Life Sciences Commons^™

Evaluating Current And Future Potential Distribution Of Epiphytic Orchids In The Congo Basin With Ecological Niche Models, Michael L. Ngoh

Masters Theses

The Congo Basin Forest harbors a rich diversity of epiphytic communities, with the Orchidaceae alone making up more than 50% of all epiphytes in the region. Despite the huge diversity of epiphytes, many species, including epiphytic orchids, are at risk to a diverse array of threats. Climate change for instance poses severe threats to epiphytic orchids due to elevated temperatures, prolonged periods of droughts, as well as reduced rainfall across the Congo Basin Forest. In this study, we used ecological niche modeling and GIS techniques to identify spatial patterns of species richness, potential future climate refugia, and novel climatic suitability …

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 …

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. …

Influence Of Environmental Conditions And Inundation History On Bacterial Diversity Of Salt Marsh Soils In Southern Louisiana, Brandon M. Bagley

Masters Theses

Diversity patterns and controls on bacterial community composition were investigated from coastal salt marsh soils in southern Louisiana (USA) from 2012 – 2014. These salt marshes are part of an extensive coastal landscape that is experiencing land loss due to subsidence, sea-level rise, and anthropogenic activities, including from the impacts of the Deepwater Horizon oil spill in 2010. Prior to the oil spill, microbiology research focused predominately on biogeochemical roles and not on taxonomic representation in the soils or on understanding the significance of taxonomic diversity at the microbial level to marsh food webs or ecosystem dynamics. The purpose of …

Understanding Stakeholder Attitudes And Involvement In Habitat Conservation Plans And The Endangered Species Act, Kyle Andrew Rodgers

Masters Theses

The Endangered Species Act (ESA), established in 1973, was a landmark piece of environmental legislation and remains the standard for endangered species conservation. Implementation of the ESA has often been framed as pitting economic development against species conservation, inciting passions for and against endangered species conservation. The strength of opposing public opinions is highlighted by high-profile controversies such as those around the snail darter, northern spotted owl and the greater sage grouse. In an attempt to reduce conflict, the US Fish and Wildlife Service (USFWS) increasingly seeks to utilize collaborative, stakeholder-based processes that address stakeholder interests, attitudes, and values.

In …

Estimating Avian Populations With Passive Acoustic Technology And Song Behavior, Stephanie C. Prevost

Masters Theses

The need for improvements in avian wildlife monitoring efficiency, accuracy, and scope has led to use of new technologies such as autonomous recording units (ARUs). As a monitoring tool, passive acoustic recording has numerous benefits, but it is still limited to use in human-accessible areas. There is also need for monitoring technologies in areas that are inaccessible. Military installations, which host a disproportionately large number of threatened, endangered, and at-risk species compared to other federal lands, pose the accessibility problem with sizeable impact areas that are too hazardous for humans to access. This thesis introduces the Balloon Aerial Recording System …

Urbanization Impacts On Land Snail Community Composition, Mackenzie N. Hodges

Masters Theses

Urbanization has tremendous impacts on most native species. Urban ecosystems are becoming increasingly prevalent, while urban ecology is a relatively underdeveloped field. This is especially true for terrestrial mollusks, which are a surprisingly understudied organism. Due to their low mobility and dispersal potential, land snails are valuable indicators of ecosystem disturbance. For this study, land snails were collected in 54 city parks along an urban gradient to understand influences of urbanization on snail communities. Sampled parks include small extensively landscaped downtown parks, neighborhood and community parks, district parks, and large nature parks, each with variable vegetation, soil characteristics, disturbance regimes, …

Rare Occurrences Of Free-Living Bacteria Belonging To Sedimenticola From Subtidal Seagrass Beds Associated With The Lucinid Clam, Stewartia Floridana, Aaron M. Goemann

Masters Theses

Lucinid clams and their sulfur-oxidizing endosymbionts comprise two compartments of a three-stage, biogeochemical relationship among the clams, seagrasses, and microbial communities in marine sediments. A population of the lucinid clam, Stewartia floridana, was sampled from a subtidal seagrass bed at Bokeelia Island Seaport in Florida to test the hypotheses: (1) S. floridana, like other lucinids, are more abundant in seagrass beds than bare sediments; (2) S. floridana gill microbiomes are dominated by one bacterial operational taxonomic unit (OTU) at a sequence similarity threshold level of 97% (a common cutoff for species level taxonomy) from 16S rRNA genes; …

Environmental Controls On The Diversity And Distribution Of Endosymbionts Associated With Phacoides Pectinatus (Bivalvia: Lucinidae) From Shallow Mangrove And Seagrass Sediments, St. Lucie County, Florida, Thomas Walters Doty

Masters Theses

Lucinid bivalves are capable of colonizing traditionally inhospitable shallow marine sediments due to metabolic functions of bacterial endosymbionts located within their gills. Because lucinids can often be the dominant sediment infauna, defining their roles in sediment and pore fluid geochemical cycling is necessary to address concerns related to changes in coastal biological diversity and to understanding the sensitivity of threatened coastal ecosystems over time. However, there has been limited research done to understand the diversity and distribution of many lucinid chemosymbiotic systems. Therefore, the goals of this thesis were to evaluate the distribution of Phacoides pectinatus and its endosymbiont communities …

A New Adaptive Landscape: Urbanization As A Strong Evolutionary Force, Lauren Christie Breza

Masters Theses

Urbanization is rapidly increasing as human population growth steadily grows, but there is little consensus of the ecological consequence of this population shift and almost no information of the evolutionary consequences for local biodiversity. Nearly two-thirds of the world’s population will live in city centers by 2050 with profound impacts on landscapes that can act as important agents of selection. This study aims to identify 1) the net effect of urbanization on species richness, 2) how phylogenetic diversity varies between urban and rural sites, and 3) the strength of urbanization as a selection pressure. First, a meta-analysis was conducted in …

Freshwater Mussels (Bivalvia: Margaritiferidae And Unionidae) Of The Buffalo River Drainage, Tennessee, Matthew Philip Reed

Masters Theses

The Buffalo River in Tennessee once hosted a rich population of freshwater mussels. During the 1980s, monitoring efforts demonstrated evidence of drastic declines and extirpation of entire assemblages. Increases in municipal development in the headwater tributaries and agriculture in the main stem of the Buffalo River are suspected causes for mussel community declines throughout the river. In 2011, collection data documented evidence of recovery in the lower Buffalo River. The aims of this project were: 1) to update the status, distribution, and species composition of mussels in the Buffalo River and its major tributaries through qualitative sampling, and 2) to …

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 …}

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 …

The Impacts Of Surface Mining Restoration Efforts On Soil Dwelling Nematode Communities In The Appalachian Region, Haley Shae Smith

Masters Theses

Traditional restoration of post mining sites in the southeastern U.S. utilizes methods that discourage above and below-ground succession of native floral and faunal communities. Recent advances in mining restoration techniques proposed by the Appalachian Regional Reforestation Initiative (ARRI) have improved above-ground plant succession and growth rates in reclaimed sites by developing the Forestry Reclamation Approach (FRA), a process that discourages substrate compaction and encourages native plant succession. The below-ground component of these reclaimed areas remains undescribed, however. Below-ground invertebrate communities in mining restoration sites have been largely ignored, despite their potential importance to the long-term recovery of these profoundly disturbed …