Master of Science, The Ohio State University, 2023, Environment and Natural Resources

The American elm (Ulmus americana) was once found lining the streets of many cities. Now, with the continued threat of Dutch elm disease (Ophiostoma ulmi and O. novo-ulmi), large American elms are uncommon. Efforts by researchers have led to the development of Dutch elm disease-tolerant American elm selections. Yet we have little understanding of how these selections may react to a range of environments when used in restoration. Our goal is to better understand how DED-tolerant elms differ in phenology across locations and genotypes to develop predictions for how they may respond to restoration and future climate change. In common gardens in central Ohio and northern New England, we tracked the progression, time to initiation and time to completion of budbreak and leaf-out, in DED-tolerant elms. We assessed individuals across five genotypes – Princeton, R18-2, Del-2, New Harmony, and Valley Forge – which have been cultivated to produce DED-tolerant lines. Phenological data, i.e., dates at which a tree's buds reached a given stage, collected in central Ohio over two field seasons (spring 2022 and spring 2023) and in New England over one field season (spring 2023) were used to determine the relationship between time and phenology, and the effects of location, year, genotype, and genotype interactions. Data on bird presence and use of elm trees in sites in central Ohio during spring 2023 were used to better understand the potential role of restored elms within the landscape. We found that year and location effects were significant at more stages than genotype or interaction effects – colder locations and the year with later spring warming tended to result in elms reaching key phenological stages later than warmer locations and the year with earlier spring warming. This indicates that environmental factors may have a stronger influence on spring phenology in American elms than genotype. We also found that bird presence had a strong positive correl (open full item for complete abstract)

Committee: Stephen Matthews (Advisor); Jo Peacock (Committee Member); Matt Davies (Committee Member); Kristin Mercer (Advisor) Subjects: Forestry; Natural Resource Management

Master of Science, The Ohio State University, 2024, Environment and Natural Resources

We are living in a period of rapid global climate change, which is altering species interactions in complex ways. One well-documented consequence of this is an advance in the onset of spring in temperate regions. Unequal shifts in phenology between producers and consumers can lead to phenological asynchrony, or mismatch between an organism's peak resource requirements and peak availability of resources, which can decrease productivity and result in population declines. For bird species, advances in breeding phenology can decrease the risk of mismatch. Yet, the ability of migratory species to advance their breeding phenology is constrained by their spring migration timing. Flexibility in migration timing enables individual responses to changing environmental conditions, which in turn has led to advances in the timing of spring migration across many species. However, migration timing is determined by a complex set of exogenous, endogenous, and organismal factors and responses to environmental stimuli vary greatly between species. Therefore, there is much still to understand regarding flexibility in spring migration timing and how it may aid or impede phenological responses to climate change. My research explores how stages of the annual cycle interact to influence arrival timing at the species-, population-, and individual- levels in the prothonotary warbler (Protonotaria citrea), a species which has not shifted its arrival timing in response to climate change. Understanding how environmental variation influences the arrival timing of a species may aid in predicting that species' vulnerability to climate change. In my first chapter, I determine the relative influence of nonbreeding and stopover environmental conditions on arrival timing of prothonotary warblers at the species-level using 11 years of participatory science data (2012–2022). I additionally explore how mechanisms of arrival timing vary across a breeding distribution. Consistent with my predictions, I (open full item for complete abstract)

Committee: Christopher Tonra (Advisor); Jo Peacock (Committee Member); William Peterman (Committee Member) Subjects: Ecology; Wildlife Conservation

Doctor of Philosophy, Miami University, 2024, Biology

Climate change has the potential to alter interactions between species if it leads to range shifts that create new areas of sympatry. Understanding how species respond to these changing interactions is essential in predicting the effects climate change will have on population and community dynamics. Two sympatric species of Peromyscus in the Great Lakes region have experienced range shifts that can potentially alter how they compete. Peromyscus leucopus noveboracensis (PLN) has expanded its range into areas where P. maniculatus gracilis (PMG) was previously the only forest mouse, while PMG has disappeared from the southern portion of its range. To understand the potential effects of competition on these species, I sampled from locations that have mostly PLN, equal proportions of the two species, or mostly PMG. I examined how winter severity affects population size, overwinter survival, and breeding phenology by comparing between sites. I also examined how changing community dynamics influenced genetic structure. Lastly, I examined how microhabitat use and niche partitioning can alleviate the effects of climate change and altered competitive dynamics. While community composition influences population growth rates, genetic diversity remains stable in PMG, and microhabitat features appear to allow it to persist in certain areas. These results indicate that examining multiple aspects of a species' ecology, including interactions with possible competitors, is essential to understand the impacts of climate change on terrestrial animals.

Committee: Susan Hoffman (Advisor) Subjects: Biology; Ecology

Doctor of Philosophy, Case Western Reserve University, 2024, Biology

Organisms are shifting breeding phenology and thus exposing offspring to novel photoperiods. Rising global temperatures are also expanding the growing season and changing the relationship between photoperiod and temperature. This raises the question of whether species' responses to photoperiod that evolved prior to contemporary climate warming could lead to maladaptive responses under future global change. In Chapter 1, I examined how photoperiods representing two seasons affected freshwater communities composed of amphibians, phytoplankton, periphyton, and zooplankton. Both gray treefrogs and green frogs developed faster under the early-season photoperiod, and copepod nauplii abundance also increased. While there were taxa-specific effects of photoperiod, there were no widespread shifts in community composition nor strong indirect effects detected across the community. In Chapter 2, I explored the carryover effects of photoperiod and temperature, as well as their potential interaction, on gray treefrog life history. Both early- and late-season (shorter) photoperiods and the warm temperature treatment increased development rate but had opposing effects on size at metamorphosis: the shorter photoperiods reduced size, and the warm treatment increased size. While juveniles from the warm treatment grew slower during the short-term growth period after metamorphosis, there was no effect on long-term growth. Conversely, juveniles from the shorter photoperiods did not grow differently from the longer (average-season) photoperiod during the short-term growth period but grew slower during the long-term growth period. Overall, photoperiod had stronger effects across amphibian traits than that of temperature. In Chapter 3, I investigated the effects of three photoperiod treatments on traits associated with overwintering ability in gray treefrogs. Juveniles under the late-season photoperiod exhibited dramatically increased cryoprotectant levels, greater cold tolerance, and reduc (open full item for complete abstract)

Committee: Michael Benard (Advisor); Elliot Gardner (Committee Chair); Diana Koester (Committee Member); Jean Burns (Committee Member); Karen Abbott (Committee Member) Subjects: Biology; Climate Change; Ecology; Freshwater Ecology; Zoology

Master of Science (MS), Ohio University, 2023, Plant Biology (Arts and Sciences)

Masting is defined as highly synchronized seed production within a population that varies in intensity among years. Reproductive output of masting species and the occurrence of years with high seed production are thought to be influenced by climate and resource availability. In oaks, spring weather seems to be particularly influential to seed production. However, there is also significant variation in seed production among individuals in the same population. The goal of this study was to examine if individual variation in seed production of Quercus montana (chestnut oak) was explained by differences in pollen availability. Phenological synchrony and conspecific density were examined as indicators of pollen availability. I also asked if these variables were influenced by differences in microclimate related to topography and spring weather. The study included 36 Q. montana individuals from populations in Vinton Furnace Experimental Forest and Zaleski State Forest in southeastern Ohio. For each individual, microclimate was quantified by collecting data on elevation, slope, aspect, air temperature, soil temperature, and humidity during spring of 2022 and 2023. Observations on individual flower development were made from March to May of 2022 and 2023, and relative density of conspecifics within 50 m was also quantified. Results showed that individuals at higher elevations and on more south-facing slopes experienced warmer and drier microclimate conditions during spring, but these conditions did not significantly influence phenological synchrony in either year. Based on seed production data from 2022, there was not a significant relationship between either phenological synchrony nor conspecific density and individual seed production, however there was a significant positive relationship between individual dry weight of collected catkins and number of acorns produced. Analysis of long-term seed production collected since 2000 also revealed a positive relationship between e (open full item for complete abstract)

Committee: Rebecca Snell (Advisor) Subjects: Ecology; Plant Biology

Doctor of Philosophy, The Ohio State University, 2022, Environmental Science

Discovered in 2012, beech leaf disease (BLD) is a lethal forest epidemic affecting American beech (Fagus grandifolia Ehr.) in northeastern North America. Due to the relative novelty of BLD, there is little information about the disease in general, including information about its etiology and general epidemiology. In ten short years, nine states and the Canadian province of Ontario have become affected by BLD. This rapid spread exemplifies the need to better understand the Fagus grandifolia – BLD pathosystem to assist in preventing the functional extinction of American beech. A major objective of this research was to explore the etiology of BLD using a high-throughput sequencing-based metabarcoding analysis of the whole foliar microbiome of American beech. The main goal of that study was to discover the true causal agent of BLD by comparing the microbial communities of all known plant pathogen types present in or on symptomatic American beech leaves compared with asymptomatic leaves. From this analysis, the amplicon sequence variant (ASV) of the exotic nematode Litylenchus crenatae subsp. mccannii (LCM), which was proposed by others as the causal agent of BLD, was detected in all symptom types, i.e. including asymptomatic and apparently healthy beech, albeit at significantly lower levels. However, four ASVs associated with the bacterial genera Wolbachia, Erwinia, Paenibacillus, and Pseudomonas and one ASV associated with the fungal genus Paraphaeosphaeria were detected only in symptomatic samples. These results suggest that LCM may not be fully responsible for BLD and that other microbes may be contributing to the syndrome, i.e. LCM may be necessary but not sufficient to cause disease. Given that the symptom progression of BLD had not yet been characterized, a phenological observation study was carried out to determine how BLD symptoms develop within a growing season and in subsequent seasons. This study was designed to determine if symptoms 1) were present on (open full item for complete abstract)

Committee: Pierluigi Bonello (Advisor); Jason Slot (Committee Member); Rongjun Qin (Committee Member); Richard Dick (Committee Member); María-Soledad Benítez Ponce (Committee Member) Subjects: Environmental Science; Plant Pathology

Doctor of Philosophy, The Ohio State University, 2021, Evolution, Ecology and Organismal Biology

Humans engineer their environments by transporting species around the planet. In a new environment, most introduced species will perish, but a small proportion can become invasive, spreading widely and impacting their environments. My dissertation explores how evolutionary processes shape invasive species. I studied two mechanisms of invasive species evolution that can induce rapid evolutionary change: hybridization (mating between genetically distinct individuals) and whole genome duplication (WGD, when offspring inherit an extra set of chromosome pairs). In Chapters 1 and 2, I describe experiments with members of the model plant genus Arabidopsis differing only in genome size and status as either parent or hybrid, effectively isolating the independent effects of WGD and hybridization on traits. I grew plants together under controlled conditions and measured traits and phenotypic plasticity (the change in trait values across imposed environmental gradients). For the handful of traits and gradients in which WGD shifted plasticity values, WGD consistently increased plasticity (Chapter 1). This study provides the most controlled experimental evidence to date in support of the hypothesis that WGD increases plasticity, a hypothesis invoked to help explain how WGD has driven evolution. In contrast to WGD, I found that hybridization produced larger effects on both mean traits and plasticity (Chapter 2). This experiment is the first to fully isolate hybridization and WGD effects on plasticity. In nature, genetic and trait variation provide the raw material allowing invasive species to initially prevail in and, potentially, adapt to the introduced environment. I examined patterns of variation related to hybridization and WGD for two invasive plant systems (Chapters 3 and 4). Chapter 3 focuses on purple loosestrife (Lythrum salicaria), a well-studied species for which other authors have documented post-introduction changes in traits and genetics. A little-studied, mo (open full item for complete abstract)

Committee: Stephen Hovick (Advisor); Alison Bennett (Committee Member); Andrea Wolfe (Committee Member); Kristin Mercer (Committee Member); Amanda Simcox (Committee Member); Robert Klips (Committee Member) Subjects: Biology; Botany; Conservation; Ecology; Evolution and Development; Genetics; Horticulture; Morphology; Organismal Biology

Master of Science in Environmental Science, Cleveland State University, 2021, College of Sciences and Health Professions

Urban forests are increasingly threatened by climate change and the environment of cities. Past dendrochronological studies have focused on more rural ‘natural' forests and has sought to reconstruct past climate regimes and the impacts of drought in these areas. Dendrochronology has begun to expand the urban ecosystem and incorporate traditional ecological principles and functional trait ecology to gain a more thorough understanding of the ecosystems. The confluence of these disciplines, dendroecology, will help guide better understanding of urban forests and aid urban planners and forester in reforestation and afforestation of urban areas. To gain better insight to how species are responding to the urban ecosystem, we analyzed the growth variability of twelve species at Secrest Arboretum and then compared the variability of growth to measures of the climate conditions, functional traits, of phenological characteristics of these species. In May 2019 and June 2020, we extracted increment cores from 59 individuals representing 12 species of commonly planted trees in the Cleveland area from the Shade Tree Evaluation Plot at Secrest Arboretum in Wooster, OH. These increment cores were measured, crossdated, and chronologies of growth were prepared from which we determined the temporal variability of growth. The temporal variability of growth was compared to the climate conditions at Secrest Arboretum. We then compared the temporal variability of growth and climate-growth sensitivity to the functional traits and phenological characteristics of these species. We found evidence that different species exhibit differing variability of growth, that the variability of growth is positively influenced to growth and that unique functional traits and phenological characteristics determine different responses to different climate factors among species.

Committee: Kevin Mueller (Advisor); Emily Rauschert (Committee Member); Julie Wolin (Committee Member); Gregory Wiles (Committee Member) Subjects: Environmental Science

Doctor of Philosophy, The Ohio State University, 2021, Evolution, Ecology and Organismal Biology

Many migratory animals time reproduction using environmental cues (e.g., photoperiod) that signal favorable conditions for offspring (e.g., food availability). However, environmental change can decouple these cues from the conditions relevant to offspring success. In turn, variation in reproductive behaviors may be critical to population persistence in a changing environment. For example, while natal homing can lead to valuable local adaptations in a stable environment, straying to new breeding sites can buffer against environmental change. Among exploited species, knowledge of reproductive behavior, such as spawn timing (phenology) and spawning site selection, has proven useful to fisheries management by influencing angling dynamics, estimates of biological reference points, and stock delineations. Thus, a well-developed understanding of reproductive phenology, breeding site selection, and fishery dynamics could help agencies effectively conserve and manage fisheries in ecosystems experiencing environmental change. Accordingly, my dissertation research sought to better understand the reproductive behaviors and angling dynamics of Lake Erie's walleye population. In collaboration with other researchers and agency biologists, I used acoustic telemetry, creel surveys, environmental monitoring data, and quantitative techniques to discern the spawning behaviors and angling dynamics of this population. We assessed the timing of residency in spawning sites, focusing on how environmental cues and individual characteristics drive observed variation (Chapter 2), developed a quantitative framework to estimate the frequencies of each potential spawning site selection strategy (Chapter 3), demonstrated sex based-differences in spawning behavior and male-biased walleye harvest during the spawning season (Chapter 4), and modeled the impact of fishery characteristics and angler behaviors on recreational catch outcomes (Chapter 5). Each chapter generated new insights to the (open full item for complete abstract)

Committee: Stuart Ludsin (Advisor); Elizabeth Marschall (Committee Member); Suzanne Gray (Committee Member); Janice Aski (Committee Member); Christopher Vandergoot (Committee Member); Thomas Binder (Committee Member); Christopher Tonra (Committee Member) Subjects: Aquatic Sciences; Ecology; Freshwater Ecology; Natural Resource Management; Wildlife Management

MS, Kent State University, 2021, College of Arts and Sciences / Department of Biological Sciences

The loss of ecosystem function and services resulting from worldwide insect population declines and species loss has alarming ecological implications. The potential impacts of the decline of native and managed bees on plant reproduction are receiving considerable attention; however, there is insufficient information about the current conservation status of tropical bees. In the first chapter, I compared pollinator bee communities in the seasonally dry tropical forest (SDTF) of Palo Verde National Park (PVNP) and neighboring SDTF in Guanacaste, Costa Rica, from 1971-2018, using museum collections and field surveys. I also proposed that changes in bee communities result from changes associated with habitat, climate change, and the arrival of Africanized Apis mellifera in the mid to late 1980s. To establish the composition and abundance of historical pollinator communities, I examined the records of 6,475 specimens collected in the seasonally dry tropical forests of Guanacaste. I compared the historical records with dry season surveys conducted at PVNP in 2016-2018. There was a general decline of solitary bee diversity and abundance in PVNP, with a clear declining trend at the species level for some solitary bee genera. Melipona beecheii appears extirpated from PVNP, which coincides with the timing of increases in tthe abundance of A. mellifera. Because of the relationship between precipitation-cued flowering plants and the declining bee species, my second chapter investigated how variation in precipitation cues could likely cause a mismatch between flowering time and bee activity. Meteorological data was gathered from several sources to create a dataeet of precipitation information. To examine the relationship between precipitation patterns and the availability of floral resources, I used pollen samples taken from bee specimens from four museum collections and published data to create a historical dataset of flowering times of SDTF trees and bee communities (open full item for complete abstract)

Committee: Oscar Rocha (Advisor); Matthew Lehnert (Committee Member); Mark Kershner (Committee Member) Subjects: Biology; Botany; Ecology; Entomology

Master of Science, Miami University, 2021, Biology

Zooplankton represent an important link for the transfer of energy in aquatic food webs. Reservoirs and lakes are key sentinels and integrators of environmental changes because they are sensitive to terrestrial inputs. Here we use a 24-year (from 1996 to 2019) dataset to analyze the long-term seasonal responses of rotifer zooplankton biomass and phenology (using center of gravity, COG) to long-term trends and interannual variability (IAV) in temperature, discharge, turbidity, and biotic factors in a eutrophic reservoir. Rotifers decreased while cyclopoid copepods increased over the 24-year period. Rotifer community composition shifted, and this change was more drastic during the spring than summer. The only rotifer genus showing a significant change in COG was Brachionus, which was later in both seasons. The correlations between the IAV of rotifer biomass and environmental drivers were species- and season-specific. The phenology (COG) of rotifer biomass was positively correlated with the COG of environmental factors. Short-term correlations did not provide strong support for either top-down or bottom-up control of rotifer biomass changes. Interannual correlations often did not support long-term correspondence of rotifer measures with environmental drivers, and our results suggest that different mechanisms likely underly interannual vs. long-term trends in rotifer biomass and phenology.

Committee: María González (Advisor); Michael Vanni (Committee Member); Seonjin Kim (Committee Member); Craig Williamson (Committee Member) Subjects: Aquatic Sciences; Biology; Ecology; Environmental Science

Doctor of Philosophy, University of Toledo, 2021, Biology (Ecology)

Prior to the recent upward climb, global average temperatures were relatively stable and was described by Mann et al. 1999 using a hockey-stick model. The hockey-stick model consists of two line segments (with the x-axis as time and temperature as the y-axis) meeting at a single changepoint. The hockey-stick model also describes North American average temperatures. The line segment prior to the changepoint is flat (indicating a stable average temperature), and the line after the changepoint has a positive slope (indicating increasing average temperatures). Because the long-term average temperature change is a defining characteristic of climate change, researchers have shown that changes in many phenological variables over time can also be described by a hockey-stick model. For phenological variables, the changepoint and the slope of the line after the changepoint represent the timing of the onset and the effect the change in phenological signal in response of climate change. However, large annual variation often obscures the pattern when analyzed using data from a single location/species, whereas regional differences due to spatial variability of climate and weather patterns render pooling data from different locations impractical. The Bayesian hierarchical modeling approach is effective in separating these two sources of variability by partially pooling data from multiple location/species. As such, I develop a Bayesian hierarchical hockey-stick model and apply it to different biological and physical systems that respond to temperature. Our systems of interest are 1) North American lilac first bloom dates, 2) Great Lakes ice coverage duration, and 3) spring and fall migratory bird migration season at Powdermill Nature Reserve – Avian Research Center (PNR - ARC). After applying the hockey-stick model to the systems of interest, North American lilac first bloom dates generally began to response to the long-term change in temperature in 1973 and are shifting roughly on (open full item for complete abstract)

Committee: Song Qian (Advisor); Gronewold Andrew (Committee Member); Refsnider Jeanine (Committee Member); Shao Qin (Committee Member); Streby Henry (Committee Member) Subjects: Climate Change; Ecology; Environmental Science; Statistics

BS, Kent State University, 2021, College of Arts and Sciences / Department of Biological Sciences

Many animals are facing pressure to adapt to the new conditions in their environments caused by climate change. Two such adaptations are the advancement of spring arrival date in long-distance migratory birds and the shift of temperate distributions northward. These events show a change in historically stable phenological processes and species range over the past few decades due to human impact. Though these phenomena have been widely studied, most analyses have been conducted at the aggregate level. Our study focuses on a specific guild of neotropical migrants: aerial insectivores that breed in Eastern and Central North America. We aim to understand some of the effects of climate change on each of the 19 species selected by looking at shifts in the timing and rate of spring and fall migration from 1988-2020 as well as the centers of abundance on the breeding ranges from 1990-2019. Datasets from eBird, a global citizen science project, were used to assess the earliest sightings of each species above the 35th latitude in the spring and the latest sighting above this latitude in the fall at the start and end of each of the last three decades. Linear regression was used to compare differences in the rate of northward movement in the spring and southward movement in the fall across years. To assess changes in breeding range distribution, centers of abundance for each species from 1990-2019 were calculated using the latitude and longitude of sightings from the North American Breeding Bird Survey. Statistical analysis showed 5 species saw significantly faster rates of northward movement in the spring over time while 8 saw significantly slower rates. In the fall, 2 species saw faster rates of southward movement over time while 11 saw slower rates. Strong evidence exists for changes in centers of the breeding distributions as 17 of the 19 species saw significant directional shifts. Of these, a majority were to the north and west. No statistical tests were performed on the (open full item for complete abstract)

Committee: Mark Kershner PhD (Advisor); Timothy Assal PhD (Committee Member); David Singer PhD (Committee Member); Christie Bahlai PhD (Committee Member) Subjects: Animals; Biology; Climate Change; Conservation; Ecology; Wildlife Conservation; Zoology

Master of Science (M.S.), University of Dayton, 2021, Biology

Ecological invasion is one of the most important processes of global change influencing ecosystems in practically every biome on Earth. Invasive species shift ecosystem dynamics, community structures, nutrient cycling, and ecosystem function. Invasive species pose a significant challenge to land managers who are charged with maintaining biodiversity and managing long-term ecosystem structure. Pyrus calleryana is an ornamental tree species that escaped cultivation and grows rapidly in highly disturbed soils with high light intensities. Former agricultural fields are highly susceptible to invasion from Pyrus calleryana. Observational evidence suggests that two features of this species' biology may be particularly important to invasion success: (a) an extended leaf phenology and (b) the ability to persist in grasslands following disturbance via epicormic sprouting. While this tree is one of the most problematic invasive species within the Eastern and Central parts of the United States, it is relatively understudied. This thesis is divided into two distinct studies that address the invasion biology of Pyrus calleryana. The first study, detailed in Chapter One, is an analysis of the timing of leaf development (phenology) in relationship to co-occurring native trees. In the second study, detailed in Chapter Two, I conducted a replicated field experiment to assess P. calleryana sprouting as a mechanism of persistence in response to experimental disturbance treatments including prescribed fire and experimental freezing using a treatment of liquid nitrogen. The experiments we conducted in this project are in cooperation with the conservation staff at the Five Rivers Metroparks and all activities took place on their properties. In the first study, I discovered that P. calleryana has a longer leaf duration than native trees through earlier leaf out, and delayed abscission. In addition, a late season frost event allowed for a serendipitous study that revealed much greater frost (open full item for complete abstract)

Committee: Ryan McEwan PhD (Advisor); Chelse Prather PhD (Committee Member); Albert Burky PhD (Committee Member) Subjects: Environmental Science

Master of Science, Miami University, 2020, Biology

Zooplankton in reservoirs within agricultural landscapes exhibit unique dynamics due to highly variable discharge as well as elevated nutrient inputs and productivity. Here we explore the long-term response of crustacean zooplankton biomass and phenology and relate these to long-term trends and interannual variability (IAV) in environmental factors in a eutrophic reservoir over a 24-year period. We also investigated bidirectional effects among zooplankton taxa, chlorophyll, and larval fish using convergent cross mapping (CCM). Cyclopoids increased and rotifers decreased over time, while the center of gravity (COG, week of peak biomass) of calanoids advanced over time. We detected the largest number of significant correlations between the IAVs of crustacean taxa and temperature, and between the IAVs of crustacean taxa COG and chlorophyll COG. CCM identified numerous interspecific relationships among zooplankton taxa and effects of inorganic turbidity, temperature, and food quality. Bottom-up effects of chlorophyll on cyclopoids and rotifers as well as rotifers on copepods were significant, while top-down effects were marginally significant. Our findings suggest phytoplankton and temperature likely drove long-term changes in the zooplankton community. Management of eutrophic reservoirs should consider the temporal scale and complexity of food web dynamics to understand effects from climatic factors and watershed inputs.

Committee: María González Dr. (Advisor); Michael Vanni Dr. (Committee Member); Craig Williamson Dr. (Committee Member); Thomas Fisher Dr. (Committee Member) Subjects: Aquatic Sciences; Biology; Ecology; Environmental Science; Limnology

Master of Science in Environmental Science, Cleveland State University, 2020, College of Sciences and Health Professions

Compared to their natural counterparts, trees in urban ecosystems experience distinctive environmental conditions which can be both beneficial and harmful to tree functions and fitness. Thus, the morphological, phenological, and physiological functions of trees in urban ecosystems can be unique and might not be predictable from patterns identified in natural forests where most research on tree ecology has occurred. To better understand how different tree species contribute to ecosystem services in urban environments, we estimated a number of key performance metrics and functional traits for species commonly planted in urban areas. Between April of 2017 and December of 2019, we monitored 42 species of trees across two sites growing in open, urban settings. Radial growth of each individual was measured weekly from April to December using dendrometer bands. Leaf phenology was assessed weekly during leaf development and senescence. Wood phenology was estimated using the RDendrom package in R. Annual C sequestration was estimated using radial growth data, allometric equations (Urban Tree Database), and species-specific wood density and stem C% estimates (TRY database). We also measured several important anatomical, morphological, physiological, and phenological traits. In 2019, we measured a number of canopy characteristics on a smaller subset of individuals (n=137) across 38 species. Lastly, we measured a number of potentially important abiotic covariates, including soil texture, soil pH, canopy light availability, and various topographic variables. We found evidence that performance metrics (basal area growth), canopy characteristics, and functional traits varied significantly among the species in our study. Moreover, the performance metrics and traits which are directly linked to specific ecosystem services, such as aboveground carbon sequestration and drip line leaf area index, also varied significantly among the species in our study. This suggests that particular (open full item for complete abstract)

Committee: Kevin Mueller (Advisor); Emily Rauschert (Committee Member); Thomas Hilde (Committee Member) Subjects: Botany; Ecology; Environmental Science; Statistics; Urban Forestry

Ph.D., Antioch University, 2019, Antioch New England: Environmental Studies

Golden Eagles (Aquila chrysaetos) have a broad range globally and in general are well-studied. However, Arizona's Golden Eagle population remained essentially unstudied until 2011, when Arizona Game and Fish Department (AZGFD) began nest surveys for cliff nesting Golden Eagles throughout the state. As a result of this data collection, the natural history of Arizona's Golden Eagles is finally revealing itself. This dissertation outlined a reliable description of their nesting phenology that provides a framework for timing surveys and a baseline to monitor the effects of climate change on Golden Eagles. The mean date for egg-laying was February 14 and pairs nesting in the high desert initiate nesting about ten days later than their southern counterparts. A brief study collecting prey remains determined that Black-tailed Jack Rabbit (Lepus californicus) was the central prey species for Golden Eagles in northern Arizona. The results of a multiscale habitat suitability model (HSM) determined that slope between 18º-28º was the most important habitat characteristics for Golden Eagles and the sagebrush landcover was the least important. The multiscale productivity prediction model did not predict with high accuracy; however, the results did reveal some data gaps and provided guidance for adjustments in the future. The results of this entire dissertation can guide future research priorities for Golden Eagles in Arizona. For example, more research on Golden Eagle prey dynamics is needed to determine the impact prey have on their nesting success. Additional research should focus on adding human impact factors such as recreational activity or elemental mining as possible factors that negatively influence nesting productivity. Finally, quantifying climate features on a finer temporal scale should be considered and continued nest site data collection will increase the sample size for more informative results.

Committee: Peter Palmiotto DF (Committee Chair); Lisabeth Willey PhD (Committee Member); Todd Katzner PhD (Committee Member); Tyler Coleman PhD (Committee Member) Subjects: Animals; Biology; Conservation; Ecology; Environmental Management; Wildlife Conservation; Wildlife Management

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

With climate change, global average temperatures are increasing and becoming more variable. As a result, reproductive phenology is shifting earlier, body size is decreasing in ectotherms, and snow cover is decreasing. I examined how these effects of climate change affected amphibians and their ecological interactions across life stages. In Chapter 1, I investigated whether an early shift in phenology could alter subsequent life history events, if the organisms were able to compensate, and if compensation was costly. Despite a seven day difference in hatch date, frogs from the delayed egg phenology treatment accelerated growth and development to metamorphose at the same time as the early egg phenology treatment. Frogs that accelerated development metamorphosed at the same size as frogs that did not accelerate development but had the same food availability, indicating that there was no size cost of compensation. In Chapter 2, to understand how climate change-induced shifts in phenotype could affect important interspecific interactions, I examined how a shift in wood frog larval phenology, and body size altered post-metamorphic competition with American toads. The interaction of wood frog metamorphic size and phenology affected toad body condition such that wood frogs that metamorphosed earlier and smaller, as expected under climate change, led to toads with higher body condition. Finally, in Chapter 3, I tested whether the effects of climate change on wood frogs were altered by early ecological interactions. I examined how predation during larval development affected how wood frogs would tolerate a reduced snow cover winter. Exposure to predators during larval development increased mass at metamorphosis, time to metamorphosis, and larval growth rate. Snow removal increased frog mortality. The interaction of larval exposure to predators and reduced snow cover caused a steeper relationship between mass and body length in animals that experienced both. I f (open full item for complete abstract)

Committee: Michael Benard (Advisor); Abbott Karen (Committee Member); Burns Jean (Committee Member); Garcia Tiffany (Committee Member) Subjects: Ecology

Master of Science (MS), Ohio University, 2018, Plant Biology (Arts and Sciences)

The Allium tricoccum complex is native to eastern North America and encompasses broad and confusing morphological variation. Previous studies have led to contrary classifications to account for the diversity of morphologies in the Allium tricoccum complex. Living plants of the complex, leaf tissue samples and soil samples were collected from 28 natural populations in seven states. Plants were cultivated in the Ohio University common garden for biweekly observations of morphological traits; growth patterns and phenology of leaves, flowers and fruits; and weekly photography of plant structures. Morphology, phenology, ecology, and genetic diversity were analyzed to delineate and compare distinct taxa found in the Allium tricoccum complex. Two new characteristics of the species were described for the first time: scape growth direction (orientation) and depth of bulb in the ground. Two major groups in the Allium tricoccum complex, Red Ramps (A. tricoccum sensu stricto) and Green Ramps, were broadly distinguished based on many differences in leaf shape and size; pigmentation of leaf, scape and bulb; number of buds, flowers and fruits; scape growth direction, bulb size and depth in the ground. Three distinctive taxa within the broader Green Ramps group were separated based on differences in morphology, ecology, phenology and geography.The Green Ramps group consisted of A. burdickii (Hanes) G. N. Jones in the Great Lakes and Great Plains regions; a South Green Ramps taxon in the Interior Highlands of Kentucky and Tennessee, similar to A. burdickii but distinct in its tendencies toward narrower leaves, more flowers, shorter perianth and shorter stamens, consistent retention of leaves during scape elongation, and preference for more silty or clayey soils; and a Highland Green Ramps taxon in the Appalachian Mountain region, producing broader distinctly petiolate leaves similar to A. tricoccum, with somewhat intermediate flower and fruit traits between A. burdickii and A. tric (open full item for complete abstract)

Committee: Harvey E. Ballard (Advisor); Arthur Trese (Committee Member); Rebecca S. Snell (Committee Member) Subjects: Botany; Ecology; Morphology; Plant Biology; Systematic

Master of Science (MS), Ohio University, 2018, Geography (Arts and Sciences)

This project acquired high-resolution, RGB images of a deciduous forest in Athens, Ohio from an unmanned aerial vehicle over the course of a year. With UAVs, greater temporal and spatial scales exist today than what were available in the recent past with the full capabilities of these images yet to be fully assessed. The goal of the project was to follow the different phenology patterns of various deciduous trees to accurately map the project site while formulating a reproducible methodology for future work. Acquiring mosaics for 29 dates in 2017, a supervised Maximum Likelihood Classification scheme was employed to classify various species using 15 of the mosaics. Simultaneously, spectral profiles were built for 16 common species at the site using 25 of the mosaics. A community level map displaying three main groups was produced for the study site along with a phenology calendar which highlights key dates for identifying various species. The results of this project show that many species have a high amount of overlap in their spectral signals following phenology, making differentiation of individual species difficult when employing a pixel-based approach alone.

Committee: James Dyer Dr. (Advisor); James Lein Dr. (Committee Member); Jana Houser Dr. (Committee Member) Subjects: Geography