arid area with scarce local water resources, this has led to extensive diversions of river water to supply the high demand from municipalities and irrigated agricultural activities. The extensive water diversions over the last few decades have affected the composition of the native riparian vegetation by decreasing the area of cottonwood and coyote willow and increasing the spread of invasive species such as Tamarisk and Russian Olives, harmful to the river system, due to their high transpiration rates, …

Soil Moisture Responses In Traditional And Drought Adapted Landscapes In The Intermountain West, James Gregory

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water conservation in the Intermountain West will be an important issue in the future as population and demand for limited water resources increases. In Utah, outdoor water use accounts for up to 60% of total per capita water use with 67% of that outdoor water being used to irrigate non native plant species to maintain a uniform green appearance. The objective of this study was to measure intra landscape changes in soil water potential during a 21.5 day dry down from DOY 215 to 236.5 in the summer of 2005 and 2006. Four, 2 x 2 replicated traditional and drought …

Decadal-Scale Changes On Coral Reefs In Quintana Roo, Mexico, Thaddeus Allen Nicholls

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In 1988 data on coral reef community composition were collected from two areas, Akumal and Chemuyil, Quintana Roo, Mexico, ranging from 5-35m depth. These areas were revisited in 2005 and data were collected by the same methods and at the same depths as in 1988. Data from 1988 and 2005 were compared to determine if the coral reefs had undergone significant changes, and what specific changes had occurred. Chi-square analysis determined that community composition data collected in 1988 are significantly different from data collected in 2005 at all sites and depths within the categories of corals, gorgonians, sponges, and macroalgae. …

Vascular Plant Species Richness And Distribution In A Heterogeneous Landscape, Kelly J. Mccloskey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution of vascular plant species and species richness in a mid-elevation Rocky Mountain landscape can be attributed to a number of variables. The distribution of species with respect to physiognomic type, patch size, shape, and environmental heterogeneity was assessed for a mosaic landscape comprised of conifer forest, deciduous forest, and shrub-steppe physiognomic types in the southwest comer of Grand Teton National Park, Wyoming. This vegetation is representative of that found in other montane landscapes of the central Rocky Mountains. The vegetation was mapped to physiognomic type; distinct vegetation patches were sampled using one or more small (50 m^{2 …}

Statmod: A Tool For Interfacing Arcview® Gis With Statistical Software To Facilitate Predictive Ecological Modeling, Christine M. Garrard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As geographical information systems and spatial data become more accessible, predictive spatial modeling in ecology is becoming more common. Unfortunately, not all ecologists possess the necessary skills to successfully combine statistical models and geographical information systems. In response to this problem, I wrote an extension for ArcView^® GIS called StatMod. This extension interfaces ArcView GIS with SAS^® and S-PLUS^® statistical software and walks the user through creating and mapping logistic regression and classification and regression tree models.

StatMod was then used to run a series of analyses that would have been difficult without such a tool. A …

The Reproductive Biology And Edaphic Characteristics Of A Rare, Gynodioecious Saxifage: Saxifraga Bryophora Var. Tobiasiae (Saxifragaceae), Kimberly Pierson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I examined the reproductive biology and general ecology of Saxifraga bryophora var. tobiasiae, a rare saxifrage endemic to the West Salmon River Mountains of central Idaho. Saxifraga bryophora var. tobiasiae combines asexual reproduction via bulbils with a sexual mixed-mating system. Flower production occurred in 1996 only, whereas bulbil production occurred in 1995, 1996, and 1997. Bulbil production precedes floral bud formation and is the dominant form of reproduction. When flowering occurs, outcrossing is promoted by protandry and the gynodioecious mating system found in all populations. No autogamous or agamospermous seed set was observed in either female or hermaphrodite flowers, …

Where Language Touches The Earth: Folklore And Ecology In Tohono O'Odham Plant Emergence Narratives, Jennifer L. Hughes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The historical and ecological relationships between the Tohono O'odham and the Sonoran desert landscape are expressed in the stories they tell. The Tohono O'odham have lived in the deserts of southwestern Arizona and northern Mexico for centuries, interacting with their environment and gaining intimate knowledge of desert botanical communities. Many of these interactions are dramatized in their traditional oral narratives. I have characterized those traditional oral narratives that illustrate and articulate Tohoro O'odham interrelationships with Sonoran desert botanical communities as "plant emergence narratives." These stories embody and express the reciprocal relationship between the Tohono O'odham and the plants they cultivate …

Comparative Foraging Ecology Of Sheep And Goats In Caatinga Woodland In Northeastern Brazil, Scott L. Kronberg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Small-ruminant production is an important part of the agricultural economy of northeastern Brazil. However, mild-to-severe undernutrition of livestock is an annual occurrence. Goats can tolerate the marginal forage conditions better than sheep, but the mechanisms underlying their superior tolerance are not understood.

An analysis of animal liveweights at the end of the year-long study indicated that reproducing mixed-race goats gained nearly twice (P<.05) the weight of reproducing hair-sheep of the Santa Ynez breed, and non-reproducing goats gained about 1.2 times more (P<.05) weight than non-reproducing sheep. Daily weight gains of lambs were less (P<.10) than those of kids for their first 80 days of life.

In the wet season, reproducing sheep and goats gained similar (P>.05) weight, while non-reproducing sheep gained more (P≤.05) than non-reproducing goats. Non-reproducing goats had greater (P<.05) forage organic matter intake (OMI) than the corresponding sheep in the two wet periods. In the late-wet period, non-reproducing goats had greater (P<.05) digestible energy intake (DEI) than corresponding sheep did but had similar (P>.05) digestible protein intake (DPI) as sheep.

In the dry …

Determinants Of Small Rodent Distribution And Abundance In A Shrub-Steppe Ecosystem: Influences Of Seeds, Ants And Shrubs, Linda Suzanne Broome

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study had two major objectives; firstly to test the hypothesis of ongoing competition for seeds between small rodents and harvester ants, Pogonomyrmex occidental is, in a cold desert ecosystem; secondly to elucidate how seed abundance and shrub cover influence the distribution and abundance of deer mice, Peromyscus maniculatus. The study area was a sagebrush (Artemisia tridentata) dominated shrubsteppe in southwestern Wyoming. Responses of the small mammal community to ant removal and food addition were assessed on replicated study plots between September 1981 and September 1983. Food addition and shrub removal manipulations were continued from September 1983 …

Investigation Of Selected Aspects Of Kokanee (Onchorhynchus Nerka) Ecology In Porcupine Reservoir, Utah, With Management Implications, Paul Joel Janssen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several aspects of kokanee (Onchorhynchus nerka) ecology were studied in the fluctuating, 80ha Porcupine Reservoir, Utah in order to determine optimum management strategies. In 1981, escapement was enumerated and estimates of egg deposition were made. An estimate of the resulting fry recruitment was also attempted and was successful up to the arrival of spring runoff. In 1982, escapement was enumerated and estimates of egg deposition were made, with subsequent estimates of egg deposition and percent survival to the advanced eyed stage. Age and growth rates were determined and survival rates estimated.

Escapement for 1981 and 1982 was 5,463 …

Ecology Of The Common Snipe In Northern Utah, Samuel C. Winegardner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The study addresses five areas relating to the biology and management of common snipe (Capella gallinago), including habitat requirements, food habits, breeding biology, sexing and aging and census techniques.

The primary habitat requirement of snipe was determined to be areas that were saturated or covered with shallow water. Secondary requirements were vegetation of less than 3 decimeters in height and between 30 and 50 percent density.

Food habit studies determined that snipe selected animal material with larger and more abundant organisms being preferred without regard to species . Plant material appeared to be ingested only incidentally.

Common snipe …