Digital Commons Network^™

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Acclimation, Long-Term Repeatability, And Phenotypic Correlations Of Aerobic Metabolic Traits In The Gulf Killifish, Fundulus Grandis, Jessica E. Reemeyer

University of New Orleans Theses and Dissertations

This research examined the effects of acclimation to lowered salinity, elevated temperature, and hypoxia on aerobic metabolism of the Gulf killifish, Fundulus grandis, a common estuarine resident of the Gulf of Mexico. Standard metabolic rate (SMR), maximum metabolic rate (MMR), absolute aerobic scope (AAS), and critical oxygen tension (P_crit) were each influenced by one or more acclimation treatments. Assessing the consistency of these traits measured in the same individuals over time, all were found to be significantly repeatable with no indication that the repeatability of any traits was affected by acclimation conditions. Significant correlations were found between …

Predation Effects On Mid-Marsh Ribbed Mussel Mortality, Cluster Size, And Facilitation Of Cordgrass Growth, Colten Winter, Keith Walters

Honors Theses

Reciprocal facilitation between Geukensia demissa, ribbed mussels, and Sporobolus alterniflorus, cordgrass, has a positive effect on salt marsh ecosystems. Mussel clusters enhance cordgrass growth and drought resistance and cordgrass provides attachment and shade for mussel aggregations. Along with benefits for both mussels and cordgrass, the mutualism facilitates increased biodiversity and shoreline stabilization and enhances marsh ecosystem functions. Aspects of mussel patch configuration including cluster size, perimeter and connectivity modulate the reciprocal facilitation effects of cordgrass and mussels on marsh ecosystems. In a northern South Carolina marsh system, mussel patch configuration positively influenced cordgrass biomass. Predation affected mussel patch …

A Landscape On The Threshold Of Change: Patterns Of Soil Microbial Ecology Along Dynamic Geomorphic And Hydrologic Features In A Polar Desert, Kelli L. Feeser, David J. Van Horn, Heather N. Buelow, Daniel R. Colman, Theresa A. Mchugh, Jordan G. Okie, Egbert Schwartz, Cristina D. Takacs-Vesbach, Becky A. Ball, Andrew G. Fountain, Michael N. Gooseff, Joseph S. Levy, Maciej K. Obryk

Biology ETDs

The McMurdo Dry Valleys (MDV) of Antarctica are on the threshold of widespread landscape scale change due to increasing temperature and solar radiation and altered hydrology: buried ice is melting, the soil active layer is thickening, thermokarst features are developing along streams, water tracks are expanding, and lake levels are rising. These changes will impact the microbial communities found in each of the affected habitats. The purpose of this work is to first, understand the spatial distribution of soil bacteria in the MDV, specifically investigating the scale-dependent effects of environmental heterogeneity, and second, to perform surveys and coupled experiments to …

Mojave Desert Ecosystem Recovery: Potency Of Biotic And Abiotic Restoration Methods In Low Elevation Plant Communities, Mary Amanda Balogh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The historic and current state of land in the Mojave Desert, including land managed by the National Park Service with fundamental goals of natural resource conservation and preservation, been severely degraded by a variety of anthropogenic disturbances. Due to increasingly sporadic and unpredictable precipitation patterns, land managers struggle to implement restoration projects with high success rates and are resource-limited for post-treatment monitoring. In this study, I examined success rates of biotic (outplanting, seeding) and abiotic (soil manipulation, vertical mulch) restoration treatments on various disturbance types in the creosote-bursage (Larrea tridentata-Ambrosia dumosa), blackbrush (Coleogyne ramosissima), and Joshua tree woodland (Yucca brevifolia) …

Trade-Offs Between Survival And Reproduction In Starvation-Selected Drosophila Melanogaster, Tammara Beeghly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evolutionary outcomes are demonstrated by traits that affect an organism’s schedule of reproduction and survival. These life history traits are reflected in an organism’s physiology, development and behavior. Environmental changes, such as availability of nutritional resources, can profoundly affect evolutionary outcomes of individuals and populations. When shortages arise, there will be trade-offs in the allocation of resources, where one trait prevails at the expense of another.

In the laboratory, we can mimic conditions in nature and study the specific effects of the conditions that we re-create. In our case, over 100 generations of Drosophila melanogaster have been selected for starvation …

Landscape Scale: Inter- And Intraspecific Variation In Plant Interactions Along A Stress Gradient In The Sheep Range Of Nevada, Jordan Dowell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Impending threats to shrubland ecosystems, posed by climate change, necessitate niche modeling efforts to project vegetation range shifts. However, efforts often remain unguided by individual-scale interspecific plant interactions. The stress gradient hypothesis posits that facilitation should increase in areas of high abiotic stress, only if the individuals are able to ameliorate the surrounding area via functional traits. The Sheep Range of Nevada was used to assess the role of functional traits as predictors of plant association. Larrea tridentata, Coleogyne ramosissima, and Artemisia nova were selected as shrubs with variable life history strategies and ranges in order to identify general patterns …

Mojave Desert Plant Community Long-Term Response To Disturbance, Dominic M. Gentilcore

UNLV Theses, Dissertations, Professional Papers, and Capstones

All vegetation communities have been shaped by disturbances. This dissertation consists of three separate chapters: Blackbrush (Coleogyne ramosissima) natural regeneration in the Great Basin-Mojave Desert Transition Zone on two fires, Long-term Response to Fire in Eastern Mojave Desert semi-arid shrubland communities, and an Annotated Checklist of Gold Butte National Monument in the Mojave-Colorado Plateau Transition Zone. The section on blackbrush natural regeneration was a long-term dataset from two fires in Basin and Range National Monument that burned in 2008 with monitoring events in 2009, 2010, 2011, 2018 and 2019. The monitoring documented some of the strongest post-fire regeneration for the …

An Evolving Epigenome That Determines Tissue And Cell Specificity, Renee Louise Sears

Arts & Sciences Electronic Theses and Dissertations

Understanding the mechanisms driving phenotypic variation is a major goal of biology that unifies classical genetics with the emerging fields of genomics and epigenomics. Human and mouse share over 90% of genes and global tissue-specific patterns of expression are maintained between the species. Thus, it is hypothesized that gene expression is influenced through distinctive regulation among species in order to account for the unmistakable phenotypic divergence. DNA methylation, histone modifications, open chromatin patterns, transcription factor binding, and other epigenetic factors are all associated with shaping, maintaining, and repressing regulatory regions which in turn coordinate gene expression. It is vital to …

Pre-Juvenile Naked Goby (Gobiosoma Bosc) Age And Growth, Annamaria Deitz, Juliana Harding

Honors Theses

Due to the abundance of larval naked gobies, Gobiosoma bosc, within the estuarine ichthyoplankton, it is important to understand their age and growth. Naked gobies are a largely distributed, both geographically and within an estuary, small, benthic fish species. There are 3 pairs of otoliths, calcium carbonate structures within the ear canal, that detect vibrations and record the age of the fish, both daily and annually. Using laboratory-reared gobies of a known age (Tremont et al. 2015), daily signatures on the sagittal otoliths were first validated to be daily, then a growth curve for the wild caught larvae was …

California Stream Condition Index (Csci) Score Analysis Of Streams Sampled From 1998 To 2017 In The San Francisco Bay Region, Jenna Rais

Master's Projects and Capstones

Human impacts to California’s streams have altered the state’s riparian and hydrological landscape. This is a critical issue with regard to natural resources, including ecosystem services such as water availability and water quality. Regulations have a limited amount of impact on the improvement of this landscape and can also become complicated by politics. Scientific advances have developed ways to quantify and describe the quality of streams, this includes the development of the California Stream Condition Index (CSCI) which is based on benthic macroinvertebrate (BMI) population numbers and functions. This index allows scientists to not only score the quality of a …

The Best Management Practices For Addressing Human-Caused Riparian And Wetland Degradation, Aldo Lopez

Master's Projects and Capstones

Riparian and wetland ecosystems accomplish a variety of significant ecological purposes, especially in the State of California where a majority of these ecosystems have been removed, degraded, or altered due to human interferences. A large portion of this interference comes from a strong agricultural presence throughout the state. In order to combat further ecological loss, private and public entities have begun strong restorative and managerial efforts. This project reviews the effects of agriculture in riparian and wetland areas, and what are the best management practices focusing on the Santa Clara River Watershed and the Elkhorn Slough found in Monterey Bay. …

Fish Passage And Hydropower: Investigating Resource Agency Decision-Making During The Ferc Hydropower Relicensing Process, Sarah Vogel

Electronic Theses and Dissertations

Hydropower dams represent a significant challenge for the successful migration of sea-run fish, many species of which are in decline. Most hydropower dams in the United States are regulated by the Federal Energy Regulatory Commission (FERC), an independent federal agency responsible for granting 30 to 50-year licenses to projects for their continued operation. Licenses typically include conditions for the conservation of sea-run fish such as fish passage construction, operational changes, monitoring of effectiveness, and other mitigative conditions. While FERC remains the primary authority in licensing, the current regulatory framework stipulates input from other federal and state resource and regulatory agencies, …

Reconstructing Energy Flow Through Modern And Historical Marine Communities: Insights From Amino Acid Isotope Analysis, Emma A. Elliott Smith

Biology ETDs

The fundamental currency of life is energy. Organisms need energy to grow, to survive and to reproduce. Understanding the acquisition of energy by consumers is thus a foundational aspect of biological research. This is especially important in the modern era, as impacts of ongoing anthropogenic effects will be mediated or amplified through food webs. Here, I explore how isotopic analysis of individual amino acids – a technique new to ecological studies – can be used to trace energy flow through animal communities in modern and ancient time periods. In particular, I focus on kelp forest food webs, which are nearshore …

A Male-Female Genotype-By-Genotype Interaction Mediates The Effect Of Mating On Female Immunity In Decorated Crickets, Kylie J. Hampton

Theses and Dissertations

Sexually antagonistic coevolution should lead to the rapid divergence of male and female genotypes related to the effects of ejaculatory substances on female physiology. Hence, the outcome of mating should depend on an interaction between male and female genotypes. Although mating has been shown to influence female immune responses in diverse insect taxa, a male-female genotype-by-genotype effect on female immunity post-mating remains largely unexplored. Here, we investigate both the effects of mating on female immunity and the potential for a male-by-female genotype interaction on the form and magnitude of this response in decorated crickets. Females from three distinct genotypic backgrounds …

Springs Of The Arabian Peninsula: Historical Trends, Current Status And Human Impact In Saudi Arabia, Oman And Jordan, Kamal M. Aljohani

USF Tampa Graduate Theses and Dissertations

This research was conducted to update previous studies of the springs of the Arabian Peninsula (Saudi Arabia, Oman and Jordan). Approach: 76 springs were surveyed in between March and July 2018: 15 Saudi Arabia, 41 Oman and 20 Jordan to ascertain the current status, water quality and zooplankton benthos and fish communities. Investigation of the changes of biota and chemical parameters downstream from the springs source in Saudi Arabia. Results: Mercury exceeded the WHO and USEPA maximum contaminant level (MCL) in 63 of 76 springs, Aluminum exceeded MCL in 8 of 76 springs, and both were the common dissolved heavy …

Diet Composition And Mercury Exposure In Bank Swallows (Riparia Riparia) Breeding At Lakeshore And Aggregate Pits, Corrine S. V. Génier

Electronic Thesis and Dissertation Repository

Bank Swallows (Riparia riparia), a threatened species in Ontario, breed primarily in banks at lakeshores and in artificial aggregate pits. Inland pits may be ecological traps for this species, but the relative tradeoffs between these two nesting habitats are unknown. Availability of aquatic emergent insects at lakeshores may have associated nutritional benefits (e.g. Omega-3 fatty acids) and contaminants (e.g. mercury) that can directly influence juvenile growth. This study compares these breeding habitats to evaluate dietary differences as revealed by fatty acids, stable isotopes (δ¹³C, δ¹⁵N, δ²H), fecal DNA barcoding, and mercury. Lakeshore-nesting …

Snowshoe Hare (Lepus Americanus) Abundance In Relation To Habitat And Predator Assemblage Across The Apostle Islands, Jarod Reibel

Masters Theses

Snowshoe hares (Lepus americanus) are a climate sensitive species that have a southern range boundary moving northward. Snowshoe hares are found on the Apostle Islands, Wisconsin which are near their southern boundary and differ by island in vegetative and carnivore communities. The archipelago serves as a natural laboratory to assess how top-down and bottomup forces interact and impact snowshoe hare populations. The objectives of this study were to determine the influence of vegetative characteristics, specifically visual obstruction, and the presence of predators on snowshoe hare abundances across the Apostle Islands. We conducted fecal pellet surveys to estimate hare abundance, measured …

Impacts Of Shoreline Restoration And Source Of Nutrient Enrichment On Macrophytes And Epiphytic Algal Communities, Paige Marie Kleindl

Masters Theses

Macrophytes and their epiphytic algal communities are integral for optimizing littoral ecosystem functioning in lakes. Epiphytic algae’s placement on the plant’s surface can reduce light and nutrient availability (i.e., nitrogen and phosphorus) for the host macrophyte. Macrophyte and epiphytic algal proximity complicates these primary producer group interactions and responses to bioavailable nutrients in the water column or porewater. For example, epiphytic algae may have a competitive advantage over surface water nutrients compared to macrophytes, which may have a competitive advantage over porewater nutrients via root systems.

Muskegon Lake’s industrial history and designation as an Area of Concern prompted shoreline restoration, …

Seasonal Offshore/Inshore Migration Of Round Gobies, Erik Carlson

Theses and Dissertations

Since the invasion of round gobies (Neogobius melanostomus) in Lake Michigan, they have become integrated into both the nearshore and offshore food webs. Round gobies can be found in shallower water (<20 m) during the summer, but they disappear from these depths in early fall. They have been collected, occasionally, offshore in depths greater than 70 m during fall and early spring. These observations and other anecdotal evidence indicate that round goby migrate offshore during the fall and return in the spring. To study this, a large remotely operated vehicle (ROV) was used to conduct video transects offshore at various depths. The offshore sampling showed that round gobies migrated away from nearshore habitat in early October and were almost exclusively found deeper than 20 m by November. The round gobies remained offshore (>30 m) until mid-May, when they began the return to nearshore habitat. The cues to start the offshore and return migrations were not the focus of this project, but the fall offshore migrations coincided with decreasing temperatures nearshore in the fall, and in spring, the offshore movement of the thermal bar. The offshore migration in fall provide an increase in forage opportunity for deep, cold-water predators such as …

Assessing & Protecting Dark Night Skies In El Morro National Monument, Leslie Kobinsky

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Light pollution is causing the disappearance of dark night skies around the world. In the United States alone, 1/3 of people are unable to see the Milky Way where they live (Ramlagan, 2016). National Park Service sites contain some of the darkest skies in the country. Here at El Morro National Monument, these dark skies are a beautiful and healthy benefit to people in the local community and visitors traveling from afar. El Morro’s current park legislation does not include specific measures of protection for the night sky. This capstone project will create a baseline data set of night sky …

The Implementation Of Qpcr Beach Monitoring Methods: Analysis Of A Multi-Lab Validation Study And The Role Of Environmental Parameters On A Comparison Of Colilert And Qpcr Methods, Molly J. Lane

Masters Theses

Public beaches are routinely tested for potentially pathogenic bacteria to protect beachgoers from possible illness. An EPA approved method, Colilert™, used for testing E. coli in recreational water requires 18 – 22 hours before a result is reported but, recreators have already contacted unsafe water before the beach is closed. My study focused on a U.S. EPA proposed qPCR method (Draft Method C) to quantify E. coli in recreational waters that can provide same-day results. In Chapter 2, I examined the calibration procedure used to validate Draft Method C and compared standard curve intercept and slope estimates calculated with a …

Habitat Use Of The Climate-Sensitive Snowshoe Hare (Lepus Americanus) In The Manistee National Forest In Michigan’S Lower Peninsula, Spencer D. West

Masters Theses

Snowshoe hares (Lepus americanus) are a wide-ranging lagomorph that are important forest herbivores and a popular game species throughout their range. Across the southern boundary of their geographic range, snowshoe hares are experiencing population declines and possible extirpation due to increased predation pressure driven by climate change induced camouflage mismatch, competition for forage, degraded and fragmented habitat. One method of reversing the negative trends in snowshoe hare distribution is to increase and improve available hare habitat. A specific habitat analysis for local regions will most effectively advise managers how to target habitat management. I radio-collared 11 snowshoe hares in the …

Ecology And Conservation Of Shrubland Bird Communities In The Eastern Ghats Of Indi, Anant Deshwal

Graduate Theses and Dissertations

Anthropogenic disturbance, in its multiple facets represents a major threat to biodiversity and habitat quality. Consequently, extensive research is guided towards understanding anthropogenic disturbance and their effects on wildlife for development of wildlife management plans. However, for development of effective wildlife management plans it is imperative that we understand the habitat use and preference by local fauna along with effects of anthropogenic presence. In this dissertation, I studied the habitat usage and preferences of Shrubland birds in the Eastern Ghats of India during the pre-monsoon and post monsoon seasons. Eastern Ghats show a marked difference from pre-monsoon season to post-monsoon …

Eastern Collared Lizard (Crotaphytus Collaris) Population Declines In Ozark Landscapes: An Assessment Of Environmental Constraints., Casey L. Brewster

Graduate Theses and Dissertations

The Eastern Collared Lizard (Crotaphytus collaris) has experienced extensive population declines over the past half century in the Ozark Mountains. Previous research suggests that glade habitat degradation through woody vegetation encroachment is an important factor resulting in population declines. In this dissertation I used information on time-energy budgets to investigate the link between habitat degradation and shifts in life history traits likely resulting in population declines of Eastern Collared Lizards (Crotaphytus collaris) in the Ozarks. In chapter one, I addressed the influence of dense woody vegetation encroachment on age-specific growth, body size, body condition and reproduction of C. collaris in …

A Survey Of Earthworm Communities Across Areas Of Varying Land Management In Northwest Arkansas, Alyssa M. Ferri

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Earthworms are an integral component of the soil ecosystem, impacting factors including soil formation, maintenance of soil structure, and nutrient recycling. Earthworm abundances and distributions are related to abiotic soil properties and can influence the community structure. The goal of this study was to survey earthworm populations across areas of different land management histories and soil characteristics to determine if a relationship between earthworm density and land management characteristics was present. Earthworm and soil samples were collected at irregular temporal intervals from September 2017 to March 2018. In total, five sites were sampled, three at the Botanical Garden of the …

Mammal Species Inventory Using Various Trapping Methods In Zone 4 Of Billy Barquedier National Park, Belize During Rainy Season, Mersady Redding

Animal Science Undergraduate Honors Theses

Belize is a small country, but it is extremely ecologically diverse. Based on the few studies conducted in Belize, the abundance of mammals is low but diversity is high. Particular findings note the number and identity of species differed between four sites in the Maya Mountains of Belize, indicating that a data set from a single site is not representative of the Neotropical region. Insufficient data is available to estimate current species richness of many areas in Belize, including Billy Barquedier National Park (BBNP). The objective of this study was to explore trapping and documentation methods of terrestrial mammals in …

Behavioral Aspects Of Chemoreception In Juvenile Cottonmouths (Agkistrodon Piscivorus), Chelsea E. Martin

MSU Graduate Theses

For snakes, chemical recognition of predators, prey, and conspecifics has important ecological consequences. For example, detection of predator cues can reduce predation risk. Similarly, scent trailing of conspecifics to communal hibernacula can improve overwinter survival for neonates. I used y-maze choice trials to examine scent-trailing ability of 32 captive-born juvenile cottonmouths (Agkistrodon piscivorus) in two separate experiments. In conspecific trailing tests, subjects preferred to follow cues from their own mothers over a blank control cue, but also preferred to trail cues from unrelated adult females compared to cues from their own mothers. My results are consistent with previous …

Effects Of Water Table Depth And Edaphic Characteristics On Plant Diversity In A Southern Mississippi Pitcher Plant Bog, Patrick Kirby

Master's Theses

This study examined the effects that water table depth and soil characteristics have on plant species richness and species composition within pitcher plant bogs across seasons. Eight piezometers were installed at random distances to monitor long-term water table depth and pressure fluctuations along a ~710-meter line transect traversing upland and bog habitats. Vegetation sampling quadrats (n=128) were set up near each piezometer. Cover data and water table depths were collected in spring and late summer. Soil samples collected from each treatment group were used to obtain soil texture and nutrient data. The summer collection period yielded a total gdiversity of …

Effects Of Infanticide Risk And Timber Harvest On American Black Bear Space Use, D. Cody Norton

All NMU Master's Theses

Space use is an important aspect of bear ecology that maybe influenced by infanticide risk and timber harvest. I used generalized linear mixed models (GLMM) to determine if female American black bear (Ursus americanus) space use was consistent with avoidance behavior to reduce infanticide risk in the Upper Peninsula of Michigan during the 2009–2011 and 2013–2014 breeding seasons. Females with cubs occupied core areas and home ranges of similar size and relative probability of male use to females without cubs. Additionally, females with cubs did not reduce movements during times of day when male movements were greatest. Female …