Electronic Theses and Dissertations

Permanent URI for this collectionhttps://hdl.handle.net/20.500.11875/18

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Browsing Electronic Theses and Dissertations by Author "Adu-Prah, Samuel"

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    Detection and Analysis of Shoreline Changes Along Louisiana Barrier Islands: Grand Isle and Isle West Grand Terre
    Aucoin, Lindsey; Adu-Prah, Samuel
    Louisiana barrier islands defend inland communities from storms, but they experience the highest rates of erosion in North America. Grand Isle and Isle West Grand Terre are barrier islands that have been subjected to stabilization and restoration. High resolution multispectral images and topographic LiDAR of Grand Isle and Isle West Grand Terre were gathered between 1998 and 2017. The images were processed to identify vegetation, bare earth, and water land classes using supervised classification techniques. Changes in land cover class were identified and quantified using postclassification image comparison tools. Digital elevation models were created from LiDAR point clouds and exported for shoreline extraction. Transects placed perpendicular to shorelines at 10 meter intervals measured shoreline position change. The study area experienced a 16.67% decline in vegetated land cover, a 47.57% gain in bare earth land cover, and a 0.39% gain in water class area between 1998 and 2017. The shoreline of Grand Isle experienced a landward movement of about 2.1 mm/yr and Isle West Grand Terre also saw landward shoreline movement at a rate of about 20.2 mm/yr. These rates are evidence of land area decline. This study identifies locations prone to change in Grand Isle and West Grand Terre. The results reveal changes that occur on Louisiana barrier islands with heavy human activity. Observations can be compared to long term or small-scale land cover change studies on the same coast.
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    Geographic Analysis of Current and Historical Vegetation of East Texas
    (2017-04-12) Hoffpauir, David R.; Adu-Prah, Samuel; Chapman, Brian R.; Leipnik, Mark; Pascarella, John B.
    This study uses two sources of secondary data to compare vegetation communities in East Texas and analyze how they have changed in the past eight decades. The first data source is a hand-drawn timber survey map generated by the U.S. Department of Agriculture circa 1935. The second data source is the Texas Parks and Wildlife Department’s Ecological Mapping Systems of Texas (EMS-T) finished in 2014. A third data source is used to crosswalk between the two principal sources. Using digital mapping techniques, classification boundaries of the historic map were digitized creating an overall area of interest. This was used to extract attribute data from the second data source creating a data extent defined by the digitized boundaries of the 1935 map. Although identical, their resulting attribute data contained no mechanism for a data join. The third data source, McMahon’s The Vegetation Types of Texas, Including Cropland provided this attribute bridge. This study found that 2.49% of the overall area has been converted to urban use. This shift in land use underscores an overall rise in population, which, in turn, drives the need for natural resources and conversion of ecosystems to other land uses. For example, 34% of the ’Shortleaf, Loblolly, Hardwood’ classification is now exclusively devoted to timber production. In the ‘Bottomland Hardwood’ classification, reservoirs now account for 13% of its total area. Today only 0.07% of the 1935 longleaf pine extent is exclusively longleaf pine and 56% of areas that once were longleaf pine are now pine plantation. Areas of urban growth have had the greatest impact on the ‘Loblolly, Hardwood’ classification where 10.3% has been converted to urban cover. Invasive species are evident as well. For example, of the ‘Loblolly, Hardwood’ classification, 3.7% is now invasive Chinese Tallow (Triadica sebifera). The resulting analysis allows for comparisons based on “Common Name” attributes, LU/LC value, and associated area values. Beneficially, such comparison allows for general assumptions about environmental impact and provides an analytical mechanism by which to mitigate future loss due to human or natural influences.