Life Sciences Commons^™

Long-Term Effects Of Harvesting Disturbance And Site Preparation On Soil Properties And Tree Growth In A Loblolly Pine (Pinus Taeda) Forest, Kyle M. Caccamesi

LSU Master's Theses

Productivity decline between rotations has long been a concern in intensively managed forest plantations. Research done over the last century has provided greater clarity on why this phenomenon occurs. The objective of this research was to observe long-term soil and tree growth characteristics that are likely to be influenced by operational harvesting activities. The experiment was conducted in Washington Parish, Louisiana on a site dominated by Ruston soil series, a well-drained, fine loamy, siliceous and thermic typic Paleudult. A randomized complete block design with 2 x 2 x 2 factorial treatments was used. The treatment factors were harvesting method, fertilization, …

Using Fecal Diagnostic Tests To Assess The Prevalence Of Fasciola Hepatica In The United States Sheep Population, Brooke A. Delcambre

LSU Master's Theses

Fasciola hepatica, the common liver fluke, is endemic in the Pacific Northwest and Gulf Coast of the United States. To provide updated information on F. hepatica prevalence, as part of the USDA National Animal Health Monitoring System Sheep 2024 study, sheep operations in the top 30 sheep-producing states were identified, and producers were invited to participate. For each operation, feces were collected from at least eight sheep and pooled to form a single composite sample. Two methods were used to identify sheep infected with F. hepatica: fecal sedimentation and indirect sandwich ELISA. At the national level, across 318 operations, 7.1 …

Irrigation Water Conservation And Accelerated Composting: An Exploration Of Environmentally Conscious Practices For Ornamental Horticulture, William James Carson Dunford

LSU Master's Theses

Best management practices for ornamental horticulture include proper management of irrigation water resources and substrate components. The first study investigated the effects of wind speed, wind direction, water pressure, and spray stake height on irrigation efficiency in nursery containers. Results indicated that lower spray stake height positions and lower wind speeds significantly improved the irrigation water volume captured within nursery containers by as much as 18% to 39%. Orienting spray stakes against prevailing winds further enhanced water retention, particularly at 0 and 1 inch heights. In contrast, higher stake elevations led to increased irrigation water loss by as much as …

Nitrogen Management Strategies For Specialty Tea Production In Louisiana: Rate, Source Type, And Nutrient Dynamics, Autumn D. Hilderbrand

LSU Master's Theses

Tea (Camellia sinensis L.) is an emerging specialty crop in Louisiana and the southeastern United States; however, region-specific nitrogen (N) management recommendations remain limited. This research evaluated N fertilizer source, application rate, and nutrient leaching to identify management strategies that improve nitrogen use efficiency (NUE) and environmental sustainability during tea establishment.

Three complementary studies evaluated N source replacement, application rate, and fertilizer source effects on nutrient retention and movement. The first study evaluated the replacement of urea ammonium sulfate (UAS) with blood meal (BM) while maintaining a constant annual N application rate. Fertilizer replacement did not significantly affect leaf …

Influence Of Genetic Relationships On The Spatial Distribution Of Breeding Eastern Wild Turkeys (Meleagris Gallopavo Silvestris) In West-Central Louisiana, Rachel D. Price

LSU Master's Theses

Eastern wild turkeys (Meleagris gallopavo silvestris) have a complex social system influenced by dominance hierarchies and exhibit seasonal variation in gregarious behaviors. Previous work has examined the influence of kin relationships on interactions between same sex conspecifics and flock associations, but information on how genetic relatedness influences interactions between individuals remains lacking. We constructed a dyad-based social network using high-resolution GPS data from 179 female and 68 male wild turkeys in west-central Louisiana during the 28-day period before a females’ 1^st nest initiation to quantify interaction probability based on genetic relatedness and age. Our findings suggest that …

Assessing Integrated Pest Management Protocols For The Invasive Aquatic Weed Giant Salvinia (Salvinia Molesta), Samantha Lee Prinsloo

LSU Doctoral Dissertations

Giant salvinia (Salvinia molesta) is free-floating aquatic fern that originates from South America. Through human introduction, giant salvinia has escaped its native range and is listed as an invasive species across multiple continents causing negative socio-economic and environmental impacts. This research aimed to expand our understanding of integrated pest management for controlling giant salvinia by combining chemical and biological control. The objectives were to assess the effects of rainfastness, carrier volume, and growth stage on herbicide efficacy, assess augmented biological control and optimal weevil release densities, assess weevil populations in the field, determine herbicide and surfactant toxicity to …

Understanding The Needs And Practices Of Cut Flower Growers In Louisiana, Jessie M. Hoover

LSU Doctoral Dissertations

The specialty cut flower industry is expanding nationwide, including southeastern states such as Louisiana. Existing studies and market analyses focus on national trends of other regions with established floriculture networks, leaving a critical gap in understanding the unique challenges and opportunities faced by growers in Louisiana. This lack of data limits the ability of extension professionals, policymakers, and industry stakeholders to develop targeted strategies that support local production and market development. This study used qualitative case study methods to investigate the practices, challenges, and needs of 13 specialty cut flower growers in Louisiana. The study utilized Urie Bronfenbrenner’s (1979, 1986) …

Evaluating Soil Health And Crop Yield In Louisiana Agricultural Systems: Impacts Of Best Management Practices And Prediction Models, Hector J. Mendoza Lagos

LSU Doctoral Dissertations

The adoption of conservation management practices is critical for improving soil health, enhancing nutrient use efficiency, and sustaining crop productivity in row crop systems in Louisiana. This study evaluated the role of conservation agronomic practices, soil biochemical indicators, and machine learning predictive models to improve soil nutrient dynamics, soil health indicators, microbial communities (MC), and crop productivity on a corn (Zea mays L.) research plot scale and in a commercial forty-hectare cotton (Gassypium hirsutum L.)-corn-soybean (Glycine max L.) rotation system in northeast Louisiana. The objectives of the study were to evaluate soil nutrient dynamics and MCs under …

Recent Wetland Elevation Dynamics In Coastal Louisiana, Usa, Elizabeth Harris

LSU Master's Theses

Coastal marshes globally are increasingly vulnerable to accelerating relative sea-level rise (RSLR), which threatens their capacity to maintain elevation through feedbacks among sediment supply, vegetation productivity, hydrology, and soil processes. Although many marshes can persist under moderate rates of sea-level rise through vertical accretion and belowground biomass production, this resilience is strongly constrained by sediment availability and subsurface processes such as autocompaction and organic matter decomposition. High accretion is often assumed to confer marsh resilience; however, subsurface processes, particularly autocompaction driven by surface loading, can substantially offset elevation gains. Coastal Louisiana experiences among the highest rates of RSLR worldwide due …

Comparison Of Sampling Methods For Estimation Of Aquatic Insect Diversity And Abundance Across Seasonal Gradients In A Southern U.S. River System, Albert Henry Gasperecz

LSU Master's Theses

Determination of benthic macroinvertebrate assemblage composition plays a vital role in assessment and management of lotic systems throughout the U.S. However, the validity of biomonitoring programs depends on accurate and precise measures of macroinvertebrate abundance, which in turn are dependent on sampling gears and protocols. The goal of this project was to assess how gear selection influences estimates of aquatic insect abundance and diversity, and how this selection can affect biological monitoring practices. I used 4 different gears in 3 southern Mississippi streams to aquatically and terrestrially collect aquatic insects seasonally throughout 2024. I identified and recorded all genera present …

Genome Wide Association Study (Gwas) On Different Economic Traits And Epigenetic Stability Of Sweetpotato In Louisiana, Ajay Dhungana

LSU Doctoral Dissertations

Sweetpotato [Ipomoea batatas (L.) Lam] is a globally important food, feed, and industrial crop, yet its improvement is constrained by a complex hexaploid genome, clonal propagation, and susceptibility to multiple diseases. In Louisiana, production is threatened primarily by Fusarium oxysporum f. sp. batatas (Fusarium wilt) and Ceratocystis fimbriata (Black rot). Furthermore, the in vitro propagation methods essential for disease-free planting material and germplasm conservation can introduce epigenetic instability that undermines clonal fidelity. This dissertation integrates genome-wide association studies (GWAS), genotype by environment interaction (GEI) and DNA methylation profiling to dissect resistance mechanisms and assess epigenetic stability in Louisiana sweetpotato …

Curriculum For A Two Semester Calculus Course Specializing In Life Science And Data Science, Patrick Mcclain

LSU Master's Theses

Traditionally, introductory calculus has been designed for engineering and physics students, often leaving students majoring in data science or life sciences with a curriculum that lacks professional relevance and is overly reliant on problems that focus on computational fluency. This thesis proposes a two-semester sequence, called MATH 153X and MATH 154X, specifically tailored for the Louisiana State University (LSU) Dual Enrollment program and university-level data science and life sciences majors. By integrating modern computational tools—such as symbolic calculators and artificial intelligence (AI) tools—the proposed curriculum shifts the pedagogical focus from procedural symbolic manipulation toward conceptual literacy.

Through a series …

Key Elements Of Mission-Based Urban Agriculture In The United States Aimed At Addressing The Social Determinants Of Health, Jordan Losavio

LSU Doctoral Dissertations

Urban agriculture (UA) in the United States (U.S.) is increasingly positioned as a multi-domain strategy for addressing social determinants of health (SDOH), yet evidence is fragmented and often focused on participant outcomes rather than the organizational and environmental conditions that determine whether those benefits can be sustained, expanded, or maintained over time. This dissertation uses an exploratory sequential mixed-methods design to clarify (1) what SDOH outcomes are associated with UA in the peer-reviewed literature, (2) which internal and external factors leaders perceive as driving UA organizational success or failure, and (3) which factors predict comparative organizational functioning across a national …

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 …

An Examination Of Trends And Factors Influencing Teen Retention In 4-H Youth Development Program: A Case Study, Bethany R. Corona

LSU Master's Theses

Teen participation in 4-H has declined nationally in recent years, raising concerns about long-term program sustainability and youth engagement. Understanding the factors that influence teens’ decisions to remain involved in 4-H is critical for informing program design and delivery. Guided by the theory of planned behavior, this qualitative study explored teen perceptions of 4-H programming, youth voice, social influences, communication, and barriers to participation. Data were collected through two group interviews with teen 4-H members representing multiple parishes. Interviews were audio recorded, transcribed verbatim, and analyzed using the constant comparative method through a three-phase coding process consisting of open, axial, …

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 …

Supplemental Bibliographic Details. From 2001 Mars Odyssey To Earth’S Climate Crisis: Integrating Gamma Spectroscopy, Martian Soil Simulants, And Plant Genomes For Agroecology, Anchored In Sri Lanka’S Mars-Context Serpentinites, Suniti Karunatillake, Maheshi Dassanayake, Carlos Gary Bicas

Planetary Science Lab

Bibliographic details follow to supplement hyperlinked citations in the multinational GANGOTRI-supporting project conceived by Karunatillake, Dassanayake, and Gary-Bicas

Characterizing The Role Off The Sp1/Klf Transcription Factor Huckebein In The Drosophila Melanogaster Ventral Nerve Cord, Benjamin Almond

Distinguished Undergraduate Researcher Program

Over the course of embryonic development, the ectodermal cell layer gives rise to a vast array of neurons and glia patterned across the central nervous system (CNS). Neurulation and specification is achieved in the ectoderm through temporospatial patterns of transcription factor (TF) expression, many of which are conserved across evolutionary history. These conserved regulatory motifs allow the use of Drosophila melanogaster to study the mechanisms of neurodevelopment across the animal kingdom. The huckebein (hkb) gene encodes a conserved SP1/KLF TF known to play important roles in cell cycle regulation, tissue morphogenesis during tubular organ development, and gut specification in Drosophila. …

Measuring The Rise And Fall Of Plasma 25-Hydroxyvitamin D Concentrations In Blue-Tongued Skinks (Tiliqua Scincoides) Following Ultraviolet B Exposure And Withdrawal, Ashleigh Godke, Haerin Rhim, M. Graciela Aguilar, Keishla Marrero-Acosta, Mark Mitchell

Distinguished Undergraduate Researcher Program

Species-specific husbandry guidelines remain limited for blue-tongued skinks (Tiliqua scincoides), especially in relation to ultraviolet B (UVB) lighting and vitamin D requirements. This study aimed to determine whether UVB exposure is necessary for these skinks and how long 25-hydroxyvitamin D (25-OHD) concentrations persist after UVB withdrawal. Eleven adult skinks who had been fed with wet cat food were exposed to 12 or 2 h of UVB per day for four weeks. Plasma 25-OHD concentrations were very low at the baseline, and significantly increased post-UVB in both groups (p < 0.01), with the 12-hour group increasing from baseline concentrations of 18.5 [12.8–20.5] nmol/L to 820 [730–1251.3] nmol/L and the 2-hour group increasing from baseline concentrations of 22 [15.5–22] nmol/L to 635 [401–892.5] nmol/L. Following the discontinuation of UVB exposure, 25-OHD gradually declined and was not significantly different from baseline concentrations at 7 and 4 months for the 12-hour and 2-hour groups, respectively. Dietary vitamin D3 (2.5 IU/g as dry matter basis), provided through wet cat food alone, appeared insufficient to support sustained plasma 25-OHD concentrations. These findings strongly suggest that blue-tongued skinks rely on UVB exposure to increase their 25-OHD concentrations. Moreover, the shorter 2-hour exposure provided a significant rise in 25-OHD concentrations and remained above baseline for 4 months, suggesting the shorter exposure can benefit these animals, while potentially reducing secondary risks associated with UVB exposure.

Structural Determination And Regulatory Mechanisms Of Rice Lipoxygenase-1, Lillie Ballanco, Nathaniel Gilbert, Adam Offenbacher

Distinguished Undergraduate Researcher Program

Lipoxygenases (LOXs) are non-heme iron containing enzymes that catalyze the oxygenation of polyunsaturated fatty acids (PUFAs) such as linoleic acid (LA). These lipoxygenase enzymes are found in both plants and animals. In humans, LOXs have been linked to inflammatory diseases such as asthma, atheroscelerosis, and allergic rhinitis. Plant LOXs have been primarily linked to the growth, development, and stress response of the plant. This paper focuses on Oryza sativa lipoxygenase-1 (OsLOX1), an enzyme found in rice (Oryza sativa). OsLOX1 has been associated with enhanced drought tolerance in rice and may play a role in regulating growth under water-limited conditions. Understanding …

Role Of Cellular Stress Responses In Innate Immune Defense Against Acute Respiratory Infections, Amit Sharma

LSU Doctoral Dissertations

The endoplasmic reticulum (ER) stress sensor inositol-requiring enzyme 1α (IRE1α) is an important regulator of innate immune cells. However, its role in pulmonary innate host defenses remains poorly understood. This dissertation elucidates the dual, context-dependent role of IRE1α in host defense against methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. We demonstrate IRE1α’s function as both a detrimental mediator of acute pathology and an essential facilitator of innate immune memory. Our work revealed that acute IRE1α activation during primary MRSA infection is detrimental. In lungs and alveolar macrophages (AMs), IRE1α is activated in response to MRSA infection. Consequently, IRE1α activation triggers a hyperinflammatory …

Advancing Louisiana's Cropping Systems: Sustainable Bioenergy Production, Cover Crops, And Technology Integration, Pedro R. Carrillo

LSU Doctoral Dissertations

The adoption of cover crops in Louisiana is lower than the national average, underscoring the need for region-specific research to address environmental challenges and demonstrate the short-term benefits of these practices within existing production systems. This research evaluated the integration of cover crops (CC) in energy cane (Saccharum spp.) and no-till cotton systems, focusing on their effects on soil health, nitrogen (N) management, and biomass production. Soil health indicators (SHIs), including enzymatic activities (β-glucosidase, β-glucosaminidase, and urease), protein N, inorganic N concentrations (nitrate and ammonium), soil organic matter (SOM), and microbial community composition assessed through ester-linked fatty acid …

Population Dynamics, Host Range, And Impact Of The Naturalized Weevil Ochyromera Ligustri: A Potential Biological Control Agent Of Invasive Ligustrum Sinense, Brandi H. Misiaszek

LSU Master's Theses

Invasive woody plants have become dominant components of many forest understories in the southeastern United States. These species can displace native species, disrupt ecosystem processes, and reduce biodiversity. Chinese privet (Oleaceae: Ligustrum sinense Lour.) is an invasive shrub distributed through the Southeastern United States. The ligustrum weevil (Coleoptera: Curculionidae: Ochyromera ligustri Warner) is a non-native insect that was first found in the U.S. on Ligustrum in 1959. This weevil is considered a potential fortuitous biological control agent of invasive Ligustrum spp. in the U.S. The objectives of this study were to evaluate O. ligustri as a potential biological control agent …

Effects Of Photo-Oxidized Crude Oil On Gulf Killifish Early Life Stages, Charles Campbell

LSU Master's Theses

Photo-oxidation of spilled crude oil generates polar compounds that can heighten toxicity to marine fish embryos. We investigated the effects of photo-oxidized crude oil on early life stages of Gulf killifish (Fundulus grandis) by exposing embryos under flow-through conditions to water-accommodated fractions of four oil treatments: fresh oil unexposed to either sunlight or weathering referred to as dark control (DC), a UV-light oxidized whole oil (LT), the polar fraction extracted from LT (Pol) and the remnants after extracting the Pol from LT (NP). Oil loadings of 0.38–3.00 g oil/kg water were tested. Total PAH concentrations and chemical profiles …

Uav Remote Sensing For Assessment Of Conservative Management Practices In Maize-Soybean Cropping System, Aakriti Poudel

LSU Master's Theses

Sustainable agriculture practices promote cover cropping, which enhances nutrient management and impacts subsequent crop productivity in field crop rotations. Precision agriculture technology, particularly Unmanned Aerial Vehicle (UAV) remote sensing, enables a detailed evaluation of crop management. The studies were conducted in a maize-soybean rotation system with winter cover cropping and fallow management. The maize experiment investigated the effect of nitrogen application rates and cover cropping, using UAV-derived Normalized Difference Red-Edge (NDRE) to monitor crop performance. NDRE effectively captured the N response and the effect of cover cropping across growth stages, particularly during mid-season (55-81 DAP), where it showed a strong …

Management Of Herbicide-Resistant Italian Ryegrass Using Cover Crop And Fall Residual Herbicide, Connor T. Mckoin

LSU Master's Theses

A field study was initiated in the fall of 2023 and repeated in 2024 at the LSU AgCenter Northeast Research Station near St. Joeseph, LA, to determine the impact of fall-applied soil residual herbicide at different growth stages (spike and one-leaf stage) on grass cover crop species, cereal rye and black oats. In most instances, clomazone (631 g ai ha^-1) and treatments containing the higher rates of metribuzin (263 g ai ha^-1)resulted in the greatest amount of cover crop injury both years, with biomass impacted by clomazone both years and in one of two years with …

Integrating Cereal Rye Cover Crop And Herbicide Programs To Manage Glyphosate-Resistant Italian Ryegrass In The Midsouth, Bhupesh K. Dhaka

LSU Master's Theses

Glyphosate-resistant (GR) Italian ryegrass (Lolium perenne ssp. multiflorum) has become an economically significant weed management challenge in Louisiana row crop production systems. The problem is further exacerbated by the occurrence of biotypes with resistance to acetyl-CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors—herbicide sites of action (SOAs) commonly used for ryegrass control in soybean (Glycine max) and cotton (Gossypium). Field, greenhouse, and laboratory experiments were conducted during the 2023–2024 and 2024–2025 growing seasons at the LSU AgCenter Northeast Research Station in St. Joseph, LA, and at the LSU AgCenter Weed Science facilities in Baton …

Examining Private Landowner And Stakeholder Attitudes, Perceptions, And Knowledge Of Prescribed Fire In Louisiana, Chloe E. Crawford

LSU Master's Theses

Periodic fire was a primary driver of ecosystems across the Southeastern United States for millennia; however, fire suppression policies have become pervasive in the United States and led to increased fuel loads in forests as well as reduced biodiversity and reduced disease resilience. Prescribed fire presents a risk mitigation strategy and land management tool whereby practitioners can apply fire to the landscape in a controlled manner, thus reaping the benefits of fire while minimizing the risks associated with fire. Land in Louisiana is primarily privately managed and owned, so state-level conservation goals cannot be met without private landowner participation. As …

Detection Of Sweet Potato Feathery Mottle Virus Infection Via Remote Hyperspectral Imaging, Clayton Blake

LSU Master's Theses

In sweetpotato, global production exceeds 90 million tons annually, yet yields are threatened by numerous pathogens, including the potyvirus sweet potato feathery mottle virus (SPFMV). Virus infections can reduce yields by 25–40%, but surveillance is hampered by asymptomatic infections and the labor-intensive nature of detection. Hyperspectral imaging (HSI), combined with machine learning (ML), offers a promising pathway to scalable, non-destructive detection; however, studies focused on virus infection in sweetpotato remain limited.

This study demonstrates the feasibility of ML-enabled HSI for SPFMV detection under greenhouse conditions via a curated spectral library of two commercial cultivars, 'Beauregard' and 'Orleans', and the biological …