Physical Sciences and Mathematics Commons^™

Ecological Implications Of Rockweed, Ascophyllum Nodosum (L.) Le Jolis, Harvesting, Jill C. Fegley

Electronic Theses and Dissertations

Harvesting of natural resources usually entails substantial removal of the target species. Where such species are dominant members of natural communities, their removal can have important consequences for their own regeneration as well as for the species assemblages associated with them. Rockweed is an ecologically and commercially important intertidal alga in the North Atlantic, and is increasingly being harvested in Maine. The effects of harvesting on regrowth are well known but little is known about its effects on the species that use this alga as habitat. This research focused on the ecological implications of A. nodosum harvesting on the associated …

Intensification In A Risky Environment: The Case Of Improving Private Grazing Land For Beef Production In Utah, Louise D. Sainsbury

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Utah ranchers commonly face risks to their livelihoods. The objective of this work was to determine if ranchers could make profitable improvements to private land forage given the combined threat of low beef prices, drought, and possible loss of public grazing.

We used linear programming (LINDO) to identify the most profitable solutions for private land investment with an 11-year simulation. Operations were divided into small, medium, and large size classes. Various forage improvements and public permits were options. Two phases of a beef price cycle (peak and trough) and 2 precipitation patterns (wet and drought) were combined as joint favorable …

Ecology Of Treeline Whitebark Pine (Pinus Albicaulis) Populations In Central Idaho: Successional Status, Recruitment, And Mortality, And A Spring Temperature Reconstruction From Whitebark Pine Tree Rings, Dana Lee Perkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research investigated the successional status of treeline whitebark pine (Pinus albicaulis) populations on 14 stands in central Idaho and used empirical statistical models to determine the principal factors affecting recruitment and mortality. The longest lived whitebark pines from four additional high-elevation sites were used to develop a tree-ring chronology to reconstruct over 1,000 years of average April-May temperature.

The assessment of stand structures using size-frequency distributions generally provides evidence that treeline whitebark pine populations are currently self-sustaining in areas of low to nonexistent incidence of white pine blister rust (Cronartium ribicola). However the presence of …

Effectiveness Of Earthen Escape Ramps In Reducing Big Game Mortality In Utah, Mary L. Hammer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

One-way escape gates and earthen escape ramps are structures used to enable deer to exit the highway right-of-way along fenced roads. I compared the use of one-way escape gates and earthen escape ramps by mule deer on two highways in Utah to determine if deer exhibited a preference for either structure. Results showed that earthen escape ramps were used by mule deer 8-11 times more frequently than one-way gates. Highway mortality data suggest that the installation of the escape ramps likely reduced mortality of mule deer in both study locations, because we could not attribute reductions in mortality to decreased …

The Foraging And Habitat Ecology Of Black Terns In Maine, Andrew Gilbert

Electronic Theses and Dissertations

The population of Black Terns in Maine is small and factors related to the ecology of this species’ foraging and habitat ecology might limit population growth and recovery. The objectives were to (1) determine if diet and provisioning rates are limiting chick growth, (2) identify and rank suitable habitat in Maine, and (3) determine if precipitation patterns and water level dynamics are limiting in Maine. I compared growth rates of chicks in 1998-2000 in Maine to rates from other studies, determined the influence of colony, year, and diet on growth rates and food deliveries and used an energetics model to …

A Comparison Of Phytoplankton Communities In Lake Prince And The Western Branch Reservoir, Suffolk, Virginia, Cara Marie Muscio

Biological Sciences Theses & Dissertations

Lake Prince and the Western Branch Reservoir are two eutrophic bodies of water located in Suffolk, Virginia. Lake Prince and its two small tributaries join the Western branch via a constructed spillway. This lake system is a source of water for the surrounding municipalities, and a recreational area for community citizens. In the past, these bodies of water had repeated incidents of low oxygen and nuisance algal blooms, particularly cyanobacteria species. As a result aerators have been installed in the main body of both Lake Prince and the Western Branch Reservoir. In addition, a pipeline has been installed from North …

Effects Of Human Disturbances On The Behavior Of Dabbling Ducks, Melissa Lynn Pease

Biological Sciences Theses & Dissertations

Disturbance of wintering and migrating birds by human activities can cause birds to expend energy in avoidance of humans and reduces the time available for resting and feeding at a time in the annual cycle when fat deposition and energy conservation are important. Also, human disturbances can effectively cause habitat loss by displacing birds from feeding or resting habitat. Managers of natural resources are increasingly faced with decisions about the types and amounts of public use that should be allowed without lowering the value of the resource for wildlife. In order for managers to make decisions about how to minimize …

The Implications Of The Target-Area Hypothesis On The Population Dynamics Of The Spotted Spiny Lobster, Panulirus Guttatus, Denice N. Robertson

Biological Sciences Theses & Dissertations

The target-area hypothesis, based on the theory of island biogeography, predicts that larger islands are more effective at intercepting passive immigrants. Most marine invertebrates have meroplanktonic larvae and open population dynamics, so immigration to populations in isolated benthic habitats is primarily by pelagic larval recruits. Thus, recruitment to isolated habitat “islands” may be more continuous and predictable on large islands than on small ones. Consequently, populations on large islands should not only be larger than those on small islands, but should also have more evenly distributed size structures. These differences in size structure among populations in isolated habitats of differing …

Effects On The Red-Cockaded Woodpecker From Various Spatial And Temporal Applications Of Management Practices, Chad F. Schroeder

Theses and Dissertations

The Red-Cockaded Woodpecker (RCW) is an endangered species endemic to southeastern pine forests in the United States. RCWs are cooperative breeding birds that live together in clusters of old-growth pine trees in which they construct their nesting cavities. The cavities are constructed in living pines, which are predominantly longleaf pines. RCWs also forage upon older pines, preferably longleaf pine. The Endangered Species Act, along with other DoD regulations, requires DoD installations to protect the RCWs and restore their habitat. A popular management practice converts off-site (non-native) pines back to a region's indigenous pines. Conversion provides the best long term RCW …

A Study On The Effect Of Storage Time On Specific Gravity And Eggshell Quality, Brock Kendall Laborde

Honors Theses

No abstract provided.

Measures Of Denitrification In Selected South Dakota Semi-Permanent Prairie Pothole Wetlands, Beverly S. Klein

Electronic Theses and Dissertations

Wetlands are an integral part of agricultural systems in the prairie pothole regions of the North Central United States and Canadian Provinces. Little research has been done on denitrification in prairie potholes, and a better understanding of their denitrifying capability could aide in optimizing management practices near pothole areas. Most probable number (MPN) and denitrifying enzyme activity (DEA or Phase I) assays were conducted. Most probable number (MPN) measures were used to give an estimate of dissimilatory nitrate reduction to ammonia (DNRA) and denitrifying populations present in the wetlands. This study involved 3 selected semi-permanent prairie pothole wetlands near Madison, …

Assessment Of Development Impacts On Coastal Zone: Integrated Approach, Northampton County, Eastern Shore, Virginia, Sarunas Zableckis

Dissertations, Theses, and Masters Projects

No abstract provided.

Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin

Dissertations, Theses, and Masters Projects

The interactive effects of humic acids (HAs) and salinity on the bioavailability and toxicity of the pesticides chlorpyrifos and 4,4'-dichlorodiphenyltrichloroethane (DDT) were investigated. The effects of various HAs on the toxicity of chlorpyrifos were initially assessed with the chronic MicrotoxRTM test. Environmentally relevant concentrations of Aldrich, Peat, Leonardite and Suwannee River HAs had no significant effect on the toxicity of either chlorpyrifos or copper (Cu), the test's positive control. as reductions in contaminant toxicity had previously been reported for some contaminants by HAs, it appeared that salinity might be a mitigating factor. Thus salinity effects were further investigated with Aldrich …

Vitellogenin -- A Biomarker Of Exposure To Environmental Estrogens For Mummichog (Fundulus Heteroclitus) From A Creosote-Contaminated Site?, Sara Mirabilio

Dissertations, Theses, and Masters Projects

Vitellogenin (VTG) is widely used as a biomarker for environmental estrogens and reproductive disruption in fish. Vitellogenesis is the process by which yolk is formed. The endpoint is most sensitive in male fish where vitellogenesis is an abnormal process. Research examining effects of environmental mixtures of chemicals (e.g. creosote) on vitellogenesis is limited. This study examines plasma VTG expression in both male and female mummichog, Fundulus heteroclitus, collected from a creosote-contaminated site and two reference sites in lower Chesapeake Bay, USA, and in wild-caught male reference fish exposed in the laboratory to creosote-contaminated sediment. Further, this study uses tissue somatic …

Use Of Pop-Up Satellite Tag Technology To Estimate Survival Of Blue Marlin (Makaira Nigricans) Released From Pelagic Longline Gear, David Kerstetter

Dissertations, Theses, and Masters Projects

No abstract provided.

Evaluation Of Opercular Bones For Aging Eight Species Of Chesapeake Bay Fishes, Ann M. Sipe

Dissertations, Theses, and Masters Projects

No abstract provided.

Growth Patterns Of Three Species Of Catfish (Ictaluridae) From Three Virginia Tributaries Of The Chesapeake Bay, William J. Connelly

Dissertations, Theses, and Masters Projects

No abstract provided.

The Chemical Mechanism Of A Brown-Rot Decay Mimtic System And Its Application In Paper Recycling Processes, Yuhui Qian

Electronic Theses and Dissertations

This work is aimed at improving our current knowledge of the non-enzymatic inecl~anisins involved in brown-rot decay, as well as the exploration of potential applications of a brown-rot mimetic model system in paper recycling processes. The study was divided into two parts. The first part focussed on the chemical mechanisms involved in chelation and reduction of iron by a low molecular weight chelator (isolated from the brown-rot fungus Gloeophyllz~m tmbeum) and its model compound 2,3- dihydroxybenzoic acid (2,3-DHBA). Chelation as well as free radical generation mediated by this system were studied by ESR measurement. The results indicate that the effects …

Heat Shock Protein (Hsp70) Response In The Eastern Oyster, Crassostrea Virginica, Exposed To Various Contaminants (Pahs, Pcbs And Cadmium), Luis A. Cruz Rodriguez

Dissertations, Theses, and Masters Projects

The stress protein response has been proposed as a general indicator of exposure to stress as their expression might integrate overall biological impact and interactions among multiple stressors. as a marker of contaminant effects, a major advantage is the premise of higher sensitivity over other indices such as condition index, scope for growth and survival. Laboratory exposure to suspended field contaminated sediments (SFCS) elicited a stress protein response (HSP70) in the eastern oyster, ( Crassostrea virginica). The stress response probably resulted from the combined effect of various contaminants including PAHs, metals and PCBs. Exposure to 1--2g suspended clay particles spiked …

Application Of The Genetic Algorithm To An Ecological Simulation, William J. Seufzer

Dissertations, Theses, and Masters Projects

A computational framework is built and demonstrated which is capable of testing plant growth strategies. The framework consists of Vgrass, a carbon based simulation model of a single Zostera marina plant, and the genetic algorithm (GA). Vgrass is based on published seagrass models, published photosynthetic data, and general plant physiology information. The model grows individual leaves whose initiation times are based on degree-day intervals. Leaf size is computed and combined with shoot density to compute population self shading. Leaf length is an emergent property since leaf growth is limited by light attenuation caused by self shading. The model is able …