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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.
1

An aeolian transport model for the selection of dune restoration alternatives

Bell, James Clayton 25 April 2007 (has links)
The landfall of hurricane Claudette in 2003 damaged and eroded most Texas coastal counties. The residents of Pointe San Luis on the west end of Galveston Island, Texas lost their protective dune front and experienced significant shoreline erosion. Following the storm, the Pointe San Luis Property Owner's Association contacted Texas A&M University to design a dune restoration strategy. The greatest natural contributor to dune reconstruction is the available sand delivered by aeolian transport. During the course of the study it became apparent that no model or software existed capable of demonstrating the effectiveness of available dune restoration alternatives. Building Beach©, a coastal aeolian sand transport simulator, was developed in response to this need. Based on discrete dynamics and requiring a minimum of technical input, the software allows coastal property owners, consultants, and coastal developers to graphically model the effectiveness of several dune restoration options including sand fence, planted vegetation, geo-textiles, and other solid protective barriers. The graphical output of Building Beach© enables the user to compare approximations of the performance of different restoration strategies to select the most effective option for a particular beach.
2

Abiotic Differences Between Green Turtle (chelonia Mydas) Nests In Natural Beach And Engineered Dunes: Effects On Hatching Success

Balfour, Martha 01 January 2010 (has links)
Habitat loss is among the biggest threats to conservation worldwide, so habitat restoration plays an increasing role in endangered species management. This is especially true for species with high site fidelity, such as nesting marine turtles. Sand replenishment is commonly used to restore coastal beaches after severe erosion events, and may affect marine turtles and other species that live or reproduce in that habitat. I investigated how abiotic characteristics of sand used in a dune restoration project at Archie Carr National Wildlife Refuge, Florida, affected reproduction of the federally-endangered green turtle (Chelonia mydas). Sand structure and composition can affect egg development and hatching success by altering nest conditions, with nests in fine-grain or very coarse sand suffering decreased hatching success. I determined that calcium carbonate content (27.0% ± 1.4 SE vs. 15.1% ± 3.8 SE), moisture content (3.29% ± 0.26 SE vs. 4.59% ± 0.25 SE), and grain size (427.53 µm ± 14.1 SE vs. 274.66 µm ± 29.1 SE) differed significantly between natural and restored dunes. Hatching success of green turtles (44.7% ± 6.2 SE vs. 65.8% ± 5.3 SE) was significantly lower on restored dunes compared to natural dunes with an estimated loss of 22,646 hatched eggs. Hatching success also decreased as the nesting season progressed. These results demonstrate the importance of regulating fill material used in beach restoration projects; substrate characteristics are easily evaluated and can significantly influence marine turtle hatching success.
3

Determining The Impacts Of Beach Restoration On Loggerhead (caretta Caretta) And Green Turtle (chelonia Mydas) Nesting Patterns And Reproductive Success Along Florida's Atlantic Coast

Hays, Allison Whitney 01 January 2012 (has links)
Artificial beach nourishment, the most common method to mitigate coastal erosion in the United States, is also considered the most ecologically friendly alternative for shoreline stabilization. However, this habitat alteration has the potential to impact nesting marine turtles and developing hatchlings. The first objective of this study was to determine how nourishing beaches with two different design templates affects loggerhead (Caretta caretta) and green turtle (Chelonia mydas) nesting success, the ratio of nests to the total number of nests and non-nesting emergences, and reproductive success, the ratio of hatched and emerged hatchlings to the total number of eggs deposited. Two types of restoration designs exist along the southern Brevard County, FL coastline, which supports some of the highest density loggerhead and green turtle nesting worldwide. Since 2005, approximately 35 kilometers of beach have undergone 1) fullscale restoration (typically called nourishment), where sand was added above and below the mean high tide line (2005, 2010) or 2) dune restoration, where sand was placed on the dune (2005, 2006, 2008, 2009). To quantify the effects of these restoration types, we used a Before-After-ControlImpact-Paired Series (BACIPS) model, which tests for significance between the difference in nesting success rates at the impact (engineered) and control sites (natural beach) before and after restoration ( ). For loggerheads, there was a significant difference in after dune restoration during the years of construction (2005, 2006, 2008, and 2009; p

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