Digital Commons Network^™

Chemical And Non-Chemical Control Of Potato Pink Rot, Xuemei (Missi) Zhang

Electronic Theses and Dissertations

Pink rot of potato (Solanum tuberosum) is a widespread soilborne disease that causes significant losses in the field and storage. It is caused by Phytophthora erythroseptica (Pethybr.), an oomycete pathogen that produces sexual spores that can survive in soil for years. The management of pink rot mainly relies on chemical control. However, the most effective chemical in pink rot control, mefenoxam, is losing its efficacy owing to the development of mefenoxam resistance in P. erythroseptica. To evaluate alternative fungicides (including chemical and biological fungicides) to mefenoxam in pink rot control, two greenhouse experiments and three field trials …

A Spatial Inquiry Into Childhood Lead Poisoning In Shelby County, Tennessee, Cem Akkus

Electronic Theses and Dissertations

Review of the recent literature suggests that integration of geographical information systems (GIS) into childhood lead exposure studies significantly enhances identifying lead hazards in the environment and determining at risk children. The purpose of this study is to find at-risk areas of childhood lead poisoning as well as determining risk factors in Shelby County, Tennessee. The two common deduplication methods: the first blood lead level (BLL) test result and the highest BLL test result were compared. Kappa statistic was used to investigate the effect of residential mobility on hot spots. Global and local spatial autocorrelations, Moran’s I and Getis and …

An Environmental History Of The Rio Grande In The Panama Canal Zone, 1521- 1950., Francisco Javier Bonilla

Electronic Theses and Dissertations

This thesis is an examination of the history of environmental change in the defunct Rio Grande river valley in the former Panama Canal Zone. By mining secondary sources and engineering records, this study provides a narrative of the historic river’s role in the formation of the so-called interoceanic corridor through the isthmus of Panama from 1521 to 1950. More importantly, however, as a case study of river histories in Latin American environmental history, this understudied, Pacific-draining river illustrates how nature and non-human nature made Panama’s strategic transit region into a loci for material flows over time. The Rio Grande played …

Interspecific Association Between Two Distantly Related Species, White-Tailed Deer And Eastern Wild Turkey, Lauren Ashley Madeira

Electronic Theses and Dissertations

Interspecific association between two distantly related species, Odocoileus virginianus(white-tailed deer) and Meleagris gallopavo (eastern wild turkey) was examined in western Tennessee using infrared-triggered cameras. The prediction that presence of one species was independent of the other was tested. Presence or absence of each species, based on occupancy determined from photographs, was assessed using Cohen's kappa coefficient. Additionally, activity patterns were determined using presence-absence data. Results indicated a neutral association between the species. Site visitation by either taxa did not differ significantly by area or year. White-tailed deer occurred at significantly more sites than eastern wild turkey and visited locations over …

Highly Seasonal Reproduction In Desmophyllum Dianthus From The Northern Patagonian Fjords, Keri Feehan

Electronic Theses and Dissertations

The purpose of this study was to determine the basic reproductive biology and seasonality of the Patagonian fjord coral Desmophyllum dianthus. Desmophyllum dianthus is a deep-sea solitary scleractinian found throughout the world’s oceans and an important benthic habitat builder. The Chilean Patagonian fjords are the only known location where this species occurs >50 m and thus are the only place to collect samples efficiently, effectively and economically. Corals were collected via SCUBA approximately every three months (when conditions permitted) from August 2012 to September 2013 from three sites within the Northern Patagonian fjords – Lilihuape (n=76) and Punta Huinay …

Transforming The Aquatic Urban Landscape: Nutrient Status And Management Of Stormwater Basins, Lindsay Skovira

Electronic Theses and Dissertations

Urbanization is a largely irreversible anthropogenic change that degrades environmental quality, including aquatic ecosystems. Stormwater ponds are a popular best management practice (BMP) to mitigate the effects of urban land use on downstream water bodies and contribute significantly to the total area of aquatic ecosystems in some urban watersheds. My research investigated the distribution of stormwater ponds and examined how different urban land uses influenced biophysicochemical conditions and management of those ponds in a rapidly developing suburban watershed in the Econlockhatchee River basin in Florida, USA. I evaluated limnological and ecological parameters in randomly-selected ponds distributed among three urban land-use …

Maurice Merleau-Ponty, Marshall Mcluhan And Communication Ethics: The Taming Of Americanitis, Julie A. Cramer Hunsberger

Electronic Theses and Dissertations

In 1880 neurologist George Miller Beard identified the diagnosis of neurasthenia. Popularly referred to as Americanitis, Beard treated an increasing number of people for symptoms of anxiety, malaise and gastric discomfort. Per Beard, the illness resulted from the rapidly changing mechanical landscape of modernity. Similarly, contemporary Media Ecology literature suggests that Americanitis continues amidst our current digital moment. Manifest as narcissistically anxious nervous exhaustion, digital Americanitis results due to technological encouragement of existential and communicative closure, thereby negatively implicating the human condition, human communication and communication ethics practices. As such, this project considers Marshall McLuhan’s Media Ecology to examine the …

Spatial, Temporal And Within-Species Variation In The Foraging Ecology Of A Marine Predator Across A Dynamic Seascape, David James Yurkowski

Electronic Theses and Dissertations

Spatial, temporal and within-species variation in the foraging ecology among consumers add to the complexities of trophic structure and its processes across all biomes on Earth. In this dissertation, I investigated the foraging ecology and plasticity of an ice-adapted marine predator, the ringed seal (Pusa hispida), inhabiting the Arctic marine environment – a dynamic seascape undergoing rapid climatic changes – across age, space and time using stable isotope analysis and animal satellite telemetry. I used a long-term dataset (1990 – 2013) of ringed seal muscle (n = 630) and liver (n = 558) samples, as well as satellite telemetry data …

An Examination Of Plant Community Composition In Six Carolina Bays On The Coastal Plain Of South Carolina, Katherine L. Altman-Goff

Electronic Theses and Dissertations

Historically high rates of human impact and recent Supreme Court cases, which have affected the regulation of geographically isolated wetlands in the United States, suggest that Carolina bays may be at high risk of human impacts in the future. Conservation efforts should be established based on applied ecological data and, if regulations by state and federal agencies are unable to conserve Carolina bay wetlands, it may be important to prioritize individual bays for preservation on protected lands. I examined plant community composition, diversity, richness, and rarity and soil parameters in six Carolina bays across South Carolina, using a replicated ecological …

Raptors In Temperate Grasslands: Ecology Of Ferruginous Hawk, Golden Eagle, And Northern Harrier In The Northern Great Plains, Shubham Datta

Electronic Theses and Dissertations

Ferruginous hawks (Buteo regalis) are a grassland and shrubland obligate nesting raptor and prefer lightly grazed pasture or idle areas for nesting. Their population reportedly declines in number if more than 30% of an area is cultivated and they rarely nest in areas dominated by croplands. Golden eagles (Aquila chrysaetos) are long-lived raptors with high nest-site fidelity and relatively low reproductive success. Population trends of golden eagles in western United States are unclear although long-term monitoring of populations shows declines in occupancy and breeding performance. Northern harriers (Circus cyaneus) prefer relatively open grasslands and …

Changes In Wetland Conditions And Wetland Plant Communities In The Prairie Pothole Region After 50 Years, Ryann Cressey

Electronic Theses and Dissertations

Wetlands in Stutsman County, North Dakota were revisited after 50 years to assess changes in wetland conditions and plant communities within wetland zones in the Prairie Pothole Region. In 1961-1966, Robert E. Stewart and Harold A. Kantrud conducted a study to investigate the relationship of wetland plant communities to variations of water permanence and chemistry on three study areas: Crystal Springs, Cottonwood, and Mt. Moriah. Within in this region, a severe drought occurred in 1988- 1992 followed by the longest deluge starting in 1993 with wetlands still impacted today. In 2013 and 2014, I revisited 80 of the original wetlands …

Combined Effects Of Tetrakis Hydroxymethyl Phosphonium Chloride And Ammonium On Plankton Community Structure In Blackwater Pond Mesocosms, Marina N. Osier

Electronic Theses and Dissertations

Flame retardant chemicals enter aquatic systems through municipal and industrial wastewater, and despite being detected in surface waters, most have not been thoroughly assessed for environmental risk. Halogenated flame retardants, known to be persistent and highly toxic to aquatic organisms are being phased out, and replaced with new or under-tested organophosphorus flame retardants. Organophosphorus flame retardants, such as tetrakis hydroxymethyl phosphonium chloride (THPC), often have similar applications to and are generally not as persistent as halogenated flame retardants. Single-species toxicity tests of organophosphorus flame retardants reveal a wide range of toxicity values within the range of environmentally relevant concentrations in …

The Spatial Distribution Of Terrestrial Stable Carbon Isotopes In North America, And The Impacts Of Spatial And Temporal Resolution On Static Ecological Models, Sydney M. Firmin

Electronic Theses and Dissertations

Due to the unique spatial and temporal characteristics of ecological phenomena, the extent and grain size of spatial data sets essentially filter the observations. This thesis examines the impacts of temporal and spatial resolution on the modeling of terrestrial stable carbon isotopic landscapes (isoscapes). I model the distribution of leaf stable carbon isotope composition (delta¹³C) for the continent of North America at multiple temporal and spatial resolutions. I generate each delta¹³C isoscape variation by first predicting the relative abundance of C3/C4 vegetation cover using monthly climate grids, crop distribution/type grids, and remote sensing data of plant …

Improving The Inference Of Some Experiemtal Studies By Using Ranked Auxiliary Covariates, Rajai Jabrah

Electronic Theses and Dissertations

In many studies, the measurement of sampling units according to the response variable is costly or time consuming, however, it is possible to rank sampling units according to baseline auxiliary covariates, which are available, easily obtainable, and cost efficient. In these cases, when estimating the population mean, Ranked Set Sampling (RSS) can be a more efficient sampling method than the Simple Random Sampling (SRS) method. In this dissertation, we propose a modified approach of the RSS method to allocate units into an experimental study, aimed to compare two or more groups.

Ranked auxiliary covariates, which are typically correlated with the …

Addressing Data Deficiencies In A Threatened Mobile Marine Predator, Heather M. Christiansen

Electronic Theses and Dissertations

Knowledge of ecological and life-history traits over ontogeny for long-lived migratory marine species is vital to creating effective conservation and management strategies, however these details are often difficult to obtain. Incrementally growing biomineralized structures, such as elasmobranch vertebrae, are metabolically stable and provide the potential to investigate changes in spatial and trophic ecology over ontogeny. In the present dissertation, chemical tracer analysis (δ13C, δ15N, and Δ14C) and opportunistic sightings data are used to address data deficiencies for a threatened marine predator (white shark, Carcharodon carcharias).

Current Status Of Falcon Populations In Saudi Arabia, Albara M. Binothman

Electronic Theses and Dissertations

Falcons (Falco spp.) are widely used for falconry in the countries of the Middle East. During the 2015 breeding season, we surveyed historic and active nest sites of Barbary (Falco pelegrinoides pelegrinoides) and Lanner (F. biarmicus) Falcons in Saudi Arabia. Field and questionnaire surveys were conducted and personal contact with falconers was made to document the current distribution and price changes for Lanner Falcons, Barbary Falcons, Saker Falcons (F. cherrug), Peregrine Falcons (F. peregrinus), Gyrfalcons (F. rusticolus), and Hybrid Falcons in Saudi Arabia. We categorized our survey into three geographic groups; southwest (A), northwest (B), and central (C) regions of …

The Biotic Effects Of Tertiary Geoclimatic Change In The Southern Hemisphere, Stuart Val Nielsen

Electronic Theses and Dissertations

I explore how pre-Quaternary geoclimatic phenomena and geographical heterogeneity influenced sub-continental speciation processes and contemporary biogeographic patterns across the Southern Hemisphere, with particular focus on two regions that have experienced elevated levels of ongoing aridification – sub-Saharan (particularly Southern) Africa and Australia. I used standard methods from the molecular phylogeneticists’ toolbox (e.g. tree building using maximum likelihood and Bayesian approaches, haplotype networks, uncorrected p-distances) combined with environmental niche modeling, morphometric principal components and fossil calibrated molecular dating analyses in order to ascertain the role that Miocene geo-climatic events played in promoting lineage accumulation and diversification through time. I found a …