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Earth Sciences

University of Texas Rio Grande Valley

Theses and Dissertations

2020

Articles 1 - 8 of 8

Full-Text Articles in Physical Sciences and Mathematics

Influence Of Landscape Factors On Wildlife Presence And Road Mitigation Structure Performance, Taylor M. Hopkins Aug 2020

Influence Of Landscape Factors On Wildlife Presence And Road Mitigation Structure Performance, Taylor M. Hopkins

Theses and Dissertations

There are roughly 80 ocelots (Leopardus pardalis) remaining in the United States, with the entire population constrained to south Texas, with roadkill being a predominant source of mortality. To prevent additional roadkill and maintain wildlife movement, Texas Department of Transportation constructed 11.9 kilometers of wildlife exclusion fencing, 5 wildlife crossing structures (WCS), and 18 wildlife guards on State Highway 100. This thesis focused on determining the effort required for a control-impact monitoring study, the influence of biotic and abiotic factors around the roadway on wildlife presence, and the performance of mitigation structures and the road mitigation corridor. This …

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Predicting Patterns Of Heavy Metal Contamination In Rio Grande Valley Agricultural Soils, Joy Z. Youwakim Aug 2020

Predicting Patterns Of Heavy Metal Contamination In Rio Grande Valley Agricultural Soils, Joy Z. Youwakim

Theses and Dissertations

The Rio Grande Valley of Texas is the statewide leader in the production of produce and grains and is irrigated by the Rio Grande River, in which heavy metal contaminants have been documented by both the International Boundary Water Commission and the United States Geological Survey. This work attempts to observe and document patterns of heavy metal pooling in order to mitigate the increased risk of contamination due to urbanization. We hypothesize that relationships exist between heavy metal content and proximity to roads, land use, and soil type. This research tests these relationships through soil sampling and atomic absorption spectrometry …

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The Application Of Advanced Technologies For Agriculture And Rangeland Management, Matthew D. Kutugata Aug 2020

The Application Of Advanced Technologies For Agriculture And Rangeland Management, Matthew D. Kutugata

Theses and Dissertations

This project demonstrates two applications of remote sensing in agricultural and rangeland environments. In the first, an unmanned aerial system (UAS) equipped with a multi-spectral sensor was used to estimate canopy cover across four different cover crop trials at four time periods. In the second, a local database of stationary camera trap images of wildlife was used to train a convolutional neural network to automatically catalogue images by identifying the animal in those images. Both projects aimed to provide an example of how remote sensing platforms and machine learning techniques can facilitate the rapid collection and processing of large-scale field …

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The Influence Of Human Disturbance On Wildlife Use Of A Highway In South Texas, Thomas J. Yamashita Jul 2020

The Influence Of Human Disturbance On Wildlife Use Of A Highway In South Texas, Thomas J. Yamashita

Theses and Dissertations

Roads can greatly impact wildlife. Wildlife vehicle collisions contribute to population declines while disturbance from human activity may prevent wildlife from using areas around roads. The construction of mitigation structures may lessen these effects through fine scale modification of animal use of roadside areas. In this thesis, how the construction of wildlife mitigation structures impacted the fine scale distribution of wildlife on State Highway 100 in Cameron County, Texas was examined. Spatial and temporal scale may also influence these relationships. The relationship between human activity and wildlife activity around the highway was explored and how the distribution of wildlife road …

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Analysis Of The Facilitative Interaction Between Batis Maritima And Avicennia Germinans As A Mangrove Restoration Strategy, Javier R. Navarro Jul 2020

Analysis Of The Facilitative Interaction Between Batis Maritima And Avicennia Germinans As A Mangrove Restoration Strategy, Javier R. Navarro

Theses and Dissertations

The multiple experiments conducted in an Avicennia germinans forest in Laguna Vista, TX was focused on determining if facilitation theory could explain the behavior observed between the herbaceous halophyte Batis maritima and A. germinans. I hypnotized that a positive interaction exists but through which mechanisms of facilitation I did not know. The overarching theme of the study is the presence or absence of B. maritima. Facilitation theory tells us that positive interactions are most often found under stressful conditions such as those on the coastal tidal flat of the Laguna Madre. Locally B. maritima has been found to …

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Detection And Enumeration Of Bacterial Pathogens In The American Oyster (Crassostrea Virginica), Mohammad Maruf Billah May 2020

Detection And Enumeration Of Bacterial Pathogens In The American Oyster (Crassostrea Virginica), Mohammad Maruf Billah

Theses and Dissertations

American oyster (Crassostrea virginica) is a popular seafood for its delicacy and high nutritional value. Based on increasing concern about contamination of bacterial pathogens in raw oyster, my research objectives have been focused on detection and enumeration of two important bacterial pathogens, Escherichia coli and Salmonella spp. in the American oyster in south Texas waters, local markets and controlled laboratory studies. Immunohistochemical and RT-PCR analyses showed substantial bacterial pathogen’s presence in gills and digestive glands of oysters collected from San Martin Lake and South Padre Island as well as local markets. Laboratory studies showed increasing trend of both …

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Wildlife Use Of Road Mitigation Structures In Relation To Their Construction, Structural Characteristics, And Environmental Factors Along A South Texas Highway, Anna D. Rivera Roy May 2020

Wildlife Use Of Road Mitigation Structures In Relation To Their Construction, Structural Characteristics, And Environmental Factors Along A South Texas Highway, Anna D. Rivera Roy

Theses and Dissertations

Roads are known to negatively impact wildlife by fragmenting habitat and mortality caused by wildlife-vehicle collisions. Road mitigation structures, such as wildlife crossing structures (WCS), wildlife guards (WG), and fencing are commonly used to address the issue of roads. In South Texas, such structures were built or modified along State Highway (SH) 100 in Cameron County as an effort to conserve the endangered ocelot (Leopardus pardalis). Camera traps were deployed to monitor these structures as a way to assess their effectiveness in restricting wildlife entry into the roadway with fencing and WG and conveying wildlife movement across roads …

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Survival Of Off-Host Rhipicephalus (Boophilus) Annulatus (Acari: Ixodidae) Larvae In Study Arenas In Relation To Climatic Factors And Habitats In South Texas, Usa, Emily Jesselle Zamora May 2020

Survival Of Off-Host Rhipicephalus (Boophilus) Annulatus (Acari: Ixodidae) Larvae In Study Arenas In Relation To Climatic Factors And Habitats In South Texas, Usa, Emily Jesselle Zamora

Theses and Dissertations

The cattle fever tick, Rhipicephalus (Boophilus) annulatus (Say), is an economically destructive arthropod because of its ability to vector bovine babesiosis. Cattle fever ticks can spend more than 90% of their life cycle as questing larvae, but the effect of climatic factors on their off-host behavior and survival is unclear. The goal of this study was to measure the effects of specific ecological factors on off-host larvae in nature. The study was conducted in a south Texas pasture over a 20-mo period, during which time larval populations were surveyed and ambient weather variables - relative humidity and temperatures – were …

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