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Mechanisms Of Adaptation In The Newly Invasive Species Brachypodium Sylvaticum (Hudson) Beauv., Gina Lola Marchini

Dissertations and Theses

It is common knowledge that invasive species cause worldwide ecological and economic damage, and are nearly impossible to eradicate. However, upon introduction to a novel environment, alien species should be the underdogs: They are present in small numbers, possess low genetic diversity, and have not adapted to the climate and competitors present in the new habitat. So, how are alien species able to invade an environment occupied by native species that have already adapted to the local environment? To discover some answers to this apparent paradox I conducted four ecological genetic studies that utilized the invasive species Brachypodium sylvaticum (Hudson) …

Ability Of Skin Bacteria On The Panamanian Frog Species, Craugastor Fitzingeri, To Inhibit The Fungal Pathogen Batrachochytrium Dendrobatidis, Tiffany N. Bridges

Senior Honors Projects, 2010-2019

An emerging infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd) is leading to global amphibian declines and is threatening the biodiversity of amphibians. Bd susceptibility varies among individuals, species, and populations perhaps due to defensive mechanisms such as symbiotic skin microbes. Some species of amphibians such as Craugastor fitzingeri, a terrestrial frog native to Central America, continue to persist in Bd-positive environments in Panama. My study focused on identifying antifungal bacterial isolates and determining the culturability of the bacterial community on 15 individuals of C. fitzingeri. Morphologically distinct isolates were challenged against Bd in …

Restoration Of A Wet Longleaf Pine (Pinus Palustris) Savanna In Southeast Louisiana: Burning Toward Reference Conditions, Alex K. Entrup

University of New Orleans Theses and Dissertations

This study quantifies the changes in vegetation composition and structure of a fire-excluded Pinus palustris (longleaf pine) wetland savanna restoration site in southeastern in comparison to a proximate contemporary reference site. The restoration site was invaded by hardwood species and off-site pines, and never underwent extensive soil disturbance. The restoration treatments involved logging across portions of the site and the reintroduction of fire across the entire site. All species present in 10m² quadrats were recorded prior to treatment and throughout the 17 year study at reference and treatment sites. The community composition of both logged and unlogged sites converged …

Explaining Migratory Behaviors Using Optimal Migration Theory, Jennifer D. Mccabe

Electronic Theses and Dissertations

Bird migration is the regular seasonal movements between breeding and nonbreeding grounds. In general, birds that breed in the Northern Hemisphere tend to migrate northward in the spring to take advantage of increasing insect populations and lower predation pressures and fly south when food availability and weather conditions decline. Embarking on a journey that can stretch a thousand miles round trip is a dangerous and arduous undertaking. While en route migrants must stop and feed to replenish their depleted energy reserves, often in unfamiliar locations with unknown predation pressures. They also must react to weather conditions during flight and while …

Response Of Fishes To Restoration Projects In Bayou St. John Located Within The City Of New Orleans, Louisiana, Including Hydrological Characterization And Hydrodynamic Modelling, Patrick W. Smith

University of New Orleans Theses and Dissertations

Quantifying the impacts of restoration on coastal waterways is crucial to understanding their effectiveness. Here, I look at the impacts of multiple restoration projects on urban waterways within the city limits of New Orleans, LA, with an emphasis on the response of fishes. First I report the effects of two projects designed to improve exchange down estuary on the hydrologic characteristics of Bayou St. John (BSJ). Within BSJ, flow is dominated by subtidal wind driven processes. Removal of an outdated flood control structure did not appear to alter exchange in BSJ, but removal combined with sector gate openings did. I …

Females In Control: Female Sensitivity To Predation Risk Affects Courtship And Reproductive Behaviours, Tin Nok Natalie Cheng

Electronic Thesis and Dissertation Repository

Even in the absence of direct killing, predators have a pervasive effect on prey populations through costly anti-predator behavioural responses. In high risk environments, animals can reduce conspicuous behaviours such as courtship displays decreasing exposure at the cost of reproduction. Previous studies typically looked at male behaviour immediately following a predator cue, thus, not considering temporal variations in risk or the impact of female receptivity on male courtship. I placed male and female brown-headed cowbirds under chronically elevated predation risk with periods of high and low risk. Under high predation risk, females performed fewer chatter calls and were more likely …

Deeply Rooted: The Story Of Congaree National Park, Taylor Karlin

Senior Theses

This photo-essay book was written to fulfill requirements for completion of a senior thesis project to graduate with honors from the South Carolina Honors College. Its purpose is to promote the enjoyment and preservation of the Congaree National Park by educating the public on the historical and ecological significance of the land and the many activities it has to offer. Despite its proximity to downtown Columbia, there remains a lack of public awareness about the park and the amazing activities and opportunities it has to offer. I have compiled information and pictures that will best depict the unique qualities of …

Fear Of Predators Compromises Parental Care And Juvenile Survival In A Songbird, Philip Blair Dudeck

Electronic Thesis and Dissertation Repository

Predators kill, but the risk of being killed is also a powerful force affecting survival because scared prey eat less, thereby increasing the likelihood of starvation. Young of most animals are extremely vulnerable to predators and may alter their behaviour to limit detection. I investigated the previously unexplored effects that predation risk has on the behaviour of newly fledged offspring and their parents, and the impact this has on offspring survival. I manipulated predation risk using sound and found that parent song sparrows reduced their feedings, providing 60% less food overall. Critically, not only did this parental response estimate survival …

Feeding Ecology Of The Invasive Lionfish (Pterois Spp.) And Comparison With Two Native Species: Schoolmaster Lutjanus Apodus (Walbaum, 1792) And Graysby Cephalopholis Cruentata (Lacepède, 1802), Jesse J. Secord

HCNSO Student Theses and Dissertations

Predator satiation and prey-size preference were determined for locally caught lionfish, schoolmaster, and graysby, all co-occurring predatory fishes in the Florida coral reef ecosystem. Individuals were evaluated by exposing them to wild-caught killifish over a gradient of four size classes (20 mm to 60 mm, in 10 mm increments). Preference trials extended over a 2 hr time period and were filmed to determine the order in which each prey item was consumed. Satiation was evaluated by exposing the predators to an equal number of excess prey items for 24 hrs and evaluating consumed prey weight. Lionfish and schoolmaster showed a …

The Evolution Of Kin Recognition, Timothy Ja Hain

Electronic Thesis and Dissertation Repository

The discovery that many animals are promiscuous has challenged the importance of Hamilton’s Rule because it reduces the net benefits of helping nestmates. To resolve this challenge, biologists have investigated animals’ abilities to determine degrees of relatedness among individuals using kin recognition mechanisms. I conducted a literature review and found that most animals use one of two mechanisms: “familiarity” whereby kin are remembered from interactions early in life, such as in a nest, or “phenotype matching” whereby putative kin are compared to a template of what kin should look, smell, or sound like based on relatives encountered during early life …

Seasonal And Long-Term (1995-2009) Changes In The Distribution And Abundance Of Submerged Aquatic Vegetation And Dreissenid Mussels In Inner Long Point Bay, Lake Erie, Robin Tj Churchill

Electronic Thesis and Dissertation Repository

Invasion by mussels can cause rapid increases in the abundance of submerged aquatic vegetation (SAV) by increasing water clarity and altering nutrient cycling, but rapid expansion of the mussel population is often followed by a decline until a new regional carrying capacity is reached. I sampled Long Point Bay (LPB), Lake Erie, in 2009 to quantify changes in SAV communities and densities of zebra mussels (Dreissena polymorpha) since the peak of the latter in the early 1990s, and modeled influences of year, water depth, and substrate type on the probability of SAV detection. I detected a 96% decrease …

The Biology Of Eastern Kingbirds At Malheur National Wildlife Refuge: Survival, Reproduction, And Testosterone Secretion, Lucas J. Redmond

Dissertations and Theses

This dissertation presents the results of a study that I undertook to better understand the breeding biology of Eastern Kingbirds (hereafter, kingbirds) at Malheur National Wildlife Refuge in southeastern Oregon from 2003 to 2009. Kingbirds are long-distance migratory songbirds that breed across much of North America. This species is socially monogamous but, via frequent extra-pair copulations, is genetically polygamous. Kingbirds exhibit relatively high breeding site fidelity, often returning to the same tree to nest in subsequent years. Both members of a pair provide parental care, but there are often specific duties performed by both male and female kingbirds. For example, …

Systematics And Diversification Patterns Of Morphologically And Ecologically Diverse Lineages Of Agaricomycetes: Clavariaceae And Cantharellales, Joshua Mark Birkebak

Doctoral Dissertations

The recent advent of molecular tools and methods to understand the diversity of living organisms allows for exploration of former untestable theories concerning the diversity of fungi. Here we assess the morphologically based classification of the family Clavariaceae in light of molecular phylogenetic reconstruction and propose a revised classification base on natural assemblages. We used stable isotope ratios to uncover a biotrophic nutritional mode for much of the family, which had not been well understood historically. We also investigate several enigmatic lineages of agaricoid or cantharelloid fruiting body producing fungi within a clade of otherwise clavarioid fruiting bodies. We provide …

Linking Physiology And Biogeography: Disentangling The Constraints On The Distributions Of Ant Species, Lacy Danikas Chick

Doctoral Dissertations

Understanding the factors that limit the distribution of species is at the core of ecological and biogeographical research, and is critical if we are to predict the responses of key ecosystem components to ongoing climatic changes. My doctoral research seeks to provide an understanding of how thermal physiology influences species’ distributions and better define the mechanisms underlying geographic variation in biodiversity. By using natural temperature gradients (both elevational and latitudinal) and coupling controlled laboratory experiments with field observations and null modeling approaches, I was able to document the role of inter-specific variation in thermal physiology and, more interesting, inter-population variation …

Native Deer Mice (Peromyscus Maniculatus) Use Of Invasive Grass Seed (Ehrharta Calycina) In Coastal California, Megan Wong

Biological Sciences

No abstract provided.

Territorial Defense Strategies In The Northern Cardinal (Cardinalis Cardinalis): Who Is The Bigger Threat?, Kaylee M. Gentry

Master's Theses

This thesis examines the use of defensive strategies in relation to territories year round in the northern cardinal (Cardinalis cardinalis). Responses to recorded neighbor song and stranger song playback from the middle of a focal male’s territory were measured. This allowed for an estimation of aggression in both the winter and spring seasons. Each focal male was subjected to both treatments (stranger song and neighbor song). Males were more responsive over-all to neighbor song playback, however in the winter months, persistence of response to neighbor song playback increased. It was also shown that southeastern United States cardinals show …

Contribution Of Lianas To Plant Area Index And Canopy Structure In A Panamanian Forest, Maria Elizabeth Rodriguez-Ronderos

Theses and Dissertations

Lianas are an important component of tropical forests, where they reduce tree growth, fecundity and survival. Competition for light among plants may be intense; however the amount of light that lianas intercept is poorly understood. We used a large-scale liana removal experiment to quantify light interception by lianas in a Panamanian secondary forest. We measured the change in plant area index (PAI) and forest structure six weeks after cutting lianas in eight 80x80 m plots and in eight control plots, and then annually for four years. We used ground-based LiDAR to measure the 3-dimensional canopy structure before cutting lianas and …

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 …

Impacts Of River Influence And Wave Exposure On The Epipsammic Diatoms Of The Lake Superior Wave Zone, Leon R. Katona

All NMU Master's Theses

Although little is known about primary productivity in wave zone habitats of very large lakes, it is presumably dominated by microalgae that attach to mineral substrates. Watershed energetics are linked with these wave zones through river mouth habitats, which provide nutrient and organismal input to lake systems. In this study, I assessed the abundance, productivity, and community composition of epipsammic diatoms in river mouth and beach habitats along the south-central coast of Lake Superior. Chlorophyll a concentrations were more than three-fold greater in river mouths (mean ± 1SE = 1.17 ± 0.45 mg/m²), than in wave zone (0.36 …

A Survey Of The Common Loon (Gavia Immer) Genome Reveals Patterns Of Natural Selection, Zach G. Gayk

All NMU Master's Theses

With rapid advances in Next-Generation Sequencing technology, comparative genomics has become a viable method for studying the adaptation of species to their environment at the genome level. I investigated this in common loons (Gavia immer)—for which molecular adaptation has not been characterized—by finding signatures of positive selection as evidence for genomic adaptation.

I used Illumina short read sequencing data from a single female common loon to produce a fragmented assembly of the common loon (Gavia immer) genome. The resulting assembly had a contig N50 of 814 bp, a total length of 767,326,331 bp, and 45.7 % …

Demography And Disease Of The Rare Shrub Buckleya Distichophylla (Santalaceae) In Northeastern Tennessee, William Seth Ratliff

Undergraduate Honors Theses

Piratebush (Buckleya distichophylla (Nutt.) Torr.) is a rare, hemiparasitic shrub with the only extant populations in western North Carolina, northeastern Tennessee, and southwestern Virginia. The preferred natural hosts of piratebush, Carolina and eastern hemlocks, have seen sharp declines over the last decade due to the invasive hemlock woolly adelgid. Virginia pine, another important host of piratebush, is also susceptible to disease, specifically Cronartium appalachianum, a rust fungus for which piratebush is the secondary host. This study described and analyzed current demographic parameters of three Tennessee piratebush populations. Additionally, spatial patterns of disease and demographic characters were analyzed. These …

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. …

More Than Movement – Ant Seed Dispersal Inhibits Phytopathogenic Fungi, Charlene H. Gray

Biology Theses

Seed dispersal by ants is a cosmopolitan mutualism involving thousands of plant species. Ants gain a food reward (elaiosomes) from the plant seed, and ant-mediated plants gain several presumed benefits, including dispersal away from parent plants and placement in 'safe site' microhabitat. Higher plant germination and survival in ant nest soils has been attributed to higher levels of nutrients, aeration, and soil moisture than surrounding soils, but evidence in support of these benefits is inconsistent. Ants secrete anti-microbial compounds that inhibit microbial pathogens. I explore the possibility that ants transfer anti-microbial properties to the soil they inhabit, and there is …

Macrobenthic Communities In The Northern Gulf Of Mexico Hypoxic Zone: Testing The Pearson-Rosenberg Model, Shivakumar Shivarudrappa

Dissertations

The Pearson and Rosenberg (P-R) conceptual model of macrobenthic succession was used to assess the impact of hypoxia (dissolved oxygen [DO] ≤ 2 mg/L) on the macrobenthic community on the continental shelf of northern Gulf of Mexico for the first time. The model uses a stress-response relationship between environmental parameters and the macrobenthic community to determine the ecological condition of the benthic habitat. The ecological significance of dissolved oxygen in a benthic habitat is well understood. In addition, the annual recurrence of bottom-water hypoxia on the Louisiana/Texas shelf during summer months is well documented.

The P-R model illustrates the decreasing …

Same-Sex Socio-Sexual Interactions Among A Group Of Captive Bottlenose Dolphins (Tursiops Truncatus), Natalia Botero Acosta

Master's Theses

Bottlenose dolphins (Tursiops truncatus) frequently engage in non-reproductive sexual behavior, including homosexual encounters. In order to better understand the nature and function of these interactions, a longitudinal study of the patterns of association and the dynamics of initiator/recipient role exchange was conducted. Underwater video footage of a colony of bottlenose dolphins housed at the Roatan Institute for Marine Sciences (RIMS), collected between March of 2010 and May of 2013, was analyzed. Associations occurring during homosexual interactions were transitory for most individuals. Nonetheless, subsequent analyses allowed the rejection of the null hypothesis of random association, suggesting the existence of …

Plant Toxins Influence Diet Selection And Intestinal Parasites In A Specialist Herbivore, Marcella Rene Fremgen

Boise State University Theses and Dissertations

Herbivores select plants and patches that generally maximize nutrient intake and minimize intake of plant secondary metabolites (PSMs). Protein is important for growth, reproduction and maintenance, but maximizing intake of protein is often limited by concentrations of PSMs that are potentially toxic to herbivores and energetically expensive to process. However, the consequences of ingesting PSM are often dose-dependent. At high doses, PSMs generally have negative physiological effects and are avoided, but some PSMs can be therapeutic against parasites at low doses and could therefore be selected. We used Greater Sage-grouse (Centrocercus urophasianus, hereafter, sage-grouse) to test how PSMs influence …

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 …

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; …

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 …