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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

Garbage or Godsend?: Contested Meanings Among Conservation and Humanitarian Groups on the United States Border

Shellabarger, Rachel Marie 23 March 2010 (has links)
Conservation and human rights are currently threatened by direct and indirect effects of border enforcement practices on the Arizona-Sonora border. Increased border enforcement in urban areas has pushed migrants into remote conservation areas, threatening both the vulnerable borderland ecosystems and the human migrants passing through them. This study examines responses to human and environmental impacts of border policies in the case study region of Altar Valley in southern Arizona, where migrant traffic has increased greatly as a result of the expanded border enforcement near urban centers. We use ethnographic methods to explore and understand the actions of land-management and humanitarian aid groups attempting to address the socio-ecological crises wrought by increased border enforcement, in order to look for ways to reduce the crises through a better understanding of the context. Community partners include the Buenos Aires National Wildlife Refuge, the Coronado National Forest, and the No More Deaths humanitarian aid group, all located within 25 miles of the Arizona-Sonora border. The results of this study, carried out largely during the summer of 2008, describe how the actions of land-management and humanitarian groups eventually conflicted and resulted in littering citations for the humanitarian aid volunteers who left water for migrants along trails on the wildlife refuge. The conflict was branded as an issue of conservation versus human rights. I argue that the conflict between land-management personnel and humanitarian aid volunteers arose not just from differing conservation and humanitarian goals, but from their different conceptions of problems associated with border activity and different ideas of the borderlands as a place.
22

Impact of Plant Organic Matter on PAH Desorption from Petrogenic-Polluted Sediments

Musella, Jennifer Suzanne 08 January 2007 (has links)
Polycyclic aromatic hydrocarbon (PAH) bioavailability does not correlate directly with total PAH sediment concentration because PAHs strongly sorb to organic matter. Many current toxicological models assume that PAHs present in the dissolved phase reflect actual PAH bioavailability to organisms. Plants can release significant amounts of plant organic matter (POM) to soils and sediments; however, the mechanisms by which POM may affect PAH bioavailability in sediments are unclear. The rhizosphere may increase PAH bioavailability by destabilizing soil organic matter (SOM) and enhancing PAH desorption, or the rhizosphere may alter SOM composition and provide new carbon matrices to sorb/sequester PAHs and reduce PAH desorption. Desorption studies were conducted to determine if vegetation decreased or increased the rate and mass amounts of desorbable PAHs. Replicate desorption studies were conducted using vegetated and non-vegetated bulk sediment and HF/HCl humin fractions; sediments were collected from a coastal refinery distillate waste pit (RP) and refinery-impacted sediments from a freshwater canal (IH). Desorption isotherms for four PAHs were determined by two methods, aqueous and TenaxTM bead extractions. PAHs were quantified by gas chromatography/mass spectrometry selected ion monitoring (GC/MS SIM). Results showed differences in PAH desorption based on the amount of time vegetation had been present in sediments. Vegetated sediments with 30+ years of vegetative growth (RP) desorbed more PAHs than non-vegetated sediments by TenaxTM extraction in both bulk and humin sediment fractions. Recently vegetated, IH freshwater sediments desorbed fewer PAHs than non-vegetated IH sediments by aqueous and TenaxTM extractions in bulk and humin sediment fractions. These findings suggest that initial exposure of sediment to vegetation slows PAH desorption and that extensive exposure to vegetation enhances PAH desorption from both labile and refractory SOM.
23

APPLICATIONS OF GEOGRAPHIC INFORMATION SYSTEMS FOR GROWTH MANAGEMENT PLANNINGAND WATER QUALITY PROTECTION IN THE COASTAL REGION OF NORTH CAROLINA

ESSIC, JEFFERSON FORREST 14 January 1998 (has links)
<P>ESSIC, JEFFERSON FORREST. Applications of Geographic InformationSystems for Growth Management Planning and Water Quality Protection inthe Coastal Region of North Carolina. (Under the direction of Hugh A. Devine.)<P>Research efforts conducted in coastal areas of North Carolina andother regions have documented numerous examples of negative impacts toestuarine water quality as a result of unplanned and unmanaged development.However, new construction is continuing at a rapid pace in these areas,forcing local planners to make complex decisions regarding land uses andprotection of cultural and natural resources.<P>A Geographic Information System (GIS) is a computer-driven toolthat has proven valuable in assisting with this decision making process.GIS technology provides the means to efficiently collect, store, and retrievevast amounts of spatial data. Then, this information may be visually displayedin a manner that supports better understanding and analysis of the physicalenvironment and the potential impacts of growth.<P>There have been many instances during the past decade in whichGIS has been used to meet the educational and informational needs of citizensand local officials who want to ensure a strong economy and healthy environmentis planned for the future of their community. Most of these projects haveoriginated at the state level, either through the North Carolina CooperativeExtension Service, or other agencies.<P>A number of zoning options and growth management planning measureshave recently been recommended that coastal government officials shouldconsider for promoting stewardship and protecting important natural resourceswhile continuing to maintain economic vitality. This paper focuses on theapplication of GIS for analyzing and implementing many of those strategieswith emphasis on local responsibility.<P>In particular, the natural suitability of cluster development forCurrituck County, North Carolina, is examined with GIS. Attention to growthmanagement planning in this coastal county is critical since the populationis projected to increase over 73 percent from 1990 to 2020. GIS data layersfrom the North Carolina Center for Geographic Information and Analysis,as well as digitized Federal Emergency Management Agency Flood InsuranceRate Maps, are used to determine the extent of Primary Conservation Areasin the county. In addition, Secondary Conservation Areas are identified
24

A Comparison of Digital Vegetation Mapping and Image Orthorectification Methods Using Aerial Photography of Valley Forge National Historical Park

Koch, Frank Henry Jr. 18 April 2001 (has links)
<p>In recent years, mapping software utilizing scanned?or ?softcopy??aerial photographs has become widely available. Using scanned photos of Valley Forge (PA) National Historical Park, I explored some of the latest tools for image processing and computer-based vegetation mapping. My primary objective was to compare different approaches for their efficiency and accuracy. In keeping with the USGS-NPS Vegetation Mapping Program protocol, I classified the park?s vegetation according to The Nature Conservancy?s National Vegetation Classification System (NVCS).<p>Initially, I scanned forty-nine 1:6000 color-infrared air photos of the area at 600 dpi using an Epson desktop scanner. I orthorectified the images by two different methods. First, I did so on a single-image basis using ERDAS Imagine. In this approach, United States Geological Survey (USGS) Digital Ortho Quarter Quadrangles (DOQQ) and a 10-meter Digital Elevation Model (DEM) served as references for between seven and twelve ground control points per photo. After achieving a root mean square error (RMSE) of less than 1 meter for an image, I resampled it into an orthophoto. I then repeated the process using Imagine Orthobase. Via aerial triangulation, Orthobase generated an RMSE solution for the entire block of images, which I resampled into orthophotos using a batch process. <p> Positional accuracies were remarkably similar for image mosaics I created from the single-image as well as the Orthobase orthophotos. For both mosaics, planimetric x-coordinate accuracy met the U.S. National Map Accuracy Standard for Class 1 maps, while planimetric y-coordinate accuracy met the Class 2 standard. However, the Orthobase method is faster?reducing process time by 50%?and requires 20% (or less) of the ground control points necessary for the single-image method.<p>I delineated the park?s vegetation to the formation level of the NVCS. Using ESRI ArcMap, I digitized polygons of homogeneous areas observed from the orthophotos. This on-screen mapping approach was largely monoscopic, though I verified some areas using a scanning stereoscope and the original hard-copy photos. The minimum mapping unit (MMU) was 0.5 acres (ac), smaller than that recommended by the USGS-NPS protocol. Based on field data, thematic accuracy for this map met the National Map Accuracy Standard of 80%. Misestimation of the hydrologic period of certain polygons resulted in some classification errors, as did confusion between evergreen and deciduous vegetation. <p>In addition to orthophotos, Orthobase creates a stereo block viewable in ERDAS Stereo Analyst, a digital stereoscopic software package. Using Crystal Eyes? eyewear and a high-refresh-rate monitor, a user can observe imagery full screen, three-dimensionally. Features delineated on the images are stored in ESRI shapefile format. I created a preliminary vegetation map at the alliance level of the NVCS with this software. Thematic accuracy of this map will be known when assessment is completed this summer. Notably, the classification scheme has required revision to accommodate the anthropogenically altered landscape of Valley Forge. <p>Nevertheless, it is clear that Stereo Analyst offers advantages for vegetation and other types of mapping. Stereoscopic view and sharp zoom-in capabilities make photo interpretation straightforward. Because features are delineated directly into a GIS, Stereo Analyst cuts process time by 70% and avoids two steps that can introduce errors in conventional mapping methods (i.e., transfer to map base and digitizing). Perhaps most importantly, joint use of Orthobase and Stereo Analyst allows simultaneous orthophoto creation and GIS data collection; in contrast, the ArcMap approach requires finished orthophotos before features can be delineated. Ultimately, though, both monoscopic and stereoscopic methods have roles in vegetation mapping projects. The level of detail required for the project should determine which technique is most appropriate. <P>
25

Voluntary Conservation: Private landowner participation in North Carolina's Natural Heritage Program (spatial analysis of the Natural Heritage Program in North Carolina)

Cassingham, Kirsten Michaele 22 August 2001 (has links)
<p>Conflict between the public interests in non-timber amenities of forests and the private rights of forest owners has focused attention on voluntary conservation agreements as a policy tool. In North Carolina, the Natural Heritage Program identifies ecologically significant sites and provides two mechanisms for landholders to participate in conservation of those sites. Evaluation of the program from a spatial perspective focused on the mountain province of North Carolina, using a geographic information system (GIS) to characterize the conservation outcome of the program (i.e., what has been conserved) and the determinants of participation in the program (i.e., who has conserved). To characterize the participation decision, literature was reviewed on voluntary forest stewardship and conservation programs and spatial analysis of land-use. The effect of neighborhood characteristics (e.g., near-by protected areas) and distance (e.g., from highways and cities) was considered, as well as characteristics of the landowner and of the site. The conservation outcome of the program was evaluated in terms of protection of ecologically significant sites, considering both Heritage Program rankings and land cover.<P>
26

Development of a digital protocol for vegetation mapping

Harrell, Melani Hix 07 November 2001 (has links)
<p>ABSTRACTHARRELL, MELANI HIX. Development of a digital protocol for vegetation mapping. (Under the direction of Dr. Hugh Devine)Softcopy photogrammetry has proven useful to reduce mapping time with aerial photography and aids in producing a digital product that is easily transferable over other electronic media. This study brings together computer stereo viewing with scanned aerial photos in a GIS to produce a fully digital protocol for mapping vegetation to the formation level. Erdas Imagine was used to generate digital images from aerial photos, Erdas Orthobase was applied to orthorectify the images through a joint triangulation solution for 42 photos, and Erdas StereoAnalyst provided on screen stereo viewing for vegetation delineation. Vegetation polygons were then classified using the National Vegetation Classification System formations in ArcView 3.2, and a thematic accuracy assessment was carried out on the vegetation map using the USGS-NPS standards. A positional accuracy assessment was conducted on the photo mosaic produced from the orthorectified images. Thematic accuracy was 77.55% initially, and the revised map had an 88.70% thematic accuracy. Positionally, the photo mosaic had Class 1 positional accuracy along the X-coordinate with 0.603 meters RMSE and had Class 2 accuracy along the Y-coordinate with 2.415 meters RMSE. A protocol using entirely digital methods was produced with the software cited that meets the formation level USGS-NPS vegetation mapping standards. <P>
27

State-making and community-based natural resource management : cases of the Vhimba CAMPFIRE Project (Zimbabwe) and the Chimanimani Transfrontier Conservation Area (Mozambique) /

Singh, Jaidev, January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 151-163).
28

Integrated research in natural resources : an exploratory analysis of five case studies /

O'Toole, Elaine Susan. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 138-144). Also available on the World Wide Web.
29

Individual Behavioral Phenotypes of the Cliff Chipmunk (Tamias dorsalis): Effects on Female Reproductive Success and Juvenile Habitat Selection

Kilanowski, Allyssa LeAnn January 2015 (has links)
Differences among individual responses to behavioral stimuli have been observed throughout a variety of taxa and these individual differences can affect female reproductive success and juvenile settlement decisions. In this study, we examined the effect of reversed sexual dimorphism on behavior phenotype and the effect of behavior on maternal reproductive success and juvenile dispersal of a fossorial rodent (Tamias dorsalis) in southeastern Arizona. We found that multiple behavioral phenotypes existed within this population and female litter size was not affected by behavioral type. We also found that natal habitat preference induction (NHPI) does occur at the population level, but only weakly occurs for the individual. We also found no effect of personality on site selection. Our results indicate that sex and mass may explain differences in behavioral phenotypes; however, individual behavioral differences are weakly related to female reproductive success and settlement decisions during juvenile dispersal.
30

Fire History and Fire-Climate Relationships in Upper Elevation Forests of the Southwestern United States

Margolis, Ellis January 2007 (has links)
Fire history and fire-climate relationships of upper elevation forests of the southwestern United States are imperative for informing management decisions in the face of increased crown fire occurrence and climate change. I used dendroecological techniques to reconstruct fires and stand-replacing fire patch size in the Madrean Sky Islands and Mogollon Plateau. Reconstructed patch size (1685-1904) was compared with contemporary patch size (1996-2004). Reconstructed fires at three sites had standreplacing patches totaling > 500 ha. No historical stand-replacing fire patches were evident in the mixed conifer/aspen forests of the Sky Islands. Maximum stand-replacing fire patch size of modern fires (1129 ha) was greater than that reconstructed from aspen (286 ha) and spruce-fir (521 ha). Undated spruce-fir patches may be evidence of larger (>2000ha) stand-replacing fire patches. To provide climatological context for fire history I used correlation and regionalization analyses to document spatial and temporal variability in climate regions, and El-Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) and the Atlantic Multi-decadal Oscillation (AMO) teleconnections using 273 tree-ring chronologies (1732 - 1979). Four regions were determined by common variability in annual ring width. The component score time series replicate spatial variability in 20th century droughts (e.g., 1950’s) and pluvials (e.g., 1910’s). Two regions were significantly correlated with instrumental SOI and AMO, and three with PDO. Subregions within the southwestern U.S. varied geographically between the instrumental (1900-1979) and the pre-instrumental periods (1732-1899). Mapped correlations between ENSO, PDO and AMO, and tree-ring indices illustrate detailed sub-regional variability in the teleconnections. I analyzed climate teleconnections, and fire-climate relationships of historical upper elevation fires from 16 sites in 8 mountain ranges. I tested for links between Palmer Drought Severity Index and tree-ring reconstructed ENSO, PDO and AMO phases (1905-1978 and 1700-1904). Upper elevation fires (115 fires, 84 fire years, 1623- 1904) were compared with climate indices. ENSO, PDO, and AMO affected regional PDSI, but AMO and PDO teleconnections changed between periods. Fire occurrence was significantly related to inter-annual variability in PDSI, precipitation, ENSO, and phase combinations of ENSO and PDO, but not AMO (1700-1904). Reduced upper elevation fire (1785-1840) was coincident with a cool AMO phase.

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