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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.
21

A Hydrologic and Hydraulic Assessment of Cypress Creek for the Identification of the Potential Habitat for the Bald Cypress and Water Tupelo

Gracer, Tara 01 May 2020 (has links)
Cypress Creek is an under researched sub-watershed of the larger Cache River system located in Southern Illinois and is managed by the Cypress Creek National Wildlife Refuge (CCNWR). In 1996, the Cypress Creek Watershed and its encompassing wetlands were listed under the United Nations Education, Scientific, and Cultural Organization (UNESCO) and Ramsar as a “Wetland of International Importance”. These wetland habitats house unique aquatic woody species, such as the Bald Cypress and Water Tupelo, and have diminished in size due to agricultural priorities and changes in hydrology (Demissie et al. 1990; Illinois Department of Natural Resources 1997). Heitmeyer and Mangan (2012) conducted by the U.S. Fish and Wildlife Service (USFWS), assessed the Cypress Creek Watershed using historical references of pre-settlement topography and geomorphology and present-day soils to determine habitat potential. These variables alone do not address the needs of the aquatic woody species who require flood inundation to survive. This hydrologic and hydraulic assessment examines the present-day hydrologic conditions within the boundary limits of CCNWR by collecting channel geometry and stream discharges, building flow frequencies, and constructing a hydraulic model of Cypress Creek to simulate water surface elevations (WSELs) for the bankfull, 2-year, 5-year, 10-year, 20-year, and 25-year exceedance probabilities. Flood inundations were generated from simulated WSELs and local topography. The calculated potential habitat for Bald Cypress and Water Tupelo is 289 hectares and is located in the northwest part of the study area, south of Cypress Creek Road and above Hickory Bottoms Bridge on CCNWR land. Potential habitat overlap found between Heitmeyer and Mangan (2012) and this assessment is roughly 19 hectares.
22

Evaluation, assessment, and determination of risk to high trophic level piscivores in the Mid-Atlantic: A spatial, biological, and comparative case study of mercury in Virginia bald eagle populations

Kramar, David E. 08 May 2014 (has links)
This research is focused on explaining the concentrations of mercury found in juvenile bald eagles (Halieattus leucocephallus) as a function of the physical and anthropogenic landscape. Due to it's location in the food chain this species is susceptible to a wide range of contaminants (xenobiotics), particularly those that bioaccumulate and biomagnify as they move through the food chain. Previous research has indicated that areas in coastal environments are less susceptible to methylation than those in freshwater environments. Sampling efforts for this research were conducted in such a manner as to obtain an equivalent number of samples from the coastal plain (expected to be low mercury) and the inland regions (expected to be statistically significantly higher). In all cases, results indicated that both feather and blood mercury concentrations were higher in the inland population (Blood: Prob > t = 0.0003, Feather: Prob > t = 0.0002). Utilizing classification and regression tree models (CART), we were able to relate metrics such as the percent of deciduous forest, percent of mixed forest, percent of pasture, and percent of wetland to measured blood mercury concentrations. We also found that the best models were produced using the USGS HUC 12 watersheds (the smallest watershed produced by the USGS). Moreover, we found that metrics describing the amount and type of fragmentation within the watersheds exhibited a significant influence on measured blood mercury concentrations. Contrary to previous research, we found wetlands to be negatively associated with higher blood mercury, whereas the abundance of core forest and a larger patch density (PD) in the deciduous and mixed land cover classes was positively associated with higher blood mercury concentrations. We also found that a higher percentage of pasture was associated with higher blood mercury. / Ph. D.
23

Exploration Of The Genomes Of Two Diverse Conifers

Thummasuwan, Supaphan 13 December 2008 (has links)
My research is focused on advancing understanding of the genomes of two important distantly related conifer species, loblolly pine (Pinus taeda L.) and bald cypress (Taxodium distichum (L.) Rich. var. distichum). Loblolly pine is the most commercially important tree crop in the United States, the major source of pulpwood for paper manufacturing, a source of quality lumber, a prime bioenergy feedstock, and an important part of the ecosystem of the southeastern U.S. Bald cypress is the dominant tree species in the aptly named ¡°cypress swamps¡± of the South.Its ecological importance to the wetlands of the southern U.S. is immeasurable. Moreover, bald cypress is a popular ornamental due to its attractive appearance and extreme resistance to pests, pathogens, and weather. Maintaining the security and productiveness of these important crop/forest species in the face of new pest, pathogen and environmental threats will require a better understanding of their genes and the structures of their genomes. We have conducted a study of loblolly pine and bald cypress in which Cot analysis and DNA sequencing of Cotiltered DNA were utilized to study genome structure. Cot analysis revealed that loblolly pine and bald cypress genomes are each composed of three major kinetic components which we have deemed highly repetitive (HR), moderately repetitive (MR), and single/low copy (SL). In loblolly pine, the HR, MR, and SL components account for 57, 24, and 10%, of genomic DNA, respectively. Of note 2.71% of random genomic sequences (i.e., 580 Mb, an amount roughly three times that of the Arabidopsis genome) show significant (bit score ≥ 60) homology to mRNA sequences. This result suggests that the loblolly pine genome contains many genes or pseudogenes, and/or gene duplications. In bald cypress, the HR, MR, and SL components account for 52, 38, and 4%, of genomic DNA, respectively. Sample sequencing was performed only on the HR component of bald cypress; sequence analysis shows only 0.81% of HR sequence reads with homology to mRNA sequences. My research provides insight into the evolution of these distant conifers and key sequence data that should greatly facilitate ongoing molecular breeding programs.
24

Greater black-backed gull and bald eagle predation on American coots

Sobkowiak, Stefan January 1986 (has links)
No description available.
25

Potential Silvicultural Effects on Bald Eagle Nesting Substrate and Economic Yields at a Navy Installation in the Chesapeake Bay: An Approach Using the Forest Vegetation Simulator and Mahalanobis Distance

Wilburn, John D. 19 March 2012 (has links)
In the interest of maintaining lands to fully support the military mission, Department of Defense (DOD) installations must manage competing objectives under constraints related to mission operations, regulation and compliance requirements, and budget reductions. Silviculture offers promise for ecosystem management while providing financial means through the sale of forest products. This study used forest inventory and bald eagle nest site data to investigate the potential effects of silviculture on bald eagle nesting habitat at Naval Support Facility Indian Head. Mahalanobis distance was used to define and classify preferred nesting substrate. Silviculture was simulated using the Forest Vegetation Simulator (FVS) to assess forest nesting substrate, economic yields and the tradeoffs between these two objectives. An alternative substrate model based on cumulative distribution functions (CDFs) and Boolean logic allowed evaluation of the strengths and weaknesses of the Mahalanobis distance method. The Mahalanobis distance model provided greater relative fit to the sample of nest sites compared to the CDF model but had lower discriminating power between presence and absence data. Simulation results indicate that top performing silvicultural treatments resulted in greater substrate availability compared to no-action over equal time periods. Uneven-age management was shown as the best system for providing nesting substrate as well as favorable economic yields in hardwood stands. Results also stress the importance of thinning in providing future nesting substrate and maintaining preferred substrate late in the rotation. Economic and habitat tradeoffs varied by treatment, suggesting that optimum prescriptions could be identified to provide for both objectives and minimize tradeoffs. / Master of Science
26

Modeling Long-Term Changes, 1958-2011, In The Reproduction And Territory Dynamics Of Bald Eagles Of Florida Bay, Southern Coastal Everglades

Unknown Date (has links)
As top-level piscivores, Bald Eagles are a compelling subject for the study of territory dynamics and are highly representative of the distinctive suite of avian species that occupy Florida Bay. Despite successful recovery of Bald Eagles (Haliaeetus leuocephalus) throughout the species range, the population breeding within Florida Bay has not mirrored this trend. Beginning in the late 1980s, Florida Bay has suffered in its capacity to support species diversity and abundance as a result of extreme changes in hydrology related to altered flows of incoming freshwater. In fact, Bald Eagle territory use in Florida Bay has declined by as much as 43% as year to year variation and sensitivity to transitions between territory states have increased. Florida Bay’s populations of other large, conspicuous fish-eating birds, including Ospreys, Great White Herons, Roseate Spoonbills, and Reddish Egrets each exhibit a similar pattern of decline. The effects of environmental degradation throughout Florida Bay are magnified at higher trophic levels. The negative trend in territory occupancy is most pronounced in southeast Florida Bay whereas effects on territory occupancy in the northwest are minimal. The presence of spatial patterns in territory occupancy, despite regionally available breeding birds, suggests that individuals are evaluating differences in habitat quality for which certain territories are no longer considered viable. Building on our current understanding of the health of this population of Bald Eagles, we have successfully implemented modeling approaches that identify key territory breeding decisions. Loss of early breeding season activity (occupied and active territories) despite maintaining high breeding success indicates that changes in territory dynamics are the result of a failure to breed and not a reproductive failure. As such, future conservation actions should promote early breeding season activity (decisions by breeding pairs to initiate nesting) in areas of Florida Bay that were historically occupied but are now abandoned. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
27

The influence of perch tree distribution and abundance on bald eagle distribution on the northern Chesapeake Bay, Maryland

Chandler, Sheri Kay 12 September 2009 (has links)
Forested shoreline is important perching habitat for bald eagles (Haliaeetus leucocephalus). Bald eagles hunt, feed and loaf on shoreline perches. I measured trees suitable for bald eagle perches along the northern Chesapeake Bay during 1990-1991 to determine the influence of shoreline perch tree availability on bald eagle distribution. The shoreline was divided into 250 x 50 m segments. A segment was considered used if at least 1 eagle had perched on it during 1985-1992. I determined the number of suitable shoreline perch trees, percent forest cover, and distance from the water to the nearest suitable perch tree for each segment. Segments along the Chesapeake Bay had an average of 1 suitable perch tree per 10 m of shoreline. Shoreline segments used by eagles had more suitable perch trees (P = 0.0008) and a larger percent of forest cover (P = 0.0008). Suitable trees on segments with eagle use were closer to water than suitable trees on segments without eagle use (P = 0.0087). The differences in segments with and without eagle use appear to be largely due to the lack of trees in marshes which were used only seldomly. Marsh had few suitable perch trees, less forest cover and a greater mean distance from water to the nearest suitable perch tree than the other land types (P < 0.0001). These factors are unfavorable for foraging eagles and most marsh segments (66.7%) were unused, probably for this reason. The number of suitable perch trees and the percent of forest cover were lower on developed areas than undeveloped, forested areas (P < 0.01 for both tests). Also the distance from water to the nearest suitable perch tree was greater on developed land than forested land (P < 0.01). Thus, development appears to decrease the availability of suitable shoreline perch trees when compared to forested areas. Logistic regression models were created to predict the probability of eagle use, given the conditions at the time of this study. Varying values of development density, percent forest cover, number of suitable perch trees and distance from water to the nearest suitable tree were inputs used in these models to create curves to predict eagle use under different conditions. These curves indicated that, for a given development density, the probability of eagle use increased as the number of suitable perch trees or percent forest cover on the segment increased. Also, for a given development density, the probably of eagle use increases as the distance to water decreases. / Master of Science
28

Movements and home range size of bald eagles from Glacier Bay National Park and Preserve, Alaska: with an analysis of satellite telemetry

Kralovec, Mary L. 23 June 2009 (has links)
During 1991-1993, I studied movements of 23 adult and 7, 8-10 week old nestling bald eagles captured in Glacier Bay National Park and Preserve, Alaska. I estimated locations by homing and satellite telemetry. During the breeding season, the distances adult eagles moved from successful, unsuccessful, and mixed-success nests were not significantly different (£ = 0.148). Regardless of nest success, the proportion of adult eagle locations within 750 m of their nest were not significantly different during the breeding season (£ = 0.152) and between the breeding and non-breeding seasons (£ = 0.075). On average, bald eagles were perched 91 % of the time; and perching was the most frequently observed activity (£ < 0.001). Adult eagles perched more often in conifers than cottonwoods, snags, or intertidal debris (£ < 0.001). Perch types selected (£ = 0.473), as well as eagle activity (£ = 0.126) were not significantly different during the breeding and non-breeding seasons. Fifty-eight percent of radio-ma~ked adult eagles used 3 watersheds in Glacier Bay from August through January 1991-1993. Six adult (26%) and 6 (86%) fledgling eagles moved out of Glacier Bay during the non-breeding season. Four adult eagles (17%) traveled to the Chilkat Bald Eagle Preserve in late November and December (mean distance from nest to preserve = 74 km) and 57% of the fledgling eagles were on the Chilkat River in October, where they remained for 2-12 weeks. After leaving the Chilkat River, all fledgling eagles traveled in a southeasterly direction; one male fledgling traveled 435 km in 28 days to Prince Rupert, British Columbia. / Master of Science
29

Root-Zone Hydrology: Why Bald-Cypress in Flooded Wetlands Grow More When It Rains

Davidson, Gregg R., Laine, Brian C., Galicki, Stanley J., Threlkeld, Stephen T. January 2006 (has links)
Bald cypress (Taxodium distichum) is known to respond to increases in precipitation with increased radial growth even when rooted in continuously saturated sediments where water is not a growth-limiting factor. Measurements of δ¹⁸O, Cl⁻, ³H and hydraulic head in surface water and shallow groundwater in an oxbow lake-wetland in northern Mississippi show that rapid downward flow of surface water into the root zone is initiated only after precipitation-induced increases in surface water depth exceed a threshold value. Rapid flow of surface water through the root zone has the potential to introduce oxygen to sediments that would otherwise be anoxic, facilitating nutrient uptake and growth. Climatic reconstruction using tree rings from bald cypress in this environment appears possible because increases in precipitation generally correlate well with increases in water level, which in turn enhances the delivery of oxygenated water to the roots.
30

Community, cult and politics : the history of the monks of St Filibert in the ninth century

Harding, Christian January 2010 (has links)
In the ninth century, the community of St Filibert, which was established on the island of Noirmoutier in the late-seventh century, relocated five times reportedly due to pressures caused by the invasions of the Northmen. The community produced texts during the period of relocations which emphasised the agency of the Northmen and whose testimony has been readily accepted in most subsequent historical analysis. The twofold aim of this thesis is to re-examine the body of literature produced by the community in order first to measure the narrative it provides against the paradigm of flight from the Northmen, and second to understand the nature of the texts themselves. It will argue that rather than being a community in flight, the Filibertines were involved in some of the most important concerns in the ninth-century kingdoms of Louis the Pious and Charles the Bald. They were not only at the centre of successive royal patronage circles, but they developed the cult of their patron, St Filibert, through the process of relocation in both architectural and devotional spheres. Moreover, their economic activity, which had always been a concern of theirs since the late-seventh century, developed through the use of salt-pans and vineyards as well as through the donation of exemptions from taxation on the transit of goods. Overall this thesis proposes that the ninth century was, for the community of St Filibert, a period largely dominated by growth on a number of levels and argues that the texts that put flight from the Northmen at their heart were written as a method of defining an identity for a community in flux.

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