Digital Commons Network^™

Wolbachia-Host Interactions And The Implications To Insect Conservation And Management, Amy Michelle Truitt

Dissertations and Theses

Parasitic reproductive endosymbionts are emerging as formidable threats to insect biodiversity. Wolbachia are prevalent maternally inherited intra-cellular bacteria found in >50% of arthropod species. These symbiotic bacteria interact with their hosts in diverse ways, most often they alter host reproduction causing four conditions that all selectively favor infected females: feminization, male killing, parthenogenesis, and cytoplasmic incompatibility (CI). Furthermore, depending on strain-type and host genetic background, Wolbachia are known to affect insect behavior, expand or shift host thermal tolerance ranges, and confer anti-viral protection to their hosts. Because Wolbachia both reside in and are transmitted with host cell cytoplasm, mitochondria and …

Incorporating Place And Space: A Hierarchical Spatial Approach To Exploring Preventable Congestive Heart Failure Hospitalizations In New York City, Rachael Weiss Riley

Dissertations and Theses

Background: Faced with rising medical care costs, increasing prevalence, and widening health disparities, preventing congestive heart failure (CHF) hospitalizations is a central public health concern. Despite evidence of geographical clustering in preventable CHF admissions, there is a lack of research designed to examine spatial patterning of CHF and the local area neighborhood determinants that contribute to this variability. This study sought to assess and evaluate the importance of both space and place in analyzing preventable CHF hospitalizations and readmissions by applying appropriate statistical techniques, clarifying the assumption inherent in each method, and interpreting the findings within the context of existing …

Are Weevils Picky Eaters? Community Structure And Host Specificity Of Neotropical Saproxylic Beetles (Coleoptera: Curculionidae), Jhunior A. Morillo

Dissertations and Theses

Abstract Primary saproxylic beetles play a major role in forest nutrient cycling and making deadwood accessible to other decomposers. Understanding beetle host preferences and patterns of community assembly is critical for their conservation, and for predicting which species might become invasive. This project aims to investigate the ecological and host specificity, as well as the community composition of curculionids in a mosaic of old-growth (OG) and secondary forest on the Osa Peninsula, Costa Rica. The subfamily Scolytinae was expected to be the most species-rich and abundant. Ambrosia beetles were expected to have more generalist species than other curculionids. Old growth …

Connecting To Nature, Community, And Self: A Conservation Corps Approach To Re-Engaging At-Risk Youth In Science Education, Sara Jo Linden

Dissertations and Theses

The social and environmental challenges of the coming decades will require that individuals possess environmental literacy: the understanding of natural systems combined with a sense of care for the earth, and the confidence and competency to act on its behalf. At the same time, disengaged youth need education environments that foster belonging and promote affective outcomes. The youth conservation corps model provides a natural context for engaging academically at-risk youth in environmental science education, while fostering connection to nature and student self-efficacy in ways that are experiential, relevant, and relationship-based. The focus of this study was a conservation corps program …

Pharmaceutical Contaminants As Stressors On Rocky Intertidal And Estuarine Organisms: A Case Study Of Fluoxetine, Joseph Richard Peters

Dissertations and Theses

Contaminants such as pharmaceuticals are of increasing concern due to their ubiquitous use and persistence in surface waters worldwide. Limited attention has been paid to the effects of pharmaceuticals on marine life, despite widespread detection of these contaminants in the marine environment. Of the existing studies, the majority assess the negative effects of pharmaceuticals over an exposure period of 30 days or less and focus on cellular and subcellular biomarkers. Longer studies are required to determine if chronic contaminant exposure poses risks to marine life at environmentally relevant concentrations. Also scarce in the literature is examination of whole organism effects …

Modern Foraminiferal Assemblages Of The Denmark Strait, Laura Larocca

Dissertations and Theses

Foraminifera occupy a geological range from the early Cambrian to the present day. Their well preserved shells, high relative abundance, and short response time to changing environmental conditions make foraminifera ideal proxies for environmental change. Benthic foraminifera are a valuable but poorly understood paleobiological proxy for the reconstruction of environmental conditions on continental shelves occupied by arctic and subarctic waters. This study identifies, examines, and quantifies calcareous benthic foraminiferal faunas from a sediment core taken from the Denmark Strait. Our analysis of three-thousand individuals from ten discrete samples aim to provide a better understanding of the modern patterns of foraminiferal …

Localized Ecological And Educational Effects Of Environmental Service-Learning In Portland, Oregon, Steven Matthew Braun

Dissertations and Theses

Environmental service-learning is an intentional educational experience(s) wherein learners engage in meaningful activities designed to serve the environment. Environmental service-learning activities vary according to their learning and service goals and include ecomanagement, persuasion, legal action, economic action and political action. The purpose of this mixed methods research was to explore the ecological and educational impacts of grades 6-12 environmental education, with special attention to environmental service-learning throughout Portland, Oregon.

Ecological impacts considered restoration and conservation outcomes of several environmental service-learning programs including plant communities, soils, litter removal and trail maintenance. Educational outcomes considered aspects of environmental literacy including locus of …

Advances In Aquatic Target Localization With Passive Sonar, John Thomas Gebbie

Dissertations and Theses

New underwater passive sonar techniques are developed for enhancing target localization capabilities in shallow ocean environments. The ocean surface and the seabed act as acoustic mirrors that reflect sound created by boats or subsurface vehicles, which gives rise to echoes that can be heard by hydrophone receivers (underwater microphones). The goal of this work is to leverage this "multipath" phenomenon in new ways to determine the origin of the sound, and thus the location of the target. However, this is difficult for propeller driven vehicles because the noise they produce is both random and continuous in time, which complicates its …

Building And Maintaining Plankhouses At Two Villages On The Southern Northwest Coast Of North America, Emily Evelyn Shepard

Dissertations and Theses

Plankhouses were functionally and symbolically integral to Northwest Coast societies, as much of economic and social life was predicated on these dwellings. This thesis investigates both plankhouse architecture and the production of these dwellings. Studying plankhouse construction and maintenance provides information regarding everyday labor, landscape use outside of villages, organization of complex tasks, and resource management.

This thesis investigates three plankhouse structures at two sites, Meier and Cathlapotle, in the Lower Columbia River Region of the southern Northwest Coast of North America. Methods consisted of digitizing over 1,100 architectural features, creating detailed maps of architectural features, and conducting statistical and …

Sustainability Education As A Framework For Enhancing Environmental Stewardship In Young Leaders: An Intervention At Tryon Creek Nature Day Camp, Andrea Nicole Lawrence

Dissertations and Theses

UNESCO established Sustainability Education as a top priority when it declared 2005 - 2014 to be the global decade for sustainability. Sustainability education can be implemented in outdoor programs such as nature summer camps in order to build environmental stewardship and ecological literacy in counselors and campers. This study sought to determine the extent to which an ecology and leadership training given to assistant counselors at Tryon Creek State Natural Area day camp achieved the goals of sustainability education--for the assistant counselors to learn about ecology, develop stewardship attitudes and behaviors toward the environment, and become positive role models for …

A Systems Approach To Ecological Economic Models Developed Progressively In Three Interwoven Articles, Takuro Uehara

Dissertations and Theses

My dissertation develops and analyzes ecological economic models to study the complex dynamics of an ecological economic system (EES) and investigate various conditions and measures which can sustain a developing economy over the long term in view of resilience and sustainability. Because of the intrinsic complexity of the system, I take a systems approach, using economics as the foundation for the basic structure of an ecological economic model, and system dynamics as the method to build and analyze such a complex ecological economic model. Throughout my dissertation, the model developed by Brander and Taylor (1998) is adopted as a baseline …

Externally-Expressed Fluorescence Across Sexes, Life Stages, And Species Of Spiders, Erin Brandt

Dissertations and Theses

Although all spiders possess fluorophores in their hemolymph, the expression of external fluorescence is much more restricted. The purpose of this study was to evaluate differences in externally-expressed fluorescence between sexes, life stages, and species of spiders. To approach this question, we developed novel instrumentation to capture fluorescence with photographs of our specimens. We paired these fluorescence measurements with spectrometer measurements to attempt to determine the role that fluorescence plays in the overall coloration in spiders. The study was divided into four sections. First, we examined how fluorescence varies in sexes and life stages in Misumena vatia, an ambush predator …

The Effect Of The Study Region On Gis Models Of Species Geographic Distributions And Estimates Of Niche Evolution; Preliminary Tests With Montane Rodents (Genus Nephelomys) In Venezuela, Ali Raza

Dissertations and Theses

Various niche-based techniques exist to model a species' potential geographic distribution in a Geographic Information Systems (GIS) framework. These models compare the environmental conditions of localities of a species' occurrence versus those of the overall study region. In addition to uses in areas such as macroecology and conservation biology, this approach has been applied recently to studies of niche evolution and historical biogeography. Definition of the study region is critical for all of these applications but has not been addressed previously. Here, I examine the effect of changes in the extent of the study region on potential distribution models of …

The Nature Of People's Perceptions Of Wolves, Laura Briana Nobel

Dissertations and Theses

European immigrants once regarded wolves as the "devil in disguise" (Lopez, 1978, p.40). With our growing awareness of other cultural perspectives and flourishing body of scientific knowledge with regard to wolves' behavior, our perceptions of wolves have become more complicated and nuanced. Our collective awareness of the environment in which we live also gathers complexity. I examine these issues in this study. Wolves are returning to Oregon. The arrival of wolf B-45 in 1999 heralded the beginning of the return of wild wolves to Oregon. More wolves are expected to cross the border as young sub-adults disperse from the growing …

Zoonotic Disease Emergence : A Study Of Host-Pathogen-Ecosystem Dynamics, Laurie Jeanne Dizney

Dissertations and Theses

A growing body of work demonstrates that loss of biodiversity negatively impacts ecosystem functions. One function, or service, that biodiverse ecosystems provide is suppression of zoonotic diseases, which are defined as diseases carried by wildlife hosts that can spill over into human populations. Ebola, SARS, West Nile virus, Hantavirus, Avian Influenza and Lyme disease are just a few of the recently emerging zoonotic diseases. Disease suppression has been shown for Lyme disease by the dilution effect, whereby increasing species diversity decreases disease prevalence in the host populations. But does a dilution effect apply to other disease systems? To test this …

Woodland Amphibian Distribution In Parks And Greenspaces Of The Portland, Oregon Metropolitan Area: A Multiple Scale Investigation, Laura A. Roberts

Dissertations and Theses

Loss of biodiversity due to habitat fragmentation is worldwide problem. With growing human populations and increasing urbanization, it is a necessity to conduct studies on wildlife occurring in urban areas. Currently there is a deficit of research investigating woodland amphibians in urban environments. My objectives were to describe amphibian species richness and abundance in the Portland, Oregon, Metropolitan region, and relate patterns of variation to variables at three increasingly large spatial scales: 1) local microenvironmental (i.e. amphibian/substrate interaction), (2) macrohabitat/patch (i.e. park or greenspace), and 3) landscape (surrounding parks and greenspaces). Environmental variables occurring within the three spatial scales were …

Low-Income Homeownership In Portland's Albina Community: A Comparative Analysis Of Housing Quality In Market-Rate And Subsidized Houses, Carolyn Emily Collopy

Dissertations and Theses

The purpose of this study was to detem1ine which of these two options, market-rate or subsidized, offer higher quality affordable housing to low and moderate-level income households. Through field observation and GIS analysis, the study compared the structural, block, neighborhood amenity, crime, and proximity to CBD characteristics of affordable market-rate and subsidized houses in Portland's Albina Community. The study samples were approximately 100 houses per sample; market-rate houses consisted of houses that sold during 2000 for $125,000 or less, and subsidized houses were selected from housing created by three local non-profit development agencies.

General characteristics of the two samples revealed …

The Impacts Of The Introduced European Green Crab, Carcinus Maenas, On Selected Bivalves And Meiofaunal Communities, Zasha A. Bassett

Dissertations and Theses

This thesis examines the potential impact of the invasive green crab, Carcinus maenas, in Yaquina Bay, Oregon. I sampled the current extent of crab colonization in the intertidal zone of Yaquina Bay using a standardized trapping regimen in selected intertidal sites in August and September 1999. I also evaluated the potential impacts of C. maenas on the commercially important bivalve, Crassotrea gigas. Carcinus' preferred size ranges of C. gigas and other species were experimentally determined. Additionally, Carcinus species preference for C. gigas was examined in relation to two common bivalves, Mytilus trossolus and Macoma nasuta. Experiments were …

The Effects Of Urbanization And Human Disturbance Upon Plant Community Structure And Bird Species Richness, Diversity, And Abundance In A Natural Forested Area (Forest Park) In Portland, Oregon, Nancy Ellen Broshot

Dissertations and Theses

The effects of urbanization and continual human disturbance on the plant and avian communities of Forest Park and forested lands surrounding Portland, Oregon, were studied. I examined characteristics of plant and avian communities at 25 sites, 24 which were in Forest Park and surrounding areas and one which was in the Ancient Forest Preserve (old-growth stand) northwest of Forest Park. Data were analyzed using multiple regression, ANOV A, and Bonferonni/Dunn. Seven variables were selected representing different urbanization gradients. An additional covariable coded for the old-growth stand, allowing it to be used as a control.

Many tree variables, especially those related …

Gene Expression In Two Cyanobacteria, Freshwater Synechococcus Sp. Pcc 7942 And Oceanic Synechococcus Sp. Wh 7803, In Response To Ammonium, Nitrate Or Iron, Abbas Sadeghi

Dissertations and Theses

The transcriptional response of freshwater Synechococcus sp. PCC 7942 and oceanic Synechococcus sp. WH 7803 to ammonium, nitrate or iron was studied in single or multiple factor limited cultures. Both strains showed maximum production of NiR mRNA when grown in nitrate-containing media. When grown in ammonium-containing medium, they did not show any signal for NiR mRNA synthesis. The influence on the transcription of NiR mRNA by iron as sole limiting nutrient was also evaluated. Iron increased the NiR mRNA whether or not the positive effect of nitrate was already present. The hybridization signal of mRNA for the large subunit of …

Enculturing Nature, William Lloyd Cornett

Dissertations and Theses

Human activity is embedded within a myriad of seldom-acknowledged ecological relationships. Anthropology and ecology, two holistic disciplines concerned with these activities, struggle with the topic of human/nature relationships because both are grounded within larger western discourses separating human behaviors from those of the natural world. This thesis examines the histories of anthropology and ecology in the 20th Century, and the effect these disciplines have had upon the formulation of contemporary urban worldviews that are based upon the separation of humans from nature.

Ecology, Wilderness Selection, And The Salmonhuckleberry Roadless Area, Jason Scot Barker

Dissertations and Theses

In the 1970s, the Forest Service used ecology in the process that led to the SalmonHuckleberry roadless area in the Mount Hood National Forest becoming a Congressionally designated Wilderness in 1984. This case study of the history of SalmonHuckleberry roadless area confirms the criticism made by environmentalists that noncommercial forest values have received much less priority than commercial uses in forest planning during the late 1960s and 1970s. This study of the area also reveals that the Forest Service's planning process was fundamentally flawed because Forest Service planners often lacked scientific data to support management decisions and downplayed the sigificnace …

The Periphyton Community Of A Second Order Subalpine Stream Following Salmon Carcass Decomposition, Jonathan Micheal Honea

Dissertations and Theses

To protect and manage Pacific Northwest salmonid stocks, sound management programs must be developed that incorporate knowledge of the ecological processes critical to their survival. One such process is the nutrient dynamic in headwater spawning streams. It is essential that we understand the trophic relationships among the spawners, the I to 3 year-old juveniles, the invertebrates, and the primary producers in these streams.

The hypothesis that I tested is that photoautotrophic production increases due to the decomposition of salmon carcasses. Increased primary production would stimulate the production of invertebrates which are an important food resource of juvenile salmonid species. The …

The Summit Vegetation Of Saddle Mountain, Oregon Coast Range, Charles Thomas Carlson

Dissertations and Theses

Saddle Mountain (1000 m) is the highest peak in the Northern Oregon Coast Range. Meadows are found to occur at and near the summit of the mountain which contain abundant wildflowers. Although the majority of these meadow species have been collected and identified in the past no formal study has been done to classify them into communities. The purpose of this study is to examine the character and origin of the plant communities located at or near the summit of Saddle Mountain. Data were collected on 4 study sites during the Summer of 1996 and analysis of the data lead …

Phytoplankton In Mt. St. Helens Lakes, Washington, Cynthia Fay Baker

Dissertations and Theses

Phytoplankton communities in fifteen lakes in the Mt. St. Helens area were surveyed to assess the abundance and species present. Eleven of the lakes were inside the blast zone of the 1980 eruption and four were located outside the blast zone as a comparison. The hypothesis is that lakes will cluster together based on the algal species present and that some algae will be correlated with certain environmental conditions. A cluster analysis was performed to determine if the lakes would group together based on algal abundance. There did not appear to be any distinct clustering among the study lakes, but …

Fringe Area Growth In Metropolitan Portland: An Analysis Of Space-Time Variations In Residential Housing And Land Conversion, 1970-1980, Sheku Gibril Kamara

Dissertations and Theses

Urban ecological problems have hitherto been addressed using one of two major approaches. The first has a social impetus directed at ethnic, economic and family characteristics and their relationships with the spatial distribution of urban residential housing. The second approach emphasizes the influence of the physical environment and the services available to subareas. The sociological method has had much more attention in modeling applications than the physical analytic technique. This study adopts the physical approach with a focus that is emphatic on infrastructural factors and land attributes, and their influence on the differential rates of fringe area residential growth in …

A Biogeographical Study Of Currently Identified Oregon Pseudoscorpions With An Emphasis On Western Oregon Forms, Ellen M. Benedict

Dissertations and Theses

The biogeography of the 50 currently identified Oregon species is reported from analyses of data from 2220 Berlese samples collected in a stratified, extensive sampling procedure, and from collection data on several hundred specimens from major private and public collections of pseudoscorpions. Individual species accounts including maps and data relating to geographical and seasonal distribution and habitats are provided, distributional areas and habitat types are categorized, dispersal mechanisms including examples of phoresy are presented and an illustrated key to Oregon species is given.

The Effects Of Urban-Rural Life Histories Of The Aged On Urban Adaptation, Michael R. Deshane

Dissertations and Theses

Among the major interests of students of urbanism and urbanization in the United States have been the understanding and explication of differences between urban and rural segments of American society. Coupled with this has been an attempt to theoretically delineate the effects of these differences on the social psychological adjustment of urban and rural inhabitants. The culmination of this work in sociology is to be found in Wirth's (1938) essay "Urbanism as a Way of Life." Wirth identified three major differences between urban and rural lifestyles which have been the impetus for considerable research and controversy. The three major differences …

Thermal Ecology And Movement In The Leopard Lizard, Gambelia Wislizeni, Baird And Girard, Marvin Lynn Abts

Dissertations and Theses

Thermal ecology and movement of the Leopard Lizard, G. wistizeniwere studied at Frog Spring, adjacent to the Alvord Desert, and at various locations throughout the Alvord Basin. Seasonal activity is known to occur from early May to mid-October, but abundance. gradually decreases after late July. During favorable late spring, and summer weather lizards exhibit a bimodal pattern of diel activity with some activity occurring at all hours of the day between 0600 and 1800 H. At other times activity was unimodal. Emergence was apparently largely temperature dependent and did not occur until sand temperature approximated 21°C. Retreat appeared to …

Interactions In The Frequencies Of Electric Organ Discharge By Eigenmannia Virescens (Sternopygidae, Pisces) During Social Behavior, Philip Gaddis

Dissertations and Theses

The extent to which individuals of Eigenmannia virescens modulate their electric organ discharge frequencies to accommodate the frequencies of others of the same species during social interactions was investigated. Recordings of the fish's discharge frequencies, taken with Tektronix 3L5 and 5L4N spectrum analyzers, showed that, although movements of up to 60 Hz in a day may be made, the frequency movements would be made more or less synchronously by all fish in the group. An apparent preference for, and a tendency of the fish to follow one another in frequency, at frequency ratios of 2:3 (a musical fifth), 3:4 (fourth), …