Master of Science (MS), Bowling Green State University, 2024, Geology

The long-nosed peccary (Mylohyus nasutus) and flat-headed peccary (Platygonus compressus) are two of the most recently extinct members of Family Tayassuidae from North America. The aim of this study was to create ecological niche models (ENMs) for both species during the Heinrich Stadial 1, Bølling-Allerød, and Younger Dryas intervals of the latest Pleistocene across the contiguous United States and parts of northern Mexico to provide insight on their distribution, how it changed over the time intervals, and what environmental (climate and floral frequency) factors affected both species' ranges just prior to their extinction around the Pleistocene/Holocene transition. The Neotoma Paleoecology Database, Paleobiology Database, and published research articles were used to compile peccary occurrence data. Climatic raster data were derived from PaleoClim. Floral data (specifically pollen abundance) was compiled from Neotoma, then ISODATA clustering was used in GIS SAGA to create frequency ratio maps for several dominant floral groups to rasterize floral abundancy maps. Peccary occurrence data and environmental rasters were input into Maxent, which was used to create both jackknife and response curve ENM models. Lastly, the ENMs were combined with Paleoindian archeological data (via p3k14c) to provide insight on human and peccary relationships. M. nasutus was found to have insufficient dated occurrence points to create ENMs for the targeted time slices. P. compressus was found to have had a large potential range across much of the modeled region throughout all three time intervals. P. compressus was very tolerant of vast ranges in temperature and preferred to live in forested habitats, but avoided areas with low precipitation, high precipitation seasonality, forests abundant in oak, or more open grassland/scrubland. P. compressus' large potential range through both cold and warm intervals of the Late Pleistocene suggests that the changing environmenta (open full item for complete abstract)

Committee: Margaret Yacobucci Ph.D. (Committee Chair); Jeff Snyder Ph.D. (Committee Member); Peter Gorsevski Ph.D. (Committee Member) Subjects: Geographic Information Science; Paleontology

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2024, Biological Sciences

As human-modified landscape and climate changes proliferate, maintaining biodiversity and understanding the function and quality of available habitat is imperative. Anurans (frogs/toads) can be indicator species of habitat quality and ecosystem productivity, due to their permeable skin, small body size and ectothermy. We explored the relationship between Anurans and habitat quality by assessing the effects of spatial and temporal heterogeneity on the presence of Anurans. Across the Toledo Metropolitan Area (TMA), including the biodiversity hotspot Oak Openings Region (OOR), we surveyed across three years, 67 different wetland sites (N=1800). There was a difference in community assemblage between rural and suburban/urban habitats driven by factors related to human-modification (impervious surface), composition (landcover type) and productivity (e.g., NDVI). Areas with more impervious surface, lower amounts of swamp forest, and lower NDVI had fewer species. The differences in spatial structure but lack of differences in temporal variables among sites suggest spatial factors dominated. We also developed spatial models for predicting species richness across the region to evaluate spatial variables driving community composition and ecosystem productivity. The amount of cropland best predicted species richness, followed by amount of swamp forest. Among individual species, the most important variables differed; cropland (Acris blanchardi, Lithobates catesbeianus, Anaxyrus americanus, Anaxyrus fowleri and Hyla versicolor), floodplain forest (Lithobates clamitans), wet prairie (Lithobates pipiens), and swamp forest (Pseudacris crucifer, Pseudacris triseriata, Lithobates sylvaticus) were leading influences. Finally, we surveyed 304 local residents to assess their views on topics from support of new parks/preserves to fees to utilize parks, before a 25-minute presentation on Anurans, and resurveying them. There was strong support for many conservation-oriented questions, but (open full item for complete abstract)

Committee: Karen Root Ph.D. (Advisor); Paul Moore Ph.D. (Committee Member); Ashley Ajemigbitse Ph.D. (Other); Jeffrey Miner Ph.D. (Committee Member); Helen Michaels Ph.D. (Committee Member) Subjects: Biology; Conservation; Ecology; Wildlife Conservation; Wildlife Management

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2024, Biological Sciences

Conflict with wildlife continues to escalate as human population increases and development expands. Understanding how vertebrates interact with the environment is a critical component to conservation ecology. Movement patterns reflect spatial and temporal changes associated with resource availability, life history stages, and habitat use. This study explored how vertebrate mortality could be used to understand the critical factors impacting the consequences of permeability, i.e., ability to move between patches on the landscape, in a mixed disturbance landscape. We assessed how spatial and temporal heterogeneity influenced terrestrial vertebrate mortality. In the biodiversity hotspot of the Oak Openings Region (OOR) of northwest Ohio, we surveyed repeatedly, across three years, approximately 50 kilometers of road segments. Vertebrate mortality locations (N=654) were related to road (e.g., traffic, road width), structural (e.g., canopy cover, soil average water capacity), compositional (e.g., landcover) and productivity (e.g., NDVI) measurements. We found vertebrate mortality locations were positively related to traffic, road width, canopy cover, and normalized difference vegetation index (NDVI) but negatively related to landcover as it becomes more altered (i.e., natural to agricultural). Our consistent findings across years suggest that the spatial components were influencing mortality differences more than temporal differences, and intra-year differences do not impact mortality in a way that would steer long term mitigation of permeability issues. We developed spatially explicit models for predicting current vertebrate mortality probabilities across the entire OOR. Proportion of residential/mixed landcover area was the most influential variables of mortality occurrence probability. We found mortality was well predicted and the results of the same key variables were robust across taxa and years. The models developed can serve as an assessment tool for evaluating co (open full item for complete abstract)

Committee: Karen Root Ph.D. (Committee Chair); Timothy Schetter Ph.D. (Committee Member); Raymond Larsen Ph.D. (Committee Member); Jeffrey Miner Ph.D. (Committee Member); Erin Labbie Ph.D. (Other) Subjects: Biology; Conservation; Ecology; Wildlife Conservation; Wildlife Management

Master of Arts, Miami University, 2021, Geography

The Pacific Golden Chanterelle (Cantharellus formosus) is a widely sought-after mushroom most abundant in the forests of Washington and Oregon, USA. This project used the species to investigate how accurately the species distribution could be modeled using natural history (herbarium) as model training data and citizen science (iNaturalist) as validation data. To combat the potential sampling bias towards population centers an effort variable weighting scheme was used to consider observations in harder to reach areas more than those in easier to access areas. Four models were created and run using the natural history data as training points: Random Forests (RF), Maxent, General Linear Model (GLM), and Artificial Neural Network (ANN); the effort variable was only applied to the ANN and GLM models. Out of these four, RF was found to perform the best with an equitable skill score (ETS) 0.987 when tested against the iNaturalist citizen science validation points. Overall, this project provides a good proof of concept and framework for the use of herbarium and citizen science data for use in biogeographical modeling projects in the future.

Committee: Mary Henry (Advisor); Jessica McCarty (Committee Member); Nicholas Money (Committee Member) Subjects: Geography

Master of Science, Miami University, 2019, Biology

Crop wild relatives can be a source of beneficial traits to be used for crop improvement. Carica papaya is a staple crop throughout the globe, domesticated from wild relatives native to Central America. I used the program Maxent to model the bioclimatic aspects of wild papaya's niche and compared these models to regions of known farmed areas and areas where papaya has invaded outside its native range. I developed two models after optimizing for resampling and bias-curbing schemes. A simpler model employing non-covariate predictors was used to identify the main aspects of wild papaya's climatic niche while a more complex model, including all 19 bioclimatic predictors, was utilized to make predictions to new environments. Models were consistent with known farmed areas, supporting the utility of the model. Additionally, I compared predictions to known invasions, and results were consistent overall, minus one invasion in Texas. Global projections under climate change resulted in likely over-predictions, but the current climate model is likely to be accurate based on consistency with farmed and invaded areas. These results can be used to identify locations where farms may be successful, assess risk of invasions, and identify under-sampled areas for biological studies.

Committee: Richard Moore (Advisor); Tereza Jezkova (Committee Member); David Berg (Committee Member) Subjects: Agriculture; Biology; Botany; Geographic Information Science

Master of Science, The Ohio State University, 2018, Evolution, Ecology and Organismal Biology

Fish can display a variety of movement and habitat-use patterns across different ecosystems. Because these movements and habitat-use patterns are fundamental components of fish life history, knowing where, when and why fish are found in certain habitats as well as understanding the factors driving movement patterns can provide a biological framework for developing fish conservation plans. Identifying seasonal habitat-use can help inform fish-stocking programs, can help managers determine the best locations for fish sampling, can enhance angler catch rates, and can elucidate interactions among species. Knowledge of movement patterns, specifically when these movements are directed out of a stocked system, can allow managers to recognize systems where emigration may be a potential source of fish loss, and to reduce fish loss via emigration in these systems. To benefit the management of two popular sportfish in the Midwest, muskellunge (Esox masquinongy) and saugeye (walleye [Sander vitreus] × sauger [Sander canadense]), this study sought to evaluate the abiotic and biotic factors influencing saugeye and muskellunge habitat-use patterns in large flood-control reservoirs; to estimate the contribution of emigration, natural mortality, and angler harvest to loss of fish from the reservoir fishery; and to assess the factors influencing emigration probability. To understand emigration patterns in conjunction with other sources of fish loss from the reservoir (angler harvest, natural mortality) (Chapter 1), we implanted passive integrated transponder (PIT) tags in saugeye and adult muskellunge and monitored emigration events through the Alum Creek Lake (Delaware County, OH) dam complex via a PIT-tag antenna array. We incorporated emigration data, live-recapture data, and angler harvest data into a multi-state mark-recapture model to estimate survival, emigration and harvest rates as functions of age and time. We used logistic regression analysis to model daily emigra (open full item for complete abstract)

Committee: Elizabeth Marschall Dr. (Advisor); Mazeika Sullivan Dr. (Committee Member); Christopher Tonra Dr. (Committee Member) Subjects: Aquatic Sciences; Ecology; Environmental Science; Freshwater Ecology; Natural Resource Management; Organismal Biology; Wildlife Conservation; Wildlife Management

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2016, Biological Sciences

Eastern Box Turtles (Terrapene c. carolina) have experienced range-wide declines as the result of extensive habitat loss, fragmentation, and alteration. The Oak Openings Region of northwestern Ohio is a biodiversity hotspot that exists in a highly fragmented landscape and provides a unique case study from which to examine the effects of anthropogenic disturbance on Eastern Box Turtles. In an effort to inform management and conservation efforts in the Oak Openings Region, I initiated a radio-telemetry project with the following objectives: 1) examine the spatial ecology of Eastern Box Turtles over several years to understand how they interact with their habitat in an area as unique as the Oak Openings Region, 2) develop predictive models depicting the temporal distributions of Eastern Box Turtles, 3) examine the impacts of one of the most common management tools in the Oak Openings Region, prescribed fire, on Eastern Box Turtles, and 4) evaluate pattern-recognition software as a low-cost alternative of identifying individual Eastern Box Turtles. Turtles at my study site exhibited larger home ranges than previously reported for this species as well as hierarchical habitat selection at multiple scales. Predicted distributions followed phenological shifts in habitat use and were influenced primarily by habitat type and canopy cover. Prescribed fires have the potential to have a devastating effect on box turtle populations, but management activities that take box turtle ecology into account will minimize these impacts while maintaining a critical disturbance regime. Computer-assisted photo-recognition has a great deal of potential as a supplemental method of identifying box turtles and provides a low-cost means of incorporating citizen science data into mark-recapture studies. My work suggests that conservation for Eastern Box Turtles in the Oak Openings Region should focus on maintenance and restoration of remaining box turtle habitat, connectivity between critical hab (open full item for complete abstract)

Committee: Karen Root Dr. (Advisor); Shannon Pelini Dr. (Committee Member); Jeff Miner Dr. (Committee Member); Enrique Gomezdelcampo Dr. (Committee Member); Salim Elwazani (Other) Subjects: Conservation; Ecology; Wildlife Conservation; Wildlife Management

Master of Science (MS), Bowling Green State University, 2016, Biological Sciences

The Oak Openings Region of Northwest Ohio of Northwest Ohio is an incredibly biodiverse area that is home to many rare and endangered plant and animal species. Furthering our knowledge and understanding on the resident bat species within the region is critical as populations of many species have declined from White-nose Syndrome, habitat loss and fragmentation, and wind energy barotrauma. To further bat-specific research in the region, my thesis research focused on: 1) identifying the relationships between bat activity and diversity and fragmentation features; 2) monitoring trends in activity and richness between forested and savanna sites over time; and 3) developing refined spatially explicit habitat models of bat occupancy using data collected from protected and unprotected habitat and comparing them to models created from strictly protected habitat. Ecological knowledge on bats and their response to features commonly associated with habitat fragmentation is lacking, so I acoustically surveyed thirty roads with Anabat SDII monitors within and outside of protected areas. I utilized logistic regression analysis to examine the relationship between presence/absence and activity of each species with each feature (e.g. proportion of road with overstory) to select candidate variables for multivariate models. I then created candidate multivariate models for each species and selected final models based on parsimony, AIC values, and adjusted R square values. Bats had a differential response to features between species, and park managers must consider the management of roads on a species- specific viewpoint if they plan to focus conservation efforts on bats. ii For the second part of my research, I surveyed bat relative activity within forest and savanna sites and compared the data to previous monitoring efforts. Within the single year I monitored, savanna sites appeared to host a greater activity for many species and a greater species richness. Between years, savanna si (open full item for complete abstract)

Committee: Karen Root (Advisor); Kevin McCluney (Committee Member); Andrew Gregory (Committee Member) Subjects: Conservation; Ecology; Wildlife Conservation; Wildlife Management

Master of Environmental Science, Miami University, 2016, Environmental Sciences

A species distribution model (SDM) was developed to predict the presence and suitable habitat of the federally threatened plant, Euphorbia telephioides, in northwest Florida using data acquired from the U.S. Fish & Wildlife Service. I used two machine-learning models, MaxEnt and boosted regression trees (BRTs), as previous research has shown them to yield high predictability, especially with presence-only data and different types of predictor variables. Different methods were used to reduce effects of spatial autocorrelation and sampling bias in the model predictions since E. telephioides populations are strictly located along the coast. The 29 predictor variables were a combination of categorical, continuous, and distance-based variables. Both the MaxEnt and BRT models had high accuracy as measured by area under the curve (AUC), sensitivity, specificity, and true skill statistic (TSS), but the BRTs had a much lower deviance. The BRT models were also validated with the discovery of a new population in an area predicted as high probability of occurrence. This study demonstrates that machine-learning SDMs can be used by conservation organizations as cost-effective tools to find and protect new populations of threatened or endangered species.

Committee: Mary Henry (Advisor); David Gorchov (Committee Member); Thomas Crist (Committee Member) Subjects: Conservation; Environmental Science; Geographic Information Science; Statistics

Master of Arts, Miami University, 2016, Geography

A current assessment of wildebeest (Connochaetes taurinus) distribution throughout the Masai Mara National Reserve (MMNR) and adjoining group ranches has not been investigated for over 15 years. This information is greatly needed to protect populations of wildebeest and their ranges. MaxEnt, a statistical model, was used to evaluate influential factors for wildebeest distribution and predict suitable habitats throughout the northern extent of the Serengeti National Park, the MMNR, and adjoining group ranches. There were thirty five abiotic and biotic variables used to create two distribution models in MaxEnt across the study area for two different time periods. Both models performed well with training AUCs >0.80. Precipitation seasonality, isothermality, and distances to lodges were the greatest contributing variables to wildebeest distribution in the November model. Kauth-Thomas wetness, annual temperature range, and distances to camps were significant factors for wildebeest distribution in the June model. Predictive maps from the June 2010 model revealed higher concentrations of predicted habitat suitability in areas historically impacted by the expansion of mechanized farming practices. It is recommended that the MMNR collaborate with local group ranch conservancies to secure seasonal dispersal sites for wildebeest and impose land use policies in unprotected areas. Results from MaxEnt also revealed that bioclimatic variables and soil and plant moisture are significant contributors to wildebeest distributions. The MMNR should evaluate the potential effects imposed by climate change to wildebeest distributions and populations.

Committee: John Maingi Dr. (Advisor); Amélie Davis Dr. (Committee Member); Thomas Crist Dr. (Committee Member) Subjects: Animal Sciences; Biographies; Ecology; Geographic Information Science; Geography; Statistics

Doctor of Philosophy, The Ohio State University, 2016, Evolution, Ecology and Organismal Biology

The Eastern Massasauga Rattlesnake (Sistrurus catenatus catenatus) is a rare species across its range and is thought to be experiencing widespread population declines. Application of conservation-oriented management practices to this species is hindered by incomplete knowledge of the spatial distribution of populations and suitable habitat. To address this obstacle to conservation efforts I developed species distribution models (SDMs) for northeastern Ohio and Michigan and incorporated the resulting habitat suitability maps (HSMs) in a range of landscape ecology applications. These models were generated using the software program Maxent and a series of environmental variables that represent different elements of Eastern Massasauga habitat association, including vegetation attributes (Landsat derived vegetation indices; LiDAR) and relative elevation (topographic position index). The Maxent model with the best predictive capacity to identify extant northeastern Ohio populations used location data from across the state. The model selected LiDAR data as the top contributing variable. Northeastern Ohio is a priority for Eastern Massasauga conservation in the state so I also conducted an analysis of historical land use and land cover change to better understand the distribution of populations and habitat in this region. I used object-based classification techniques to analyze historical aerial photographs (covering ~75 years) and found that present day populations and suitable habitat largely coincided with abandoned agricultural fields. In the absence of natural disturbance agents, agricultural fields that were allowed to go fallow represented an important source of early successional habitats that are vital to Massasauga. The early successional, open canopy habitats that Eastern Massasauga rely on are not permanent fixtures in this landscape making habitat management a necessity. The Michigan SDM was on a much broader scale than the Ohio modeling effort incorporating 60 (open full item for complete abstract)

Committee: Thomas Hetherington (Advisor) Subjects: Ecology; Wildlife Conservation

Doctor of Philosophy, The Ohio State University, 2014, Environment and Natural Resources

In recent years, a holistic ecosystem conceptualization has emerged that structurally and functionally links the river, and its riparian and floodplain zones into an integrated ecological unit - the riverine landscape. The riverine landscape often exhibit lotic water-driven disturbance biophysical complexity (e.g., patchiness) over both fine and broad spatio-temporal scales. However, despite the well-documented importance of river corridors (e.g., as biological refuges in human-modified landscapes), the role of riverine landscape pattern and composition on ecosystem structure and function is largely unknown. This study investigated the influence of internal (river size, lateral flow connectivity) and external (catchment land use and land cover) factors on site-specific riverine landscape patterns. It then used riparian spiders of the family Tetragnathidae and ants as model organisms to explore the associations between internal riverine landscape patchiness and the distribution, diversity, and trophic dynamics [e.g., trophic position (TP), and dependency on aquatically derived carbon (CA)]. Riverine landscape patchiness was measured using a combination of field (vegetation surveys, canopy photography, shoreline habitat measurements) and remote-sensing approaches [e.g., using a GIS, aerial photos, and Light Detection and Ranging (LiDAR) data]. Ants and spiders were surveyed on each side of the river at each study reach. A suite of analytical methods were used including Analysis of Variance (ANOVA), linear regression, Principal Component Analysis (PCA), Maximum Entropy (MaxEnt) modeling, a model-selection approach using Akaike Information Criterion (AIC) and Non-Metric Multidimensional Scaling (NMDS). Results indicate that both external and internal factors were associated with riverine landscape pattern (patch area and shape and size) including drainage area (a proxy for ecosystem size), proximity to impoundment (a proxy for lateral flow connectivity), and catchm (open full item for complete abstract)

Committee: Mazeika Sullivan Dr. (Advisor); Charles Goebel Dr. (Committee Member); Desheng Liu Dr. (Committee Member) Subjects: Ecology; Environmental Management

Master of Science (MS), Ohio University, 2011, Geological Sciences (Arts and Sciences)

In this study, the relative niche stability of Late Ordovician articulate brachiopod species from the Cincinnati Arch were analyzed before, during, and after an immigration of extra-basinal taxa into the Cincinnati, OH region, known as the Richmondian Invasion. The primary hypothesis investigated with this project is whether species preserve (niche conservation) or alter (niche evolution) the parameters of their ecological niche during intervals of biotic (invasive regime) vs. abiotic change (gradual environmental change). Ecological niche modeling (ENM), which is a process that utilizes computer-based algorithms to mathematically estimate a species ecological niche was employed to test this hypothesis. Additionally, the efficacy of the ENM program Maxent for use with fossil data was tested against a well established ENM method (GARP). Results indicate that during intervals of gradual change, species conserve the parameters of their ecological niches to higher degrees than during intervals of ecological rapid biotic change, when niche evolution is common.

Committee: Alycia Stigall (Advisor); Douglas Green (Committee Member); Elizabeth Gierlowski-Kordesch (Committee Member) Subjects: Ecology; Geographic Information Science; Geology; Paleoecology; Paleontology

Master of Arts, Miami University, 2010, Geography

The goal of this research was to characterize the distribution of elephants in the Tsavo Conservation Area (TCA) and relate the distribution patterns to biophysical and anthropogenic factors. Elephants in the TCA exhibited spatial clustering at distances between 60 km and 100 km, and were concentrated near the confluence of the Athi, Tsavo, and Galana rivers. Elephant density was negatively correlated with distance to rivers, human settlements density of water holes and was positively correlated with poaching density. Most elephants occurred in areas dominated by woody rather than herbaceous vegetation. Seasonal variation in green biomass captured by Enhanced Vegetation Index (EVI) from MODIS was an important predictor of elephant distribution. A probability distribution model implemented using Maxent used density of water holes, MODIS EVI, and distances to towns to predict the distribution of elephant habitat in the TCA. This map can be used to inform managers in elephant conservation strategies.

Committee: John Maingi PhD (Advisor); Kimberly Medley PhD (Committee Member); Thomas Crist PhD (Committee Member) Subjects: Geography

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

The Oak Openings Region of Northwest Ohio is unique in terms of the flora and fauna that exists within a relatively fragmented area. It contains more rare and endangered plant species than any other area of its size in Ohio and much is known about a number of terrestrial and aquatic animals in the area as well. One group of animals that has not been studied is that of the order Chiroptera, bats. Bats are threatened on many fronts, from the effects of human persecution, to habitat loss, to the recent effects of a deadly fungus, White Nose Syndrome. The Oak Openings is an ideal area to study this group of animals because of its unique composition that includes many natural areas, including that of oak savannas, within an urban/suburban/agricultural matrix. My research objectives included 1) developing a spatially explicit habitat model of bat presence within protected areas of the oak openings region 2) determine the relative difference in activity and presence between forest and savanna sites within the oak openings region and 3) determine the knowledge and attitudes people of the area hold in regards to bats and then develop educational opportunities to increase knowledge and attitudes about bats. Ecological knowledge regarding bats within protected areas, and potential habitat needs, is lacking so I began by acoustically surveying for bats using the Anabat bat detector to determine bat presence within protected areas. I then developed Maxent species distribution models for each of seven species of bats. These models were then tested using citizen science collected data. Models for all seven species performed well when tested with this data, demonstrating the use of Maxent modeling and citizen science collected data for refinement and testing of data sets. With these models I was able to determine areas of potential importance both within and outside of current protected areas as well as critical habitat characteristics for bat presence. Second, I again used Anaba (open full item for complete abstract)

Committee: Karen Root (Advisor); Helen Michaels (Committee Member); Karen Sirum (Committee Member); Moira van Staaden (Committee Member); Enrique Gomezdelcampo (Other) Subjects: Conservation; Ecology

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

Master of Science (MS), Ohio University, 2013, Geological Sciences (Arts and Sciences)

Changes in niche stability levels in deep time are evaluated by assessing the niche dynamics of a diverse suite of invertebrate taxa from the Late Ordovician Cincinnatian series of North America. During this interval, periodic sea-level fluctuations, storm events, and extrabasinal species invasions disrupted stable shallow-marine communities as taxa responded to both rapid and gradual environmental changes. Variations in relative niche stability through time and across clades are determined using ecological niche modeling (ENM) to produce and compare models for 11 invertebrate genera (crinoids, trilobites, bivalves, gastropods, bryozoans and corals) at high spatial and temporal resolution. The maximum entropy (Maxent) algorithm was used to generate ecological niche models for each genus for 9 time-slices across three sequences. Previous studies provided sedimentologically derived environmental layers, and geo-referenced occurrence data were compiled from primary field research augmented by published data. To evaluate niche stability, models were compared geospatially (in two-dimensional G-space), and in environmental space (n-dimensional E-space) between time-slices. Environmental parameters, which define individual niche models, were also tested for statistical dissimilarity between time-slices. These analyses were designed such that high degrees of similarity and range-overlap indicate niche stability, whereas statistical dissimilarity and low percentage range overlap indicate niche evolution. Complementary ENM studies of brachiopod species across this interval have documented higher levels of niche evolution during intervals of rapid sea-level rise and during the Richmondian Invasion. To determine if niche responses were congruent across clades, this analysis focuses on the niche dynamics of non-brachiopod taxa at the genus level and comparison of niche stability patterns between different clades, feeding styles, and at different taxonomic scales. The res (open full item for complete abstract)

Committee: Alycia Stigall PhD (Advisor); Douglas Green PhD (Committee Member); David Kidder PhD (Committee Member) Subjects: Ecology; Geology; Paleontology