Life Sciences Commons^™

Exploring Biotic And Abiotic Drivers Of Ecosystem Properties: The Influence Of Waterbirds And Photodegradation On Wetland Ecosystems, Lindsay Miller

All Graduate Theses and Dissertations, Fall 2023 to Present

Wetlands provide a wide range of valuable ecosystem services: these are benefits from the environment that support human well-being, such as water filtration, fish and bird habitat, and shoreline protection. Despite their importance, wetlands are among the most threatened ecosystems, facing increasing pressure from natural and human activities. To better predict the future of wetlands and guide effective management and restoration practices, we need to understand the various forces shaping their ecological properties. In this thesis, we examined the influence of two forces: waterbirds and photodegradation (the process by which sunlight breaks down plant material). To explore each of these …

Multi-Crop Systems And Crop-Switching Strategies To Enhance Water Use Efficiency And Climate Resilience In Arid Agricultural Regions, Shahryar Fazli, Wenzhao Li, Surendra Maharjan, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Agriculture in the Lower Colorado River (LCR) region faces mounting challenges from climate change, arid conditions, and water scarcity. This study evaluates water use efficiency (WUEc) and crop-switching strategies under SSP2-4.5 and SSP5-8.5 scenarios for 2025–2049, 2050–2074, and 2075–2099. Using historical data, climatic drivers such as temperature and precipitation were analyzed for their influence on key crops, including durum wheat, winter wheat, and corn. Results show SSP2-4.5 supports water use reductions up to 16%, stable profits (80–90%), and modest calorie increases (up to 15%), while SSP5-8.5 poses severe challenges, with water use reductions of 2–5%, profits dropping to around 20%, …

A Simple Guide For Describing Soils, 2nd Edition, Angela Stuart-Street, Nicolyn Short Dr, Paul Galloway, Noel R. Schoknecht

Natural resources published reports

Soils are enormously diverse and can be very confusing to understand and talk about. This simple guide for describing soils helps to identify the most important parts of a soil profile and provide an easy way to understand and explain what you see. It gives you a step-by-step guide of what soil properties to describe and how to describe them, along with the tools to make basic soil classifications. The soil descriptors help you to identify the soil type and aid in assigning a simple and standardised name to the soil. While this guide is designed to link with a …

Assessing Effectiveness Of Runnel Restoration In New England Salt Marsh Habitats, David M. Burdick, Grant Mckown, Gregg Moore, Jenny Gibson, Wenley Ferguson, John Herbert, Nancy Pau, Susan Adamowicz, Geoff Wilson

Faculty Publications

Rising sea levels that increase flooding in salt marshes recovering from hydrologic impairments is reducing nesting habitat for salt marsh sparrows. Abandonment of colonial farming practices (1600s through 1900s) has resulted in large, waterlogged basins characterized by shallow depressions (pannes) dominated by short-form Spartina alterniflora and unvegetated megapools that are subsiding. A relatively new technique designed to provide regular tidal flooding and drainage to the waterlogged basins that have formed on the marsh is runnelling – creation of shallow hydrologic features on the marsh surface. Will runnels result in revegetation of pannes and pools with productive perennial grasses that are …

Adaptive Crop Switching For Irrigated Agriculture In Response To Climate Change In The Western U.S., Shahryar Fazli, Wenzhao Li, Surendra Maharjan, Rejoice Thomas, Aqil Tariq, Hesham El-Askary

Mathematics, Physics, and Computer Science Faculty Articles and Research

Adaptive irrigation strategies are crucial for balancing water use, economic viability, and food security in the arid Western United States. However, as a key indicator vital in regulating agricultural productivity and crop irrigation, water use efficiency (WUEc) is becoming increasingly complex to estimate due to climate change. This study explores the critical role of key meteorological drivers, such as maximum temperature (tmax) and vapor pressure deficit (vpd), and their impacts on crop-specific WUEc. Future impacts are also assessed through integrating machine learning models with climate projections from the CMIP6 framework under SSP2–4.5 and SSP5–8.5 scenarios to forecast WUEc trends from …

High Spatial Resolution Crop Type And Land Use Land Cover Classification Without Labels: A Framework Using Multi-Temporal Planetscope Images And Variational Bayesian Gaussian Mixture Model, Minh Tri Le

Mathematics, Physics, and Computer Science Faculty Articles and Research

Previous studies often combined high spatial resolution data (e.g., PlanetScope) with wider spectral range data (e.g., Sentinel-2) and relied on supervised classification methods to produce land use and land cover (LULC) maps. This study proposed a new unsupervised framework to generate crop type and LULC maps at high spatial resolution (< 5 m) using available PlanetScope data solely without requiring ground truths. We used PlanetScope surface reflectance images and their derived spectral indices during growing seasons to create multi-temporal input features, which were fed into an unsupervised Variational Bayesian Gaussian Mixture Model (VBGMM). The VBGMM, unlike the traditional unsupervised classification methods, (1) first estimated optimal parameters that are most suitable based on the input features and then (2) assigned pixels to the cluster with maximum posteriori probability of a mixture of several Gaussian distributions. The crop type and LULC maps were then generated by labeling the derived clusters using the best possible assignment method, referring to the existing crop type or LULC products. We evaluated the produced PlanetScope-based crop type and LULC maps using true labels, corresponding reference maps, and other unsupervised classification methods. The results demonstrated the robustness and effectiveness of the proposed framework in mapping crop types and LULC at 3–5 m pixels across various ecosystems, climate zones, and human-managed landscapes. The spatial patterns of PlanetScope-based maps were (1) highly comparable with all the reference datasets at 10–30 m spatial resolution and (2) better than the traditional GMM and K-means clustering methods. The VBGMM produced classification maps with high confidence, yielding class probabilities above 0.9 for over 90 % of all study areas. The area percentage for all crop type and LULC classes agreed well with their reference maps, with R2 of 0.95 and RMSE of 1.04 %. The confusion matrices using true labels indicated that PlanetScope-based maps achieved a higher overall accuracy of 84 % than the supervised referenced maps of 81 %. Besides, the entropy comparison showed that our framework-based maps were better at capturing fine-scale features such as developed areas within cities that commonly mix with open space and vegetation, deforestation and cropland conversion in South America, smallholder croplands in Africa and Asia, and generating homogeneous crop fields in North America. This study further highlighted the potential for future research to implement our proposed framework to generate timely and extensive annotated datasets, which can be used for operationally training machine learning models to map crop types and LULC, track deforestation, detect wildfires, and delineate flooded areas at larger scales using medium/coarse Earth observations.

The Nature Of Anthropogenically Driven River Drying: Spatiotemporal Causes And Consequences, Eliza Inez Gilbert

Biology ETDs

Streambed drying naturally occurs in over 60% of rivers and streams worldwide. Climate change and human regulation of surface and groundwater have increased drying in naturally intermittent systems and caused perennial systems to transition to intermittency, impacting water security, water quality, and biodiversity. To understand human-induced drying dynamics, we used 12 years of daily drying data along a 154-km regulated reach of the Rio Grande. We conceptualized river drying as a regime analogous to the natural flow regime paradigm and quantified drying magnitude, rate of change, and duration. Although linear models predicting drying magnitude and rate of change were uninterpretable, …

Transformation With Genes To Improve Lipid Production And Barcoding To Identify Unknown Algal Species, Michelle T. Rada

Theses and Dissertations

With the rising demand for alternative fuels, algal-based biofuels are a promising, sustainable source that meets commercial interest while producing lower greenhouse gas emissions compared to fossil fuels. This thesis explored two studies, evaluating microalgae for their future potential in lipid yield for biofuel production.

The first study involved developing a cost-efficient electroporation protocol that allowed for the genetic transformation of Chlamydomonas reinhardtii using the pChlamy_4 vector, which supports future cloning of genes to enhance lipid production. Parameters affecting DNA uptake and integration into algal genomes were studied: the effect of cell density, the settings of the electroporation device, and …

Patterns And Processes Behind Secretive Marshbird Movement, Abundance, And Distribution Across Southeastern Louisiana, Leah Moran

LSU Doctoral Dissertations

Restoration and conservation of coastal Louisiana hinges on understanding the patterns and processes underlying habitat heterogeneity on the landscape and therefore the species that inhabits this region, including secretive marshbirds. Elusive in nature, this guild of birds has evolved under dynamic hydroperiods, and myriad plant communities present within wetlands. Only recently, however, has research focused on the role of hydrologic dynamics and vegetative structure and distribution on abundance, movement and detection of marshbirds, specifically within southeastern Louisiana. This study aimed to quantify the ecological patterns and processes, particularly hydrologic processes and landscape structure, driving breeding secretive marshbird movement, abundance and …

Post-Wildfire Erosion And Sedimentation: An Escalating Threat For Utah Fisheries, Colton James, Kendall Becker, Scott Hotaling, Aish Chandrasekaran, Alex Fiedler, Timothy E. Walsworth, Patrick Belmont

All Current Publications

Wildfires are a natural part of the western U.S. landscape and provide numerous benefits, including enhanced nutrient cycling and habitat rejuvenation. Utah’s fish populations evolved with wildfire as a common disturbance. However, the increasing size and severity of wildfires, combined with Utah’s heavily engineered and fragmented stream networks, pose a contemporary risk to fish populations. This fact sheet reviews wildfire impacts on erosion and Utah's watersheds and fisheries. It outlines measures we can take to prevent post-wildfire fish die-offs.

Spatiotemporal Responses To A Rural Highway By Four Mammal Species, Caitlin K. Brett, Anna Rose Mehner, John H. Young Jr., Sarah E. Lehnen, Richard J. Kline

School of Earth, Environmental, & Marine Sciences Faculty Publications

Roads can negatively impact the wildlife communities they transect. Road mortalities from wildlife-vehicle collisions are one direct effect, but roads may also indirectly affect wildlife behavior, movement, or local distribution. Quantifying the spatial extent of these road-effects is important for understanding how roads indirectly affect species of concern, identifying potential sources of disturbance, and for estimating the effectiveness of road mitigation structures. Farm-to-Market Road (FM)106, which transects part of the Laguna Atascosa National Wildlife Refuge in Cameron County, Texas, has been identified as a potential source of wildlife road mortalities, particularly for one of the two remaining breeding populations of …

Integrating Belowground Recovery Into Tropical Forest Restoration Design And Monitoring, Lauren Toro, Leland K. Werden, Shalom D. Addo-Danso, Kelly M. Andersen, Sarah Batterman, Matilde M. Bragadini, Pooja Choksi, Rebecca J. Cole, Liza S. Comita, Daniela Cusack, Daisy H. Dent, Lee H. Dietterich, Joshua B. Fisher, Katrin Fleischer, Lucia Fuchslueger, Nohemi Huanca-Nunez, Janey R. Lienau, Lindsay A. Mcculloch, Ember M. Morrissey, Jennifer S. Powers, Mareli Sánchez-Juliá, Oscar Valverde-Barrantes, Anita Weissflog, Michelle Y. Wong

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

There is growing recognition that tropical forest restoration is key for sequestering carbon and enhancing ecosystem resilience. Soils, roots, and soil biota are central to ecosystem function and services, but belowground recovery is largely overlooked in restoration monitoring frameworks. Here, we outline current understanding of the links between above- and belowground recovery in tropical forests by examining how belowground properties before and after intervention influence recovery; by evaluating whether aboveground recovery can serve as a proxy for belowground dynamics; and by proposing a blueprint for monitoring dynamic soil physical (bulk density, aggregate stability), chemical (organic matter or carbon, pH), and …

Occurrence Of Pesticides In Oregon Coastal Waters And Effects On The Intertidal Sea Anemone, Anthopleura Elegantissima, Gabriella Mae Bleil

Dissertations and Theses

Pesticides are used globally for a wide range of applications including agricultural, forestry, roadsides, freshwater systems, and personal use. While pesticides have ensured efficient crop production, they are frequently transported away from application sites and are ubiquitous in terrestrial and aquatic environments. Pesticides are often detected in watersheds and rivers globally, which can have unintentional toxic effects on non-target organisms by interfering with cellular processes, behavior, feeding, reproduction, and disrupting endocrine processes. The aggregating anemone, Anthopleura elegantissima, is an important species along the North American Pacific coast due to its symbiotic relationships that contribute to high productivity, and its …

Factors Motivating Clothing Choice: Environmental Impact Of T-Shirts, Lauren Hunt

DePaul Discoveries

Second only to oil, the fashion industry is one of the most pollutive industries globally. Due to the rise of fast fashion, this environmental issue is continually growing. The level of production has dramatically increased while quality of apparel has decreased, causing shorter garment lifespans. This research utilizes life cycle assessment to identify the environmental impacts of various textiles used in the production of t-shirts, including cotton, polyester, viscose, and elastane. The research scope focuses from material extraction through garment disposal. The life cycle assessment research is paired with a community survey to determine consumer behavioral patterns surrounding clothing consumption …

Environmental Justice And Soil Lead Contamination: Spatial Analysis Across Seven Community Areas, Arsene Lionel Apabaga

DePaul Discoveries

Pb is a pervasive metal with toxicity linked to numerous human health issues. Urban soil is a well-documented environmental sink for Pb, persisting as a legacy pollutant decades after the phaseout of leaded gasoline. This study measured, mapped, and analyzed the spatial distribution of total soil Pb concentrations across seven Chicago Community Areas (CCAs). The objectives were to: (1) assess the relationship between mean soil Pb concentration and mean Community Environmental Justice Index (CEJI) score per CCA, (2) determine the relationship between soil Pb levels and the percentage of industrial land use, and (3) quantify and compare the percentage of …

Planetary Thinking: Hellbenders As Emissaries Of Appalachia, Tierra R. Curry

Critical Humanities

Hellbenders are prehistoric salamanders that have thrived in cold rivers since before the continents divided. Once found throughout Appalachian watersheds, due to exploitation and habitat degradation only a few dozen healthy populations survive. Monstrous yet fascinating, hellbenders were often reviled historically, but in recent decades they have gained iconic status and are now celebrated as charismatic indicators for clean rivers. Hellbenders are symbols of the wild because of their ancient history, elusive nature, and contribution to ecosystem resilience. The same forces that drove the decline of these amphibian sentinels have sacrificed public health in Appalachia. Their demise echoes the struggle …

Vibrio Cholerae Endemic To The Lower Rio Grande Delta Segregate Into Urban And Rural Phylotypes, Daniele Provenzano, Jeffrey W. Turner, Jorge Duran-Gonzalez, David A. Laughlin, David Silva, Viviana Trevino, Miguel F. Gonzales, Boris Ermolinsky, Stefan Pukatzki

School of Integrative Biological & Chemical Sciences Faculty Publications

The lifestyle of Vibrio cholerae is primarily environmental, yet a chance encounter with a human host can lead to cholera, a potentially lethal form of diarrhea. Strains belonging to O1 and O139 serogroups have pandemic potential, but the contribution of non-O1/non-O139 serovars towards the genesis of cholera remains unclear. Endemic V. cholerae lineages were investigated given several historical accounts describing cholera epidemics and sporadic, contemporary cholera-like outbreaks along the lower Rio Grande Delta (LRGD). Seven isolates were recovered from an urban segment of the Rio Grande and six from a rural segment where the river empties into the Gulf of …

Healthcare Administration Within Free Medical Clinics And The Impacts On The Sustainable Development Goals, Saneywongse Le Mar

Goal 3: Good Health and Well-Being

No abstract provided.

Soil Health In Nebraska: Exploring Practitioners' Needs And Insights From A Long-Term Organic Farm, Ingrids Isabel Mata Vigil

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Soil health is foundational to sustainable agriculture, environmental resilience, and long-term food security. Yet, the adoption of soil health assessments remains limited, often perceived as too technical, costly, or difficult to implement in real-world contexts. To better understand these challenges, the first chapter presents findings from a statewide survey of 41 soil health practitioners in Nebraska, including farmers, extension educators, NRCS staff, and conservation professionals. Respondents highlighted the need for simpler, more accessible, and context-specific tools for soil health assessment that help practitioners make informed decisions aligned with their management goals. Complementing these insights, the second chapter includes an independent, …

Fisheries Science Update - Pilbara Fishing Competition Science 2020 To 2024 - July 2025, Department Of Primary Industries And Regional Development, Western Australia

Fisheries Science Updates

Key Points:

• Pilbara recreational fishing competitions are helping to track the sustainability of pelagic species like Spanish mackerel.
• Over 500 pelagic fish have been sampled at Pilbara fishing competitions over 5 years.
• This information goes towards DPIRD’s assessment of Spanish mackerel and monitoring the large pelagic resource in the North Coast Bioregion.

Catching A Fever: A Comparison Of Vachellia Xanthophloea Populations In The Limpopo And Luvuvhu River Floodplains Of The Makuleke Contractual Park, Kianie B. David

School of Natural Resources: Dissertations, Theses, and Student Research

This study investigates patterns of stand structure regeneration, growth characteristics, and coarse woody debris (CWD) patterns in Vachellia xanthophloea (fever tree) stands within the Makuleke Contractual Park (MCP), a semi-arid savanna system in northern Kruger National Park (KNP), South Africa. Fieldwork was conducted across two stand types: a monospecific fever tree stand in Rietbok Vlei and a mixed-species stand in the Western Nhlangaluwe Floodplain where fever tree is established with Faidherbia albida (ana tree). Data were collected from 20 total 1/4-acre (1,011 m²) circular plots between both stands in 2024 and 2025, including seedling root collar diameter (RCD), …

Bioenergy Crop Production: Implications For Grassland Bird Communities In Southwestern Nebraska, Grace E. Schuster

School of Natural Resources: Dissertations, Theses, and Student Research

Biofuel and bioenergy systems are components of most climate stabilization pathways to reduce greenhouse gas emissions and limit global warming. Currently, corn (Zea mays) is the predominant feedstock used for bioenergy production in the United States. However, widespread production of this monoculture crop has resulted in many negative environmental impacts. The most notorious impact has been the loss of grassland habitat due to agriculture expansion which has had detrimental effects on wildlife that depend on grassland habitat. One such group, grassland birds, has faced steeper, more consistent, and more widespread declines than any other avian guild. Therefore, strategies …

Response Of Soybean To Variable Irrigation Levels In Eastern Nebraska Using The Aquacrop Model, Anmol Singh

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

AquaCrop was calibrated and validated for soybean [Glycine max (L.) Merr.] using 19 irrigation treatments from five years using data from field experiments. The model accurately simulated canopy cover (CC), soil water content (SWC), and grain yield, with overall validation nRMSE values of 12%, 7%, and 7%, respectively. The overall validation nRMSE for SWC in individual 30-cm soil layers was comparatively higher, at 19%. The model was subsequently applied for long-term simulations (2010–2024) to estimate soybean yield and water requirements for two dominant soil types, Yutan silty clay loam and Tomek silt loam under three irrigation levels - rainfed, …

Longitudinal Surveillance Of Aedes Aegypti (Diptera: Culicidae) In Urban Coastal Kenya: Population Dynamics, Blood Feeding Frequency And Dengue Virus Infection Rates, Josephine Osalla, Louis Clement Gouagna, Gilbert Rotich, Maureen Nzilani, Penina Safari, Kennedy Senagi, Francis Mutuku, Baldwyn Torto, David P. Tchouassi

All Peer-Reviewed Publications

The coastal region of Kenya has emerged as a focal point for urban dengue virus transmission driven by Aedes aegypti as the primary vector. To gain a deeper understanding of the epidemiological situation, we carried out a year-long longitudinal study (December 2021- November 2022) of the population dynamics of A. aegypti through weekly mosquito surveys using ovitrap and CO2-baited Biogents (BG) mosquito traps in Ukunda, an urban township in the coastal region. Aedes eggs laid in ovitraps were exclusively A. aegypti with 80.8% mean hatch rate. A total of 35,109 adult A. aegypti were captured, with twice as many females …

Assessment Of Spatial Autocorrelation And Scalability In Fine-Scale Wildfire Random Forest Prediction Models, Madeleine Pascolini-Campbell, Joshua B. Fisher, Kerry Cawse-Nicholson, Christine M. Lee, Natasha Stavros

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Wildfire prediction models that can be applied across diverse regions at fine scales (<  100 m) are critical for wildfire management. Remote sensing offers a path forward by providing heterogeneous and dynamic measurements of fuel load, type, and flammability. Machine learning methods such as random forests provide an empirical framework that are high-accuracy, computationally efficient, interpretable and able to model complex ecological relationships. Here we use high resolution (70 m, every 3–5 days) remote sensing observations of evapotranspiration and evaporative stress index, which represent plant water stress, from Ecosystem Spaceborne Thermal Radiometer on Space Station (ECOSTRESS), as well as topography and weather data, to predict burn severity and occurrence for 8 large wildfires that burned 3715 km² from 2021 and 2022 in New Mexico, USA. These fires ranged from low to high burn intensity, and covered a diverse range of ecoregions (deserts, grasslands, forests), plant species, and topographies. We used a single model to predict the burn severity of all wildfires one week before occurrence. The prediction accuracy was greatest when using all predictors (ECOSTRESS, weather, topography) (R² = 0.77). We assessed the role of spatial autocorrelation in driving model performance by: (1) increasing the sample spacing of our dataset, (2) …

Status Of The Western Australian Pastoral Rangelands 2024: Total Vegetative Cover, Cover Risk And Pasture Condition, Department Of Primary Industries And Regional Development, Western Australia

Natural resources published reports

The Department of Primary Industries and Regional Development (DPIRD) monitors and reports on the vegetation condition of pastoral rangelands in Western Australia. Two levels of reporting are provided: every 5 years a full report (this report) details the state, trend and risk of decrease of vegetation condition in the pastoral rangelands using information derived from remotely sensed and on-ground data; in the intervening years, short reports are provided based on remotely sensed data.

This full report is based on remotely sensed vegetation cover data, rainfall data, livestock data and station-level rangeland condition assessment (RCA) data available in November 2024. Data …

A Demand Systems Analysis Of Energy Sources In The United States, Rafael Bakhtavoryan

Faculty Publications

This study estimates a Generalized Exact Affine Stone Index model to quantify demand structure among such energy sources as natural gas, coal, nuclear, wind, solar, and geothermal energy, employing monthly time-series data ranging from January of 2009 through December of 2020. The demand for natural gas, coal, and nuclear energy emerges as inelastic. A significant substitutability relationship is empirically established between the energy sources. All the computed expenditure elasticities are positive, with natural gas being the most sensitive and nuclear energy being the least sensitive to energy source expenditures. Pre-committed consumption is found for geothermal energy. Finally, the welfare implications …

Digital Infrastructure For The Regenerative Movement: A Case Study Of The Mycelium Learning Network, Abigail Karparis

Journal of Nonprofit Innovation

The regenerative movement is gaining momentum worldwide, driven by communities working to restore ecological and social systems through place-based, culturally rooted action. Yet many of the groups leading this work, especially in the Global South or in hyper-local contexts, remain digitally invisible due to structural barriers, including limited access to appropriate technology, funding constraints, and misalignment between available tools and local values. Conventional digital infrastructures often exclude or marginalize these efforts, leaving regenerative practitioners disconnected from each other and from potential sources of support.

This article explores these challenges and presents a case study response: the co-creation of accessible, relational …

A Battle Of Armies: Massive Attack Of Natural Enemies To The True Armyworm Mythimna Unipuncta (Haworth, 1809) (Lepidoptera: Noctuidae) In Forage Crops, Armando Falcon-Brindis, Raul T. Villanueva

Insecta Mundi

Understanding the interactions between plant-host-parasitoid plays a major role in insect pest management. Farmers in the southeastern United States rely on pasture systems for cattle milk and beef production, but the benefits of parasitoids and predators on major lepidopteran pests on pasture lands are still overlooked. Here, we aimed to identify and quantify the effect of parasitism on the true armyworm Mythimna unipuncta (Haworth, 1809) (Lepidoptera: Noctuidae) attacking teff grass Eragrostis tef (Zucc.) Trotter (Poaceae) and crabgrass Digitaria sanguinalis (L.) Scop. (Poaceae) in western Kentucky. In early August of 2023, 547 larvae of M. unipuncta were collected from experimental …

The Link Between Environmental Change And Invasive Species, Marion Murray, Meg Kast

All Current Publications

Climate change and invasive species represent two pressing environmental challenges facing our planet. Each poses a threat to global biodiversity and ecosystem stability, and together, they amplify the impacts of the other. As global temperatures rise and ecosystems are disrupted, new conditions are created that allow invasive species to spread more easily, establish themselves in new areas, and outcompete native species.