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A Systematic And Biogeographic Study Of Trillium (Melanthiaceae), Jayne A. Lampley

Doctoral Dissertations

Trillium (Melanthiaceae, Parideae) has a disjunct distribution occurring in eastern and western North America, and eastern Asia. Past studies have examined the phylogeny and historical biogeography of Melanthiaceae and Parideae, however these studies either did not fully examine these aspects within Trillium or did not employ sufficiently broad taxonomic or character sampling to clarify relationships among taxa. The first phylogenetic analysis presented in this study provides a resolved phylogeny for Trillium s.l. and Paris s.l. by using a dataset of 70 plastid coding genes and by sampling broadly from Trillium s.s., Pseudotrillium, Trillidium, Paris s.s., Daiswa, and Kinugasa. The results …

Geographic Patterns Of Genetic Diversity Under Climate Change: Linking Genes And Ecosystems, Shannon L. Bayliss

Doctoral Dissertations

Climate change is having profound effects on species distributions. However, much less is understood about how climate change may alter the distribution of genetic variation within species across landscapes. Maintaining genetic diversity within populations is essential for the survival of species in the face of rapid climatic changes, but importantly, losses of genetic variation will also have significant consequences on entire ecosystems. The objective of this dissertation is to understand how genetic variation in a riparian cottonwood species, Populus angustifolia, affects mass and energy exchange between the land and atmosphere across ~1700 km of latitude of the western United …

Microbial Community Dynamics Of A Microcystis Bloom, Helena Pound

Doctoral Dissertations

Harmful algal bloom events are notoriously associated with massive economic and environmental consequences, causing wildlife and human health risks. As these blooms increase in occurrence, duration, and severity around the world, it is essential to understand conditions leading to bloom formation and why they persist. Abiotic factors such as nutrients are commonly considered in bloom dynamics, but biotic interactions with co-occurring microbial species and viruses must also be taken into account. Harmful algal blooms dominated by the cyanobacterial genus Microcystis occur in bodies of water around the world and provide an ideal system in which to study top-down controls on …

Impacts Of Anthropogenic Change On Plant Reproduction And Fitness, Alexandra S. Faidiga

Masters Theses

Humans are altering natural systems around the globe in myriad ways. For plant species, such anthropogenic changes have resulted in increasingly fragmented populations, desynchronized interactions with mutualists, and shifted geographic ranges, among other effects. However, despite numerous examples of human impacts on plant populations, the consequences of these changes on plant reproduction remain poorly understood. In my thesis, I investigate the impacts of two forms of anthropogenic change–habitat disturbance and climate warming–on plant reproduction and fitness. I take two distinct approaches to address questions posed at local and regional scales. In Chapter I, I ask how inbreeding depression varies across …

Pollinator Community Homogenization And Pollination Services In Agroecosystems, Devon S. Eldridge .

Masters Theses

Pollination, or the transfer of pollen to plant stigmas, is an essential part of plant reproduction. The term “pollination system” refers to the floral phenotype and pollinator of a given plant. Although angiosperms exhibit a variety of different pollination systems, most rely partially or completely on animals, particularly insects, to vector their pollen. In agricultural systems, understanding the pollination system of the crop species is necessary to produce an economically valuable yield. Moreover, agricultural management may affect pollination systems by altering the abundance, diversity, or function of the pollinator community. In natural ecosystems, there is a great diversity of pollinating …

Seasonality, Distribution, And Biological Control Of Crapemyrtle Bark Scale, A New Invasive Threat In Tennessee, Amira Cornish

Masters Theses

Crapemyrtle bark scale, Acanthococcus (= Eriococcus) lagerstroemiae (Kuwana), an invasive pest from Asia, is a threat in the United States. to crape myrtles grown in ornamental nurseries and in landscapes. Although mortality to crape myrtles is rare, its negative effects on aesthetics is considerable. It should affect the sale (valued at >$66 million wholesale) and use of crape myrtle in landscapes. This pest species has been found in numerous states, including Tennessee, where little is known about its state-wide distribution, lifecycle, biology, natural enemies, and impact on crape myrtles. The purpose of this two-year study is to gain additional knowledge …

A Novel Approach For Characterizing The Ultra-Micro Size-Fraction Community, Abdullah Ahmed Salim, Priscilla Nicole Pineda, Isabella Alamilla, Andrew Dean Putt

EURēCA: Exhibition of Undergraduate Research and Creative Achievement

A Novel Approach for Characterizing the Ultra-Micro Size-Fraction Community

Students: Abdullah Salim, Priscilla Pineda, Isabella Alamilla

Mentors/Supervisors: Andrew Putt, Terry C. Hazen

ABSTRACT

The ultra-micro size-fraction (UMSF) are bacteria that can pass through the 0.2 µm pore membrane filters employed in environmental surveys. Despite being ubiquitous and having high metabolic activity, UMSF remain elusive and largely uncultured. Investigations of UMSF are skewed by difficulties in culturing and a lack of techniques for measuring UMSF biogeochemical signatures. This study measures surface stream UMSF community diversity, and community response to the addition of the synthetic pharmaceutical and cosmetic carbon product cyclodextrin which …

Evaluating The Winter Diet Of A Reintroduced Herd Of Elk In The Cumberland Mountains, Tennessee, Using Next-Generation Sequencing Techniques, Dailee L. Metts

Masters Theses

A distinct subspecies of elk (Cervus canadensis), the North American elk (C. canadensis canadensis), once inhabited portions of the southeastern United States, including Tennessee, until their extirpation in the mid 1800s. From 2000 to 2008, 201 Manitoban elk were reintroduced on the North Cumberland Wildlife Management Area (NCWMA). A year-long food habits study using histological analysis of plant material from feces was completed for the NCWMA elk from 2003 to 2004 and has since aided managers in their landscape planning. Since then, more elk have been released onto the area, food plots have been established throughout …

Supplementing East Tennessee Landscapes For Pollinators With Native Perennials, Amani Khalil

Masters Theses

Tennessee, home to the Great Smoky Mountains, is a biodiversity hotspot for many plant and animal species, yet it receives relatively few conservation dollars (Jenkins et al., 2015). As a biodiversity hotspot, this region may be home to many endemic species, but little is known about the abundance or diversity of insect pollinators. In order to both estimate pollinator communities in East Tennessee and pollinator forage preferences for native Tennessee plants, we established four plots, comprised of three plant families across five common land use types. Over two field seasons we collected nearly 7,300 insect specimens with a total sampling …

The Hidden Life Of Tropical Roots: Functional Root Traits And Their Response To Climatic Disturbances, Daniela Yaffar

Doctoral Dissertations

Roots play a critical role in plant nutrition, and terrestrial carbon cycling. However, they are often understudied compared to their aboveground counterparts; especially in the tropics, where more carbon is cycled than in any other ecosystem. Some tropical forests, like in Puerto Rico, are more represented in scientific studies than others. However, this information is sparse, complicating the interpretation of root trait patterns. Trees in Puerto Rico have adapted mechanisms for withstanding hurricane disturbances, including in their roots. Additionally, as many tropical forests, some in Puerto Rico have low available phosphorus (P); thus, trees rely on root traits to enhance …

Applications Of Comparative Genomics And Data Science To Agricultural And Clinical Research, Katrina A. Schlum

Doctoral Dissertations

The advent of inexpensive, high-throughput whole genome sequencing (WGS) technologies has led to the generation of thousands of related genomes, even from a single study. Large-scale genome analysis has resulted in hypothesis-generating approaches in the fields of clinical, human and agriculture genomics. Additionally, population-level genomic sampling has resulted in a decrease in false positives in genotype-phenotype associations and an increase in understanding of the basis of disease, antibiotic and pesticide resistance. Deeper understanding of migration, genetic divergence and evolution has also been made possible due to WGS. This research applies comparative genomics, population genomics and data science approaches to whole …

The Effects Of High Temperatures On Mating Communication In Songbirds, Casey Marie Coomes

Doctoral Dissertations

Due to climate change, animals around the globe are experiencing the negative impacts of hot temperature extremes. Hot temperatures can affect animals is by inducing behavioral changes. Some of these behavioral changes include reductions in important, fitness-related behaviors such as foraging and mating. One aspect of mating behaviors that high temperatures can impact is communication. In many systems, mating communication consists of a male signaler transmitting a signal to a female receiver, who then uses the signal to assess the male’s quality as a potential mate. High temperatures can impact this process at the level of the signaler, the receiver, …

The Effects Of Urbanization On The Avian Gut Microbiome, Mae Berlow

Doctoral Dissertations

The gut microbiome influences and is influenced by the host, and can affect the host organism by contributing to health, development and immunity. Similarly, the host can influence this community; it’s makeup can vary with host species, locality, diet, social stressors, and environmental stressors. Some of these environmental stressors have arisen due to human-induced rapid environmental change, like urbanization. The physiology and behaviors of organisms that are able to persist in urban environments are often different from their non-urban congeners. Nutrition, development, and immunity—all of which are affected by the gut microbiome—are important factors that can determine survival in urban …

Social Context Influences On Behavior Of Carolina Chickadees, Brittany A. Coppinger

Doctoral Dissertations

This dissertation assesses fundamental social factors that drive variation in calling and other behaviors of experimental flocks of Carolina chickadees. Specifically, I tested how group member familiarity and group composition affected individual behavior. In addition, I performed a direct experimental test of the Social Complexity Hypothesis for Communicative Complexity, which states that groups that are more socially complex will communicate with greater signal complexity than groups that are less social complex. I consider complexity to be a combination of three factors: the number of parts in a system, the variation among the parts, and the variation in the way those …

Evolution And Resurrection Ecology Of A Foundational Coastal Marsh Plant, Jennifer L. Summers

Doctoral Dissertations

Stratified storage of dormant seeds in soil can result in natural archives useful for studying evolutionary responses to environmental change. However, few studies leverage soil-stored seed banks as natural archives, in part because of concerns over attrition, bias, and sediment mixing. Here, I examine the persistent seed bank of Schoenoplectus americanus, a foundational brackish marsh sedge, to a) determine whether it can serve as a resource for reconstructing demographic and population genetic/genomic variation, b) whether and how evolution may be occurring across a century. After extracting seeds from radionuclide-dated soil cores taken across the Chesapeake Bay, I “resurrected” age …

Life History, Diet And Habitat Of The Federally Endangered Laurel Dace (Chrosomus Saylori), Shawna M. Fix

Masters Theses

Laurel Dace (Chrosomus saylori) is a small, freshwater minnow that is endemic to headwater streams on Walden Ridge, Tennessee. The species was listed as federally endangered in 2011 and the U.S. Fish and Wildlife Service Recovery Plan indicates a need for life history, diet and habitat studies. A literature review, samples of archived specimens, and a surrogate species, the Tennessee Dace (Chrosomus tennesseensis), were used to describe the life history and diet of the Laurel Dace. A total of 370 Tennessee Dace were collected from Laurel Ford Branch, a stream 8.6 km from the Laurel Dace …

Ecogeographical And Micromorphological Differentiation Between Selfing And Outcrossing Sister Species, Alannie-Grace Grant

Doctoral Dissertations

Since their emergence during the Cretaceous period, Angiosperms, or flowering plants, have achieved incredible success on land, colonizing an extensive range of environmental conditions and creating the structure of the Earth’s ecosystems. As they have adapted to these conditions, Angiosperms diverged in their niche breadth, morphological, physiological, biochemical, and phenological traits and evolved into the plant species known today. Some of the diversification within Angiosperm species is attributed to the adaptive evolution of floral traits that facilitate cross-fertilization by attracting and rewarding animal pollinators who transport their pollen or reductions in these traits to maximize self-fertilization.

In this dissertation, I …

Competitive Interactions Among Co-Infecting Symbionts In A Model Animal-Associated Microbiome, Justin L. Pritchett

Chancellor’s Honors Program Projects

No abstract provided.

Rediscovery Of The Pallid Shiner, Hybopsis Amnis, In The Black River System Of Arkansas And Missouri Including Notes On Ecology And Life History, Daniel P. Morrill, Calvin R. Rezac, Ginny Adams, S. R. Adams, Robert Hrabik

Southeastern Fishes Council Proceedings

The Pallid Shiner, Hybopsis amnis, is a rare and understudied minnow with little information about its ecology. This species is listed as a Species of Greatest Conservation Need (SGCN) throughout much of its range and is generally considered to be declining. It had not been detected in the Black River system of Missouri and Arkansas in over 75 years, or the state of Missouri in over 60 years. We sampled over 100 sites in the Black River system between 2017 and 2020 to assess temporal trends in fish assemblage structure and to update the status of SGCN species in …

Distribution, Status, And Life History Aspects Of Two Rare Logperches, Percina Burtoni And Percina Apina, Jeffrey W. Simmons

Southeastern Fishes Council Proceedings

The Blotchside Logperch, Percina burtoni, and Tennessee Logperch, Percina apina, are Tennessee-Cumberland River drainage endemics that have experienced range reductions due to anthropogenic influences. All known collection records were gathered to fully describe the historical distribution of these species for comparison to their currently inhabited range. Discussion of major impacts to rivers that contain or contained these species is included for an understanding of factors that may have influenced contemporary distributions. Extensive field surveys were conducted during 2014 to 2017 to aid in determination of the current status and distribution of populations. New information of previously unreported or …