Life Sciences Commons^™

Wood Decomposition In A Warmer World, Emily Elizabeth Austin

Doctoral Dissertations

Climatic warming is altering species distributions and ecosystem functions across the globe. Wood is an important carbon pool and the fungal communities in wood are relatively simple compared to those in soil. These factors make decomposing wood an ideal system for exploring the influence of decomposer community on the response of decomposition to warming. My research has focused on the effects of warming wood decomposition rates and wood decomposing communities. Using field and lab- based manipulative experiments and field observations I explore the influence of tree species, wood decomposition stage, geography and warming on fungal community structure and activity. In …

Population Demographics And Genetic Structure Of Black Bears In Coastal Louisiana, Jesse Charles Troxler

Masters Theses

The range and abundance of the Louisiana black bear (Ursus americanus luteolus) were greatly diminished during the 20th century. This subspecies was reduced to 3 small, isolated subpopulations in Louisiana as bottomland hardwood habitat was converted to agriculture. These bears were listed as threatened by the U.S. Fish and Wildlife Service in 1992 and a recovery plan was published in 1995. Recovery requires estimates of population parameters to evaluate current population status and future viability. I conducted a mark-recapture study from 2010 to 2012 to estimate demographic parameters of the coastal population of Louisiana black bears. Because inbreeding …

Body Size Variation In Two Adjacent Populations Of Black Kingsnakes (Lampropeltis Nigra) In East Tennessee, Jesse Weber, Joshua Ennen

Chancellor’s Honors Program Projects

No abstract provided.

Hybridization As A Stimulus For Adaptation To A Novel Environment, Dylan Robert Dittrich-Reed

Doctoral Dissertations

Understanding processes contributing to the origin of novelty, including ecological transitions in resource or habitat use, is fundamental to evolutionary biology. Early geneticists speculated about the sudden appearance of new species via special macromutations, epitomized by Goldschmidt’s infamous “hopeful monster”. Transgressive segregation during hybridization is a more plausible mechanism for producing “monstrous” phenotypes beyond the range of parental populations. Transgressive hybrid phenotypes can be products of epistatic interactions or additive effects of multiple recombined loci. However, the importance of hybridization in the origin of novelty is contested because we do not know how often hybridization enhances the probability of an …

Evolution Of Acquiescence To Manipulation, Mauricio González-Forero

Doctoral Dissertations

A productive framework to study phenotypic evolution is based on the notion of ``inclusive fitness'', which considers how an individual's phenotype affects the fitness of other individuals. A promising extension of the notion of inclusive fitness is that of the ``extended phenotype'', which considers how an individual's phenotype affects its environment, including the phenotype of other individuals. Affecting another individual's phenotype is sometimes referred to as manipulation (which introduces indirect genetic effects). However, manipulated individuals may evolve resistance to manipulation, possibly reducing or eliminating the manipulated behavior (and the indirect genetic effects). In this dissertation I use mathematical modeling to …

Prevalence And Transmission Potential Of Borrelia Burgdorferi In Three Species Of Wildcaught Plestiodon Spp. Skinks Of The Southeastern United States, Teresa Dianne Moody

Masters Theses

In the southeastern United States, blue-tailed skinks (Plestiodon spp.) are important hosts for Ixodes scapularis ticks, the principal vector of Lyme disease (LD) in this region. Skinks and other southeastern lizards are not thought to be reservoir competent for Borrelia burgdorferi sensu stricto (Bbss), the etiological agent of LD in the United States. . Lizard-feeding by southeastern I. scapularis may tend to suppress sylvatic cycles of B. burgdorferi, and thus may be an important reason why LD case rates in the Southeast are much lower than in the Northeast and upper Midwest. Nevertheless, some skinks …

Molecular Systematics Of The Subfamily Phasiinae (Diptera: Tachinidae), Jeremy Daniel Blaschke

Masters Theses

The subfamily Phasiinae (Diptera: Tachinidae) is composed of obligate endoparasitoid flies that attack heteropteran insects, many of which are important agricultural pests. To lay a foundation for future studies in phasiine life history and their potential for use as biological control agents, the phylogenetic relationships within Phasiinae were explored using nucleotide sequences of two genes, CAD and LGL. A total of 63 taxa for CAD and 73 taxa for LGL were included in the analyses, representing 58 genera. Maximum likelihood inference methods were employed to reconstruct phylogenetic relationships in separate analyses of each gene and in a combined dataset. Phylogenetic …

Pelagic Larval Duration Links Life History Traits And Species Persistence In Darters (Percidae: Etheostomatinae), Morgan Jessica Douglas

Masters Theses

Pelagic larval duration (PLD) likely influences evolutionary processes including dispersal, genetic connectivity, and extinction in aquatic organisms. PLD has been well studied in marine systems, but very few freshwater species have been studied. Darters are a diverse group of freshwater North American fish with available information on the length of this stage from propagation efforts. There is surprising variation in the length of this stage ranging from 0 to 60 days. By compiling information from Conservations Fisheries, Inc. (Knoxville, TN) and the literature, we were able to make comparisons between the PLD of 23 species and other life history characteristics. …

Interactions In A Warmer World: The Relative Effects Of Experimental Warming, Intraspecific Density, And Insect Herbivory On Seedling Dynamics, Melissa Ann Burt

Masters Theses

Many effects of a changing climate for organisms, communities, and ecosystems are already apparent. Less studied are the effects of increases in temperature on species interactions. While warming may potentially disrupt interactions among species, species interactions may also mediate individual species responses to ongoing climatic change. In this experiment we manipulated temperature in field-based, open-top chambers for three years to examine the relationship between biotic interactions and climatic warming on the population dynamics of seedlings of Quercus alba. We investigated the effect of warming on rates of insect herbivory on Q. alba seedlings. Additionally, we assessed the relative effects …

Trends In Borrelia Spp. Prevalence In Ixodes Spp. Ticks From The Southeastern Coastal United States, Lauren Paul Maestas

Masters Theses

The Lyme borreliosis (LB) cycle, involving Ixodes scapularis and Borrelia burgdorferi sensu stricto (Bbss), is well documented in the northeastern US, where LB is becoming increasingly prevalent. In coastal North Carolina, I. affinis has been shown to have a higher incidence of Bbss than I. scapularis. My objectives were, to assess changes in prevalence of Bbss in Ixodes spp. along a transect from Virginia to Florida, and to assess the value of dogs and mesomammals as sentinels for spread of Borrelia burgdorferi sensu lato.

Ixodes spp. were collected at sites from 37.4^o N to 30.0^{o …}

Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble

Doctoral Dissertations

This dissertation seeks to provide an understanding of how species coexist and, further, how climate change may alter communities by acting on the mechanisms that promote coexistence. Specifically, I examined coexistence among ant species in eastern deciduous forests and the effects that warming may have on foraging activity. Through a series of field observations, I sought evidence for the importance of four of the most commonly cited mechanisms for coexistence among ant species: the dominance – discovery tradeoff, the dominance – thermal tolerance tradeoff, spatial segregation, and niche partitioning. In this system, I did not find evidence for any of …

Federal Conservation Spending Allocated By Agency, Emily Clare Manneschmidt

Chancellor’s Honors Program Projects

No abstract provided.

Genetic Variation And Dispersal In Penstemon Hirsutus And P. Tenuiflorus, Anna Katherine Becker

Masters Theses

Studying plant-pollinator relationships essential for understanding angiosperm evolution. In the large endemic genus Penstemon (Plantaginaceae), shifts in pollination syndrome are proposed to be important for explaining taxonomic and morphological diversity (Wilson et al., 2004; Wolfe et al., 2006). However, little work has been done to determine the relationship between morphological and genetic divergence within pollination syndromes. This study utilized genetic data to explore whether divergence in corolla morphology among nine closely related, bee pollinated Penstemon species was consistent with pollinator-driven selection.

Bee pollinated species in Penstemon subsection Penstemon are often divided into two morphological groups based on inflation of the …

Soil Microbial Community Succession During Cadaver Decomposition, Kelly Lynn Cobaugh

Masters Theses

Microbes play critical roles in nutrient cycling in terrestrial ecosystems. In particular, microbial decomposition of organic matter is a key step in carbon and nutrient cycling, linking above-ground and below-ground pools. It is well known that the microbial community changes in structure and function following the introduction of organic matter into a terrestrial system. The decomposition of plant litter has been extensively investigated but the decomposition of animal-derived organic matter has often been overlooked. The unique characteristics of animal input are hypothesized to dictate a distinct decomposition process. This study examined the microbial community responsible for decomposition of animal-derived organic …

Vegetation Response To Oak Savanna And Woodland Restoration In The Mid-South Usa, Andrew Lee Vander Yacht

Masters Theses

The decline and degradation of oak savanna and woodland communities throughout the Mid-South underscores the need to develop management techniques capable of their efficient and successful restoration. Therefore, my objectives for this work were to document plant community response to variations in canopy disturbance level, fire seasonality, and herbicide control of hardwood midstories. In Chapter One, I provide a thorough review of the current body of knowledge concerning open-oak communities and their restoration, with specific focus on herbaceous and woody plant response to canopy disturbance, fire, and herbicide midstory management. Chapter Two details the response of herbaceous and woody vegetation …