Other Ecology and Evolutionary Biology Commons^™

Determining The Role Of Maumee River Sediments In Microbial Nitrogen Transformations And Net Fluxes, Ashlyn Stanalonis

Master's Theses

The Maumee River watershed is the largest of any river feeding into the Laurentian Great Lakes and is primarily comprised of agricultural land uses. Most cultivated crops require fertilizer applications to sustain growth and productivity. Fertilizer runoff is a major source of nutrient loading to the river, and total nitrogen (N) and phosphorus (P) inputs contribute to eutrophication and cyanobacterial blooms in the western basin of Lake Erie. This study aimed to characterize Maumee River sediments as net N sinks or sources to the western basin and evaluate N removal efficiency (a valuable ecosystem service) to determine if river sediments …

A Genetic Analysis Of The Rare Endemic Astragalus Ripleyi Barneby, Juan Antonio Jaramillo-Chico

Master's Theses

Astragalus ripleyi Barneby is a rare endemic species found in the San Luis Valley of the southern portions of the Rocky Mountains in Colorado and New Mexico. Though not federally listed as endangered, the species is on the Bureau of Land Management’s Sensitive Species List, warranting protection and continued management. This study aims to provide information about the genetic health of the species to inform conservation efforts and provide updated management recommendations. A genetic health analysis was conducted investigating the levels of diversity present in the species, how genetic diversity is structured across the known range of the species and …

Re-Examining Endemic Smoky Dace As An Indicator Species In The Upper Little Tennessee River Index Of Biological Integrity, Tayton C. Alvis, William O. Mclarney, Radmila Petric, Jason P. Love

Southeastern Fishes Council Proceedings

Fish communities can be used to evaluate water quality and stream ecosystem health, helping resource managers understand the effects of anthropogenic disturbance. Fish species inform indexes of biological integrity through their ecological traits and tolerance to stressors (e.g. tolerant of disturbance, intolerant of disturbance), but these designations are difficult to determine without localized, species-specific information. The Upper Little Tennessee River watershed is subject to long-term aquatic biomonitoring, applying an index of biological integrity tailored to the region. In this index, the undescribed endemic Smoky Dace (Clinostomus sp.) is classified as intolerant based on a previous designation for the Rosyside Dace …

Mobile Genetic Elements Shape Microbial Diversity And Functions In Thawing Permafrost Soils, Jiarong Guo, Samuel T. N. Aroney, Guillermo Domínguez-Huerta, Derek Smith, Dean Vik, Carlos Owusu-Ansah, Akbar Adjie Pratama, Sergei Solonenko, Funing Tian, Cristina Howard-Varona, Zhi-Ping Zhong, Aminata Fofana, Garrett J. Smith, Suzanne B. Hodgkins, Dylan Cronin, Isogenie Field Teams 2010–2017, 2019, Emerge Coordinators, Ben J. Woodcroft, Gene W. Tyson, Virginia I. Rich, Matthew B. Sullivan, Simon Roux, Sarah C. Bagby, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Ecosystems are shaped by communities of microorganisms whose niches and impacts depend on functional profiles influenced by gene gains and losses. Culture-based experiments demonstrate that mobile genetic elements (MGEs) can mediate gene flux, but quantitative understanding of these dynamics in natural systems remains limited. Here we develop and apply a systematic, meta-omic framework to investigate MGEs in a complex natural system using an 8-year soil time series collected at Stordalen Mire, in Sweden’s thawing permafrost margin. In this climate-critical peatland, we identify ~2.1 million MGE recombinases across 89 microbial phyla and assess ecological distributions, affected functions, past mobility and current …

Testing The Accuracy Of A Bear-Tracking Satellite Transmitter Collar Under Natural Conditions, K. A. Watson, K. Phipps, C. Drexler, C. R. Middaugh, M. Means, M. Hooks

Journal of the Arkansas Academy of Science

The Arkansas Game and Fish Commission tracks American black bears (Ursus americanus) using Global Positioning System (GPS) satellite telemetry collars in southeastern Arkansas to assess habitat use and behaviors. Companies test the accuracy of their devices, but researchers have found that natural environments, such as the forested habitat of black bears, can cause an increase in spatial error rates. We therefore tested 1 GPS collar in realistic conditions to help refine data interpretation. We placed the collar at 20 random locations in Columbia County, AR, stratifying habitat type based on data collected from black bears. We determined the …

Exploring The Effects Of Pest-Induced Hemlock Mortality On Growth In Neighboring Trees, Sidney L. Booher

McNair Culminating Research Projects

Trees provide many important products and services to humans. In particular, tree growth is critical to carbon storage, air and water quality, and helps determine demographic processes like population growth and reproductive success. Importantly, tree growth is sensitive to both abiotic (environmental) and biotic factors and is vulnerable to ecological disturbances. Understanding how tree populations respond to disturbances, like invasive pests, is therefore crucial to formulating timely and effective forest management practices.

Here, I used tree ring analysis to investigate how competition for water between neighboring trees changes following the decline of Eastern and Carolina Hemlock(ECH) trees due to the …

Investigating Cryptic Diversity In The Hawaiian Endemic Plant, Psychotria Mariniana (Rubiaceae), Uyen Thi Hoang Nguyen

Master's Theses

Islands, with their isolation and steep environmental gradients, serve as natural laboratories for studying speciation. Molecular phylogenetic and population genetic methods utilizing Next-Generation Sequencing (NGS) have revolutionized our ability to document patterns of genetic divergence and diversity. Cryptic diversity, genetically distinct populations that were previously unrecognized as unique, and cryptic speciation, where divergent genetic populations may be deserving of status as unique species, have been observed in many taxa. The Hawaiian Islands provide an ideal setting for studying divergence and speciation due to their extreme isolation, known ages, and volcanic origin. Previous work has investigated the evolutionary relationships of the …

Improving Human-Wildlife Coexistence: An Ecological And Educational Approach To Rewilding Grizzly Bears (Ursus Arctos Horribilis) In California, Amanda C. D. Rosales

Master's Projects and Capstones

Megafauna extinction during the Holocene has been both caused and amplified by climatic changes and human influence. By the last half century, large carnivores were diminished in Europe and the United States, but policies increasingly addressed species decline and their territories expanded. This research examined large carnivore rewilding across the European Union and United States, specifically for rewilding brown bears, Ursus arctos, in historic habitat. Next, case studies for the health status of climate-impacted whitebark pine, Pinus albicaulis, a high energy food for bears, was assessed. Ultimately, research case studies, human perspective surveys, and the California Department of Education content …

Insects And Arthropods And Their Role In Human Society, Emily Marie Perez-Medina

Whittier Scholars Program

With brightly colored exoskeletons, an excess of both eyes and legs, and seemingly  unpredictable behaviors, insects and arthropods come across as unusual and strange to general audiences. For this reason, they are often classified as “gross,” “ugly,” or “scary,” antagonists  in popular culture. What is not recognized when being represented to the masses is how much human society depends on their presence, and how a world without insects would be a world without most things humans know and love. In order to help reduce the stigma of these tiny, yet mighty creatures, this project serves as a call to action …

Ecological And Nutritional Drivers Of Floral Fidelity In Wild Pollinators, Adelaide Elise Ergastolo

Master's Theses

Plants must receive pollen from the same species in order to successfully reproduce. For most flowering plants, the transfer of pollen occurs via animal pollinators while they forage on plants to obtain food. Therefore, the fidelity of pollinators to individual plant species during foraging trips is directly related to the amount of conspecific pollen plants receive. Low floral fidelity of pollinators can reduce plant reproductive success, which in turn has the potential to lower food resources for pollinators in the future. While many factors can potentially influence pollinator floral fidelity, several important ones may be the nutritional resources provided by …

Assessing Vegetation Health Following The 2014 Carlton Complex Fire Using Remote Sensing, Rachael Sv Pentico

2026 Symposium

Climate change, combined with decades of altered fire regimes and fire suppression, has increased fuel accumulation across western U.S. forests, contributing to more frequent, larger, and more intense wildfires. Remote sensing offers an effective approach for analyzing these large-scale fire events and their ecological impacts, as satellite imagery enables affordable, accessible, and reproducible monitoring of vegetation change across broad spatial and temporal scales. This study examined the 2014 Carlton Complex Fire in the Methow Valley, Washington. Burning 265,108 acres, it was the largest wildfire in Washington State history at the time and caused extensive agricultural and forest damage. Post-fire vegetation …

Effects Of Increased Salinity On Mississippi Coast Bacterial Community Composition And Diversity, Clifton C. Wade

Honors Theses

Bacterial communities are important to ecosystem function in coastal environments, but the response of these communities to short term increased salinity conditions is understudied. This study utilized a microcosm setup to investigate the response of coastal seawater bacterial communities to three treatments: an unamended seawater control, a reference treatment that received reverse osmosis (RO) water, and an elevated salinity treatment that received artificial seawater dissolved in RO water. Microcosms were sampled four times over a five-day period to analyze the effects of time under different salinity conditions on the seawater bacterial community. 16S rRNA gene sequencing was used to analyze …

Ectomycorrhizal Fungal Identity Strongly Influences Soil Properties Relative To Pine Presence And Soil History In A Pine–Eucalyptus System, Braedan Watters

Honors Theses

Invasive Pinus radiata has increasingly spread into native ecosystems in the Southern Hemisphere, including Eucalyptus forests in Australia, where it forms novel hybrid forest systems in which invasive and native tree species coexist. The success of these invasions is closely tied to ectomycorrhizal fungi (EMF) such as Rhizopogon spp., yet the relative roles of pines versus their fungal symbionts in altering soil properties remain poorly understood. This study investigated the independent and interactive effects of soil history (Pinus or Eucalyptus), EMF identity, and pine presence on soil properties using a controlled factorial experiment. Soil from beneath either Pinus …

Quantifying Genetic Diversity In Nematode Feeding Rate, Jacob King

Honors Theses

Understanding how populations persist under changing environmental conditions is a central question in ecology and evolutionary biology. Variation in traits related to resource acquisition may play a key role in determining population survival when resources are limited or fluctuate over time. In this study, I investigated how variation in feeding-related traits influences population persistence using a combination of computational modeling and laboratory experiments. I developed a stochastic, individual-based consumer–resource model to simulate population dynamics across varying levels of trait variance and resource regimes. Across 60,000 simulated populations, increased trait variation consistently reduced extinction risk and extended persistence time, although the …

I Lost My Number, Can I Have Yours? Body Image Satisfaction With Sexually Dimorphic Traits Is Associated With Men's Dating Anxiety And Confidence, David A. Frederick, Tania A. Reynolds, Nikoline L. Smart, Justin R. Garcia, David A. Puts

Psychology Faculty Articles and Research

Evolutionary scientists posit that sexual selection processes caused males to develop sexually dimorphic traits to aid them during intrasexual competition and increase their likelihood of being chosen as mates. Evolutionary social sciences have extensively examined women's preferences for traits such as muscle mass and voice pitch, reasoning that these traits serve as cues of men's ability to provide direct benefits (e.g., resources) and indirect (genetic) benefits passed on to offspring. At the same time, body image researchers have extensively focused on the social causes and consequences of men's dissatisfaction with their muscularity and body fat. We connected these two research …

Bottles, Butterflies, And Biomass: Recycled Glass Sand, Microbial Additions, And Herbivory Effects On Milkweed Growth, Kealey Skinner

Honors Theses

Plant-soil-microbe interactions are integral components of ecological networks and drive ecosystem function from the bottom-up. Whereas herbivores regulate ecosystem function from the top-down, having opposing and potentially complementary effects on ecosystem function. My thesis sought to understand how below-ground microbial communities contribute to herbivore preference and plant biomass across varied soil substrates. My thesis asked: how do substrate and soil microbial communities influence herbivore preference and plant biomass accumulation on swamp milkweed (Asclepias incarnata)? To address this question, seedlings of A. incarnata were sown in 2.5 cm wide × 10 cm deep pots filled with either natural beach sand or …

Preserving The Past: Exploring The Last Frontier's Ecosystem Shifts And Biodiversity Of The Tallgrass Prairies, Gisell Maldonado, Amelia Villaseñor

Anthropology Undergraduate Honors Theses

In North America, grasslands are a cornerstone of the environment. Historically, the tallgrass prairie was expansive and reached from Manitoba in Canada to Texas. Today this unique ecosystem is highly fragmented and reduced, but it remains an important ecosystem for biodiversity and cattle management. While there are many complex ecological interactions in the prairie, recent research shows that large herbivores are vital in maintaining grasslands through grazing and other behaviors that reduce woody encroachment and support nutrient cycling. Here, we examine cow and bison dietary behaviors and connect these to the ecosystem services provided by these large herbivores. In the …

Acute Effects Of The Psychoactive Pollutant Fluoxetine On The Antipredator Behavior Of The Gulf Killifish (Fundulus Grandis), Semyra Reus

Honors Theses

Pharmaceutical contaminants are increasingly prevalent in aquatic environments, yet their sublethal effects on ecologically relevant behaviors remain poorly understood, particularly in estuarine systems. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are of particular concern due to the conserved role of serotonin in regulating behavior across vertebrates. Here, we investigated how acute exposure to environmentally relevant concentrations of fluoxetine influences anti-predator behavior in Gulf killifish (Fundulus grandis), a key estuarine fish commonly found in saltmarsh habitats. Killifish were exposed to control (0 ng/L), low (17.8 ng/L), and high (596 ng/L) fluoxetine concentrations and subsequently tested in the presence …

Ecological Responses To Living Shoreline Restoration, Aaron S. Bland

Graduate Theses and Dissertations (2019 - present)

Coastal built communities and natural coastal ecosystems face similar and interrelated hazards: shoreline sediment erosion, shoreline retreat, and worsening storms, each of which is exacerbated by relative sea level rise. Living shorelines are coastal defense projects that incorporate natural habitats to provide more sustainable shoreline defense and improve the coastal ecosystem. Living shorelines have been widely adopted, but their performance has been highly variable, and the mechanisms of project success and failure are unclear. The overarching goal of this dissertation was to better understand the ecosystem responses to coastal restoration, focusing on the primary habitats of coastal salt marsh and …

Feeding Ecology In Coastal Systems, Randi L. Cannon

Graduate Theses and Dissertations (2019 - present)

Oysters (Crassostrea virginica) are critical foundation species in estuaries, providing numerous ecological and economic benefits. However, oyster populations have diminished worldwide. Effective oyster restoration and aquaculture require a mechanistic understanding of the physiological and environmental factors that govern oyster feeding, growth, and resilience under changing coastal conditions. We investigated how oyster ploidy and environmental conditions influenced oyster feeding and investigated how changes in abiotic conditions affected behavioral performance of oyster drills (Stramonita spp.), a key oyster predator. To better understand feeding responses and behaviors of both predator and prey we 1) used in-situ filter feeding assays to determine if feeding …

Storm-Drains As Ecosystems, Victoria E. Kennedy, Curtis Jang, Darlene Panvini

SPARK Symposium Presentations

Stormwater drains and culverts are installed across urban spaces to direct surface water and allow for proper drainage and prevent flooding and erosion. These structures and the water that they carry can provide unintended opportunities to wildlife. Previous research has shown that local ecosystems may utilize and adapt around these culverts in many ways. They can serve as habitats, connect fragmented habitats separated by roads or human traffic, serve as drinking spots, and promote biodiverse plant growth. This project aims to analyze these often-overlooked spaces as ecosystems themselves, so that we can learn more about their impact and significance.    Key …

Does Shape Matter?: How Salamander Head Morphology Shifts Based On Environment, Caitlyn Pinaga, Naomi Ramirez, Sonia Cerrillo

Posters - 2026

Groundwater salamanders of the genus Eurycea represent a diverse group of amphibians inhabiting the aquifer systems of central Texas, where both surface-dwelling and fully subterranean species coexist. Subterranean habitats impose extreme selective pressures, including complete darkness, limited nutrient availability, and stable environmental conditions, which drive convergent morphological traits such as eye reduction or loss, decreased pigmentation, and elongation of appendages. A key evolutionary pattern seen in these systems is sensory compensation, in which the reduction of one sensory modality, in this case vision, is accompanied by the enhancement of others. In aquatic salamanders, this often involves expansion of the lateral …

Assessing Differential Expression In Skin Of Surface Versus Subterranean Salamanders (Eurycea) Through Development, Chiara Angelyn Maldonado, Van Nguyen, Amy Torres

Posters - 2026

In salamanders, previous findings have shown that subterranean environments impose different selection pressures on sensory systems than surface environments do (1). Differences in ocular development between phenotypes is part of ongoing research to better understand the evolutionary and molecular underpinnings. Studies have shown that parallel ocular development occurred in subterranean and surface phenotypes, while pax6 expression decreased in latter stages of development of subterranean species (2). These insights of gene labeling and expression as well as reduction of ocular structures in latter stages of development provide a stage for understanding evolutionary processes and genetic mechanisms as well as having potential …

Alabama Prairie Reconstruction: Comparing Management Pathways For A Southeastern Landscape, Cecelia R. Geyer

Theses

Southeastern prairies are highly biodiverse yet increasingly threatened by land-use change, fire suppression, and habitat fragmentation. These disturbance-dependent systems rely on periodic fire and grazing to maintain plant diversity and ecosystem function. This study evaluates prairie restoration strategies by testing predictions from the Intermediate Disturbance Hypothesis and the Patch Mosaic Burn Hypothesis. The study site was divided into three treatments: prescribed burned only (B), prescribed burned with mowing (BM) to simulate grazing, and an undisturbed control (C). A standardized mix of native plant seeds was broadcast across all treatments. Ecosystem health and function were evaluated using plant community diversity and …

Assessing The Impact Of Lampenflora Growth On Invertebrate Distribution And Food Resource Use In Ryusen-Do Cave, Japan, Kazuhide Nakajima, Kanato Ando, Shuji Watanabe, Masuo Komukai

International Journal of Speleology

Subterranean spaces, such as caves with openings to the surface, represent unique environments characterized by limited resources derived from photosynthetic primary production. Consequently, organic inputs from organisms inhabiting above- and belowground habitats, such as bats, play a crucial role in maintaining cave ecosystems. However, in show caves converted into tourist attractions, environmental changes have progressed without sufficient ecological assessment. One important factor is the impact of photosynthetic organisms colonizing around artificial lights, known as lampenflora, on cave ecosystems. Lampenflora growth may influence invertebrate distribution and resource use; however, its impact on both aspects has been poorly evaluated. In this study, …

Impact Of Legacy Amf Communities On Vegetative Growth & Yield Of Soybean, Dylan Habeeb, Connor Morozumi, Natalie Christian

The Cardinal Edge

Soil microbial communities are increasingly recognized as an important factor in sustainable agriculture. Arbuscular mycorrhizal fungi (AMF), are key players in these communities, known to benefit their plant host in a number of ways, such as increased nutrient uptake. Plants can partner with multiple AMF species; however, little is known about how interactions between multispecies communities of AMF impact plant growth and yield. In an agricultural setting, the long-term development of these communities following practices such as rotational planting or cover cropping is also an important consideration, but there is little research on the long-term legacy of AMF communities or …

Leaf Droppage Delayed In Sugar Maple Trees On An Urban To Rural Gradient, Isabella S. Bastien, Isabella Bastien

The Cardinal Edge

This study investigates the timing of leaf abscission in Sugar Maple (Acer saccharum) trees along an urban-to-rural gradient in Louisville, Kentucky, to determine how proximity to urban environments influences leaf drop. We hypothesized that urban trees would retain their leaves longer than suburban or rural trees due to environmental stressors and tested this using weekly leaf collection and canopy cover measurements from three locations—urban, suburban, and rural. Results showed that urban trees exhibited delayed leaf drop and slower canopy opening compared to suburban and rural trees. These findings suggest that urban stressors significantly alter tree phenology, which may signal underlying …

No Effect In Plasma Corticosterone Levels After Observation Of Diseased Conspecifics, B. M. Hardy, M. Chang, S. Mccallum, S. Santangelo, Patricia C. Lopes

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Organisms commonly respond to stressors in their environment by increasing the secretion of corticosterone (CORT). While increased CORT is acknowledged as a response to predation risk by organisms inhabiting a landscape of fear, new research raises the potential for changes in CORT as a response to the risk of infection by organisms in their environment. An increase in CORT of a healthy, uninfected individual in response to their perception of the risk of infection in their environment could change their susceptibility to infection, highlighting a significant role for CORT to alter host–pathogen dynamics. To investigate the effects of infection risk …

Evaluating Eastern Wild Turkey (Meleagris Gallopavo Silvestris) Behavioral Ecology In The Southeastern United States, Chad Argabright

LSU Doctoral Dissertations

The wild turkey (Meleagris gallopavo spp.) is a game bird species in North America who are one of the great success stories in restoration and conservation. Wild turkeys were extirpated from most of their range in the early 20th century, but through habitat restoration and translocation efforts the population was restored to the point of being sustainably harvested in 49 U.S. States by the late 20th century. However recent declines in wild turkey population indices have necessitated ongoing research on the behavioral ecology of wild turkeys to help counteract these declines. East Texas specifically for the past century has …

Decoupling Of Reproduction And Lifespan Trade-Off In Caenorhabditis Elegans Through Microbial Programming, Nora M. Villafuerte

LSU Master's Theses

The microbiome is increasingly recognized as a major regulator of host physiology. Using the Caenorhabditis elegans model, we investigated how natural commensal bacteria modulate host reproduction and lifespan through internal egg hatching, a phenotype in which retained embryos hatch within the maternal body. Screening strains from the CeMbio collection identified four focal strains Ochrobactrum BH3, Lelliottia JUb66, Pantoea BIGb0393, and Enterobacter CEent1 that significantly increased internal egg hatching during the late reproductive period. This contrasts with pathogenic bacteria, which induce early-onset internal egg hatching. Across the focal strains, worms exhibited reduced total brood size but an expanded reproductive window relative …