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 …

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 …

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 …

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 …

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 …

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 …

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 …

Metacommunity Coupled Epidemiological And Biophysical Modeling Of An Emergent Coral Disease, Benjamin Holmes Farmer

LSU Doctoral Dissertations

Emerging infectious diseases pose imminent risk to the marine realm and coral reefs in particular. Since its emergence in 2014, stony coral tissue loss disease (SCTLD) has dramatically reduced living coral cover in Florida and charted a similar course in the Caribbean. SCTLD is by far the most severe coral disease in history and has driven highly susceptible species to local extinction, yet the mechanisms driving the regional epizootic are not well understood. Here, we developed reef-scale parameterizations of disease spread using model sites in the lower Florida Keys, developed extensive metacommunity habitat maps for the US Caribbean, and then …

Protecting Wetlands In The State Of Texas: Assessing Gaps In Regulations, Knowledge, And Professional Roles And Responsibilities, Grace A. Moy

Landscape Architecture Masters & Design Theses

Wetlands rank among earth's most productive ecosystems, providing crucial ecological services such as hydrological regulation, water purification, and habitat support (US EPA, 2015). In Texas, however, rapid urbanization, inconsistent policy enforcement, and the absence of statewide protection frameworks of hastened wetland degradation (Brody & Kang, 2011). Without a robust state regulatory framework (Environmental Law Institute [ELI], 2020), these ecosystems face increasing threats from development and hydrological disturbances.

This thesis aims to identify regulatory and knowledge deficiencies that influence Texas’ current wetland protection status and to offer targeted professional recommendations for landscape architecture professionals to address these shortcomings in future public …

Temporal Avoidance By Gray Foxes Reflects Growing Pressure From Expanding Coyotes In The Neotropics, Madison Odenbach

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Coyotes (Canis latrans) are rapidly expanding their range towards South America, potentially threatening the world’s highest canid diversity residing on that continent. A better understanding of their interactions with native species is needed to anticipate potential competitive impacts. In Costa Rica, native gray foxes (Urocyon cinereoargenteus) likely occupy a similar niche to the coyote newcomer, yet little data exists on their interactions in tropical ecosystems. We hypothesized the two species separate temporally to minimize the potential for competition in our study area, given preliminary data suggesting high spatial overlap (57.1% of coyote-detected sites overlap with fox-detected …

Ectomycorrhizal Fungi Associated With Pinus Species Of California's Northwestern Coast, Monika Audrey Richardson

Cal Poly Humboldt theses and projects

Ectomycorrhizal (ECM) fungi are vital for increasing host plant uptake of nutrients and stress tolerance within ECM forest ecosystems. The species assemblage of ECM fungi can vary locally in response to numerous biotic and abiotic environmental factors. In California’s northwestern coast the occurrence of three Pinus species, along with a disjunction between populations of Pinus muricata in Mendocino and Humboldt Counties, offer a unique opportunity to investigate the spatial and host effects on pine-associated ECM fungi. Ectomycorrhizal fungal community structure was quantified from host tree roots and sequenced sporocarps occurring at the same sites to create a project specific ITS …

Cordgrass (Spartina Alterniflora) In Bio-Restoration Integrated Coastal Substrate (Brics): Restoring The New England Coastline., Kaitlyn Frances Shelley

UNH URC Open (2026 and after)

The Engineering for Agri-Environment Laboratory (EAE) is dedicated to developing nature-based solutions that enhance the resilience of agricultural and coastal ecosystems. The study involves current work (trial 2) underway in Spring 2026 and Summer 2026, integrating principles of sustainable engineering and plant science. BRICS, our Bio-Restoration Integrated Coastal Substrate, proposes a new way to reduce erosion, stabilize root structures, provide a critical habitat for wildlife, and promote vegetation throughout the coast.

The Impacts Of Wing-Flashing By Northern Mockingbirds On Foraging, Parental Care, And Reproductive Success, Anna R. Starman

Undergraduate Honors Theses

Foraging efficiency may be enhanced by flashing patches of white wing and tail feathers and has been documented in several avian species. Northern Mockingbirds (Mimus polyglottos, NOMO) exhibit this “wing-flashing” (WF) behavior while foraging, during displays, and in response to predators. In NOMOs, WF has been hypothesized to increase foraging success, but previous findings are inconclusive. To further investigate the biological role(s) of WF behavior in NOMOs, the ventral surface of white primary feathers of male NOMOs were artificially darkened, and the foraging and provisioning rates of undarkened (control) males and their mates were compared. While foraging, undarkened …

Using Camera-Based Unmarked Spatial Capture-Recapture Modeling To Estimate Reintroduced Elk (Cervus Canadensis) Population Parameters And Distribution In Southeastern Kentucky, Claire Marie Muia

Theses and Dissertations--Forestry and Natural Resources

Estimation of population parameters is important for wildlife management decisions. Elk reintroduced to southeastern Kentucky experienced early irruptive population growth and are currently monitored using a statewide harvest-based statistical population reconstruction model (SPR) across the Kentucky Elk Restoration Zone (KERZ). Because the SPR model is spatially coarse and difficult to scale to the smaller management units comprising the KERZ, we conducted a spatially explicit capture-recapture study using a clustered camera-trapping array deployed for 10 weeks from June–August 2024 to estimate elk population parameters within Management Unit 4. Due to a lack of resights of GPS-marked elk, population parameters were estimated …

Postfire Habitat Use And Density Of Pacific Martens (Martes Caurina) In Lassen National Forest, California, Deirdre L. Replinger

Cal Poly Humboldt theses and projects

Increasing frequency, size, and severity of wildfires in western North America threatens forest-dependent wildlife species. The Pacific marten (Martes caurina) has historically been associated with mature, structurally complex forest throughout most of its range. Recently, martens have been detected in forests burned at high severity by the 2021 Dixie Fire—the largest recorded single fire in California state history. I used non-invasive remote camera traps and hair snares (n = 166 sites) to assess marten habitat use and density using spatial occupancy and spatial capture-recapture models. I detected martens across the burn severity gradient (unburned to high-severity) at …

Multiple Burn And Forest Characteristics Affect Gray Fox (Urocyon Cinereoargenteus) Occurrence Following A California Megafire, Amida Zohar Verhey

Cal Poly Humboldt theses and projects

In western North American forests, predator communities are faced with changing fire regimes and increased fire severity and size, particularly with megafires (>10,000 ha). As some wildlife communities may restructure following the loss of apex consumers, understanding post-fire space use of mid-trophic carnivores may inform species composition in these forests. I compared gray fox (Urocyon cinereoargenteus) occupancy in and around the 2021 Dixie Fire, the largest single-ignition fire in California state history, to examine which spatially variable burn and forest characteristics affected the space use of a widespread generalist mesopredator. Using 210 camera traps placed in 2023, …

American Elderberry's Next Top Pollinator: Evaluating The Role Of Arthropods In Pollination, Jenny K. Burrow

Graduate Theses/Dissertations

American elderberry (Sambucus nigra subsp. canadensis) is a woody deciduous shrub native to eastern North America. In addition to its long history of use by indigenous peoples, there is renewed interest in cultivating and consuming American elderberry, primarily driven by expanding health supplement markets. Despite recent advances in horticultural development of American elderberry, its pollination ecology remains poorly understood. In this field study, I evaluated the contribution of arthropod visitors to pollination of American elderberry. To do this, I first characterized the identities and abundances of arthropod visitors via timed arthropod collections and floral observations during peak flowering …

Factors Affecting Detection Of A Cryptic Ambush Predator Using Camera Traps, With Implications For Snake Monitoring, Sarah Elizabeth Ebert

Theses, Dissertations and Capstones

Camera traps are becoming increasingly popular in wildlife research because they can be deployed for long time periods with little maintenance and are much less invasive than traditional trapping methods. However, they are primarily used to study large mammals and have not been extensively tested for snake species, many of which are cryptic and understudied. The Adapted-Hunt Drift Fence Technique (AHDriFT) arrays were designed to improve detection of herpetofauna by attaching camera traps to drift fences. In the summer of 2022, we installed 20 AHDriFT arrays at the Marine Corps Recruit Depot Parris Island in coastal South Carolina where we …

Eastern Fox Squirrel (Sciurus Niger) Occupancy In A Southern Missouri Woodland, Daniel Garten

Graduate Theses/Dissertations

Species occupancy, which relates the probability of presence of a species at a specific place and time, is an important component of conservation and wildlife management. Principally it is used for estimation of a species’ distribution as well as understanding species interactions and quantifying environmental effects. The purpose of this study was to analyze occupancy of the Eastern Fox Squirrel (Sciurus niger) across multiple seasons (2019–2022) at Bull Shoals Field Station (BSFS), and to identify potential covariates associated with detection and colonization. Data were drawn from camera trap surveys from 26 sites during summer and fall seasons. Multi-season occupancy models …

How Semiflightless Birds Adapt: A Survey From Barú, Costa Rica, Eli P. Laloudakis

Scripps Senior Theses

When we think of birds, we think of flight. Because of this, scientific research often focuses on how birds evolved flight and how their wings function during flight. However, not all birds can fly or fly well, as wings wax and wane on developmental, seasonal, and evolutionary time scales (Dial and Heers 2021). Consequently, rudimentary wings can be found in developing birds, secondarily flightless or semiflightless birds, birds that undergo simultaneous molts, and extinct theropods with “protowings” (structures that preceded fully functional wings). Secondarily flightless and semiflightless birds often evolve where there is no/low predation, abundant year-round food supply, and …