Doctor of Philosophy, Miami University, 2024, Biology

This dissertation is structured into five chapters. Chapter I: I provide a general introduction to my dissertation, primarily introducing the different influences on intraspecific variation and providing a background on local adaptation. Chapter II: I investigate the effects of environmental conditions and demographic history on populations of desert horned lizards (Phrynosoma platyrhinos). I evaluate the demographic history of P. platyrhinos and identify signatures of selection associated with climate, which may be indicative of local adaptation. I then link signatures of selection to genes and functional genomic elements. Chapter III: I explore the influence of environmental heterogeneity on intraspecific variation of the chisel-toothed kangaroo rat (Dipodomys microps). I discover signals of selection associated with both climate and vegetation. I also find evidence that selective pressures likely vary across the species distribution and develop a permutation test to identify populations that possess more putatively adaptive alleles than expected by chance. I also link signals of selection to genes and biological functions that may be related to previously identified morphological differences between populations. Chapter IV: I perform a meta-analysis to understand general patterns of putative local adaptation in terrestrial chordates. I use previously published datasets and analyze them using a common framework to test theoretical predictions regarding the relationship between environmental and demographic factors and signals of selection. I find that signals of selection follow theoretical predictions, and, importantly, find that constant variation is an important driver of signals of selection. Chapter V: I provide conclusions and future directions from my results.

Committee: Tereza Jezkova (Advisor); David Berg (Committee Member); Donghyung Lee (Committee Member); Richard Moore (Committee Member); Susan Hoffmann (Committee Member) Subjects: Bioinformatics; Biology; Climate Change; Evolution and Development

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

Each chapter of this dissertation is intended to address a piece of the central hypothesis that complex, interacting biotic and abiotic filters drive community dynamics, including temporal synchrony between communities arising from distant propagule sources. In Chapter I, I examine the influence of three different synchrony metrics on measures of similarity between real and simulated time series, comparing methods for identifying clusters of more synchronous populations or communities, and revealing environmental drivers of those clusters. My results for this study indicate that wavelet analysis works best if the data have high frequency effects or high levels of noise. Empirical orthogonal functions work well if there are large differences in between-site magnitudes. If there are phase-lagged effects of interest, cross-correlation or empirical orthogonal function work well. For all other cases, each of these three metrics performed similarly. Therefore, these metrics may provide complimentary information if each are used to analyze the same dataset. Chapter II quantifies the filtering effects of temperature, egg bank composition, and disturbance on wetland invertebrate community dynamics and Chapter III quantifies the filtering effects of temperature, egg bank composition, and predation on wetland invertebrate community dynamics. Both chapters employ in-field mesocosm experiments in 100-gallon cattle tanks that were seeded with invertebrate propagules from either local ecosystems or from 5 different states. My results for these studies indicate that prairie pothole wetland communities are largely resistant to fluctuations in water levels though a few taxa (cladocerans, clam shrimp, fairy shrimp, damselfly larvae) saw decreased abundances in certain cases. Small changes in temperature (+1.1 °C) had little effect on the community except for intensifying the impact of the drawdown on clam shrimp and fairy shrimp. A greater change in temperature (+2.0 °C) led to more a (open full item for complete abstract)

Committee: Kevin McCluney (Committee Chair); Helen Michaels (Committee Member); Chris Patrick (Committee Member); Abby Braden (Other); Jeffrey Miner (Committee Member) Subjects: Biology; Conservation; Ecology; Entomology

Doctor of Philosophy (PhD), Ohio University, 2020, Biological Sciences (Arts and Sciences)

Rising temperatures across the planet are exposing populations to environmental conditions previously unexperienced by these lineages, and the responses to these changes are myriad. Depending on the species and population, responses to changing climates can encompass shifts in geographic ranges, rapid genetic adaptation, or new phenotypic distributions caused by plasticity. In the case where populations are unable to exhibit one of the aforementioned responses, extinction is the inevitable outcome. Scientists have recognized this issue and have worked tirelessly over the last 30 years to determine which species are vulnerable, how populations are responding to rapid environmental changes, and how to best conserve the most at-risk lineages. However, the efforts to predict how populations and species will persist after a century of consistent and strong climate change tend to ignore how these changes affect contemporary populations, and thus we risk missing the critical phenotypic trajectories that lead to rapid adaptation, range shifts, or extinction, which could provide both a platform for informing species conservation, but also enhance our knowledge of biodiversity. This dissertation explores how environmental variation over a variety of spatial and temporal scales impacts the selective environment in which species live, as well as the multiple plastic responses populations can exhibit in response to changing environmental conditions. First, the relationship between declining food availability and rising environmental temperatures is quantified. Food availability exacerbates organismal performance and reduces the availability of populations to mount adaptive phenotypic changes in response to changing environments. Second, the relationship between thermoregulatory behavior and individual fitness is quantified. Fitness is increased when lizards exhibit warmer preferred temperatures and can sprint faster to enhance their thermoregulatory ability. Third, the efficacy (open full item for complete abstract)

Committee: Donald Miles (Advisor); Shawn Kuchta (Committee Member); Willem Roosenburg (Committee Member); James Dyer (Committee Member) Subjects: Biology; Climate Change; Organismal Biology; Wildlife Conservation

Doctor of Philosophy, The Ohio State University, 2019, Horticulture and Crop Science

Climate change impacts crop production as mean and extreme temperatures increase. Yet the maintenance of crop yield depends on the continued adaptation of crop varieties to their local environments. Mexico, the crop center of origin for maize, is home to high genetic diversity in landraces that campesino farmers actively manage, conserve, and rely upon. Southern Mexico possesses strong elevation gradients and heterogeneous environments cover a relatively small area, creating an ideal study site. The overall objective of this dissertation is to explore patterns of local adaptation in maize landraces along an elevation gradient while investigating the underlying physiological mechanisms which may explain these patterns. Populations of maize landraces from two elevation gradients (600-2150 m and 1850-2400 m) were compared in common gardens over three field seasons. In the first two years, 12 populations were sourced from, and planted reciprocally into, three elevational zones (600, 1550 and 2150 m). We studied traits such as photosynthetic rate, stomatal conductance, stomatal density, and relative growth rate (RGR), some of which proved to influence landrace maize fitness. Maize fitness was affected by G x E interactions, with responses of maize from different elevations (G) responding differently across common gardens (E). Evidence for local adaptation for both years was accompanied by strong to year to year variation. In the third year, 14 populations were collected every 100 m and planted at three elevations (1850, 2100, and 2400 m), and seven additional populations were sourced from genebank accessions originating in four Mexican states. We evaluated the quantity and diversity of leaf flavonoids, which are secondary plant metabolites that serve as protectants from UV-B damage. Two flavonoids varied based on garden elevation and are known to be herbivory deterrents. Maize landraces sourced within several 100 m often performed similarly, but maladaptive (open full item for complete abstract)

Committee: Kristin Mercer (Advisor) Subjects: Biochemistry; Climate Change; Conservation; Ecology; Evolution and Development; Physiology; Plant Biology; Plant Sciences

Ph.D., Antioch University, 2017, Antioch New England: Environmental Studies

Around the world, municipalities are facing new challenges, not the least of which is climate change. This is especially true for rural communities that, for a variety of reasons, will be disproportionately affected by the climatic changes and accompanying policies or programs. This dissertation, written in manuscript-style, integrates climate change and social-ecological scholarship to address the unique character of rural communities, to communicate the complexity of rural identity through the term "rural character"; and to empower rural communities to incorporate adaptation strategies into their daily municipal operations and planning. Specifically, this dissertation seeks to answer the following questions: What is community character and what does it offer for climate change planning? What is the relationship between rural character and climate change? How can rural communities adapt to create a resilient rural character? Through this research, I argue that there is a common dialogue across multiple disciplines that shows opportunities for interdisciplinary adaptation scholarship that could inform local planning efforts. I identify a common framework of people-place-process across multiple disciplines and identify opportunities for cross-disciplinary communication. To understand the complexity of the rural identity, my single mixed-methods case-study in Northwest Connecticut develops a place-based definition as well as a transferable model of rural character that can be used to understand other rural locales. The model of elements, dimensions, and tensions presents the quantitative and qualitative nature of rurality that, in its composition, represents the components of meaning to local residents. The study also indicates the importance of a regional rural identity. Bringing the scholarship to bear in the last manuscript, I use the theoretical underpinning of socio-ecological systems and place-based definition of rural character to create a guidebook (open full item for complete abstract)

Committee: James Jordan Ph.D. (Committee Chair); James Gruber Ph.D. (Committee Member); Keith Halfacree Ph.D. (Committee Member) Subjects: American Studies; Climate Change; Cultural Resources Management; Environmental Studies; Geography; Land Use Planning; Regional Studies; Sustainability

Doctor of Philosophy, The Ohio State University, 2017, Evolution, Ecology and Organismal Biology

Predators and prey coevolve to produce some of the most fascinating phenotypic characteristics of animals. However, coevolution is not a simple race toward the most extreme traits. The occurrence, strength, and outcomes of coevolution are hypothesized to be determined by multiple factors; some are environmental and others are intrinsic to the species involved. Although this complexity has been recognized and studied in fast-evolving hosts-parasite systems, testing the key predictions of coevolutionary theory in natural populations of predators and prey has remained a difficult task. I evaluated the effects of two key factors that impact coevolving rattlesnake venom and ground squirrel venom resistance–mechanisms of interaction and population demography–and I provide evidence that the broader composition of the small mammal prey community exerts selection on the venom phenotype as well. Toward this end, I collected Northern Pacific rattlesnake (Crotalus oreganus) venom and California ground squirrel (Otospermophilus beecheyi) blood serum (which contains venom inhibitors) from multiple populations in California where California ground squirrels have evolved resistance to the venom. I developed an experiment to test for population-level adaptation of venom metalloproteinases in their interaction with ground squirrel venom inhibitors. I demonstrated local adaptation in a snake-prey relationship for the first time, where venom metalloproteinase enzymes have evolved to overcome ground squirrel resistance. Furthermore, the existence of local adaptation in these biochemical traits suggests that the mechanism of coevolution involving venom is not an escalating arms race as previously thought, but rather a phenotype matching-based interaction involving a molecular lock-and-key mechanism between multiple snake venom proteins and prey inhibitor molecules. The high levels of medically-significant intraspecific venom variation seen in snakes must now be also viewed in terms of a (open full item for complete abstract)

Committee: H. Lisle Gibbs (Advisor); Marymegan Daly (Committee Member); Bryan Carstens (Committee Member); Stuart Ludsin (Committee Member) Subjects: Biology; Evolution and Development; Genetics

Doctor of Philosophy, The Ohio State University, 2017, Evolution, Ecology and Organismal Biology

Interactions between predators and prey are widespread in nature but the ecological and evolutionary factors that shape these interactions are poorly understood. In my dissertation, I use pigmy rattlesnakes (Sistrurus miliarius) and their prey as a system in which to examine several aspects of this species interaction where different ecological and evolutionary factors may be shaping variation in adaptive traits. In Chapter 1, I review factors affecting predator-prey interactions and explain why the pigmy rattlesnake system is valuable for addressing important research questions. In Chapter 2, I present research on the behavioral component of this interaction, demonstrating that native cotton mice do not change their foraging behavior in the presence of a sit-and-wait rattlesnake predator. In Chapter 3, I explore the toxicity of venom to native prey versus non-native "models" to determine to what extent non-native species are representative of prey in the same broad taxonomic group. I show that native prey have higher resistance to venom than non-natives and encourage the use of native prey in future toxicity work. In Chapter 4, I use native treefrog prey from two different populations in Florida and venom from snakes in the same populations to see if there is a signal of local adaptation present in these populations. I show that detection of a signal of local adaptation depends on the measure of venom function used: evidence for local adaptation was observed in the time to death measure of mortality but not in the 24 hour mortality measure. In Chapter 5, I look at the function of venom at a smaller scale by exploring the amount of functional variation present across and within populations of snakes using a lizard model prey. I found the individual component of venom toxicity to be larger than the population-level differences that have been the focus of previous research. Overall, this dissertation demonstrates that rattlesnake venom function differs at bo (open full item for complete abstract)

Committee: H. Lisle Gibbs Ph.D. (Advisor); Ian Hamilton Ph.D. (Committee Member); Thomas Hetherington Ph.D. (Committee Member); Stuart Ludsin Ph.D. (Committee Member) Subjects: Animals; Behavioral Sciences; Biology; Ecology; Evolution and Development; Toxicology; Zoology

Master of Science (MS), Bowling Green State University, 2015, Biological Sciences

Local adaptation has been shown to be a key process that drives the evolution of species, influencing both their physical characteristics and ecological interactions. Local adaptation is generally expressed by higher fitness of individuals raised in their native habitats versus in a foreign location. The influence of local adaptation is especially prominent in species that subsist in small and/or highly isolated populations. This study evaluates the degree to which the federally endangered Karner blue butterfly (Lycaeides melissa samuelis) is locally adapted to its exclusive larval host plant, wild lupine (Lupinus perennis). To test for local adaptation of the Karner blue butterfly, individuals from a laboratory-raised colony were reared on wild lupine plants from populations belonging to either their native or foreign region. Specifically, nine wild lupine populations from three different regions: Indiana (native), Michigan (foreign) and Wisconsin (foreign) were grown in a common garden using growth chambers and one Karner blue larva was placed on each plant. Fitness traits related to growth and development of this butterfly on the different populations were recorded. Survival and days from pupation to eclosion both showed significant differences across wild lupine populations, indicating that wild lupine source can affect some fitness-related traits of Karner blue butterflies. However, this influence was not manifested as higher fitness on native plant populations. Results from this study have implications for programs attempting to reintroduce Karner blue butterfly populations across their historical range. The apparent absence of local adaptation to wild lupine suggests that at least some individuals of this species could be translocated from native populations to foreign reintroduction sites without experiencing decreased fitness levels. However, because variation was observed for some fitness related traits and our experimental design did not encompass all (open full item for complete abstract)

Committee: M. Gabriela Bidart-Bouzat Dr. (Advisor); Juan L. Bouzat Dr. (Committee Member); Shannon Pelini Dr. (Committee Member) Subjects: Biology; Ecology; Entomology; Evolution and Development; Plant Sciences

Doctor of Philosophy, The Ohio State University, 2014, Horticulture and Crop Science

The genetic diversity in the crop landraces and crop wild relatives (CWRs) of the world is the `biological cornerstone' of food security—we must ensure that it is conserved. Two important steps that could assist the in-situ conservation of this germplasm are: 1) determining how natural selection has shaped the distribution of functional genetic diversity across the landscape; and 2) identifying potential threats to this diversity. In addition, the former could assist landrace farmers in securing germplasm capable of withstanding future biotic and abiotic shifts by producing information on the locations of pertinent genetic diversity. In this body of work we provide examples of each of these steps—one from the maize landraces of Chiapas, Mexico (step 1) and the other from the sunflower system of the US (step 2). First, we sought understanding of how natural selection has shaped functional genetic diversity in Zea mays ssp. mays (maize) landraces grown along an elevational cline in Chiapas, Mexico by using RNA-seq approaches. We collected maize landraces from three elevational zones (highland, ~2100 m; midland, ~1550 m; and lowland, ~600 m) and planted them in a midland common garden. RNA-seq was performed on young leaf tissue. Weighted gene co-expression network analysis was used to identify co-expressed gene modules among landraces. Association analysis was then performed between landrace module expression values and environmental parameters of landrace origin. We identified an apparent tradeoff between an ABA dependent abiotic stress response in the lowland landraces and a possible plasma membrane repair/signaling response in the highland landraces. We then used the RNA-seq dataset to find signals of genetic differentiation in phenylpropanoid, flavonoid, and lignin biosynthesis between highland and lowland maize landraces. Genes differentially expressed between highland and lowland landraces were compared to a list of known and predicted genes involv (open full item for complete abstract)

Committee: Kristin Mercer Dr. (Advisor); Erich Grotewold Dr. (Committee Member); Leah McHale Dr. (Committee Member); Andrew Michel Dr. (Committee Member) Subjects: Agriculture; Biology; Conservation; Ecology; Horticulture; Molecular Biology; Plant Biology; Plant Sciences; Sustainability