This thesis contributes to modeling the dynamics of forest community response to environmental gradients and disturbances over a mountain landscape. A gap model (FACET) was parameterized for species of various forest types (Tabonuco, Colorado, Dwarf and Palm), for many terrain conditions and was modified and extended to include species response to excess soil moisture and hurricanes. Landscape cover types were defined by dominance of species of each forest type and canopy height. Parameters of the landscape model (MOSAIC) were calculated from multiple runs of FACET. These runs were determined by combining terrain variables (elevation and soil) and hurricane risk. MOSAIC runs were analyzed for distribution patterns. Geographic Information Systems software was used to process terrain variables, hurricane risk and MOSAIC model output.

The Rocker b Ranch on the southern Rolling Plains has one of the last sizeable populations of pronghorn (Antilocapra americana) in Texas. To investigate habitat utilization on the ranch, pronghorn were fitted with GPS/VHF collars and were released into pastures surrounded by a variety of fences to determine how fence types affected habitat selection. Habitat parameters chosen for analysis were vegetation, elevation, slope, aspect, and distances to water, roads, and oil wells. Results showed that pronghorn on the ranch crossed modified fencing significantly less than other types of fencing. Pronghorn selected for all habitat parameters to various degrees, with the most important being vegetation type. Habitat selection could be attributed to correspondence of vegetation type with other parameters or spatial arrangements of physical features of the landscape. Seasonal differences in habitat utilization were evident, and animals tended to move shorter distances at night than they did during daylight hours.

The purpose of this study was to use the Global Water Stormwater Sampler SS201 to characterize the urban runoff in Pecan Creek. Location of the samplers was influenced by land use and ease of installation. Determination of the constituents for analysis was modeled after those used in the NPDES permit for seven cities within the Dallas/Ft.Worth metroplex. Some metals, notably cadmium and arsenic, exceeded the U.S. EPA's MCL's. Statistical analysis revealed first flush samples to be significantly more concentrated than composite samples. Minimum discharge loadings were found to be significantly lower than maximum discharge loadings. Additionally there were significant differences of specific constituents between station locations and storm events.

Environmental management agencies make efforts to reduce pollution loading in streams and rivers by promoting vegetated buffer zones between human activity and water. Most of these efforts do not mesh water quality-based buffer zone width requirements with conservation and wildlife values, specifically, the use of these riparian forest corridors for wildlife dispersal between habitats in highly fragmented landscapes. Forest interior birds are of the most concern to management in riparian forests due to their population declines across much of their breeding range. This dissertation investigates the role that landscape-level and habitat-level factors play on the presence of breeding birds in riparian forests, particularly the landscape and habitat factors that are influenced by human-caused fragmentation. This study describes research at the Ray Roberts Greenbelt, Denton, Texas, that explores the relationships between the landscape and forest habitats of the Greenbelt with its breeding bird community. The major findings of this study are that bird communities in the corridor forests are associated with a greater array of factors than are bird communities in patches, suggesting that the birds of patch forests are somewhat insulated from landscape-scale effects. Also, habitat values can be maintained in corridors, but there does not seem to be a …

Food waste in the waste stream is becoming an important aspect of integrated waste management systems. Current efforts are composting and animal feeding. However, these food waste disposal practices rely on slow thermodynamic processes of composting or finding farmers with domestic animals capable of consuming the food wastes. Bioconversion, a potential alternative, is a waste management practice that converts food waste to insect larval biomass and organic residue. This project uses a native and common non-pest insect in Texas, the black soldier fly, which processes large quantities of food wastes, as well as animal wastes and sewage in its larval stage. The goal of this research is to facilitate the identification and development of the practical parameters of bioconversion methods at a large cafeteria. Three major factors were selected to evaluate the practicality of a bioconversion system: (1) the biological constraints on the species; (2) the economic costs and benefits for the local community; (3) the perception of and interaction between the public and management agencies with respect to the bioconversion process. Results indicate that bioconversion is feasible on all levels. Larvae tolerate and consume food waste as well as used cooking grease, reducing the overall waste volume by 30-70% …

Phytoplankton productivity of Lake Texoma was measured for one year from August 1999 to August 2000 for four stations, using the oxygen change method and laboratory incubation. Mean values of the photosynthetic parameters, PBmax and alphaB ranged from 4.86 to 46.39 mg O2.mg Chl-1.hr-1 for PBmax and 20.06 to 98.96 mg O2.mg Chl-1.E-1.m2 for alphaB. These values were in the range to be expected for a highly turbid, temperate reservoir. Estimated gross annual areal productivity ranged from 594 g C.m2.yr-1 (P.Q. = 1.2), at a station in the Washita River Zone to 753 g C.m2.yr-1 at a station in the Red River Zone, of the reservoir. Gross annual areal productivity at Station 17, in the Main Lake Zone, was 708 g C.m2.yr-1. Gross areal and volumetric productivity showed distinct seasonal variation with Photosynthetically Available Radiation (PAR) and temperature. Trophic status estimated on a station-by-station basis, using net productivity values derived from gross productivity and respiration estimates, was mesotrophic for all the stations, though one station approached eutrophy. Net productivity values ranged from 0.74 to 0.91 g C. m-2.d-1. An algal bioassay conducted at two stations in August 2000, revealed that phosphorus was most likely the nutrient limiting photosynthesis at both …

In order to assess the enhancement of seedling survival and growth during drought conditions, five-hundred bare-root seedlings each of Shumard oak (Quercus shumardii Buckl.) and green ash (Fraxinus pennsylvanica Marsh.) were planted each with four soil amendments at a Wildlife Management Area in Lewisville, Texas. The treatments were a mycorrhizal inoculant, mulch fabric, and two superabsorbent gels (TerraSorb® and DRiWATER®). Survival and growth measurements were assessed periodically for two years. Research was conducted on vegetation, soil, and site history for baseline data. Both superabsorbent gels gave significant results for Shumard oak survival, and one increased green ash diameter. For overall growth, significant results were found among DRiWATER®, mycorrhizae, and mulch treatments.

The University of North Texas Stream Research Facility (UNTSRF) was designed to examine contaminant impacts on effluent-dominated stream ecosystems. Stream mesocosms, fed municipal effluent from the City of Denton, TX, Pecan Creek Water Reclamation Plant (PCWRP), were treated with 0, 15 or 140 µg/L cadmium for a 10-day study in August 2000. Laboratory toxicity test and stream macroinvertebrate responses indicated that cadmium bioavailability was reduced by constituents of effluent-dominated streams. The Biotic Ligand Model (BLM) for Cd was used to predict a 48 hour Cd EC50 for Ceriodaphnia dubia of 280 µg/L in these effluent-dominated streams. This value is higher that an EC50 of 38.3 µg/L Cd and a 7-day reproduction effect level of 3.3 µg/L Cd generated for C. dubia in reconstituted laboratory hard water. These results support use of a cadmium BLM for establishing site-specific acute water quality criteria in effluent-dominated streams. Although not affected by 15 µg/L treatments, organisms accumulated Cd in 15 µg/L treated streams. Hence, over longer exposure periods, Cd accumulation may increase and a no effect level may be lower than the observed 10-day no effect level of 15 µg/L. A toxicity identification evaluation procedure was utilized with in vitro and in vivo bioassays …

Lewisville Lake Environmental Learning Area (LLELA) is an 809-hectare property in Denton County, TX. A study of the vegetation community identified 466 species in 104 families, with 25% of the species from only two families, Asteraceae and Poaceae. The property demonstrates the characteristics of an early successional community, dominated by weedy species. Prairie communities are dominated by Johnson grass and ragweed, with climax tall grass prairie communities only in areas that have been planted with native grass seed. Forest communities are similarly in an early successional stage, dominated by the hackberry-elm-ash alliance, with small remnants of native Cross Timbers found in isolated patches. Species richness and diversity were highest in the forests and lowest in the wetlands; evenness, though not different across ecosystems, demonstrated a strong seasonal component. The species list was compared with previously reported lists for Denton County, and 256 species identified had not been previously reported for the county. A wetland restoration study was conducted to determine if there was a difference in survival and growth between potted transplants with intact root systems and bare-root transplants. Two different mesh sizes were used for protection, and the success of the different caging was evaluated. Of eight species, only …

Triclosan (TCS) and triclocarban (TCC), widely used antimicrobial agents found in numerous consumer products, are incompletely removed by wastewater treatment plant (WWTP) processing. Methyl-triclosan (M-TCS) is a more lipophilic metabolite of its parent compound, TCS. The focus of this study was to quantify bioaccumulation factors (BAFs) for TCS, M-TCS, and TCC in Pecan creek, the receiving stream for the City of Denton, Texas WWTP by using field samples mostly composed of the alga Cladophora sp. and the caged snail Helisoma trivolvis as test species. Additionally, TCS effects on E. coli and Arabidopsis have been shown to reduce fatty acid biosynthesis and total lipid content by inhibiting the trans-2 enoyl- ACP reductase. The lipid synthesis pathway effects of TCS on field samples of Cladophora spp. were also investigated in this study by using [2-14C]acetate radiolabeling procedures. Preliminary results indicate high TCS concentrations are toxic to lipid biosynthesis and reduce [2-14C]acetate incorporation into total lipids. These results have led to the concern that chronic exposure of algae in receiving streams to environmentally relevant TCS concentrations might affect their nutrient value. If consumer growth is limited, trophic cascade strength may be affected and serve to limit population growth and reproduction of herbivores in …

During the spring 2004 a pilot school recycling program was implemented within Robert E. Lee Elementary. The primary goal of the program was to determine how recycling education in the school would affect curbside recycling rates within the surrounding community. The program was a cooperative effort between the University of North Texas, City of Denton Solid Waste Department and Keep Denton Beautiful. Throughout the first months of the study during the spring 2004, an increase in curbside recycling within the Robert E. Lee Elementary attendance zone was observed, with a dramatic decrease in participation over the summer and a rapid increase once again during the second full semester of the study. In a survey conducted with 3rd and 5th grade students at the pilot project school, most students expressed positive attitudes about recycling. Students whose survey responses indicated a high level of knowledge about what could be recycled were 37% more likely to claim to recycle regularly, than those students that scored low on the knowledge portion of the survey. Although the total amount of waste generation (recyclable and non-recyclable) at Robert E. Lee Elementary did not decrease during the study, the campus was able to divert recyclable material from …

The Consumer's Guide is designed to help consumers by providing guidelines for the purchase of specific energy-efficient household appliances- water heaters, air conditioning and heating systems, windows, dishwashers, refrigerators, clothes washers, and dryers. This serves two major purposes: to decrease the environmental impact of those products and to save consumers money over the lifetime of the products. The seven major appliances covered in this work are things that consumers tend to purchase quickly when their older models wear out and with little research into their energy and/or water efficiency. The guide begins with a general introduction and an explanation of the need for energy conservation. Explanations of how they work, purchasing tips, installation tips, maintenance tips, tips for additional energy efficiency, and case studies are given for each appliance. Printable pamphlets are included at the end.

The focus of this study was to characterize the surface water and groundwater hydrology of borrow-pit wetlands located within the borders of the Lewisville Lake Environmental Learning Area (LLELA), east of the Elm Fork of the Trinity River. The wetlands were excavated into alluvial deposits downstream of the Lewisville Lake Dam. Both surface water and groundwater contribute to the hydro-period of the borrow-pit wetlands. Nearby marshes exhibit characteristics of groundwater discharge. Salinity in groundwater-fed wetlands could affect establishment of vegetation, as suggested from plant surveys. Surface water input from storm events dilutes salinity levels. Management of LLELA wetlands should include long-term evaluation of hydrology and plantings to enhance habitat. Plans for additional wetlands should consider both surface water and groundwater inputs.

The Rio Gavilan watershed, located in Mexico 's northern Sierra Madre Occidental , has significance in conservation history. Upon visiting the remote, largely un­developed watershed during two hunting trips in the 1930s, renowned conservationist Aldo Leopold thought it was the best picture of land health he had seen. His main indicators of healthy land were slow water runoff rates regulating erosion and historical predator-prey relationships. The visits confirmed Leopold's concept of land health, inspired many of his essays, and helped shape his land ethic. Leopold proposed the area as a control site to research healthy land throughout North America . The proposal never went forward and the area has since been more intensively logged and grazed. This dissertation research used extensive literature review, archives, oral histories, citizen surveys, and rapid assessment of forest, rangeland, riparian, and socioeconomic health to assess impacts of past cultures and update the area's land health status. Projects that could restore land health, such as linked eco-tourism, forest density reduction, and rotational grazing, were assessed for feasibility. Recent critiques of Leopold's land ethic were also reviewed. Results indicate most pre-1940s impacts were light, current land health status is moderate, and local interest exists in restoring land …

Managing water quality aspects requires the use of integrative tools that allow a holistic approach to this problem. Water quality models coupled to hydrodynamic models are these tools. This study presents the application of the water quality model WASP coupled to the hydrodynamic model DYNHYD for two distinct reservoirs: Lake Texoma and Tocoma Reservoir. Modeling the former included simulations of water velocities, water level, and four chemical and physical compounds: chlorides, dissolved oxygen (DO), biochemical oxygen demand (BOD), and total suspended solids (TSS); and validation of the results by comparing with observed values during March - May, 1997. The latter is still under project status and the simulation was performed in a prospective way. The analysis included simulations of water velocities under current and for expected conditions, DO and BOD. Both models, DYNHYD and WASP, fitted pretty well to observed conditions for Lake Texoma and for where Tocoma Reservoir has been planned. Considering management and decision support purposes, the role of boundary and loading conditions also was tested. For Lake Texoma, controlling boundary conditions for chlorides is a determinant factor for water quality of the system. However, DO and TSS in the reservoir are governed by additional process besides the …

Vitellogenin in Pimephales promelas was used to assess estrogenicity of a local municipal effluent. Vitellogenin induction in male P. promelas increased in frequency and magnitude with increased exposure duration and was greater ("=0.05) than controls after 2 and 3 weeks of exposure. The level of vitellogenesis induced by effluent exposure was high compared to similar studies. A spring season evaluation followed. Biomarkers in P. promelas were used to assess the efficacy of a treatment wetland to remove toxicity and estrogenicity in final treated wastewater effluent. Comparisons were made with an effluent dominated stream and laboratory controls. Vitellogenin, GSIs (gonado-somatic indices), HSIs (hepato-somatic indices) and secondary sexual characteristics were biomarkers used in P. promelas models to assess aqueous estrogenicity. Biological indicators used to assess general fish health included hematocrit and condition factors. The estrogenic nature of the effluent was screened, concurrent with fish exposure, with GC/MS analysis for target estrogenic compounds including: 17-b estradiol, estrone, ethynylestradiol, Bisphenol A, nonylphenolic compounds, phthalates, and DDT. Plasma vitellogenin measured in P. promelas was significantly elevated (p < 0.0001) at the inflow site of the wetland and stream sites. GSIs for these exposures were less (a=0.001) at the wetland inflow site. At wetland sites closest …

I assessed fish community data collected by the Oklahoma Conservation Commission from 82 minimally impaired wadeable reference streams in eastern Oklahoma to determine whether existing aquatic ecoregions provide the best framework for spatial classification for the development of biological assessment methods and biocriteria. I used indirect ordination and classification to identify groups of sites that support similar fish communities. Although correspondence was observed between fish assemblages and three montane ecoregions, the classification system must be refined and expanded to include major drainage basins and physical habitat attributes for some areas to adequately partition variance in key measures of biological integrity. Results from canonical correspondence analysis indicated that substrate size and habitat type were the primary physical habitat variables that influenced the fish species composition and community structure.

Wildland fires in the United States are not always confined to wilderness areas. The growth of population centers and housing developments in wilderness areas has blurred the boundaries between rural and urban. This merger of human development and natural landscape is known in the wildland fire community as the wildland urban interface or WUI, and it is within this interface that many wildland fires increasingly occur. As wildland fire intrusions in the WUI increase so too does the need for tools to assess potential impact to valuable assets contained within the interface. This study presents a methodology that combines real-time weather data, a wildland fire behavior model, satellite remote sensing and geospatial data in a geographic information system to assess potential risk to human developments and natural resources within the Austin metropolitan area and surrounding ten counties of central, Texas. The methodology uses readily available digital databases and satellite images within Texas, in combination with an industry standard fire behavior model to assist emergency and natural resource managers assess potential impacts from wildland fire. Results of the study will promote prevention of WUI fire disasters, facilitate watershed and habitat protection, and help direct efforts in post wildland fire mitigation and …

The primary focus of the study was to compare dissolved organic carbon (DOC) at baseline stream flow to DOC at a higher post-rain stream flow, with a secondary focus on comparison of DOC between sites. Comparisons were also done on suspended solids at baseline flow to those of the higher post-rain flow, as well as suspended solids between sites. Significant differences did exist between DOC sampled at baseline flow and DOC in samples taken at peak flow. The study found no difference in suspended solids among sites neither on either baseflow sampling nor on the post rain event sampling.

Surfactants are used in a wide assortment of "down-the-drain" consumer products, yet they are often discharged in wastewater treatment plant effluent into receiving water, potentially causing environmental harm. The objective of this project was to predict surfactant toxic units and in-stream nutrients in the upper Trinity River watershed. Surface and pore water samples were collected in late summer 2005. General chemistries and surfactant toxic units were calculated. GIS models of anthropogenic and natural factors were collected and analyzed according to subwatersheds. Multiple regression analyses using the Maximum R2 improvement method were performed to predict surfactant toxic units and in-stream nutrients using GIS and in-stream values. Both geospatial and in-stream parameters generated multiple regression models for surfactant surface and pore water toxic units, as well as in-stream nutrients, with high R2 values. Thus, GIS and in-stream parameter modeling have the potential to be reliable and inexpensive method of predicting surfactant toxic units and nutrient loading in the upper Trinity River watershed.

A new subspecies of the plains pocket gopher (Geomys bursarius ozarkensis), located in the Ozark Mountains of north central Arkansas, was recently described by Elrod et al. (2000). Current range for G. b. ozarkensis was established, habitat preference was assessed by analyzing soil samples, vegetation and distance to stream and potential pocket gopher habitat within the current range was identified. A census technique was used to estimate a total density of 3, 564 pocket gophers. Through automobile and aerial survey 51 known fields of inhabitance were located extending the range slightly. Soil analyses indicated loamy sand as the most common texture with a slightly acidic pH and a broad range of values for other measured soil parameters and 21 families of vegetation were identified. All inhabited fields were located within an average of 107.2m from waterways and over 1,600 hectares of possible suitable habitat was identified.

Tree cores of Fraxinus pennsylvanica were used in a dendrochronological analysis investigating the species' responses to climate and flooding. The objective was to develop a model that incorporates the effects of precipitation, temperature, and flooding on radial growth in this species in north-central Texas. The trees exhibited strong climatic signals. The study clearly shows that all three factors have significant impacts on tree ring growth both prior to and during growth; however, the nature and extent of these impacts are highly dependent on what time of year they occur. The large temporal variations in growth responses emphasize the importance of considering the timing of environmental events when studying tree growth responses.

The purpose of this study was to examine the suitability of the YSI model 6600 Environmental Monitoring System (multiprobe) for long term deployment at a site in Lewisville Lake, Texas. Specifically, agreement between a laboratory extraction procedure and the multiprobe chlorophyll/fluorescence readings was examined. Preliminary studies involved determining the best method for disrupting algal cells prior to analysis and examining the precision and linearity of the acetone extraction procedure. Cell disruption by mortar and pestle grinding was preferable to bath sonication. Comparison of the chlorophyll/fluorescence readings from the multiprobe and the extraction procedure indicated that they were significantly correlated but temperature dependent.

The illustrative work of Edward Linley Sambourne for Punch magazine during the period 1901-1910 addresses a myriad of political topics prevalent during the Edwardian period in British history. This thesis examines two of those topics - Women's Suffrage and Socialism - through their artistic treatment by one of Britain's most influential periodicals. Through a study of the historical context and iconography of selected cartoons-of-the-week, one is better equipped to understand and appreciate the meaning, message, and humor in the cartoons. Chapter 1 introduces the Sambourne, Punch magazine, and the Edwardian period in general. Chapters 2 and 3 discuss four Women's Suffrage cartoons and four Socialism cartoons respectively. Chapter 4 draws conclusions regarding Sambourne's techniques as a cartoonist as well as the relationship between the text and image in his illustrations.