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  Partner: UNT Libraries
 Department: Department of Biology
 Country: United States
A Vegetative Key to the Grasses of Erath County, Texas

A Vegetative Key to the Grasses of Erath County, Texas

Date: August 1951
Creator: Robinson, Inez Evans
Description: "The orientation of this study began with a collection of the grasses of Erath County during their flowering periods. Collections were made in the Spring and Fall of 1950 and 1951 to obtain both vernal and autumnal grasses. Identifications were made from the grass floras previously mentioned and checked against specimens in the herbarium of North Texas State College for verification. In addition, the list was checked by W.A. Turney, Conservationist, United States Department of Agriculture of Dublin, Texas. Finally, the list was compared with that prepared by W.M. Cory for the plant areas of which Erath County is a part. On the basis of the above identifications, a critical study of the vegetative characteristics was made and a key based on these features prepared. The width of the blad and characteristics of the ligule, roots, culms, and sheaths were used to distinguish each of the eighty-six specimens found in the collection area. A drawing was made of the longitudinal section of the juncture of the blade and the sheath of each grass. This diagnostic section includes the collar, ligule, a part of the blade and sheath, and auricles, if present."-- leaf 5.
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Remote Sensing of Landscape-Level Ecological Attributes at Ray Roberts Lake in North Texas

Remote Sensing of Landscape-Level Ecological Attributes at Ray Roberts Lake in North Texas

Date: December 1997
Creator: Smith, David P. (David Paul), 1956-
Description: Biological diversity is a key component in assessing ecosystem health. Alteration, degradation and loss of habitat due to human influence is currently the primary stressor resulting in decreases in diversity. Reliable assessment of large areas in terms of biological integrity are needed for conservation and preservation efforts. Remotely sensed data provide an integrated view of reflected electromagnetic energy over large areas of the earth. These energy patterns provide unique spectral signatures which can be correlated to land cover and habitat. This research sought relationships between traditional ecological measures and information gathered from satellite digital imagery. Reliable interpretation of earth surface characteristics relies largely on accurate rectification to a map projection and subsequent thematic classification. Use of the Global Positioning System (GPS) for rectification was superior than digitizing topographical maps. Differentially corrected GPS locations provided optimum rectification with SPOT satellite imagery while marginally better rectifications were obtained for Landsat MSS imagery using uncorrected GPS positions. SPOT imagery provided more accurate land cover classifications than did MSS. Detection of temporal land cover change using MSS imagery was hampered by confusion among intermediate successional classes. Confusion between upland and bottomland forest classes occurred with both SPOT and MSS. Landscape analyses using thematic maps ...
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Estimated Extent and Fate of Chlorinated Solvent Contamination in the Soil of the Naval Air Station, Dallas, Texas

Estimated Extent and Fate of Chlorinated Solvent Contamination in the Soil of the Naval Air Station, Dallas, Texas

Date: August 1998
Creator: Trescott, Jill V. (Jill Virginia)
Description: This thesis estimates the spatial extent of chlorinated solvent contamination of the soil at the Naval Air Station, Dallas, then estimates the fate and transport of these contaminants, over time, using the Soil Transport and Fate database and the Vadose-Zone Interactive Processes (VIP) modeling software. Geostatistical analysis identifies two areas with serious chlorinated solvent contamination. Fate and transport modeling estimates that this contamination will degrade and disperse from the soil phase to below regulatory limits within one year, although there is a risk of groundwater contamination. Contaminants are estimated to persist in the water and air phases of the soil. Further sampling is recommended to confirm the results of this study.
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Light Spectra Distributions in Temperate Conifer-Forest Canopy Gaps, Oregon and in Tropical Cloud-Forest Canopy, Venezuela

Light Spectra Distributions in Temperate Conifer-Forest Canopy Gaps, Oregon and in Tropical Cloud-Forest Canopy, Venezuela

Date: December 1997
Creator: Monteleone, Susan Elaine
Description: Light spectra distributions were measured in two different montane forests: temperate and tropical. Spectral light measurements were made in different sized canopy gaps in the conifer forest at H. J. Andrews Experimental Forest in Oregon, USA. Researchers at Oregon State University created these gaps of 20 m, 30 m, and 50 m in diameter. In the tropical cloud forest, spectral light measurements were made in two plots that were permanently established at La Mucuy Parque Nacional in Venezuela, in collaboration with researchers at Universidad de Los Andes. In both studies, spectra and distributions of physiologically active light were analyzed: red, far-red, R/FR ratio, and blue light.
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Analysis of Phytoplankton Responses to Water Chemistry Dynamics in a Moderately Eutrophic North Texas Reservoir

Analysis of Phytoplankton Responses to Water Chemistry Dynamics in a Moderately Eutrophic North Texas Reservoir

Date: May 1998
Creator: Banks, Kenneth E. (Kenneth Edward)
Description: Canonical correspondence analysis (CCA) was used to explore relationships between measured environmental variables and in situ phytoplankton communities in a moderately eutrophic North Texas Reservoir.
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Evaluation of a Constructed Wetland to Reduce Toxicity from Diazinon at the Pecan Creek Wastewater Treatment Plant, Denton, TX

Evaluation of a Constructed Wetland to Reduce Toxicity from Diazinon at the Pecan Creek Wastewater Treatment Plant, Denton, TX

Date: May 1996
Creator: Baerenklau, Amy L. (Amy Lyn)
Description: The City of Denton Pecan Creek Wastewater Treatment Facility has periodically failed effluent toxicity testing. A Toxicity Identification Evaluation has determined that Diazinon in the effluent is contributing to the observed toxicity. Chlorpyrifos is also implicated as a factor. The City of Denton constructed a half acre experimental wetland to remove Diazinon related toxicity. Results from spiking and microcosm experiments indicate that the wetland can reduce the Diazinon.
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Development and Application of an Assessment Protocol for Watershed Based Biomonitoring

Development and Application of an Assessment Protocol for Watershed Based Biomonitoring

Date: May 1998
Creator: Schwartz, Joseph Howard
Description: With numerous bioassessment methodologies available, a regional protocol needs to be developed to ensure that results are comparable. A regional assessment protocol was developed that includes collecting five benthic macroinvertebrate samples, identifying organisms to genus, and calculating the following metrics: Number of Taxa, Total Number of Individuals, Simpson's Diversity Index, Shannon's Diversity Index, Percent Contribution of Dominant Taxa, Hilsenhoffs Biotic Index, and Percent Contribution of Dipterans. Once the protocol was developed, it was used to assess the Bayou Chico tributaries and watershed. All three tributaries had been significantly impacted by human activity as had the watershed as a whole. This study indicates that a regional protocol could be developed and is appropriate for biomonitoring at the watershed scale.
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Life History and Case-building Behavior of Molanna Tryphena Betten (Trichoptera: Molannidae) in Two East Texas Spring-fed Streams

Life History and Case-building Behavior of Molanna Tryphena Betten (Trichoptera: Molannidae) in Two East Texas Spring-fed Streams

Date: December 1998
Creator: Gupta, Tammi Spackman
Description: The life history and case-building behavior of Molanna tryphena from two spring-fed tributaries in East Texas were studied from January 1997 to May 1998.
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A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, TX Based on Chlorophyll A

A Comparison of Predicted and Actual Trophic Status of Lake Ray Roberts, TX Based on Chlorophyll A

Date: May 1999
Creator: Lytle, Lili Lisa
Description: Two years before impoundment, the trophic status of Lake Ray Roberts was predicted by applying the total phosphorus input into the Organization for Economic Cooperation and Development (OECD) eutrophication model. Predicted mean summer epilimnetic (MSE) chlorophyll a of Elm Fork arm, Isle duBois arm and Main Body were in the eutrophic category of the OECD model. Observed MSE chlorophyll a two years after impoundment of Elm Fork arm, Isle duBois and Main Body had not reached their predicted means and were at the mesotrophic-eutrophic boundary of the OECD model. Six years after impoundment, observed MSE chlorophyll a for Main Body, was closer to its predicted mean and in the eutrophic category of the OECD model. Six years after impoundment, Elm Fork arm was the most productive area of Lake Ray Roberts. Observed means of chlorophyll a, total phosphates, suspended solids and turbidity were often highest in the Elm Fork arm. Wastewater effluent from Gainesville and Valley View, TX, had an impact on productivity in Elm Fork arm.
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Biological and Toxicological Responses Resulting from Dechlorination of a Major Municipal Wastewater Treatment Plant Discharge to the Trinity River

Biological and Toxicological Responses Resulting from Dechlorination of a Major Municipal Wastewater Treatment Plant Discharge to the Trinity River

Date: August 1995
Creator: Guinn, Richard J. (Richard Joe)
Description: Federal regulations such as the Clean Water Act (P.L. 92-500), and its amendments, direct the Environment Protection Agency (EPA) to implement programs to control the releases of conventional pollutants and toxics into the waterways of the United States. The EPA began requiring treatment plants to conduct toxicity tests (biomonitoring) of their effluent discharges. To control toxicity caused by chlorination of wastewater discharges, the EPA also began requiring some treatment facilities to dechlorinate their wastewater before discharging. This research was funded by the EPA to document the changes that occurred in the Trinity River from the dechlorination of the effluent from Ft. Worth's Village Creek municipal wastewater treatment plant. The study occurred over a two year period beginning in August 1990. A wide variety of biological field assessments and toxicological assays were used to measure various responses. Seven river stations, covering approximately twenty river miles, and the treatment plant effluent were assessed. Two of the river stations were upstream from the treatment plant and used as reference sites. The remaining five river stations were downstream from the treatment plant, spread out over seventeen river miles. The study evaluated the impact of chlorination prior to dechlorination, which served as a baseline. Responses ...
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