Life Sciences Commons^™

Environmental Impacts And Carry-Over Effects In Complex Life Cycles: The Role Of Different Life History Stages, Nnaemeka F. Ezeakacha

Dissertations

A challenge faced by organisms with complex life cycles is how environmental factors experienced at an earlier life stage affect the fitness at that stage or are carried over to subsequent life stages. I used container-inhabiting mosquitoes: Aedes albopictus, Aedes aegypti, Aedes triseriatus and Culex quinquefasciatus to study the interactions and performance of life history stages under specific environmental factors. I investigated the effects of egg-desiccation tolerance on egg viability and larval performance in the Aedes mosquitoes. I found increase in egg hatch rate with relative humidity and interaction between relative humidity and egg storage period. Larval performance …

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 …

Assessing The Importance Of Nurse Plant Associations To The Growth Of Pre-~Reproductive Yucca Brevifolia, Eric James Chameroy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Facilitation and competition among plant species, in addition to abiotic factors, play an important role in determining plant community structure in arid and semi-arid environments. I conducted a study in Dry Lake Valley, Lincoln County, Nevada, USA to investigate the importance of nurse plant associations to pre-reproductive Yucca brevifolia (Joshua tree). Dry Lake Valley lies within a transition desert between the Mojave and Great Basin Deserts with ecotonal plant communities consisting of species representative of both deserts. A vegetation survey described the communities in which this study was conducted as a Y. brevifolia woodland dominated by an understory of Ephedra …

Efficacy Of Visual Surveys For White-Nose Syndrome At Bat Hibernacula, Amanda Frances Janicki

Masters Theses

White-Nose Syndrome (WNS) is an epizootic disease in hibernating bats caused by the fungus Pseudogymnoascus destructans. Surveillance for P. destructans at bat hibernacula consists primarily of visual surveys of bats, collection of potentially infected bats, and submission of these bats for laboratory testing. Cryptic infections (bats that are infected but display no visual signs of fungus) could lead to the mischaracterization of the infection status of a site and the inadvertent spread of P. destructans. We determined the efficacy of visual detection of P. destructans by examining visual signs and molecular detection of P. …

Effects Of Forest Management Practices On Raccoon Ecology In A Longleaf Pine Ecosystem, Ronald Brian Kirby

Masters Theses

Raccoons (Procyon lotor) are ecological generalists common throughout a variety of habitats across their range. Although considered an economically important furbearer species in many regions, they are considered potentially important nest predators of certain species. Because raccoons may have a significant ecological impact on the landscape, it remains important to understand their ecology in a variety of ecosystems. We studied raccoon ecology in a longleaf pine ecosystem in southwestern Georgia, where little information for the species exists. Specifically, we assessed 269 daytime resting sites (i.e., refugia) associated with 31 radio-collared adult raccoons (18M, 13F) during 2014-2015 using an …

Plant Community Responses To Invasive Shrub And Vine Removal In An Urban Park Woodland., Eric Richard Moore

Electronic Theses and Dissertations

Counter to what some people think, urban areas can be biodiversity hotspots. Maintaining this biodiversity can be challenging, since exotic shrubs and vines block sunlight and threaten native plant regeneration. Since 2007, the Louisville Olmsted Parks Conservancy (LOPC) has spent $2 million on invasive plant management in Cherokee Park. Before the project began, long-term transects were established by the LOPC to collect baseline presence/absence data on 11 invasive plant species. In 2014, I revisited these transects and documented presence/absence data on the entire plant community. I found that four species (garlic mustard, winter creeper, Japanese honeysuckle, and English ivy) have …

Impact Of Urban Factors And Invasive Species On White-Footed Mouse (Peromyscus Leucopus) Habitat Use And Foraging Behavior In An Urban Forest Park., William Persons

Electronic Theses and Dissertations

White-footed mice (Peromyscus leucopus) select for areas of greater canopy cover at the macro scale, and for areas with more CWD at the micro-scale. White-footed mice potentially avoid habitats with higher invasive species richness. White-footed mice preferentially foraged under the honeysuckle canopy in response to changes in temperature and humidity. This study suggests that the interaction between P. leucopus and ground layer invasive species is complex, and that the effect of moonlight may be diminished in this urban park. Urban ecosystems demonstrate high levels of anthropogenic land-use change, modification of abiotic inputs, and altered disturbance regimes. These changes result …

Dietary Carotenoids And The Complex Role Of Redness In The Behavior Of The Firemouth Cichlid Thorichthys Meeki., Sarah Anne Fauque

Electronic Theses and Dissertations

This dissertation takes a comprehensive approach to the role of dietary carotenoids on redness and the subsequent behaviors in the firemouth cichlid, Thorichthys meeki. I start with a brief introduction into signaling, the importance of carotenoids, and mate choice. The dissertation is then divided into three data chapters which are designed to stand as independent manuscripts. Chapter II documents how altering the availability of dietary carotenoids affects redness in the integument of male and female T. meeki. I tracked how redness changed in color and distribution in individuals over the course of 12 weeks. I confirm that a dichotomy …

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 …

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; …

The Impeccable Timing Of The Apple Maggot Fly, Rhagoletis Pomonella (Dipetera: Tephritidae), And Its Implications For Ecological Speciation, Monte Arthur Mattsson

Dissertations and Theses

Speciation is the process by which life diversifies into discrete forms, and understanding its underlying mechanisms remains a primary focus for biologists. Increasingly, empirical studies are helping explain the role of ecology in generating biodiversity. Adaptive radiations are often propelled by selective fitness tradeoffs experienced by individuals that invade new habitats, resulting in reproductive isolation from ancestral conspecifics and potentially cladogenesis. Host specialist insects are among the most speciose organisms known and serve as highly useful models for studying adaptive radiations. We are just beginning to understand the pace and degree with which these insects diversify. The apple maggot, Rhagoletis …

Generating Best Management Practices For Avian Conservation In A Land-Sparing Agriculture System, And The Habitat-Specific Survival Of A Priority Migrant, Jeffrey D. Ritterson

Masters Theses

A large amount of the world’s biodiversity is located in a disproportionately small amount of area, namely the tropics. Many of these areas are experiencing rapid landscape changes, mainly in the form of deforestation for agricultural practices. Current conservation efforts are focused on agricultural areas and their ability to provide habitat. The conservation value of a novel land-sparing agroforestry system, known as Integrated Open Canopy (IOC), was recently demonstrated on the study site when applied to coffee. IOC coffee supports forest species that are uncommon or absent in shade grown coffee. I generated best management practices for IOC farms relative …

Density-Dependent Survival In The Larval Stage Of An Invasive Insect: Dispersal Vs. Predation, Adam A. Pepi

Masters Theses

1. The success of invasive species is often thought to be due to release from natural enemies. This hypothesis relies on the assumption that species are regulated by top-down forces in their native range and implies that species are likely to be regulated by bottom-up forces in the invasive range. Neither of these assumptions has been consistently supported with insects, a group which include many highly destructive invasive pest species.

2. Winter moth (Operophtera brumata) is an invasive defoliator in North America that appears to be regulated by mortality in the larval stage in its invasive range. To …

Complex Effects Of Ungulate Browsers On Tree Recruitment And Herbaceous Layers In New England Temperate Forests, Edward K. Faison

Doctoral Dissertations

Browsing by ungulates is a leading biotic disturbance in northern forest ecosystems and an important determinant of habitat, biodiversity, and ecosystem services. A large body of work has revealed that white-tailed deer (Odocoileus virginianus) at high densities alter forest understories in strong and predictable ways; however, less is known about how lower densities of deer and the combined effects of multiple herbivores influence forest understory vegetation, particularly in stands following canopy disturbance. Using fenced exclosures, remote cameras and other field observations, I explored the foraging response and browsing effects of low densities of deer and moose (Alces …

Behavioral And Neural Mechanisms Of Impulsive Choice, Jesse Mcclure

Doctoral Dissertations

Impulsive choice is defined as the preference for a small immediate reward over a larger delayed reward. Individual variablity in impulsive choice correlates with many socially relevant behaviors. Although forms of impulsive choice have been studied in both behavioral ecology and psychology, the exchange of knowledge between these fields is just beginning. Drawing from both of these fields will improve our research methods allowing for a more detailed understanding of this complex behavior. Existing tasks to measure impulsive choice conflate the delay and quantity of the reward. To address this, I have drawn from foraging research to establish a method …

North American River Otter (Lontra Canadensis) Presence And Habitat Analysis In Florida As Compared To Historical Data, Samantha Wilber

USF Tampa Graduate Theses and Dissertations

North American river otters are considered common in the state of Florida, but their populations have not been studied since the 1980’s. Since that time, Florida’s human population has more than doubled, and many natural areas of Florida have been developed. The aim of this study was to determine the presence or absence of river otters at locations in Florida which they historically inhabited. Forty-six sample sites where otters were historically found were obtained from the Florida Museum of Natural History Mammals Master Database (FMNH MMD). These sites were condensed to two focus areas, in and around Alachua and Collier …

Identifying Humanized Ecosystems: Anthropogenic Impacts, Intentionality, And Resource Acquisition At Crystal River (8ci1) And Roberts Island (8ci41), Charles Trevor Duke

USF Tampa Graduate Theses and Dissertations

The impact of human activity on ecosystems is an issue at the forefront of global concern. Marine ecosystems are a particular concern, given their importance for human sustenance. Through the removal of species that are highly susceptible to the effects of overfishing, global fisheries have been driven to near collapse in recent decades. The long-term effects of such practices has resulted in declines in mean trophic level of aggregate fish catches over time, as well as decreasing diversity of species available for regular harvest (Jackson et al. 2001; Pauly et al. 1998). These supposedly “modern” problems have been recently identified …

Emergent Insect And Neotropical Migratory Bird Interactions And Responses To Habitat, Hydrology, And Progressive Urbanization In The Tampa Bay Region, Nathaniel Lee Goddard

USF Tampa Graduate Theses and Dissertations

The growing human population threatens the many of the earth’s biological systems. In the last 600 years extinction rates risen from 1 extinction per million species per year (E/MSY) in the 1400’s to 50 E/MSY today. During this time period 1.5% of all known birds have gone extinct, because they could not adapt quickly enough to human mediated changes. The goal of this dissertation was to determine how urbanization and anthropogenic services needed to support urban areas impact cypress dome wetland aquatic insect and migratory bird populations that depend on them. In Central Florida cypress dome hydroperiods are driven by …

A Bat-Guano-Derived Δ15N And Δ13C Record Of Paleoenvironmental Change: Zidită Cave, Romania, Daniel Martin Cleary

USF Tampa Graduate Theses and Dissertations

Because nitrogen isotopes are fractionated along the soil-plant-insect-bat-guano pathway, it may be possible to reconstruct environmental and climatic changes reflected in the nitrogen isotopic composition of guano. A 1.5-m core of bat guano from Zidită Cave (western Romania) provides a record of climatic and anthropogenic influence on the regional nitrogen cycle and paleoenvironmental controls on nitrogen transforming processes. Increasing and decreasing trends of nitrogen isotopic composition (δ¹⁵N values) correspond well with changes in the influence of farming practices, deforestation, and forest expansion. These influences likely had a significant effect on the openness of the nitrogen cycle, resulting in …

Wildlife Crime And Other Challenges To Resource System Resilience, Patricia Anne Raxter

Graduate Program in International Studies Theses & Dissertations

Although wildlife crime has exploded in Africa over the past decade —“commercial poaching” now kills an estimated eight percent of the continent’s elephant population each year—some governments have proven more successful than others at protecting wildlife and preserving habitats. To explain this variation, this study examines how the policies of three states (Kenya, Tanzania, and Botswana) have enhanced or undermined the resilience of the continent’s elephant ecosystem. Using the social-ecological system framework, the study illustrates how each state’s changing practices have either exacerbated the stresses wrought by wildlife crime or successfully protected local populations from poaching. The study finds that …

Lingcod (Ophiodon Elongatus) Habitat Associations: Implications For Conservation And Management, Megan Bassett

SNS Master's Theses

Understanding the spatial distribution of marine species and the temporal and spatial scales of the processes that drive those distributions continues to be limited, but is increasingly more critical with the implementation of marine spatial planning. Lingcod (Ophiodon elongatus) are a common demersal fish found from southern Alaska to Baja California, and are exploited both commercially and recreationally across the entirety of their range. Due to stock declines, Lingcod are managed using a variety of fisheries management tools, including spatial management. This study represents a unique in situ investigation of demersal habitat utilization by Lingcod at the southern portion of …

An Invasive Grass And A Desert Adapted Rodent: Is There An Effect On Locomotory Performance And Is It Modified By Prior Experience Or Familiarization?, Camille D. Boag

Master's Theses

Kangaroo rats (Dipodomys spp.) are frequently characterized as keystone species for their role in altering soil characteristics, changing habitat structure through seed consumption and dispersal, and being important primary consumers in their ecosystem. They are arid adapted and known to forage in areas with sparse vegetation. Studies suggests densely vegetated habitat to be unsuitable for kangaroo rats because plants are an impediment to their locomotion and predator avoidance behaviors. This study focuses on an invasive grass, South African Veldt (Ehrharta calycina), that converts landscapes with sparse vegetation into dense grassland habitats, and the Lompoc kangaroo rat …

Effects Of Supplemental Hydration On Physiology And Behavior Of Northern Pacific Rattlesnakes (Crotalus Oreganus Oreganus), Griffin D. Capehart

Master's Theses

Hydration is a critical element for many physiological processes in vertebrates, such as protein production, innate immunity, and behavioral processes such as daily activity and thermoregulation. Few studies have directly assessed the effect of hydration on these animals in nature. While it seems intuitive that drought is stressful to animals, studies examining drought are typically observational and fail to assess how the hydration state of these animals influences their physiology and behavior. We tested for an effect of hydration on several physiological and behavioral parameters in Northern Pacific rattlesnakes (Crotalus oreganus oreganus) by experimentally manipulating hydration levels in …

The Effects Of Urbanization On Tick Parasitism Rates In Birds Of Southeastern Virginia, Erin Leigh Heller

Biological Sciences Theses & Dissertations

The coastal region of southeastern Virginia is one of the largest urban areas along one of North America’s migratory flyways. Because hundreds of avian species use this flyway, understanding factors affecting birds and their health is of paramount concern. Within this region, 14 species of ticks have been documented, all of which may serve as vectors of mammal (including human) pathogens. By sampling birds at sites of varying levels of urbanization within the coastal southeastern urban matrix, I studied the relationship between ticks and their avian hosts, and how this relationship varies seasonally. Mistnets were set-up at five permanent sites …

Grappling With Wicked Problems: Exploring Photovoice As A Decolonizing Methodology In Science Education, Kristin Cook

Graduate Theses, Dissertations, and Capstones

This abstract is going to tell you what this article is about.

Morphological Response In Sister Taxa Of Woodrats (Genus: Neotoma) Across A Zone Of Secondary Contact, Michaela M. Koenig

Master's Theses

This study focuses on a secondary contact zone between two sister species of woodrat, Neotoma fuscipes (dusky-footed woodrat) and N. macrotis (big-eared woodrat). Along the Nacimiento River, on the border of southern Monterey and northern San Luis Obispo counties, the ranges of these sister species of woodrats meet and overlap forming a secondary contact zone. The zone of secondary contact is estimated to include a 500-meter (~1,650 linear feet) portion of the Nacimiento River riparian corridor.

This research examines quantifiable morphological change that is likely associated with heightened inter-specific competition within the contact zone. When in sympatry the sister species …

How Are Rare Species Maintained?: Reproductive Barriers Between Layia Jonesii, A Rare Serpentine Endemic, And L. Platyglossa, Natalie L. Rossington

Master's Theses

Reproductive barriers are vital to generating new species as well as maintaining distinct species. Investigating reproductive barriers between closely related plant taxa helps us to understand how these barriers are maintained, particularly between rare and widespread relatives. Layia jonesii, a rare San Luis Obispo County serpentine endemic, and L. platyglossa, a common coastal species, co-occur on serpentine derived hillsides and are interfertile. At these locations, L. jonesii is isolated to dry soils near serpentine rock outcrops and L. platyglossa is located on slightly deeper grassland soils surrounding the rock outcrops. On hillsides where they co-occur, I observe two morphologically …

Tactics To Stay Alive: Predation Risk Alters Body Condition And Escape Behaviour, Benjamin T. Walters

Electronic Thesis and Dissertation Repository

Recent manipulations show that when perceived predation risk is high, animals will chronically alter their escape behaviour, even if it affects physiological condition to such an extent that survival may be reduced. I tested the relationships amongst predation risk, mass change, and flying capacity in brown-headed cowbirds (Molothrus ater) housed in large outdoor aviaries. I measured changes in the birds’ body condition, take-off behaviour and flying capacity after manipulating the ambient level of perceived predation risk in their environment using various predator or non-predator cues. Cowbirds exposed to predator stimuli gained, rather than lost, body mass and changed …

Reproductive Ecology Of Black Bears In Maine: Maternal Effect, Philopatry, And Primiparity, Alyssa A. Vitale

Electronic Theses and Dissertations

The American black bear (Ursus americanus) relies upon dens in order to successfully reproduce and protect their offspring. Black bears utilize a variety of den types, each providing a different degree of protection. Black bears also exhibit an extended maternal care period in which offspring stay with their mother for 18 months. Maine’s black bear population is one of the largest in the U.S. (>30,000 bears) and since 1975, the Maine Department of Inland Fisheries and Wildlife has conducted research and monitoring to manage the population. This unique dataset allowed for examination of several generations of multiple …

Intra- And Interspecific Variation In Demographic Rates And Niche Across The Range Of A Species, The Saltmarsh Sparrow (Ammodramus Caudacutus), Katharine J. Ruskin

Electronic Theses and Dissertations

In this project, we examined various hypotheses that address one of the fundamental questions in ecology and evolution: what determines the range of a species? We used demographic data for saltmarsh sparrows (Ammodramus caudacutus) collected over the majority of the global breeding range. Saltmarsh sparrows are considered threatened by climate change, specifically sea level rise, which is predicted to result in loss of the tidal marsh habitat where saltmarsh sparrows live across their entire life cycle. For my dissertation, I investigated the reproductive biology of saltmarsh sparrows both to provide vital information for wildlife managers and to explore …