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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

Hurricane Effects on a Fagus/Magnolia Forest in Southeast Texas, USA, in the Context of Long Term Forest Monitoring

January 1995 (has links)
In 1986, Hurricane Bonnie passed over Wier Woods, a well-developed mesic forest in the Big Thicket Area of Texas, causing substantial tree mortality and opening several canopy gaps. Mortality was high during the hurricane interval, but did not vary significantly among species. Ingrowth into the 4.5 cm DBH size class was accelerated by the hurricane. Tree growth was largely unaffected by the hurricane; however, small individuals of all species experienced slightly increased growth rates after the hurricane. Mortality in the years after the storm did not decrease or increase. Even though Bonnie caused approximately three times "normal" mortality, there was only a slight decrease in basal area from 1985 to 1987. The low frequency of hurricanes and the modest effects of this hurricane suggest that hurricanes may have limited effects on the structure and dynamics of forests of the Big Thicket.
2

Vascular Plant Survey of the Canyonlands Unit of the Big Thicket National Preserve, Tyler County, Texas

Haile, Kelly 2012 August 1900 (has links)
The Big Thicket National Preserve is located in the southern part of the United States. It is within the Pineywoods vegetation region of southeastern Texas. This study area was the Canyonlands Unit, a unit located entirely within Tyler County, Texas. This unit is one of the most recently acquired units within the Big Thicket National Preserve. It was acquired in 1993 and is composed of 1,476 acres. The purpose of this study was to make a complete list of all the vascular plant species within the Canyonlands Unit. The numbers of plant species within this unit were compared to three other units within the preserve that are relatively close to the Canyonlands Unit. The plant species within these units were compared on number of species that are native versus introduced, longevity, season of growth, plant type (woody versus herbaceous), plant group (monocots, dicots, gymnosperms, ferns) and upland versus wetland plants based on region six wetland indictor values. The wetland plant species were compared among themselves as the number of obligate species versus facultative wetland plant numbers. This study also shows the number of invasive and weedy species within the Canyonlands Unit. Along with determining the number of plant species and comparing those with the number of species in the other units, a Cluster Analysis and Indicator Species Analysis was conducted on the woody vegetation within the Canyonlands Unit in order to determine woody plant communities. These analyses were conducted by using the statistical software, PC-ORD.
3

Corridors in Conservation and Philosophy

Benton, Christine S. 08 1900 (has links)
My thesis focuses on philosophical themes implicit in corridor conservation, using the Big Thicket National Preserve as an example. The way in which corridors, boundaries and communities are ambiguous, as both limits and connections, is dealt with. Corridor-patch matrices assemble ecological and human groups into temporary communities, often with conflicting interests. Such constellations foreground how a foreigner's boundary crossing is a notion important to both conservation and a philosophical study of being, seen as being always in relation with otherness. In this context, the notion of foreignness and Jean-Luc Nancy's idea of being-with is explored. Understanding the complex network of relations in which an entity exists leads to an awareness of its ambiguous nature. To facilitate judgment with such ambiguity, one needs a contextual understanding of a situation.
4

Organic carbon dynamics of the Neches River and its floodplain.

Stamatis, Allison Davis 12 1900 (has links)
A large river system typically derives the majority of its biomass from production within the floodplain. The Neches River in the Big Thicket National Preserve is a large blackwater river that has an extensive forested floodplain. Organic carbon was analyzed within the floodplain waters and the river (upstream and downstream of the floodplain) to determine the amount of organic carbon from the floodplain that is contributing to the nutrient dynamics in the river. Dissolved organic carbon was significantly higher at downstream river locations during high discharge. Higher organic carbon levels in the floodplain contributed to increases in organic carbon within the Neches River downstream of the floodplain when Neches River discharges exceeded 10,000 cfs. Hurricane Rita passed through the Big Thicket National Preserve in September 2005. Dissolved organic carbon concentrations recorded after Hurricane Rita in the Neches River downstream of the floodplain were significantly higher than upstream of the floodplain. Dissolved organic carbon was twice as high after the hurricane than levels prior to the hurricane, with floodplain concentrations exceeding 50 ppm C. The increase in organic carbon was likely due to nutrients leached from leaves, which were swept from the floodplain trees prior to normal abscission in the fall. A continuum of leaf breakdown rates was observed in three common floodplain species of trees: Sapium sebiferum, Acer rubrum, and Quercus laurifolia. Leaves collected from blowdown as a result of Hurricane Rita did not break down significantly faster than leaves collected prior to abscission in the fall. Processing coefficients for leaf breakdown in a continuously wet area of the floodplain were significantly higher than processing coefficients for leaf breakdown on the floodplain floor. The forested floodplain of the Neches River is the main contributor of organic carbon. When flow is greater than 10,000 csf, the floodplain transports organic carbon directly to the river, providing a source of nutrition for riverine organisms and contributing to the overall health of the ecosystem.

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