Western spruce budworm (Choristoneura occidentalis) outbreaks periodically disturb Western US conifer forests by defoliating canopies, which could alter the quantity and chemistry of throughfall delivered to the forest floor. Our objectives were to: i) quantify throughfall water, carbon (C), nitrogen (N), and phosphorus (P) fluxes under budworm-impacted canopies, and ii) examine the influence of herbivore intensity on flux magnitudes. In June 2015, we installed throughfall collectors in two watersheds experiencing high and background levels of herbivory. In each watershed, four plots, each with three throughfall collectors, were established (n=24) collectors), and two bulk rainfall collectors were installed in areas without canopy cover. Throughfall and rainfall were collected from late June to early November 2015. Samples were analyzed for dissolved organic carbon (DOC), ammonium (NH4-N), and soluble reactive phosphorus (SRP). Over the sampling period, throughfall fluxes ranged 8.57 to 47.59 kg/ha for DOC, 0.004-0.011 kg/ha for NH4-N, and 007 - 0.29 kg/ha for SRP. Percent throughfall was slightly, but not significantly, higher in the high (48%) compared to the background watershed (42%). There were no differences in solute concentrations among the watersheds. Net throughfall fluxes, the sum of canopy uptake and leaching and dry/fog deposition, differed significantly for NH4-N by herbivory …

Industrial ecology is a field of study that encourages the use of closed-loop material cycles to achieve sustainability. Loop closing requires the movement of materials over space, and has long been practiced in the iron and steel industry. Iron and steel (ferrous) scrap generated in the U.S. is increasingly exported to countries in Asia, lengthening the transportation distance associated with closing the loop on the iron and steel life cycle. In order to understand the environmental cost of transporting this commodity, an activity-based maritime transportation model and a theoretical in-land transportation model are used to estimate emissions generated. Results indicate that 10.4 mmt of total emissions were generated, and emissions increased by 136 percent from 2004 to 2009. Increases in the amount of emissions generated are due to increases in the amount of scrap exported and distance it is transported.

This thesis is a contribution to the work of the Texas Environmental Observatory (TEO), which provides environmental information from the Greenbelt Corridor (GBC) of the Elm Fork of the Trinity River. The motivation of this research is to analyze the short-term water dynamic of soil in response to the substantial rainfall events that occurred in North Texas in 2007. Data collected during that year by a TEO soil and weather station located at the GBC includes precipitation, and soil moisture levels at various depths. In addition to these field measurements there is soil texture data obtained from lab experiments. By comparing existing water dynamic models, water balance equations were selected for the study as they reflect the water movement of the soil without complicated interrelation between parameters. Estimations of water flow between soil layers, infiltration rate, runoff, evapotranspiration, water potential, hydraulic conductivity, and field capacity are all obtained by direct and indirect methods. The response of the soil at field scale to rainfall event is interpreted in form of flow and change of soil moisture at each layer. Additionally, the analysis demonstrates that the accuracy of soil characteristic measurement is the main factor that effect physical description. Suggestions for model …

Urbanization is seen as a threat to biodiversity within urban ecosystems, which are largely reliant on humans for their composition. Two types of extremes exist in the spectrum of urban domestic gardens; on one end, the typical urban garden which is planted by landscapers at the time the house is built and is generally left unchanged, and, at the other, a "wild" landscape planted entirely with native plants which provides habitat for native fauna and pollinators. This study assesses the plant choices made by members of organized gardening groups-the Denton County Master Gardeners (DCMG), the Elm Fork Master Naturalists (EFMN), the Trinity Forks Native Plant Society (TFNPS), and Keep Denton Beautiful (KDB)-and toward which extreme these choices put these gardens on the psectrum. TFNPS and EFMN both fall closer to the wild garden extreme, with TFNPS the closest to a "wild garden." DCMG was almost directly between the two extremes, but fell closer to the typical urban garden. By looking at how these groups manage their gardens, we begin to understand the ways in which gardeners can mitigate and soften the harsh changes between wild landscapes and urban environments. Collaboration between groups could have the potential to encourage more people …

Disease maps are powerful tools for depicting spatial variations in disease risk and its underlying drivers. However, producing effective disease maps requires careful consideration of the statistical and spatial properties of the disease data. In fact, the choice of mapping method influences the resulting spatial pattern of the disease, as well as the understanding of its underlying population characteristics. New developments in mapping methods and software in addition to continuing improvements in data quality and quantity are requiring map-makers to make a multitude of decisions before a map of disease burdens can be created. The impact of such decisions on a map, including the choice of appropriate mapping method, not been addressed adequately in the literature. This research demonstrates how choice of mapping method and associated parameters influence the spatial pattern of disease. We use four different disease-mapping methods – unsmoothed choropleth maps, smoothed choropleth maps produced using the headbanging method, smoothed kernel density maps, and smoothed choropleth maps produced using spatial empirical Bayes methods and 5-years of zip code level HIV incidence (2007- 2011) data from Dallas and Tarrant Counties, Texas. For each map, the leading population characteristics and their relative importance with regards to HIV incidence is identified …

Retail geography is a field of study that is growing in significance and importance within the academic, business, economic, and governmental realms. This study's main focus is on the changing retail environment with regards to business location and function within a small Midwestern city. The research focuses on Port Huron, Michigan because of the growth and shift of the retail community within the city over the past twenty years. The study specifically examines the changing influence and roles of Port Huron's central business district and of Birchwood Mall a retail development opened on the urban area's north end in 1990. The study uses the chi-squared, ANOVA, and cross tabulation statistical tests to analyze the changing geography of retail functions in the city. These statistics are used along with relative entropy equations to distinguish areas of high diversification, changing area functions, and common locations for multiple retail types.

The United States has the highest teen birth rate among western industrialized countries and the highest levels of pregnancy among adolescents (Alan Guttmacher Institute, 1994). While the rate of teen births is high throughout the country, considerable variations exist between and within regions. Texas is one of the 5 leading states with the highest teen birth rates to mothers less than 18 years of age. This research provides a detailed analysis of births to mothers aged between 10 and 19 years in North Central Texas counties. Due to the modifiable area unit problem and to provide a finer geographical scale of analysis, teen births in Dallas County zip codes were examined as a special case study. Statistical and Geographic Information System (GIS) analysis reveal that race/ethnicity, education and income are significant factors in teen births in the region. Single parent households and receipt of public assistance were not statistically significant. Suggestions for reducing vulnerability to teen births are presented.

Rapid Bioassessment Protocols integrate a suite of community, population, and functional metrics, determined from the collection of benthic macroinvertebrates or fish, into a single assessment. This study was conducted in Dallas County Texas, an area located in the blackland prairie eco-region that is semi-arid and densely populated. The objectives of this research were to identify reference streams and propose a set of metrics that are best able to discriminate between differences in community structure due to natural variability from those caused by changes in water quality due to watershed impacts. Using geographic information systems, a total of nine watersheds, each representing a different mix of land uses, were chosen for evaluation. A total of 30 metrics commonly used in RBP protocols were calculated. Efficacy of these metrics to distinguish change was determined using several statistical techniques. Ten metrics were used to classify study area watersheds according to stream quality. Many trends, such as taxa presence along habitat quality gradients, were observed. These gradients coincided with expected responses of stream communities to landscape and habitat variables.

Nutritional quality and availability is thought to regulate geographic patterns of variability in animal body size due to phenotypic plasticity. The purpose of this study is to determine how vegetation quality, abundance and population density influence white-tailed deer (Odocoileus virginianus) body size on a subregional spatial scale at Fort Hood, Texas. Harvest and census records are used to test the hypothesis that white-tailed deer exhibit phenotypic plasticity (e.g. larger body size) in response to differences in vegetation quality and availability. Results from these analyses suggest that forage quality and abundance alone is not a main driver of white-tailed deer body size. Analysis of deer population density (generally) resulted in an inverse relationship with body size. Areas with high quality forage and low population density support larger deer while areas with low quality forage and high density support smaller than average deer. The few exceptions occur in areas exhibiting poor quality forage and low population density or high forage quality and high density. Results from this study suggest that continued overcrowding of deer within isolated areas may eventually lead to efficiency phenotypic conditions producing smaller sized deer. These results could prove useful in interpreting deer population responses to harvest management. For …

This analysis of faunal remains from eleven archaeological sites in the northern San Juan region, extensively occupied by the Ancestral Pueblo people until they leave the region by AD 1300, explores the effects of resource intensification of small wild and domestic resources leading up to this regional depopulation. By examining multiple lines of evidence, in addition to faunal abundance, causal factors are identified to address changes in abundances through time. In particular, age- and sex-based mortality are examined for lagomorphs (jackrabbits and cottontails) and domesticated turkey, respectively, to test hypotheses generated using the prey and patch choice models. Analyses of these resources follow a systematic paleontology which provides explicit identifications made of five sites from a large study area, Goodman Point Pueblo Unit. These data are integrated with those from large village sites from the encompassing central Mesa Verde region. The results of both analyses help clarify why the Ancestral Pueblo people left southwestern Colorado. During the final twenty-year occupation period, the results of this study support a shift from reliance on turkey husbandry to intense exploitation of locally available garden resources (i.e. cottontails).

Understanding spatial perspectives on the spread and incidence of a disease is invaluable for public health planning and intervention. Choropleth maps are commonly used to provide an abstraction of disease risk across geographic space. These maps are derived from aggregated population counts that are known to be affected by the small numbers problem. Kernel density estimation methods account for this problem by producing risk estimates that are based on aggregations of approximately equal population sizes. However, the process of aggregation often combines data from areas with non-uniform spatial and population characteristics. This thesis presents a new method to aggregate space in ways that are sensitive to their underlying risk factors. Such maps will enable better public health practice and intervention by enhancing our ability to understand the spatial processes that result in disparate health outcomes.

This study is a test of a methodology to predict changes in elevation and shoreline position of coastal wetlands in Trinity Bay, Texas, in response to projected sea level rise. The study combines numerical modeling and a geographic information system. A smoothing technique is used on a United States Geographical Survey (USGS) digital elevation model to obtain elevation profiles that more accurately represent the gently sloping wetlands surface. The numerical model estimates the expected elevation change by raster cell based on input parameters of predicted sea level rise, mineral and organic sedimentation rates, and sediment autocompaction rates. A GIS is used to display predicted elevation changes and changes in shoreline position as a result of four projected sea level rise scenarios over the next 100 years. Results demonstrate that this numerical model and methodology are promising as a technique of modeling predicted elevation change and shoreline migration in wetlands. The approach has potential utility in coastal management applications.

Locational decisions based on stigma and low funding have handicapped the efficiency of community based mental healthcare in the United States since 1963. However, the pattern of services in the 21st century American South remains largely unknown. This thesis addresses this gap in knowledge by using a mixed methodology including location allocation, descriptive statistics, and qualitative site visits to explore the geography of community clinics offering both physical and mental health services. The City of Houston has proposed using these facilities to anchor new supportive housing, but introducing more fixed costs to a mismatched system could create more problems than solutions. The findings of this study suggest the presence of an unnecessary concentration of services in the central city and a spatial mismatch between accessible clinics and the poor, sick people in need. Furthermore, this research reveals a new suburban pattern of vulnerability, calling into question long-held assumptions about the vulnerability of the inner city. Building supportive housing around existing community clinics, especially in the central city, may further concentrate vulnerable people thereby contributing to intensifying patterns of service-seeking drift and the continued traumatization of mentally ill homeless persons in Houston.

This study elucidates the underlying relationships for the distribution of oak landcover on bedrock and soil orders in two counties in Texas and one in Oklahoma. ESRI's ArcGis and ArcMap was used to create surface maps for Denton and Coke Counties, Texas and Choctaw County, Oklahoma. Attribute tables generated in GIS were exported into a spreadsheet software program and frequency tables were created for every formation and soil order in the tri-county research area. The results were both a visual and numeric distribution of oaks in the transition area between the eastern hardwood forests and the Great Plains. Oak distributions are changing on this transition area of the South Central Plains. The sandy Woodbine and Antlers formations traditionally associated with the largest oak distribution are carrying oak coverage of approximately 31-32% in Choctaw and Denton Counties. The calcareous Blackland and Grand Prairies are traditionally associated with treeless grasslands, but are now carrying oak and other tree landcover up to 18.9%. Human intervention, including the establishment of artificial, political and social boundaries, urbanization, farming and fire control have altered the natural distribution of oaks and other landcover of this unique georegion.

Jamaica has an abundance of freshwater resources, however, a lack of infrastructure makes treated, piped water inaccessible in many areas. Through literature reviews and site visits, this thesis is an analysis of how the people and land, and money and policy, interact with one another in relation to Jamaica's freshwater resources and water infrastructure. Special attention is given to the island's type-example Cockpit karst geology; tourism, mining, and farming's relation to this karst; types of water delivery systems in rural southern Trelawny's Cockpit Country; southern Trelawny residents' perceptions of the water situation; and policy and development goals in the context of Jamaica and southern Trelawny. I hope to bring attention to the unique social, geologic, and developmental context of water in Jamaica, and more specifically to garner attention for major water infrastructure improvements in south Trelawny. A number of recommendations for improvements with policy and infrastructure are made.

Computer-based, mathematical models have significant value in describing the processes behind urban development and its inhabitants. The following research describes the theories and concepts behind modeling and offers insight into the potential future of the field. First, the research covers a brief history of applicable modeling strategies. This is followed by a summary of current popular approaches. The numerical background of geo-social engineering is developed through mathematical techniques. Geo-social engineering is the integration of modeling into the basic design human civilization. The mathematical models will be incorporated into a design of a computer program. From this, a possible geo-social model structure is presented and its architecture is described.

Assessing the impact of climate variability on water resources is one of the difficult tasks in planning the future growth of North-Central Texas. This study defined twelve extreme climate scenarios. Data from each scenario was input to a hydrological model (HEC-HMS) to calculate watershed runoff to Lake Ray Roberts. Model parameters are determined using Geographic Information System (GIS). The water balance was calculated for current and future water demand and resulting change in the volume and level of this reservoir. The results indicate certain climate scenarios decrease in volume. Thus, local governments should plan alternative water management strategies during droughts.

Forest encroachment is understood to be the main reason for prairie grassland decline across the United States. In Texas and Oklahoma, juniper has been highlighted as particularly opportunistic. This study assesses the usefulness of three remote sensing techniques to aid in locating the areas of juniper encroachment for the LBJ Grasslands in Decatur, Texas. An object based classification was performed in eCognition and final accuracy assessments placed the overall accuracy at 94%, a significant improvement over traditional pixel based methods. Image biomass was estimated using normalized difference vegetation index (NDVI) for 1 meter resolution IKONOS winter images. A high correlation between the sum of NDVI for tree objects and field tree biomass was determined where R = 0.72, suggesting NDVI sum of a tree area is plausible. However, issues with NDVI saturation and regression produced unrealistically high biomass estimates for large NDVI. Canopy height model (CHM) derived from 3-5m LiDAR data did not perform as well. LiDAR typically used for digital elevation model (DEM) production was acquired for the CHM and produced correlations of R = 0.26. This suggests an inability for this particular dataset to identify juniper trees. When points that registered a tree height where correlated with field …

A traditional two dimensional (planar) statistical analysis was used to identify the clustering types of North Central Texas traffic fatalities occurring in 2001-2006. Over 3,700 crash locations clustered in ways that were unlike other researched regions. A two dimensional (x and y coordinates) space was manipulated to mimic a one dimensional network to identify the tightest clustering of fatalities in the nearly 400,000 crashes reported from state agencies from 2003-2006. The roadway design was found to significantly affect crash location. A one dimensional (linear) network analysis was then used to measure the statistically significant clustering of flow variables of after dark crashes and daylight crashes. Flow variables were determined to significantly affect crash location after dark. The linear and planar results were compared and the one dimensional, linear analysis was found to be more accurate because it did not over detect the clustering of events on a network.

Population estimation in inter-censual years has many important applications. In this research, high-resolution pan-sharpened IKONOS image, LiDAR data, and parcel data are used to estimate small-area population in the eastern part of the city of Denton, Texas. Residential buildings are extracted through object-based classification techniques supported by shape indices and spectral signatures. Three population indicators -building count, building volume and building area at block level are derived using spatial joining and zonal statistics in GIS. Linear regression and geographically weighted regression (GWR) models generated using the three variables and the census data are used to estimate population at the census block level. The maximum total estimation accuracy that can be attained by the models is 94.21%. Accuracy assessments suggest that the GWR models outperformed linear regression models due to their better handling of spatial heterogeneity. Models generated from building volume and area gave better results. The models have lower accuracy in both densely populated census blocks and sparsely populated census blocks, which could be partly attributed to the lower accuracy of the LiDAR data used.

The purpose of this study was to determine the effects of attendance at a senior center on the well being and quality of life of grandparents that were rearing grandchildren. Using convenience sampling, grandparents (N=130) who were rearing grandchildren were given a self administered demographic data survey along with an attendance at a senior center questionnaire, the Quality of Life Scale, the Well Being Scale by Liang, the UCLA Loneliness Scale, the Caregiver Burden Scale, and the Role Satisfaction Scale. An initial MANOVA (F 7, 69 = 2.72, p < .01) suggesting that senior center attendance affect the measures as a set was conducted and then a series of one way ANOVAs were carried out to test the hypothesis that attending a senior center has an effect on the dependent variables: well being, quality of life, role satisfaction, caregiver burden, loneliness, current health, and heath one year ago. Subsequently, a hierarchical regression analysis was conducted to find out whether frequency and quality of attendance of a senior center predicted quality of life, caregiver burden, well being, loneliness, and role satisfaction, controlling for the demographic data. The results of the MANOVA showed that the dependent variables: quality of life, caregiver burden, …

This study looks at spatial variation of groundwater nitrate in Texas and its fluctuations at 10 year increments using data from the Texas Water Development Board. While groundwater nitrate increased in the Ogallala and Seymour aquifers across the time period, the overall rate in Texas appears to be declining as time progresses. However, the available data is limited. Findings show that a much more targeted, knowledge based strategy for sampling would not only reduce the cost of water quality analysis but also reduce the risk of error in these analyses by providing a more realistic picture of the spatial variation of problem contaminants, thereby giving decision-makers a clearer picture on how best to handle the reduction and elimination of problem contaminants.

Buruli ulcer (BU) is an environmental bacterium caused by Mycobacterium ulcerans. Modes of transmission and hosts of the disease remain unknown. The purposes of this study are to explore the environmental factors that are possibly explain the spatial distribution of BU, to predict BU cases by using the environmental factors, and to investigate the impact of land use and land cover change on the BU distribution. The study area covers the southwest portion of Ghana, 74 districts in 6 regions. The results show that the highest endemic areas occur in the center and expand to the southern portion of the study area. Statistically, the incidence rates of BU are positively correlated to the percentage of forest cover and inversely correlated to the percentages of grassland, soil, and urban areas in the study area. That is, forest is the most important environmental risk factor in this study. Model from zero-inflated Poisson regression is used in this paper to explain the impact of each land use and land cover type on the spatial distribution of BU. The results confirm that the changes of land use and land cover affect the spatial distribution of BU in the study area.

Integrating decision analytical techniques in geographic information systems (GIS) can help remove the two primary obstacles in spatial decision making: inaccessibility to required geographic data and difficulties in synthesizing various criteria. I developed a GIS model to assist people seeking optimal residential locations. Fuzzy set theory was used to codify criteria for each factor used in evaluating residential locations, and weighted linear combination (WLC) was employed to simulate users' preferences in decision making. Three examples were used to demonstrate the applications in the study area. The results from the examples were analyzed. The model and the ArcGIS Extension can be used in other geographic areas for residential location selection, or in other applications of spatial decision making.