We develop statistical methods for evaluation of regional variation of ecological stressor-response relationships, and regional variation in temporal profiles of water quality, for application to data from monitoring stations on bodies of water. To evaluate regional variation in regression relationships, we use model-based clustering procedures with class-specific regression models. Units for clustering are taken to be basins, or combinations of basins and ecoregions. We rely on a Bayesian formulation and sample the posterior distribution using a Markov chain Monte Carlo algorithm. Two general approaches to the label-switching problem are considered, each leading to procedures that we apply in data analyses. Two applications are presented. We explore some relationships among priors with a Dirichlet distribution for class probabilities. We compare two rank-based criteria for grouping stations according to similarities in temporal profiles. The two criteria are illustrated in a hierarchical cluster analysis based on measurements of a water quality variable. / Ph. D.

Currently three systems are used to categorize honey production regions in the United States, one from the United States Department of Agriculture, one from the American Bee Journal used for its monthly U.S. Honey Crop and Markets report, and one from Bee Culture’s monthly regional honey price report. These systems follow political state boundaries and are based upon climate, bee forage, and regional beekeeping practices. While these systems are popular with the general beekeeping community, to our knowledge, their accuracy has not been studied. Although differing geographic regions can vary in bee forage species availability, states with similar geography and flora should have similar honey production. This is not the case because states within the same honey production region vary in honey production, possibly due to smaller ecotype divisions within the larger honey production regions. Due to this ecotype gradient, some models divide the United States into far more regions based upon ecotypes and disregard political boundaries. While a model based on ecotypes that disregard state political boundaries may be more accurate, it is not currently possible to statistically evaluate them due to how honey production data are collected. This study developed nine novel regional honey production models that regard political boundaries while attempting to satisfy ecotype similarity. The first four alternative models are based solely on Level II ecoregions and were developed by a best fit manual approach that minimized the number of ecoregions per honey production region. The five remaining models were created using statistical k-means partitioning cluster analysis and are purely data based. Also discussed is a linear regression model produced by Page et al. Differences within and between the models were analyzed using descriptive statistics and ANOVA in order to determine an improved model that describes regional honey production in the United States. Many of the models, both preexisting and those developed for this study, had insignificant means and are not viable. Of those that had significant means, a k-means cluster based model was determined to be the statistically superior model and can be considered an improved regional honey production model for the United States.

Northern bobwhites (Colinus virginianus) are a valued game species that have seen massive population declines in the last few decades. This decline has been attributed to many factors including predation, the topic of this study. I examined the habitat selection, nocturnal movement and potential rate of encounter with quail nesting locations by coyotes (Canis latrans), bobcats (Lynx rufus), and raccoons (Procyon lotor) at the Rolling Plains Quail Research Ranch, a private 19 km2 ranch in the Rolling Plains ecoregion of west Texas. My study had 2 objectives: (1) to compare the habitat use of mesopredators in the Rolling Plains to the nesting habitat of bobwhites, and (2) to characterize the nocturnal paths of these mesopredators and measure their overlap with quail nesting locations. I placed GPS collars on 4 bobcats, 7 coyotes and 11 raccoons during the quail nesting seasons of 2009-2011. I used the chi-square test as well as a modified version of the Ivlev’s Electivity Index (1961) to calculate habitat selectivity. I also measured the proximity of the mesopredators and quail nesting locations to roads, water and quail feeders on the ranch. I used fractal analysis to calculate length and tortuosity of nocturnal paths and assessed potential risk to quail nests by determining the intersection rates of mesopredator paths with quail nesting locations. I found that a large difference existed in selectivity of habitat between bobwhite nesting locations and the bobcats and raccoons. Bobwhites selected for the upland grasslands and shrubs and against rocky ridges. Bobcats selected for riparian zones, while raccoons selected for both riparian zones and rocky ridges, neither of which were selected for by nesting quail. Bobcats and male raccoons additionally showed a propensity for road travel, which quail often nested close to. Coyotes selected strongly for grasslands, utilized their home ranges comprehensively and showed a preference for road usage, and thus had the greatest potential encounter rate with quail nest sites. However, coyotes also showed the most linear and direct movement pattern, potentially reducing their efficiency in finding quail nests. This study indicates that coyotes potentially present the largest threat to the nests of quail and female raccoons the least. Management decisions such as the levels of management needed for the 3 species of mesopredators are discussed.

In this thesis, I have first reviewed biodiversity status and its conservation in Nepal, which indicates the need of linking the gaps between research and conservation of rare and endangered flora and fauna. Using three mountain ungulates as model species (barking deer - Muntiacus muntjak, Himalayan goral - Naemorhedus goral and Himalayan serow - Capricornis thar), I have investigated effects of human disturbances on wildlife distribution in the human-dominated landscapes of western Nepal, spanning from the subtropical Bardia National Park to the mountainous Shey Phoksundo National Park. I have developed habitat suitability maps for these three ungulate species and recommended a conservation priority area for their conservation. A special emphasis was placed on the study of the distribution of Himalayan serow using different factors related to habitat fragmentation, hunting and patch characteristics and connectivity of forest in midhills landscape of Nepal. Finally, wildlife hunting pattern in the region was investigated in order to explore wildlife conservation issues from the social perspective.

The Town Creek Watershed (TCW) is a representative area of the Tombigbee River Basin and the Southeastern Plains Ecoregion in Mississippi. The principal channel and four main tributaries have been included for several years within the MS Section 303(d) list of waterbodies biologically impaired due to sediment. The TMDL developed for TCW recommended that streams located near cultivated lands, road crossings and construction activities are a priority for streambank and riparian buffer zone restoration and sediment loads reduction. Development of remedial measures and future BMPs within TCW for reducing water quality impairment and downstream dredging costs requires identification of sediment sources and loads currently transported within TCW. Streambank erosion processes were hypothesized to be an important mechanism driving sediment supply from TCW. The overall goal of this research was to identify mechanisms and the potential effects of streambank erosion processes and to quantify and model the magnitude and rates of these processes within TCW. Research goal and specific aims were addressed in four substudies combining field reconnaissance and detailed data collection, laboratory analysis and computational modeling techniques. The first substudy involved a temporal and spatial analysis of observed suspended sediment transport rates, determined the stage of channel evolution and identified streambank erosion as an important source of sediment supply for reaches in TCW. Streambank erosion contributions of up to 28.5 Mg per m of streambank were quantified in a second substudy monitoring and determining streambank erosion processes and factors within TCW. Results from a third substudy assessed predictions of the computational model CONCEPTS for time of occurrence and magnitude of streambank failures and top width retreat along a 270-m modeling reach. Empirical and analytical approaches to estimate rates and depths of fluvial erosion were developed in a final substudy. The rate and depth of fluvial erosion were estimated as a function of hydraulic and hydrologic properties of flow events, vegetation on streambanks, flow induced forces and streambank geometry and soil properties. Reduction of suspended sediment loads should focus on attenuation of geomorphic processes and stabilization of reaches and agricultural lands adjacent to streambanks along incised headwaters within TCW.

No description available.

Excessive nutrient loading from watersheds causes nutrient enrichment and water quality issues in very small streams to large rivers. Nutrient enrichment is exacerbated by urbanization and agricultural land use; however, the magnitude of the problem differs by regional landscape and environmental characteristics. Currently, we do not understand how regional variables moderate these relationships. Thus, the overall objective of this thesis was to investigate how regional landscape and environmental variables moderate developed land cover–stream nutrient relationships across the United States. The first study examined how climate and land use influences the scaling of phosphorus, total nitrogen, ammonia and nitrate loads for very large regions (Mid-Atlantic, Upper Mississippi, Ohio and Missouri) of the U.S. Results show the scaling relationships of nutrient loads with watershed size depends on the nutrient species and differed by region; the magnitude of the relationships was greater in wetter climates and developed watersheds. The second study determined 1) whether the relationships between urban and agricultural land cover intensity and concentrations of phosphorus, total nitrogen, ammonia and nitrate across the U.S., differed by ecoregion, and 2) whether regional landscape and environmental factors explained those differences. The relationships were found to differ by ecoregion and the differences were moderated by regional agriculture, topography and climate where stream nutrients increased more rapidly with anthropogenic land use in regions with high agricultural land use, wetter climates and flatter topography. The study findings will enable water quality managers create region-specific water management strategies for streams impacted by excessive nutrient loads. / Master of Science / Several factors affect the loading and concentration of nutrients, which in high amounts cause harmful algal blooms in streams. The size of watersheds and the level of urban and agricultural land use influence how much nutrient is added to streams. The main goal of this study was to determine how the effect of watershed size and urban and agricultural land cover on stream nutrient loading and concentrations, respectively, are controlled by particular environmental variables, such as climate, topography and land cover. To understand these effects, phosphorus, total nitrogen, ammonia and nitrate concentrations and loads were analyzed using statistical models. In the first study, the degree to which nutrient loading is affected by watershed size in four regions of the U.S. (Mid-Atlantic, Upper Mississippi, Ohio and Missouri) was assessed. The study found that the effect of watershed size on nutrient loading depended on the nutrient type and differed by region, and nutrient loads were greater in wetter climates and watersheds dominated by human activities. In the second study, regional differences in the effects of urban and agricultural land on nutrient concentrations was assessed. The study found that the effects of human land use differed by region and that these effects were greater in wetter, flatter regions, and those with a high degree of agricultural use. This study facilitates understanding and identification of important regional factors that regulate water quality in streams and therefore, will facilitate region-specific water management strategies for streams impacted by excessive nutrient loading.

Section 303(d) of the Clean Water Act (CWA) requires states to assess and list all streams that do not meet water quality criteria for their designated use classes. In Tennessee, the Tennessee Department of Environment and Conservation (TDEC) uses macroinvertebrate surveys to assess the condition of streams designated for “fish and aquatic life” and the progress of targeted waterbodies toward meeting established standards for sediment. As of yet, no substrate metric has been established to monitor water quality or to document progress toward water quality improvement with respect to fish and aquatic life in Tennessee. A substrate metric that could be efficiently measured and would represent the needs of aquatic species would be valuable for monitoring streams with known sediment impairment to detect water quality improvement. The objectives of this study were to (1) investigate the relationships between riffle substrates and benthic macroinvertebrate data, provided by TDEC; (2) assess the potential use of substrate metrics as a monitoring tool for benthic habitat status; and (3) examine variation in riffle substrates over time in the Ridge and Valley Ecoregion of Tennessee. Bed and interstitial sediment were characterized at sites corresponding with TDEC macroinvertebrate sampling stations. Bed sediment characteristics were significantly correlated with benthic macroinvertebrate data; however, interstitial fines yielded no significant correlations with benthic macroinvertebrate data. Substrate metrics did not differ significantly between varying levels of impairment; however, they did differ significantly when all impaired sites were combined into a single impairment group. The lack of significant differences between varying classes of reach impairment suggests that substrate metrics may not be able to distinguish impairment at the level necessary for monitoring impairment. However, substrate metrics may be of potential use in monitoring sites where impairment is less ambiguous. To investigate change in riffle substrate over time, three sites were monitored over the course of a year. Preliminary observations showed little change in riffle substrate during the study period, suggesting that seasonal restrictions on substrate surveys are unneccessary.

No description available.

No description available.