Doctor of Philosophy, Case Western Reserve University, 2019, Biology

In ecology, discerning process from pattern can be quite challenging. In plant community ecology, for example, multiple species, each with their own physiological characteristics and population dynamics, can interact in diverse ways across spatial and temporal scales. Moreover, plants can respond to multiple abiotic factors, which themselves will also vary across spatial and temporal scales. Given this complexity, both the abiotic environment itself, and the way in which species respond to it, is often simplified. This begs the question, does abiotic complexity matter? The following chapters ask when, and how, including various components of abiotic complexity will change the qualitative conclusions drawn about herbaceous layer plant communities. Previous research investigating the connection between the abiotic environment and community patterns often make at least one of three simplifications: 1) observational studies tend to consider only the mean or only the heterogeneity of abiotic conditions, even though both are known to impact plant communities. 2) Theoretical studies model survival probability as a function of abiotic conditions, even though survival depends on multiple life history events which may interact with the abiotic environment in different ways. Finally, 3) many studies assume that abiotic factors are important at large, but not small, spatial scales. Using an observational study, we show that accounting for both the mean and heterogeneity of conditions across multiple abiotic factors matters when we want to know how much variability in species richness can be explained by the abiotic environment. Using a simulation model, we show that the life stage at which species partition resources matters when we want to know how local processes will scale up to affect larger community patterns. And finally, using spatial point pattern analysis we show that both small- and large-scale structure in the abiotic environment matter when we want to understa (open full item for complete abstract)

Committee: Karen Abbott Dr. (Advisor); Robin Snyder Dr. (Committee Member); Jean Burns Dr. (Committee Member); Constance Hausman Dr. (Committee Member) Subjects: Ecology

PhD, University of Cincinnati, 2017, Business: Business Administration

This dissertation contains three essays examining new Bayesian econometric methodologies. The first develops a heterogeneous Spatial Autoregressive Model by integrating a finite mixture model structure into the traditional homogeneous specification. The second essay builds upon the first by extending this Spatial Mixture Model structure to the more general Spatial Durbin and Spatial Durbin Error specifications. Additionally, this essay covers the interpretation of these new model specifications. Finally, the third essay develops a predictive based model selection process by integrating cross-validation algorithms into standard Bayesian sampling methods with a focus on explicit out-of-sample prediction. 1.0.1 Embracing Heterogeneity: The Spatial Autoregressive Mixture Model In this essay, a mixture distribution model is extended to include spatial dependence of the autoregressive type. The resulting model nests both spatial heterogeneity and spatial dependence as special cases. A data generation process is outlined that incorporates both a finite mixture of normal distributions and spatial dependence. Whether group assignment is completely random by nature or displays some locational "pattern", the proposed spatial-mix estimation procedure is always able to recover the true parameters. As an illustration, a basic hedonic price model is investigated that includes sub-groups of data with heterogeneous coefficients in addition to spatially clustered elements. 1.0.2 Spatial Durbin Mixture Models This essay extends the finite mixture model structure to include Spatial Durbin and Spatial Durbin Error model specifications. The partial derivatives of this heterogeneous spatial model structure are shown to differ between border and interior agents; the designation of which is based on group assignment and first order neighbor designation. As an illustration, individual income based on data from the Panel Study of Income Dynamics (PSID) is examined using the Spatial (open full item for complete abstract)

Committee: Olivier Parent Ph.D. (Committee Chair); David Curry Ph.D. (Committee Member); James LeSage Ph.D. (Committee Member); Jeffrey Mills Ph.D. (Committee Member) Subjects: Economics

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2012, Biological Sciences

Oak savannas of the Midwestern U.S. are among the most imperiled North American plant communities. The 478-km2 Oak Openings region of Northwestern Ohio is one of the few landscape-scale savanna systems remaining in the Midwest. Despite conversion of large portions of the Oak Openings for human land uses, the region still supports high levels of floristic diversity. However, regional patterns of Oak Openings plant diversity within the modern landscape are not well understood. My research objectives were 1) to determine the current extent and distribution of Oak Openings plant communities, 2) to quantify multiscale patterns of plant species richness within the context of the surrounding landscape, and 3) to build predictive species distribution models of rare plants to evaluate regional patterns in habitat suitability. First, using multi-seasonal Landsat images, I determined that <3% of the Oak Openings remains covered by native savannas, prairies, and barrens, while three-fourths of the region has been converted for urban, residential, and agricultural uses. Second, using measures of spatial heterogeneity derived from field data and remote sensing, I developed models of native and exotic plant species richness at two spatial extents and at four ecological levels for the Oak Openings. These models consistently explained more variation in exotic richness (better explained at the larger spatial extent) than in native richness (better explained at the smaller spatial extent). At all ecological levels, percentage of human-modified land cover in the surrounding landscape (negatively correlated with native richness, positively correlated with exotic richness) was a strong predictor of species richness. Finally, I developed species distribution models for nine rare plant species within the Oak Openings region using the Maxent modeling algorithm. Proportional land cover surrounding species occurrences accounted for a large proportion of the predictive power of all models. As (open full item for complete abstract)

Committee: Karen V. Root PhD (Advisor); Enrique Gomezdelcampo PhD (Committee Member); Helen J. Michaels PhD (Committee Member); Jeffery G. Miner PhD (Committee Member); Robert K. Vincent PhD (Committee Member) Subjects: Biology; Ecology; Natural Resource Management

PhD, University of Cincinnati, 2024, Arts and Sciences: Geography

Governments worldwide implemented stay-at-home orders and facility closures to limit movement and stem the spread of the global COVID-19 pandemic. These policies directly impact people's daily mobility, the racial composition of people on the move, and the number and spatial arrangement of Point-of-Interests (POIs). However, few studies have explored how to measure ambient population-based racial heterogeneity, the spatial configuration of POIs, and their effects on crime. According to Shaw and McKay's social disorganization theory, racial heterogeneity can disrupt a local community's social organization and contribute to crime and delinquency. While residents play the most critical role in defining the characteristics of a community, non-residents frequenting a community may also affect the community. The perceived racial composition will likely differ from the static residential population's makeup. Crime pattern theory suggests that POIs are the general representative of facilities and can function as crime generators and attractors, shaping criminal activities. Traditional methods focus solely on POI counts, overlooking their spatial arrangement, which can significantly impact crime patterns. Given the effect of stay-at-home orders and facility closures on perceived racial heterogeneity, human mobility, and the numbers and spatial arrangements of active POIs on crime, examining how these crime-contributing factors shape crime patterns across different COVID-19 lockdown periods is essential. However, there is a lack of studies that 1) measure perceived racial heterogeneity based on human mobility, 2) capture the spatial dimension of POIs, and 3) analyze crime patterns across different periods - before, during, and post the stay-at-home orders and facility closures. Drawing on recent big data that captures human mobility and POI locations, this dissertation proposes novel methods for measuring racial heterogeneity of the ambient population and capturing the sp (open full item for complete abstract)

Committee: Lin Liu Ph.D. (Committee Chair); Diego Cuadros Ph.D. (Committee Member); Tomasz Stepinski Ph.D. (Committee Member); Kevin Raleigh Ph.D. (Committee Member); John Eck Ph.D. (Committee Member) Subjects: Geography

PhD, University of Cincinnati, 2023, Arts and Sciences: Geography

Urban flooding has become a growing threat to human society worldwide. Urban flood hazards have occurred more frequently, resulting in a growing population exposed to flood hazards and increasing flood damage to human communities. Thus, there is an urgent need to develop an urban pluvial flooding risk framework that can be used to evaluate the impacts of the flood and to provide helpful guidance on flood mitigation. The first chapter is a general introduction of this dissertation. It also reviews the existing studies related to physical and social factors affecting urban pluvial flooding. The research gaps are highlighted, and the aim of this dissertation is described. There is a lack of studies on investigating the spatial heterogeneity of the risk factors of urban pluvial flooding and their interplay impacts, and discussing how these may affect the urban flood mitigation strategies. The second chapter investigates the spatial relationship between the urban pluvial flood locations and the controlling factors through a case study in the City of Cincinnati. Three controlling factors are investigated, including precipitation, impervious area and topography. Two comparisons are conducted, one is depression-based which utilizes the random sampling method and the other comparison analysis is flooded-location-based. The results show that topography and precipitation are more important in the prediction of urban pluvial flooding risk than impervious areas. There is spatial heterogeneity of the three controlling factors as well as their interplay impacts. The third chapter develops an integrated approach for assessing urban pluvial flooding risk by combining two components, physical exposure and social vulnerability at catchment level. An exposure index (EI), a social vulnerability index (SoVI) and a composite pluvial flood risk index (PFRI) are developed. The results demonstrate the spatial heterogeneity of exposure and social vulnerability of urban (open full item for complete abstract)

Committee: Xi Chen Ph.D. (Committee Chair); Steven Buchberger Ph.D. (Committee Member); Susanna Tong Ph.D. (Committee Member); Kevin Raleigh Ph.D. (Committee Member); Lin Liu Ph.D. (Committee Member) Subjects: Geography

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2022, Biological Sciences

Bats are critically important for their control of insects but are experiencing population declines. The biggest reason for these declines is anthropogenic land use. Despite negative impacts, anthropogenic land use has variable impact on bats, with tolerance for more developed areas being species dependent and varying depending on the spatial or temporal scale. Previous studies on land use and bats lack spatial variability and are often single year. My goal was to determine how habitat factors related to human land use impact bat activity and species richness at multiple spatial scales over a period of several years. This research was conducted in the Oak Openings Region, which is a highly developed mixed-use region with high biodiversity that serves as important bat habitat. Specific objectives included determining (1) changes in bat activity and species richness over time, (2) differences in bat activity and species richness between protected and non-protected areas, (3) how factors related to human land use impact bat activity and species richness, and (4) to map current bat habitat suitability and see how it may change in the future. Calls increased each subsequent year during the 2019-2021 period, showing a trend of consistently increasing bat activity. However, during 2011-2019 bat activity significantly decreased. Protected areas had higher species richness and activity than unprotected areas. Higher activity and species richness were found in areas with greater percent upland prairie, sand barrens, and savanna and less floodplain and conifer forest and wet prairie. Activity was higher with less structural clutter at 3-6.5 m, lower understory height, taller canopy height, more canopy cover, and more structural clutter 0-3 m. Number of habitats was positively associated with bat species richness and activity along transects, but negatively associated with activity at stationary points. An opposite trend was observed for cropland. Activity and species richnes (open full item for complete abstract)

Committee: Karen Root (Advisor); Juan Bes (Other); Moira van Staaden (Committee Member); Kevin McCluney (Committee Member); Shannon Pellini (Committee Member) Subjects: Acoustics; Animals; Biology; Climate Change; Conservation; Environmental Science; Geographic Information Science; Macroecology; Wildlife Conservation; Wildlife Management

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2020, Biological Sciences

Many taxa suffer from habitat loss, spread of invasive species, and climate change; however, reptiles are especially vulnerable because they are constrained physiologically from their ectothermic nature in addition to global population declines. Like other taxa, reptilian basic ecology requirements are influenced by ecological neighborhoods, which shape the abundance of critical resources and their movement patterns. My goal was to better understand reptilian movement patterns across spatial and temporal scales to facilitate conservation efforts within Oak Openings Region (OOR), of northwestern Ohio and southeastern Michigan, using a combination of field surveys, remote sensing data and modeling. My research examined (1) climate change, (2) distribution patterns, (3) habitat use, and (4) movement patterns. At the regional scale, we found moderate increases in suitable habitat for box turtles within the future scenarios based on climatic suitability models. Individuals may be more displaced or vulnerable from temperature change during the driest quarter of the year. Dispersal is feasible; box turtles, based on tracking of individuals, can move large distances within their lifetime but the physical barriers, like roads, on the landscape may greatly hinder these movements. I modeled habitat suitability for a suite of reptiles based on occupancy data and climate, habitat, elevation, and structural features. Currently, suitable habitat was less than half the area within OOR and was more restricted for two species of concern. There is a need to examine the range of limitations, i.e., minimum and maximum models, when planning conservation efforts for a suite of species, especially emphasizing the protection of wet and dry forest. At the local scale, I found using radio telemetry that box turtles displayed typical average home range sizes; however, some were much larger than other studies. This is likely a difference in landscape heterogeneity where home range size increase (open full item for complete abstract)

Committee: Karen Root PhD (Advisor); Michael Decker PhD (Other); Kevin McCluney PhD (Committee Member); Helen Michaels PhD (Committee Member); Enrique Gomezdelcampo PhD (Committee Member) Subjects: Biology; Conservation; Ecology

Doctor of Philosophy (PhD), Ohio University, 2019, Biological Sciences (Arts and Sciences)

With the rise of obesity and the associated complications, adipose tissue, which was once thought to be an inert organ, has emerged as one of the important endocrine organs in disease pathology. Although adipose tissues appear to be homogeneous, recent studies have demonstrated the diverse developmental origins and functions of adipocytes within each region (depot) of fat. Our lab has discovered at least three distinct adipocyte subpopulations marked by the expression of Wilms' Tumor 1 (Wt1), Transgelin (Tagln), and Myxovirus 1 (Mx1), termed Type 1, 2, and 3, respectively. These adipocyte subpopulations exhibit differential response to insulin, growth hormone (GH), and inflammatory cytokines. While the majority of the research in this dissertation focuses on Type 1 subpopulation, our recent work implicates both Type 1 and Type 2 adipocytes in diabetes-related pathologies. Firstly, Type 1 subpopulation is derived from mesothelial cells. Mesothelial cells constitute a monolayer encompassing the visceral organs and visceral adipose tissue that are capable of secreting pro-inflammatory cytokines (e.g. IL6, IL-8) in response to inflammatory signals. Interestingly, Type 1 adipocytes are only found in visceral depots (where chronic inflammation occurs during obesity), and Type 1 preadipocytes are capable of maintaining high MCP-1 level basally. In vitro migration assay shows that Type 1 preadipocytes recruit macrophages when co-cultured, suggesting that Type 1 subpopulation has inflammatory characteristics. Furthermore, tissue clearing showed that Type 1 are distributed closest to urogenital organs (kidneys and gonads) and distal to the digestive tract (ileum and colon). Given the proximity of these Type 1 cells to neighboring organs, they potentially influence the overall function of these organs, as seen in creeping fat of inflammatory bowel disease. Lastly, we explore the effect of GH on adipocytes as it differentially affects adipocyte subpopulations. GH-induced lipoly (open full item for complete abstract)

Committee: Kevin Lee PhD (Advisor); Fabian Benencia PhD (Committee Member); Darlene Berryman PhD (Committee Member); Vishwajeet Puri PhD (Committee Member); Kristin Stanford PhD (Committee Member) Subjects: Biology; Molecular Biology

Master of Science, The Ohio State University, 2014, Environment and Natural Resources

Ecological forestry is an increasingly important tool for forest management and restoration efforts looking to incorporate the structures and spatial patterns created by natural disturbances into management practices. In northern Lower Michigan, jack pine (Pinus banksiana Lamb.) plantations are managed as habitat for the endangered Kirtland's Warbler (Dendroica kirtlandii Baird, KW) and have been criticized for creating homogenized stand structures, reducing natural jack pine regeneration, and excluding other threatened species. Historically, jack pine forests experienced stand-replacing wildfires on intervals of 26 to 69 years, and little is known about the impact these natural disturbances had on ground-flora composition and structure. If management plans are to incorporate ecological forestry principles, it is important to understand the disturbances and ecological processes that influence vegetation patterns and development. Ground-flora vegetation can indicate disturbance and environmental stress in an ecosystem and provide insight into ecological processes for forest managers. Ground flora composition, structure, and diversity were examined at 12 wildfire-regenerated jack pine sites either < 8 years post-wildfire (young) or > 22 years post-wildfire (mature) in northern Lower Michigan. Percent cover of woody and herbaceous vegetation ( < 1 m tall) was collected within nested 1-m^2 quadrats, in conjunction with information of the overstory composition and structure, and fuel loadings. Semivariograms were also used to examine the spatial autocorrelation in ground-flora species richness and Shannon's Index of Diversity. Young stands were dominated by blueberry (Vaccinium spp.) and sedges (Carex spp.), while mature stands were dominated by eastern teaberry (Gaultheria procumbens), mosses, and lichens. On average (± SD), mature stands had significantly higher species richness, with 13.4 ± 3.3 species per m^2 in young stands and 17.4 ± 4.8 species per m^2 in m (open full item for complete abstract)

Committee: P. Charles Goebel (Advisor); David Hix (Committee Member); Stephen Matthews (Committee Member) Subjects: Ecology; Environmental Management; Environmental Science; Forestry

Doctor of Philosophy, The Ohio State University, 2009, Evolution, Ecology, and Organismal Biology

Natural ecosystems are exposed to numerous factors that determine their structure and dynamics. Although change is typically inherent in to biological systems, very few factors change a natural ecosystem as drastically as the arrival and successful establishment of non-native species. The impact of the Mediterranean grass (Schismus barbatus) in the southwestern U.S. exemplifies such dynamics. In my dissertation, I empirically and theoretically explore two components of Schismus invasion. First, native shrubs may promote Schismus invasion if Schismus benefits from the favorable growth conditions that shrubs provide. Second, Schismus may threaten ecosystem level properties if Schismus precludes establishment of shrubs. Thus Schismus may compromise the maintenance of Islands of fertility that favor growth of native plant community. To meet these objectives, I explore Schismus performance with respect to the location and size of one of the most abundant native shrubs in the Sonoran and Mojave Deserts, the Bur-sage shrub, Ambrosia dumosa. As a first approximation to the study system, I describe the natural distribution of Schismus with respect to the location of native shrubs (Chapter 1). Then, I examine factors that control Schismus-Ambrosia interaction using a three-year field experiment (Chapter 2), and subsequent characterization of soil nutrients changes around Ambrosia shrubs in the context of Schismus invasion (Chapter 3). I found that Schismus barbatus responds to the spatial heterogeneity formed by Ambrosia. This response is strongly controlled by water availability (Chapters 1 and 2). Ambrosia creates a dichotomous landscape formed by nutrient rich areas below their canopies and nutrient poor areas at inter-shrub spaces (Chapter 2). In this landscape, performance of Schismus is favored around Ambrosia during years with good precipitation. Nevertheless, at any given growing season, shading and water interception by shrub canopies are the most influential facto (open full item for complete abstract)

Committee: Maria Miriti Dr. (Advisor); Ralph Boerner Dr. (Committee Member); Elizabeth Marschall Dr. (Committee Member); Karen Goodell Dr. (Committee Member) Subjects: Ecology

Doctor of Philosophy (PhD), Ohio University, 2010, Environmental and Plant Biology (Arts and Sciences)

Aquatic organisms are excellent indicators of human impacts on stream ecosystems because they provide valuable services and integrate the effects of multiple stressors over time and space, which would be difficult to assess if only considering water chemistry. Agriculture and acid mine drainage (AMD) from historic coal mining contribute to the concentrations of nutrients, conductivity, and pH of streams; all of which are important to the presence and abundance of diatom species. Based on diatom responses to environmental conditions, this research (1) developed indices and examined relationships of metrics with chemistry and land use variables throughout the Western Allegheny Plateau of Ohio and two watersheds, (2) identified how habitat heterogeneity and sampling methods affect diatom diversity patterns and biomonitoring, (3) examined how spatial factors influence diatom assemblage structure and bioassessments, (4) characterized how temporal variability in seven reference and seven non-reference streams affects bioassessments, and (5) documented how AMD impacts biofilm succession, structure, and function as measured by extracellular enzymes. In anthropogenically impacted streams, diatom assemblages showed significant decreased similarity to reference sites, increased % high nutrient diatoms, increased % motile diatoms, and decreased % low nutrient diatoms associated with increased agriculture, and increased % acidophilic diatoms was associated with reduced alkalinity caused by AMD impacts. Intermediate percentages of epilithic habitat promoted diatom diversity, and multiple habitat samples had stronger relationships with watershed impacts than epilithic habitat samples. Spatial factors contributed to diatom assemblage structure likely because of species dispersal within watersheds and the region, but metrics were influenced less by spatial factors. Diatom metrics responded to two-week lags in PO4-P concentrations, and samples collected toward the end of summer were (open full item for complete abstract)

Committee: Morgan Vis (Advisor); Jared DeForest (Committee Member); Kelly Johnson (Committee Member); Brian McCarthy (Committee Member) Subjects: Biology; Botany; Ecology; Environmental Science

Master of Science (MS), Ohio University, 2007, Environmental Studies (Arts and Sciences)

Periphyton is commonly used as a biomonitoring tool for stream research. Often only one or few sites are sampled and assumed to be representative of an entire stream reach. Current literature focuses on periphyton heterogeneity at a smaller scale, on individual rocks within a riffle, and larger scales, within a watershed or ecoregion. The intermediate scales, within a single riffle or among riffles have not been adequately addressed. The purpose of this research was to determine how many riffles need to be sampled in order to be representative of an entire stream reach and whether the number of necessary riffles varied according to stream health. Since periphyton is very sensitive to changes in the environment, it is hypothesized that heterogeneity will be found among riffles. For the purpose of this research, four nested spatial scales were used: eight reaches (each nested within a different stream), ten riffles (nested within a reach), five samples (nested within a riffle), and ten rock scrapings (nested within a sample). The eight streams sampled included three non-attaining, three partially-attaining, and two fully-attaining water quality standards, based on fish and macroinvertebrate data collected in 2004. These data were analyzed using the Bray-Curtis Similarity Index, Hill's N2 dominance diversity index, and the acid mine drainage diatom index of biotic integrity (AMD-DIBI). Results indicated that at intermediate scales, within a stream reach, diatoms appear to be patchily distributed. These patchy distributions often lead to different diatom assemblages from one riffle to the next. In order to account for this variation within a stream reach, when diatoms are sampled for water quality monitoring, at least two riffles should be sampled, cleaned and counted separately and the species counts should then be added together for analysis. The degree of variation does not appear to correspond directly to stream health, but rather species richness and diversity. Str (open full item for complete abstract)

Committee: Morgan Vis (Advisor) Subjects:

Master of Science (MS), Bowling Green State University, 2012, Geology

Characterization of texture using population statistics neglects spatial and temporal relations of the grains within the sample which provide valuable information about process and history. Despite the importance of space and time in textural analysis, little has been done to analyze the spatial variability of textures. In order to investigate the question of textural heterogeneity at a thin section scale in detail, the Standard Deviational Ellipse (ME) function from ArcGIS was used to create an extensive database from two different samples: an Elle simulation of crystal-plastic deformation and a weakly deformed quartz arenite photomicrograph. Both samples were deformed by the same increments of simple shear (γ = 0.00 - 0.87); the Elle sample by the deformation simulation and the quartz arenite by passively displacing grain boundaries according to the geometry of simple shear. Each sample was divided into nine cells and the textures in each was analyzed in the GIS using the Standard Deviational Ellipse as well as other parameters such as grain perimeter, area, ellipticity, and long axis orientation. In addition to using the Standard Deviational Ellipse to characterize textural variations, this tool was also evaluated for use as a finite strain marker. The study revealed non-systematic spatial and temporal variation in the change of the ME long axis orientations and ellipticity for the Elle simulation and systematic variation for the quartz arenite. The spatial variation in the texture categorized by the ME is partly due to the variations of grain distribution, shape, and grain position in the undeformed state and partly due to the nature of the deformation. The systematic variations in the quartz arenite are to be expected because of the way in which the sample was passively deformed. While analyzing the ME as a strain marker, it was found to correlate with the grain strain for quartz arenite, but varies significantly from the strains in the Elle simulation. Furthe (open full item for complete abstract)

Committee: Charles Onasch PhD (Advisor); John Farver PhD (Committee Member); Peter Gorsevski PhD (Committee Member) Subjects: Geographic Information Science; Geological; Geology