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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Relationships that Extend Beyond the Fence-Line: Private Landowner Attitudes and Interest in Conservation Easements

Vizek, Ashley Lyn 27 May 2016 (has links)
Private land conservation provides an opportunity to address problems of habitat fragmentation and biodiversity loss caused by an increase in the development and parcelization of private land. Conservation easements (CEs) are an innovative tool used by land trusts to protect significant natural qualities of private land in perpetuity, while also allowing the land to remain in private ownership. Traditionally, property represents an individualistic relationship, however, CEs redefine this relationship by seeking to maximize the overlap in private and public goods in property. In this study, I explore the relationship between the common good and private property through an analysis of landowner attitudes and interest in conveying CEs. To address my research objectives I implemented a mixed-mode survey to 664 private landowners in the Whychus Creek Watershed in Deschutes County, OR. I received 257 survey responses, yielding a response rate of 41%. The first layer of this study focuses on landowner attitudes towards CEs (Chapter 2). The results of an exploratory factor analysis suggest there are two dimensions to landowner attitudes towards CEs--internal and external dimension. I constructed logistic regression models to predict positive internal and external attitudes and found that external attitudes are primarily influenced by environmental beliefs, whereas internal attitudes are influenced by a suite of factors including financial beliefs and perceived risk to private ownership. Furthermore, landowner knowledge and awareness of CEs may play a role in attitude development. I found that as awareness increased the number of landowners perceiving low risk also increased. Additionally, I found that those who learned about CEs from a peer were more likely to have an extreme positive or negative attitude towards CEs. The second part of this study focuses on landowner interest in conveying a CE (Chapter 3). The results of a multinomial logistic regression analysis suggest that positive external and internal attitudes towards CEs provide the foundation for CE, while personal incentives and connections to the social and/or natural community serve as the motivation driving CE conveyance. Although the results of this study are only representative of landowners in the Whychus Creek Watershed I argue that some of the findings may be more broadly applicable. Contributing to our conceptual understanding of CEs, I discuss how CEs may be beneficial in reintegrating the common good into private property. Further, I highlight that landowner connections to both the social community and natural environment are important characteristics of CE conveyance as well as private land conservation in general.
142

Conservation of Ecosystem Services and Biodiversity in Vermont, USA

Watson, Keri B. 01 January 2018 (has links)
Supporting a growing human population while avoiding biodiversity loss is a central challenge towards a sustainable future. Ecosystem services are benefits that people derive from nature. People have drastically altered the earth’s land surface in the pursuit of those ecosystem services that have been ascribed market value, while at the same time eroding biodiversity and non-market ecosystem services. The science required to inform a more balanced vision for land-cover change in the future is rapidly developing, but critical questions remain unanswered regarding how to quantify ecosystem services and ascribe value to them, and how to coordinate efforts to safeguard multiple ecosystem services and biodiversity together. This dissertation addresses several of these challenges using Vermont as a model landscape. Specifically, we begin by estimating the economic value of flood mitigation ecosystem services and show that the externalized value of ecosystem services can be quite high. Second, we assess the role of demand from human beneficiaries in shifting the spatial distribution of ecosystem services, and address the biodiversity and human wellbeing implications of that shift. Third we analyze the tradeoffs and synergies inherent in pursing multiple ecosystem services and biodiversity through conservation, and show that overall ecosystem service conservation is more likely to boost biodiversity outcomes than to undermine them. Finally, I implement statewide scenarios of land-cover change and flood risk in order to assess our ability to quantify ecosystem service outcomes and identify spatial priorities for the future despite land-cover change dynamics that are complex and unpredictable.
143

Estimating Landscape Quality And Genetic Structure Of Recovering American Marten Populations In The Northeastern United States

Aylward, Cody Michael 01 January 2017 (has links)
The American marten (Martes americana) is an endangered species in Vermont and a Regional Species of Greatest Conservation Need in the northeastern United States. Though historically widespread in northeastern forests, their range presumably contracted to northern Maine and the High Peaks region of the Adirondacks by the early 1900s. Regionally, populations appear to be in recovery. Natural recolonization is believed to have occurred in New Hampshire, northeastern Vermont and the western Adirondacks. A reintroduction effort in southern Vermont that was originally declared unsuccessful is now believed to be the source of a recently detected population in the area. However, our current knowledge of distribution, population history and population connectivity relies primarily on occurrence data from harvest records, which are limited in scope and resolution. In Vermont, where population size is estimated to be extremely low, more robust estimates of population status may be critical to continued recovery. I genotyped individuals from Maine, New York, New Hampshire, northeastern Vermont and southern Vermont at ten microsatellite loci and amplified a 320 base pair segment of the control region of mtDNA to estimate the source(s) of the two Vermont populations using statistical tests of genetic differentiation. I also used Bayesian and stochastic genetic clustering methods to estimate population genetic structure in the northeastern United States. Genetic structure exists at multiple scales in the region as a result of natural barriers to gene flow, human-mediated gene flow, and lineage sorting in relic populations. My results suggest that New Hampshire is a major source of colonization of northeastern Vermont and the population in southern Vermont is either a remnant of the reintroduction or a pre-reintroduction relic that has experienced introgression from the reintroduction stock. I identified three regions where relic populations perceived to be extirpated in the 1900s may have persisted. I also developed an occupancy model for American marten in the northeastern United States using mixed-effects logistic regression based on expert opinion data. Eighteen experts from Maine, New Hampshire, Vermont and New York with backgrounds in trapping, wildlife management, and wildlife science participated in the survey. Experts were asked to estimate the probability of marten occupancy at 30 sites in the northeastern United States. Three top models described the data. Habitat covariates in those models were 1) percent canopy cover, 2) percent spruce-fir forest cover, 3) winter temperature, 4) elevation, and 5) road density. An AIC-weighted average of these three models had significant predictive ability (area under an ROC curve = 0.88) with respect to occurrence records in the northeastern United States. In addition, the model predicted that high quality habitat existed patchily along the central and northern Green Mountain spine in Vermont – where no occurrence records exist for at least a century. Top-scoring movement corridors between southern Vermont and nearby populations in northeastern Vermont/New Hampshire and New York occurred in the northern and central Green Mountains and across high resistance movement barriers in the Champlain valley. Corridors to New York were considered strong movement barriers and are unlikely to facilitate gene flow.
144

ESTABLISHMENT OF SEROLOGICAL REFERENCE RANGES FOR ELK IN KENTUCKY AND EFFECTS OF QUARANTINE AND TRANSLOCATION ON ELK

Hildreth, Aaron M. 01 January 2017 (has links)
Establishing blood serum profiles is important for understanding animal disease ecology and nutrition, the effects of capture and immobilization, and general physiological variation among individuals and populations. Elk (Cervus elaphus nelsoni) have been successfully translocated to several states for reintroduction or population augmentation, including most recently in Kentucky, where over the course of three years (2011-13) wild elk were captured, temporarily quarantined, and subsequently moved to Missouri and Virginia to establish populations in those states. I used this opportunity to collect a variety of biological samples, including blood from which I present and compare serological profiles for a variety of elk age and sex classes. Additionally, I took the opportunity to investigate the effects of the translocation process on some morphological and physiological parameters of elk. Quarantine and processing of elk can be stressful for animals and lead to injury or death. I characterized how elk respond to this process by measuring biochemical serum values along with various physiological parameters at 5 handling events from the time of capture until final transport to recipient states. Changes observed in parameters between paired workups were indicative of the physical exertion and stress associated with handling activities.
145

Sustainability Analysis of Domestic Rainwater Harvesting Systems for Current and Future Water Security in Rural Mexico

Neibaur, Elena E 24 June 2015 (has links)
Rainwater harvesting, the act of capturing and storing rain, is an ancient practice that is increasingly utilized today by communities to address water supply needs. This thesis examines whether domestic rainwater harvesting systems (DRWHS) can be a sustainable solution as defined by social, water quality, and technical feasibility for water security in semi-arid, rural environments. For this study, 50 surveys and 17 stored rainwater analyses were conducted in San Jose Xacxamayo, Mexico, in conjunction with my Peace Corps work of implementing 82 DRWHS. Results showed that all DRWHS were socially feasible because of cultural acceptance and local capacity. Water quality analyses showed that four DRWHS contained coliform bacteria; deeming water unfit for human consumption. Technical feasibility, examined through climate analyses, showed an average year-round reliability of 20-30% under current and future rainfall regime. The DRWHS can be a sustainable water supply option with roof expansion and treatment prior to consumption.
146

An energy education teaching unit for the fifth grade

Thompson, Lynn A. 01 January 1981 (has links)
No description available.
147

Botswana’s Elephant-Back Safari Industry – Stress-Response in Working African Elephants and Analysis of their Post-Release Movements

Lama, Tanya 11 July 2017 (has links)
Understanding how African elephants (Loxodonta africana) respond to human interactions in ecotourism operations is critical to safeguarding animal and human welfare and sustaining wildlife ecotourism activities. We investigated the stress response of elephants to a variety of tourist activities over a 15-month period at Abu Camp in northern Botswana. We compared fecal glucocorticoid metabolite (FGM) concentrations across three elephant groups, including: eight elephants in an elephant-tourism operation (Abu herd), three elephants previously reintroduced back into the wild from the Abu herd, and wild elephants. There were no differences in FGM concentrations between the three groups of elephants. The highest observed FGM concentrations were associated with episodic events (e.g. intraherd conflict, loud noise, physical injury) unrelated to tourist activities. FGM concentrations differed between the elephant-tourist activities with ride only and mixed ride/walk activities eliciting higher FGM concentrations compared to days when there were no elephant-tourist interactions. The elephant experience tourism industry faces challenges in managing elephants who’s aggressive or unpredictable behavior makes them ill-suited to captivity, training, and interaction with handlers and tourists. Reintroduction of these elephants back into the wild may be a favorable solution if the welfare of released individuals, recipient wild animal populations, and human populations can be ensured. We describe the post-release movements of two African elephants, one female and one bull, from an elephant-back-safari enterprise in the Okavango Delta, Botswana. We compared the movements of the female with that of two wild females collared in the same wildlife management concession. We assess their home range size, proximity to human dwellings, and fidelity to their former home range as former members of their semi-captive, working herd from which they were released. We found significant differences between the home range size of our released elephant and that of the two wild elephants. Additionally, the released female and released bull occurred more frequently in close proximity (within 250 m) to tourist lodges throughout the Delta. The released elephants also frequented sites used by the working Abu herd with greater frequency than the wild elephants, and this visitation rate did not significantly decline during respective four- and two-year post-release monitoring periods, despite the positive growth in home range size.
148

Plants, Parasites, and Pollinators: The Effects of Medicinal Pollens on a Common Gut Parasite in Bumble Bees

LoCascio, George 25 October 2018 (has links)
Declines in several pollinator species are due to a variety of factors, including pathogens. Incorporating pollinator-friendly plant species into wild and agricultural habitats could reduce the stress of pathogens if food sources act medicinally against pathogens. Previous research demonstrated one domesticated sunflower cultivar (Helianthus annuus) can dramatically reduce a gut pathogen (Crithidia bombi) of the common eastern bumble bee, Bombus impatiens. To ascertain the breadth of this medicinal trait, we tested whether pollen from several H. annuus cultivars and four relatives could also reduce C. bombi infections in B. impatiens. We also investigated whether timing of exposure to sunflower pollen relative to time of infection affected the strength of this medicinal trait. In all experiments, bees were infected and then fed their respective pollen diets for a week before they were dissected to assess infection. In our first experiment, all pollen from Helianthus species and relatives reduced C. bombi cell counts compared to our single species control of buckwheat (Fagopyrum esculentum). In our timing of exposure experiments, a one-time exposure to sunflower pollen present at the time of infection did not lower infection levels. In longer exposure trials, sunflower pollen suppressed C. bombi infection with a strength inversely proportional to the time between treatment and infection. Our results suggest that medicinal pollen may be widespread in the Helianthus genus and potentially throughout the Asteraceae family. Thus, these results provide insights into how strategic plantings of certain floral resources can help mediate and influences pollinator disease dynamics.
149

Eastern Whip-poor-will Habitat Associations in Fort Drum, NY

Spiller, Kimberly 02 July 2019 (has links)
The eastern whip-poor-will (Antrostomus vociferus: hereafter whip-poor-will) has been declining from historical population levels throughout its range in the northeast. Although whip-poor-wills have been reported to use a variety of habitats, most recent studies have associated whip-poor-wills with open habitat, such as early-successional habitats or forest edges. Population declines of other early-successional bird species have been attributed to the loss of early-successional disturbance-dependent habitats in the northeast, and it has been suggested that habitat loss is a significant factor in whip-poor-will population declines, as well. However, there remain substantial gaps in our understanding of whip-poor-will habitat associations, and quantitative habitat data in the literature are lacking. As forest management plays an important role in creating and maintaining habitat for many disturbance-dependent bird species, further characterization of whip-poor-will habitat preferences is necessary to determine whether management efforts may benefit this species as well. In order to derive quantitative estimates of habitat requirements, I studied whip-poor-will habitat associations at Fort Drum in upstate New York. In 2015 and 2016, whip-poor-wills were surveyed at night at randomly-selected point count locations and vegetation measurements were collected in the point count radii to relate whip-poor-will occupancy with structural and compositional habitat variables. Whip-poor-will occupancy was strongly related to intermediate amounts of basal area, with values that generally correspond to forest denser than most shrublands, but more open than closed-canopy forest. Occupancy was also related to lower understory height values, which supports evidence that whip-poor-wills may prefer habitat with a relatively open understory. In 2016, I also measured habitat at locations where whip-poor-wills were foraging, roosting, and nesting, to investigate the theory that whip-poor-wills require open habitat for foraging, but more closed habitat for nesting. Ten adult whip-poor-wills were tracked using radio telemetry and vegetation measurements were collected at a subset at these points where the birds were either foraging or roosting during the day, as well as at any identified nest sites. Comparisons of the vegetation measurements revealed that foraging habitat was significantly more open than roosting habitat, as foraging habitat had lower tree density, basal area, and understory height. Contrary to conventional thought, the few nest sites found in this study were in areas that had low basal area, similar to the habitat at foraging locations. The results suggest that while creating more open-canopy habitat may benefit whip-poor-wills by providing suitable foraging habitat, and potentially nesting habitat, maintaining denser forest within proximity to these open areas may also provide valuable cover for roosting whip-poor-wills. In conclusion, I suggest that land owners looking to create or maintain suitable habitat for whip-poor-wills apply forest management treatments that create openings but still maintain intermediate levels of basal area, such as shelterwood or group tree selection. Foraging habitat for whip-poor-wills appears to be generally more open than roosting habitat, both in terms of lower basal area and a more open understory, so having areas where tree and understory removal is concentrated in proximity to areas that are denser may also benefit this species.
150

Compounding Fire Disturbance History Encourages Coast Redwood (Sequoia sempervirens) Regeneration and Community Dominance

Brousil, Matthew R 01 December 2016 (has links)
Disturbance is fundamental to forest ecosystem function and overall health, but climate change is likely to increase both disturbance frequency and intensity in the future. Forests subject to increasingly frequent and intense disturbances are more likely to experience compounding disturbance effects. Compounding disturbances may exert unpredicted, non-additive stresses on ecosystems, leading to novel conditions that may exceed the capacity for local species to survive and regenerate. I further hypothesize that compounding disturbances could create conditions misaligned with species’ adaptations by altering physical and chemical growing conditions in forest soils, affecting forest composition, structure, and, subsequently, function for many years following disturbance. A better understanding of these remnant effects will be essential to managing and conserving coast redwood forests, which are projected to see increased frequency of fire under future climate scenarios. My objectives in this study were to quantify the effects of time-since-fire and single vs. compounding disturbances on coast redwood forest structure, composition, and regeneration dynamics and to evaluate the effects of abiotic soil qualities on post-fire regeneration. I mapped and sampled coast redwood forests burned in 1985, both 1985 and 1999, 2008, and 2013; modeled regeneration as a function of burn history, understory light, and post-fire nutrient levels; and tested redwood seed regeneration in post-fire soils in a greenhouse experiment. Forest structure, composition, and regeneration following compounding disturbance were most similar to the homogenous, redwood-dominated forest of the recent 2013 burn. There were no unique effects of compounding disturbance on soil nutrient levels, although variations in nutrient levels generally followed patterns seen in previous studies. Soil nitrate was positively associated with coast redwood regeneration levels, showing that soil nutrients may be influential in regeneration processes following disturbance. Time since burn and single burn histories were negatively associated with regeneration levels in the field, and there were no differences in seed germination in the greenhouse between soils from different fire histories. Increases in coast redwood forest dominance accompanied declines in bay laurel and tanoak presence, indicating a shift in post-fire forest structure and composition resulting from compounding disturbance. These results illustrate a complex relationship between regeneration dynamics, post-fire soil quality, and disturbance histories. Forest homogenization from compounding disturbances may have negative implications for ecosystem services and overall function if compounding disturbances are more frequent as predicted under future climate conditions.

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