Other Plant Sciences Commons^™

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 …

Evaluation Of Ultraviolet-C Light For Control Of Mites And Western Tarnished Plant Bug In Strawberry & Interactive Lethal Effects Of Common Strawberry Fungicides And Adjuvants On Phytoseiulus Persimilis, Colin T. Koubek

Master's Theses

California strawberry production relies heavily on chemical pesticides to manage arthropod pests and diseases, but pesticide resistance, regulatory pressure, and the need to conserve biological control agents have increased interest in alternative pest management tools. This thesis evaluated ultraviolet-C (UV-C) light as a nonchemical management tool for key strawberry arthropod pests and assessed the compatibility of common strawberry fungicides and adjuvants with the predatory mite Phytoseiulus persimilis Athias-Henriot. The first objective was to determine the ovicidal and lethal effects of UV-C light on Lygus hesperus Knight eggs and nymphs. Laboratory and field ovicide assays were conducted using UV-C doses relevant …

Developing Aero-Floating Treatment Wetland (Aeroftw) Scaffolds: A Non-Plastic Alternative To Conventional Plastic-Based Ftws, Ada C. Montoya Gomez

All Theses

This research was conducted to explore the possibility of constructing floating treatment wetlands (FTWs) without using plastic materials. FTWs are floating platforms that hold plants on the water’s surface, letting roots dangle within the water column, to help remove contaminants from contaminated water, especially in stormwater ponds. Many conventional FTWs are made with plastic components, such as mats and plastic cup containers, which can release microplastics into the environment over time. The goal of this project was to design and test a new type of FTW that does not depend on plastics to support FTW flotation. The study took place …

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 …

Evaluating Fungal Endophytes Inoculation As A Mechanism For Salt Tolerance In Juncus Roemarianus, Rani Badve

Honors Theses

Salinity stress is increasing in coastal and estuarine ecosystems due to increasing temperatures and the reduction of freshwater inputs via precipitation pattern changes. Elevated salinity can negatively affect plant survival, threatening the stability of coastal wetlands and the ecosystem services they provide. Juncus roemerianus is a common and dominant marsh plant in the Northern Gulf Coast that lives in varying salinities. Growing evidence suggests that root-associated fungal endophytes may contribute to enhanced stress tolerance; however, the response of fungal communities to salinity remains poorly understood.

This study evaluated how salinity influences the abundance and diversity of culturable root-associated fungal communities …

Succession And Alpine Plant Habitat Of A Recently Deglaciated Foreland In The Trinity Alps, California, Sebastian Evans

Cal Poly Humboldt theses and projects

The recent extinction of the Salmon Glacier in the Trinity Alps, California, provides a rare opportunity to examine post-glacial succession in a region of high endemism experiencing climatic stress. Using a chronosequence spanning ~150 years since deglaciation, I investigated (1) vegetation successional trajectories in the foreland, (2) whether the foreland functions as a climate refugium for alpine specialists, and (3) whether facilitative interactions between the dominant vascular plant (DVP) and bryophytes occur and persist through succession. I surveyed 100 plots across 11 transects within the foreland and 40 randomized plots in adjacent ecosystems. Successional patterns and refugial potential were analyzed …

Rewwild: Reimagining Environmental And Wildlife Wellbeing Through Innovative Lawn Design, Morgan J. Sandau, Maiya G. Roelen, Katia E. Chavez, Lydia K. Niedermeyer

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Manicured, monoculture lawns often dominate private land in urban areas for aesthetic organization. Colonialist roots are embedded in the history of turfgrass lawns and white-picket fences intended to suppress Indigenous knowledge and ways of caring for the diverse land around us. Private land misuse and homogenous lawns are not limited to the United States; the modern lawn contributes to biodiversity loss on a global scale. Humans are concentrated in cities across the world, and urban areas are known to have negative implications for wildlife and habitat, human health, and sustainable resource use. Management of private land in urban settings is …

Are There Enough Bees? Assessing Pollen Limitation In Native Eastern Washington Prairie Forbs, Alejandro Torres

EWU Masters Thesis Collection

Prairie ecosystems in eastern Washington have been severely degraded due to agricultural intensification, urbanization, and habitat fragmentation, leaving less than 0.1% of native prairie intact. As a result, these ecosystems have become some of the most endangered in the United States. One group of essential pollinators is the bees, which facilitate plant reproduction and contribute to the long-term persistence of restored plant communities. However, despite the presence of at least 257 native bee species in the region, the impacts of habitat fragmentation and restoration on pollinator activity and plant-pollinator networks remain poorly understood. For this study, we worked across Eastern …

Characterizing Gut Microbial Communities And Symbiont-Mediated Detoxification In Herbivorous Insects, Rachel C. Vargas

Biology Dissertations

Insect gut bacteria are vital contributors to host physiology, yet the broader prevalence and fitness implications of symbiont-mediated detoxification remain poorly understood. This thesis investigates these dynamics across three research chapters. Chapter 1 uses 16S rRNA sequencing to characterize how grasshopper gut microbial communities vary across species, dietary breadths, and gastrointestinal segments. Chapter 2 evaluates the detoxification capacity of over 150 bacterial isolates from diverse herbivores against the plant allelochemicals phenethyl isothiocyanate, rutin, and chlorogenic acid to determine if host dietary specialization predicts microbial metabolic ability. Finally, Chapter 3 employs fitness bioassays to test whether inoculating generalist herbivores with detoxifying …

Red Clover Isoflavones And Establishment In The Context Of Tall Fescue Toxicosis Mitigation In The Mid-South, Jonathan L. Stephens

Theses and Dissertations--Plant and Soil Sciences

Low levels of red clover (Trifolium pratense L.) have been shown to mitigate tall fescue (Lolium arundinaceum (Schreb.) toxicosis symptoms. This is because of the presence of plant-produced compounds known as isoflavones. Production of a red clover supplement on a commercial scale would require industrial-level processing of raw plant material into granules or pellets. The first study of this thesis evaluated the impact of drying temperature on bioavailability of isoflavones. Drying temperatures up to 104°C had minimal impact on isoflavone concentrations. Additionally, varietal differences in isoflavone concentrations were documented. The second study of this thesis evaluated optimal establishment …

Taxonomy Of Endophytic Fungi Associated With Vallisneria Neotropicalis, Md. Arafat Rashid

Graduate Theses and Dissertations (2019 - present)

This study presents the first comprehensive taxonomic and ecological investigation of endophytic fungi (EF) associated with the submerged aquatic macrophyte Vallisneria neotropicalis in the southern United States. Over a 12 month period, from April 2023 to March 2024, leaf samples were collected from two distinct sites in Mobile Bay, Alabama a disturbed, brackish Causeway location and a cleaner, less impacted site at Meaher State Park. Using culture dependent methods, a total of 257 fungal endophytes were isolated from 1,200 leaf segments. All isolates belonged to the phylum Ascomycota, distributed across 3 classes, 6 orders, 10 families, and 19 taxa. The …

Stand Strucuture Of Planted Stands In Storm-Water Retention Basins, Jason Lanza

Electronic Theses and Dissertations

Trees assist in stormwater retention basin functionality as efficient sources of water removal, and determining stand structure and leaf area of forests can be a measure of their effectiveness. The structure of forest stands on these basins managed for runoff mitigation has received little attention. We investigated the structure and species composition/diversity (tree and herbaceous) of planted, managed stands and naturally regenerated stands on stormwater retention basins managed by Harris County Flood Control District in Harris County, Texas. We determined stand structure variables (trees per hectare, basal area per hectare, quadratic mean diameter, relative density, average tree height, and percent …

Tree Story, Jia Hu

Masters Theses

What is Nature?

Nature is a system of intelligence. It means designing for efficiency—often by learning from strategies that have evolved over time. In my research, I use patterns to interpret and decode nature.

To explore nature, I began with the red cedar tree, aiming to simulate and predict its growth patterns—forms shaped by both internal biology and external forces. By analyzing its geometry, I sought to understand how trees embody the dynamic relationship between organism and environment. These patterns reveal the adaptive logic of life.

Patterns are central to understanding nature. While tree geometry may appear chaotic, it follows …

Lawn Nutrient Availability And Run-Off During Establishment Under Enhanced Biodiversity, Masami S. Kanyuk

Environmental Studies Honors Theses

Biodiversity has consistently been found to have positive ecosystem effects, including erosion mitigation and stability of nutrient cycling. For lawns, this can translate to reducing the need for fertilizer application, and reducing soil loss and leaching that can impact water quality. This paper investigates the effects of biodiversity and plant community establishment in a lawn ecosystem on soil erosion, nitrate leaching via porewater sampling, and plant available nitrogen.

In the first growing season of PLEDGE (the Pastures and Lawns Enhanced Drought and Global-Change Experiment), we hypothesized that three-species lawns (tall fescue, dwarf white clover, and creeping thyme) would experience higher …

Ms Environmental Biology Capstone: Evaluating Environmental Risks And Conflicts In Golf Course Landscapes, Meredith Boos

Regis University Student Publications (comprehensive collection)

1) This review investigates the relationship between pesticide use on golf courses and in agriculture to determine whether the adverse health effects documented in agricultural settings also apply to golf course environments. While the negative health effects from agricultural pesticide use are well established, golf courses use pesticides with greater frequency and intensity, suggesting a potentially higher exposure risk for both workers and players.

2) This study proposes methods to quantify pesticide bioaccumulation on golf courses and adjacent lands. We hypothesize that areas surrounding golf courses will exhibit a spatial gradient of pesticide accumulation, increasing with proximity to treated sites …

Place-Based Learning Practices: A Diptych Case Study Of Human And More-Than-Human Relationality At The Tribal And Western Academic Institutional Interface, Karley M. Rojas-Vienneau

Cal Poly Humboldt theses and projects

The ‘Place-Based Learning Practices Project’ is a graduate project under the Native American Studies Department Rou Dalagurr Food Sovereignty Lab and Traditional Ecological Knowledges Institute (FSL). Making contributions at the intersection of Western academia and Indigenous science, it imagines and realizes content, policies, and protocols surrounding two case studies and the larger cal poly humboldt (cph) institution which respect, honor, and uplift Indigenous sovereignty and resurgence in partnership with the Blue Lake Rancheria Tribe and the greater regional tribal community. Encompassing two projects internal and external to the institution, I aim to address the construction of controlled and protective environments …

Assessing The Potential For Bigleaf Maple Syrup Production In Humboldt County, Ca, David A. Reinhart, Juan A. Ramos-Cool, Liam H. Richardson

Undergraduate Scholarship

The bigleaf maple (Acer macrophyllum, Pursh) is the largest maple of the Pacific Northwest. While it has generally been treated as a nuisance in timber harvesting operations, a small amount of research has been conducted on its sugaring ability in Oregon, Washington, and British Columbia. This research has yet to reach further south in the species' range. This study aims to help a California landowner understand which maple trees on his property produce the most maple sap, to gauge what environmental factors contribute to maple sap production, and to find greater implications for the production of maple sap …

Foraging Opportunists: Encouraging Reconnection With The Land, Madelyne Miller, Sylvia Blodorn, Aine Fannon, Ada Scott, Luke Pruitt

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Contextualizing the history of opportunist and native plant species opens options for land management and reconnection to cultural land practices. By recognizing that opportunist species often spread as a result of relocation for practical usage, we determine that reintroducing these uses can lead to an escalation in harvesting these plants. Uses of opportunist plants are diverse and include food sources, artistic practices, and medicine. Foraging also leads to improved human-land-connectedness as well as a deeper connection to ancestral and cultural traditions, which has been found to improve mental health. Focusing on this method of land management will limit the need …

Best Management Practices: Sambucus Canadensis Propagation Techniques, Hannah Berendzen

Graduate Theses/Dissertations

American elderberry (Sambucus nigra ssp. canadensis) is a fruit-bearing shrub native to North America, traditionally utilized for medicinal and culinary purposes. In recent years, its popularity has surged due to emerging research supporting its immune-boosting properties. Despite its growing demand, standardized best management practices for elderberry cultivation, particularly propagation techniques, remain lacking. This study aims to clarify propagation recommendations by examining the influence cutting size and stem diameter on rooting success. A field study was conducted from February to May 2024, in which one-node and two-node dormant hardwood elderberry cuttings of varying stem diameters were planted in small …

Evaluating Impacts Of Footpaths On Resiliency Of Restored Dunes At Tybee Island, Georgia, Skyler J. Fox

College of Graduate Studies: Theses & Dissertations

Sand dunes provide critical ecosystem services including storm protection by acting as natural barriers. However, these systems are threatened by human disturbance, particularly pedestrian traffic occurring at footpaths that damages dune vegetation. Vegetation is essential to dune growth and stability, as dune plants trap and bind sand. When trampled, dunes become more vulnerable to erosion and less effective at providing coastal protection. On Tybee Island, Georgia—a popular tourist destination—a vegetated dune was constructed in 2020 to enhance storm protection. This study assessed how footpaths impact dune resiliency and aimed to inform management strategies. I evaluated: (1) how characteristics of vegetation, …

Salinity Effects On Cu(Ii) Bioremediation By Chlamydomonas Reinhardtii Microalgae, Jennifer Hughes

Honors Undergraduate Theses

Microalgae offer a sustainable approach to wastewater treatment by removing pollutants such as excess nutrients, CO₂, and heavy metals. Among various species, Chlamydomonas reinhardtii shows strong potential in removing Cu(II) ions from wastewater. In addition, salinity stress in C. reinhardtii has been linked to morphological and metabolic changes that enhance lipid and phytochemical production. While salinity stress has been studied for enhancing biofuel production, its impact on microalgal removal of heavy metals, particularly Cu(II), remains largely unexplored. Understanding how varying salinity conditions affect both algal growth and the efficiency of Cu(II) remediation could provide critical insights for improving integrated wastewater …

Re-Indigenizing And Collaboratively Tending Urban Greenspaces, Divinity Nnenne Adewale

University Honors Theses

This work details the active process of land tending with the intention of re-Indigenization in the Pacific Northwest at several Portland sites; The Native American Student Community Center, PSU Oak Savanna, and the Ridgefield National Wildlife Refuge. Land tending is an intuitive process, one rooted in love and respect for life of all forms as well as becoming the perpetual student; land tending is not a skill to be mastered, only practiced. Unlike environmental management, tending cannot be done separate from the earth, in a classroom or otherwise. Connections are what tending is built on top of: the foundation; effort …

Phytoplankton Responses To Changing Irradiance And Carbon Fertilization, Alison Siersma

Graduate Theses and Dissertations (2019 - present)

Phytoplankton play a crucial role in marine ecosystems due to their innate ability to fix carbon. As atmospheric CO2 levels continue to rise from fossil fuel combustion, the resulting increase in dissolved CO2 and the concurrent decrease in ocean pH are likely to impact the phytoplankton community. The response of phytoplankton to elevated CO2 can vary significantly among species and environmental conditions (e.g. light, temperature, nutrient availability). To address these variations, an experiment was conducted using a controlled photobioreactor system, maintaining high and low light, constant temperature, nutrient levels, and two pCO2 concentrations. This study focused on two regionally relevant …

Chinese Tallow Long-Term Impact On Stand Dynamics In A Bottomland Hardwood Forest Following Vegetation Management, Nicklaus R. Langlois

Electronic Theses and Dissertations

Chinese tallow (Triadica sebifera (L.) Small) is an invasive tree known to have negative impacts on bottomland hardwood forests. Chinese tallow is proficient in reproducing and surviving in bottomland hardwood forests because it is more flood and shade tolerant than most native trees. The long-term effectiveness of Chinese tallow control is an important topic to research as only a few long-term studies of Chinese tallow control have been conducted. A 10-year re-measurement of 22 paired plots installed in 2012 on the Pineywoods Mitigation Bank near Diboll, Texas following herbicide treatments examined Chinese tallow and native tree stand structure. Each …

Gps Accuracy Of Smartphones For Crowdsourcing Research, Derron L. Dike

Master of Science in Environmental Sciences and Management Projects

ABSTRACT GPS Accuracy of Smartphones for Crowdsourcing Research Derron Dike Utilizing crowdsourcing with smartphones as a method for field data collection can contribute an array of data for scientific studies and land management applications. This study used crowdsourcing to examine smartphone built-in GPS performance for providing location-specific information with potential forestry applications. The usability of smartphones for GPS data collection in forestry studies or other practical applications is dependent on the level of accuracy required for those applications. A Smartphone Accuracy Trial was designed to test the GPS accuracy performance of current smartphones. Participants used the ArcGIS Field Maps application …

Evaluation And Improvement Of The Design 4 Every Drop Course, Kenzy Fogle

All Graduate Reports and Creative Projects, Fall 2023 to Present

Utah and the greater Intermountain West are experiencing a water crisis. Many factors are contributing to this situation, including an arid climate exacerbated by climate change, rapid population growth, and a high-water-demanding landscape typology. Landscapes currently consume an estimated 60-80% of Utah’s potable water, representing a significant opportunity for water savings. However, changing the traditional water-dependent landscape typology requires educating the public regarding water-wise landscape design processes, best practices, and implementation approaches. Utah State University is the land grant university for Utah and home to one of the oldest Landscape Architecture departments in the Intermountain West. Utah State University’s community …

Impact Of Containment And Elevation On Created Marsh Plant Community And Ecosystem Dynamics, Kevin R. Stoner

LSU Master's Theses

Coastal marsh restoration is increasing globally, as marshes are impacted by anthropogenic impacts. Billions of dollars are allocated to marsh restoration in the Mississippi River delta where wetland loss rates are extremely high. The recovery of structural and functional attributes of created marshes varies by attribute measured and project. Here, two marshes created in 2018 and one natural marsh were used to examine how variations in hydrologic connectivity and marsh elevation influence subsurface hydrology and salinity, vegetation community structure, soil properties, accretion, and denitrification. I established a comparative field study in a created marsh contained within a higher elevation containment …

Characterizing The Quorum Sensing (Qs) System In The Model Eukaryote Chlamydomonas Reinhardtii, Kirstin Donnette Cutshaw

Theses and Dissertations

Group behaviors in microorganisms are often regulated by low-molecular weight molecules that enable them to sense population density, a signaling system known as quorum sensing (QS). QS in prokaryotes has provided insight into the role ‘social’ behaviors play in the bacterial world and refined our models of virulence, bacterial motility, and more. While less common, similar behaviors are observed in certain fungi, primarily yeasts, in which QS controls cell morphology, biofilm production, and other phenotypes. We have recently pursued the potential for QS to be more broadly distributed among unicellular eukaryotes, which could significantly alter our understanding of social behaviors …

Flower Study, Haven Hinds

Undergraduate Theses, Capstones, and Recitals

This project is a study into extinct flowers, their histories, environments, biology, colors, and assigned personalities then manifested in 3D models and a digital book. The goal was to select six flowers with interesting histories and or cultural connections. Since the flowers can, for the most part, not be seen or kept they were created in Blender as accurately as possible. To give people a means of connection with the flowers, each was assigned a personality based on different factors. These factors could be the colors they possess, where geographically they thrived, parts of their history, and biological factors. To …

The Influence Of Stage Of Ripeness On Consumer Perceptions Regarding Selected Aspects Of Non-Astringent Asian Persimmons (Diospyros Kaki Thunb), Robert A. Mirabello Jr

LSU Doctoral Dissertations

Asian Persimmon (Diospyros kaki Thunb.) is an important fruit crop in Asia and in recent decades has experienced expanding production around the world. Non-astringent cultivars are highly desirable in world markets. In the United States the Asian Persimmon is lesser known and consumed although it can be successfully grown in California and the Southeastern United States.This novel study examined the physical/chemical properties of the non-astringent Asian Persimmon ‘Jiro’ grown in Southern Louisiana at three distinct stages of ripeness described as Green (mid-September harvest), Light Orange (mid-October harvest) and Dark Orange (mid-November harvest). Data collected included color, weight, size, soluble …