Life Sciences Commons^™

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

Chancellor’s Honors Program Projects

No abstract provided.

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 …

Prevalence Of Rats And Rodent Borne Pathogens Across Post-Katrina New Orleans, Bruno Marco Ghersi

Doctoral Dissertations

Disasters are happening at an increasingly higher rate and intensity a trend that is expected to continue as more humans migrate to coastal urban areas. Disasters, and as importantly, disaster recovery can affect how native and pest populations will recover. My aim was to improve understanding of disease risk by evaluating the socioecological conditions that have shaped commensal rat recovery and distribution, as well as the pathogens they carry, across New Orleans after Hurricane Katrina. I first estimated relative abundance and distribution of commensal rats from rodent trapping conducted between mid-2014 and early-2017 across 96 sites in 10 areas of …

Root Stage Distributions And Their Importance In Plant-Soil Feedback Models, Tyler Poppenwimer

Doctoral Dissertations

Roots are fundamental to PSFs, being a key mediator of these feedbacks by interacting with and affecting the soil environment and soil microbial communities. However, most PSF models aggregate roots into a homogeneous component or only implicitly simulate roots via functions. Roots are not homogeneous and root traits (nutrient and water uptake, turnover rate, respiration rate, mycorrhizal colonization, etc.) vary with age, branch order, and diameter. Trait differences among a plant’s roots lead to variation in root function and roots can be disaggregated according to their function. The impact on plant growth and resource cycling of changes in the distribution …

A High Resolution Study Of Long-Term Vertebrate Decomposition In Human And Animal Model Systems, Lois S. Taylor

Doctoral Dissertations

The effects of vertebrate decomposition are wide-ranging across multiple foodwebs, and have been shown to persist in the environment, however there is a lack of systematic assessment of these changes over long periods of time or in sufficiently high resolution as to resolve seasonal flux patterns. The ultimate aim of this body of research was to explore nematode systematics in decomposition environments, culminating in a pair of long-term human decomposition seasonal trials, in high resolution, with the specific intent of integrating the fields of soil chemistry, microbial ecology, and nematology in order to assess the relationships of cross-disciplinary impacts. Of …

Root Phosphomonoesterase As A Vital Component Of Increasing Phosphorus Availability In Tropical Forests, Kristine Grace Manno Cabugao

Doctoral Dissertations

Tropical forests, relative to other terrestrial ecosystems, exchange the largest amount of carbon with the atmosphere and also constitute a significant carbon sink. However, nutrient limitation, particularly of phosphorus (P), could limit growth of tropical forests and their function with the global carbon cycle. Thus, understanding root mechanisms to acquire P is necessary to representing the P cycle and corresponding interactions with plant growth. A large portion of total soil P in tropical forests occurs in organic forms, only accessible through root and microbial production of phosphatase enzymes. These phosphatase enzymes mineralize organic P into orthophosphate, the form of P …

Costs Of Protected Areas In The United States, Diane Lebouille

Doctoral Dissertations

Protected areas, or land owned in fee by agencies and non-profits to further conservation goals, have traditionally been the go-to choice for conservation interests. The UN Environment World Conservation Monitoring Centre estimates that, currently, close to 15% of all terrestrial and inland water areas are protected. This figure falls short of the Aichi Biodiversity Target of 17% in 2020, that was added to the Convention on Biological Diversity by its 196 signatories in 2010. But as the Convention prepares to set new post-2020 targets, this percentage is expected to keep increasing. Although acquiring a parcel of land is only one …

Conservation Of Terrestrial Salamanders Through Hemlock Woolly Adelgid Management In Eastern Hemlock Forests Within Great Smoky Mountains National Park, Jonathan Lawrence Cox

Masters Theses

Hemlock woolly adelgid (Adelges tsugae; HWA), an invasive aphid-like arthropod, was first documented on the east coast of the United States in the 1950s. HWA is an herbivore which primarily feeds at the needle base of hemlock tree species (Pinaceae: Tsuga). With no evolutionary defenses and few biotic controls, the eastern and Carolina hemlock (Tsuga canadensis and Tsuga carolinensis) serve as the primary diet of HWA in eastern North America. The invasive pest began to spread rapidly throughout the hemlock’s range causing defoliation and death of the trees within 4 – 10 years. With the …

Defining Bee Pollinator Community Composition In Tennessee Soybean, Andrew L. Lawson

Masters Theses

Two planting dates of various soybean varieties were planted in Jackson and Knoxville, TN during 2018 and 2019 with the overall intent of surveying the diversity bee (Hymenoptera) genera in these agroecosystems and also to assess the potential for using late maturing soybean as a food resource for bees during the dearth of floral resources that often occurs during the fall. We also investigated how manipulating planting dates and soybean variety selection affected the occurrence of insect pests that occurred in the soybean.

Both active (netting) and passive (bee bowls and blue-vane traps) sampling were used to collect the bees, …

Carbon Metabolism In Cave Subaerial Biofilms, Victoria E. Frazier

Masters Theses

Subaerial biofilms (SABs) grow at the interface between the atmosphere and rock surfaces in terrestrial and subterranean environments around the world. Multi-colored SABs colonizing relatively dry and nutrient-limited cave surfaces are known to contain microbes putatively involved in chemolithoautotrophic processes using inorganic carbon like carbon dioxide (CO₂) or methane (CH₄). However, the importance of CO₂ and CH₄ to SAB biomass production has not been quantified, the environmental conditions influencing biomass production and diversity have not been thoroughly evaluated, and stable carbon and nitrogen isotope compositions have yet to be determined from epigenic cave SABs. …

Connecting The Social And Spatial Behaviors Of A Territorial Species (Anolis Carolinensis), Jordan M. Bush

Doctoral Dissertations

Why animals live where they do is a key question in ecology and evolution. An individual’s home range determines the resources they have access to, conspecifics they encounter, and predators and pitfalls they must avoid. Home range behaviors also have an inherently social component; where animals live affects the rivals they compete with and the mates they have access to. This is especially true in territorial species, as defensive displays make up a large portion of their social behaviors. In this dissertation, I sought to understand how territorial behaviors affect the social lives of the green anole lizard (Anolis …

Incorporating The “Invisibles” In Ant Seed Dispersal: Microbial Mortality Agents In Myrmecochory, Chloe L. Lash

Doctoral Dissertations

Ant-mediated seed dispersal, myrmecochory, is a diffuse mutualism in which ants are rewarded for seed dispersal services with food via a seed-coat derived appendage, the elaiosome. Seeds gain dispersal benefits including escape from distance- and density- dependent mortality agents, protection from seed predators, and a nutrient-rich germination site in or near ant nests. However, microbes, have been essentially overlooked in this mutualism, despite their pathogenicity to the ants and plants involved. The work presented here investigates the effects of microbial mortality agents on the risks and benefits offered to ant and plant partners in myrmecochory. First, I investigate the effects …

From Genes To Ecosystems: Resource Availability And Dna Methylation Drive The Diversity And Abundance Of Restriction Modification Systems In Prokaryotes, Spiridon E. Papoulis

Doctoral Dissertations

Together, prokaryotic hosts and their viruses numerically dominate the planet and are engaged in an eternal struggle of hosts evading viral predation and viruses overcoming defensive mechanisms employed by their hosts. Prokaryotic hosts have been found to carry several viral defense systems in recent years with Restriction Modification systems (RMs) were the first discovered in the 1950s. While we have biochemically elucidated many of these systems in the last 70 years, we still struggle to understand what drives their gain and loss in prokaryotic genomes. In this work, we take a computational approach to understand the underlying evolutionary drivers of …

Within-Reach Temperature Heterogeneity Is Limited In A Southern Appalachian Stream Network: Implications For Climate Change Refugia And Reach-Scale Temperature Mapping, Anna Kaz, Matthew Troia Dr., Xingli Giam Dr.

Chancellor’s Honors Program Projects

No abstract provided.

Morphological And Gene Expression Plasticity In Neotropical Cichlid Fishes, Sharon Fern Clemmensen

Doctoral Dissertations

Trophic divergence in cichlid fish is linked to morphological shifts in the pharyngeal jaw apparatus. For instance, in the Heroine cichlids of Central America, the ability to crush hard-shelled mollusks is a convergent phenotype with multiple evolutionary origins. These durophagous species often have very similar pharyngeal jaw morphologies associated with the pharyngeal jaw apparatus and some of these similarities could be due to phenotypically plastic responses to mechanical stress. I examined the durophagous cichlid Vieja maculicauda for differences in pharyngeal osteology, dentition, and soft tissues when exposed to different diet regimes. Here I discuss the effect on the morphology and …

Systematics And Biogeography Of The Cortinarius Violaceus Group And Sequestrate Evolution In Cortinarius (Agaricales), Emma Harrower

Doctoral Dissertations

Phylogenetics is a powerful tool used for illuminating the diversity of life on Earth, their evolution and their ecology. I created a multi-gene phylogenetic tree of Cortinarius section Cortinarius and uncovered five previously overlooked species, increasing the number of species in the section from seven to twelve. All members of the clade possess both cheilocystidia and pleurocystidia and possess a pigment known as (R)-39,49-dihydroxybphenylalanine. Ancestral state reconstruction estimated that the ancestral host was most likely an angiosperm, switching hosts when encountering novel host species in new lands, and only C. violaceus associating with the Pinaceae in North America. Biogeographic analysis …

Aspects Of The Physiological And Behavioral Defense Adaptations Of The Mountain Madtom (Noturus Eleutherus), Meredith Leigh Hayes

Masters Theses

Madtoms (Noturus spp.) are a highly endemic clade of miniature catfishes that faces widespread imperilment. Little is known about the ecology of these secretive fishes, and understanding the behavioral and physiological adaptations madtoms have evolved to resist pathogens and competitors is necessary for conservation.

Madtoms nest under cover and provide extensive paternal care. Attempts to rear eggs in captivity result in high mortality rates from infection, leading to questions about how wild nests resist disease. In many fishes, males produce antimicrobial substances that confer protection to eggs. To determine if guardian males deter disease in nests, Mountain Madtoms ( …

Assessment Of Genetic And Education Recovery Plan Objectives For The Bog Turtle (Glyptemys Muhlenbergii), Cassie Marie Dresser

Doctoral Dissertations

Unprecedented declines in biodiversity are threatening the natural world as we know it. Without human intervention, two thousand species listed under the US Endangered Species Act are likely to disappear. Fortunately, these species receive federal protection and increased research effort is needed to create and satisfy the objectives outlined in the mandated Species Recovery Plan. In this dissertation, I address three conservation objectives outlined in the Recovery Plan for North America’s smallest and rarest turtle, the Bog Turtle (Glyptemys muhlenbergii): (1) investigate the potential genetic differentiation in southern portions of the species’ range, (2) investigate the genetic impacts …

Conservation Decisions: Designing, Financing And Fundraising For Protected Areas, Rachel Elizabeth Fovargue

Doctoral Dissertations

Establishing protection for conservation is a complicated process that involves many critical decisions, from spatial prioritization to garnering the necessary financial support to complete a project. In my research, I address questions that inform various components of this process. First, I ask questions about protected area design using a case study of a large reef system in Australia. I find that simple design rules can facilitate the pursuit of conservation and extractive management goals. Second, I address questions about costs incurred by the financing of new protection. I establish a unique dataset of projects financed by a conservation non-profit through …

Stable Isotopes, Phylogenetics, And Experimental Data Indicate A Unique Nutritional Mode For Rickenella Fibula, A Bryophyte-Associate In The Hymenochaetales, Hailee Brynn Korotkin

Masters Theses

Fungal-bryophyte interactions have been documented in all lineages of bryophytes, however, many of these relationships are poorly understood. The fungus Rickenella fibula is a known associate of various mosses, but results from previous studies have not yielded conclusive evidence of its relationship to mosses or its trophic mode. The Rickenella clade exhibits a wide variety of nutritional modes, including other bryophyte-associated fungi. Here, I combine a broad range of methods, using phylogenetics, stable isotope analyses, PCR assays, in vitro experiments, and genomics to determine the nutritional mode of R. fibula. First, phylogenetic analysis of a supermatrix of 28S rRNA, …

Identifying Extinction Risk Patterns In Pollination Networks And Conservation Planning To Reduce The Cost Of Management-Necessitated Travel, Christine Elise Dumoulin

Doctoral Dissertations

Extinction rates are currently far above background levels, as a result of human activity. Although conservation spending is substantial, there is a shortfall between the cost of meeting biodiversity targets and the resources available to do so. Consequently, decision-makers are faced with the task of identifying which taxonomic groups and geographical regions are of greatest concern, and prioritizing approaches with the greatest conservation benefit. In this dissertation, I develop novel approaches in both of these areas.

First, I take a stochastic, community dynamic approach to modeling extinction risk patterns in pollination networks. Despite the ecological and agricultural importance of pollination …

Systematics, Diversification, And Functional Diversity Of Russulaceae (Russulales), Brian Patrick Looney

Doctoral Dissertations

The family Russulaceae is an iconic family of mushroom-forming Basidiomycetes both because of their importance as edible mushrooms in many parts of the world and their species richness in both temperate and tropical forested biomes. While much mycological research has been focused on this group, recent systematic and ecological research has failed to develop a comprehensive or cohesive organization by which to understand the evolutionary relationships, patterns of diversification, or functional importance of the group. Recently, interest in ectomycorrhizal fungi (EmF), of which Russulaceae is a key lineage, has greatly increased due to the recognition of the importance of EmF …

Biotic And Abiotic Drivers Of Plant Symbionts Determine Plant Performance, The Maintenance Of Diversity, And Response To Global Change, Jeremiah A. Henning

Doctoral Dissertations

Interactions among organisms regulate the structure and function of ecosystems and the response of ecosystems to global change. The outcome of species interactions is shaped by the partners involved in the interaction and the climate contexts of the systems in which they reside. Global change is altering the distributions of organisms as well as the climate contexts of the systems they reside within, shifting the biotic and abiotic factors shaping species interactions. Thus, predicting the response of ecosystem structure and function to global change remains unresolved. For my dissertation, I explored how the interactions among plants and their mutualistic communities …

Ecological And Evolutionary Dynamics Of Plant-Soil Feedbacks: Influences On Evolution And Range Dynamics, Michael E. Van Nuland

Doctoral Dissertations

Plants interact with, modify, and are affected by their soil environments. Though plant-soil interactions are well known to be important and active regulators of ecosystem function and community structure, much less is known about how these interactions affect plant evolution. The primary goal of my dissertation was to examine plant-soil interactions under a range of ecological and evolutionary contexts to better understand patterns of biodiversity, ecosystem function, and whole system responses to environmental change. Taking such an eco-evolutionary perspective allows for a holistic understanding of the causes and consequences of complex abiotic and biotic interactions that link ecosystem ecology and …

Molecular Phylogenetic Studies Of The Genera Of Tribe Polygonateae (Asparagaceae: Nolinoideae): Disporopsis, Heteropolygonatum, And Polygonatum., Aaron Jennings Floden

Doctoral Dissertations

The Polygonateae (Asparagaceae) are a subtribe of the Nolinoideae that is redefined here to include three genera which are investigated here: Disporopsis; Heteropolygonatum, and Polygonatum. This group of genera, characterized by their axillary-flowered habit, are closely related but differ greatly in their morphology, cytology, and diversity. A molecular phylogeny is presented to show their relationships to one another and to closely related outgroups based on data from whole chloroplast genomes with low taxonomic sampling. The results show that the genera of the Polygonateae are each monophyletic, and also show that a fourth genus, Maianthemum, that was …

Trait Evolution In Spiders: Perspectives On The Evolution Of Behavioral Syndromes And Web Structures, Jennifer Marie Bosco

Doctoral Dissertations

Organisms have evolved complex behavioral, morphological and physiological traits in response to various selection pressures. These phenotypes are usually composed of many traits that may or may not be genetically or phenotypically correlated. Correlations of both types can lead to evolutionary trade-offs, which may be broken over long evolutionary time periods through such mechanisms as the decoupling of genetic linkages and the development of phenotypic plasticity. Behavioral traits associated with temperament provide an excellent system in which to evaluate underlying mechanisms of the establishment and decoupling of genetic linkages. Other traits, such as the type of web that a spider …

Using Phylogenetic Comparative Methods To Understand Diversification And Geographic Range Evolution, Kathryn Aurora Massana

Doctoral Dissertations

Two key processes that have been modeled in a phylogenetic comparative framework are diversification and historical biogeography. Many questions arise on what process have shaped the abundance (or lack) of species we see today and what influences their survival and interconnectedness with other species. Many methods have been developed to answer these questions. Over the past several decades there has been a rise in parametric modeling and development of more adequate frameworks to answer biological questions of interest. However, many models still lack the incorporation of ecological, mainly biotic factors, which influence the evolution and ecology of species, while accounting …

Conservation Biology Of Bats: Invasive Threats, Research Effort, And Extinction Risk, Jessica Nicole Welch

Doctoral Dissertations

Global conservation for bats is needed: 15 percent of species are listed as extinct or threatened, signifying that they are at a high risk of extinction. An additional 17 percent are designated data-deficient, denoting that a threat category has not been assigned owing to insufficient knowledge on species abundance or distribution. In this dissertation, I use methods from both ecology and evolution to contribute to the study of bat conservation. Firstly, I review the impacts of biological invasion on bats, and provide examples of threats from each of four broad categories: predation, pathogens, competition, and indirect interactions. Overall, detailed accounts …

Spatially Explicit Population Estimates Of The Florida Black Bear, Jacob Michael Humm

Masters Theses

The Florida black bear (Ursus americanus floridanus) is currently comprised of 7 isolated subpopulations: Apalachicola, Eglin, Osceola, Ocala/St. Johns, Chassahowitzka, Highlands/Glades, and Big Cypress. The last statewide assessment of Florida black bear population dynamics was conducted by Simek et al. (2005) using traditional capture-markrecapture methods. The subspecies was removed from Florida’s List of State Threatened Species in 2012 contingent upon the formulation of a management plan that would maintain viable subpopulations of black bears in suitable habitat. Accurate population estimates for each of the remaining black bear subpopulations in Florida were needed to achieve the management goals of …

Evidence For The Priming Effect In Single Strain And Simplified Communities Of Estuarine Bacteria, Abigail Amina Edwards

Chancellor’s Honors Program Projects

No abstract provided.