Life Sciences Commons^™

Seagrass Preference Among Pinfish In The Lower Laguna Madre, Nathaniel Garza

Theses and Dissertations

Pinfish (Lagodon rhomboides) is a common estuarine fish species found from Massachusetts to the Yucatan, Mexico. As juveniles, pinfish spend a significant portion of their life in coastal seagrasses which provide both shelter from predators and food. Along the Texas coast, there are three major species of seagrass- turtle grass (Thalassia testudinum), manatee grass (Syringodium filiforme) and shoal grass (Halodule wrightii) that differ in structural complexity. The goal of this study was to determine if pinfish associate more with one seagrass species than the others. A year-long field study was completed using twelve sample sites in the Lower Laguna Madre, …

Investigating Mariculture-Associated Ecosystem Services Across The Northern Gulf Of Alaska, Josianne Haag

Oceanography

The rapid expansion of mariculture in Alaska can drive physical and chemical alterations to the marine environment by introducing non-native organisms or artificially increasing the biomass of a native species. Currently, the main mariculture products grown in Alaska include the Pacific oyster (Crassostrea gigas), the Pacific blue mussel (Mytilus trosuslus), and three macroalgae species: ribbon kelp (Alaria marginata), sugar kelp (Saccharina latissima), and bull kelp (Nereocystis luetkeana). This dissertation examines how these species can impact their surrounding environment to better inform management practices for this growing industry. This research characterized the resource use of C. gigas and M. trossulus seasonally …

Right Place, Right Time: Intermittent Habitats And Mosaic Structure Drive Juvenile Coho Salmon Growth In A Subarctic Alaska Watershed, Andrew Rothenberger

Fisheries

Pacific salmon (Oncorhynchus spp.) rely on diverse freshwater habitats to complete their lifecycle. Within Alaska’s short summer season, juveniles use a complex mosaic of habitats that vary in quality across space and time, but the patterns of habitat use in large complex watersheds are poorly known and difficult to document. To evaluate how habitat conditions of hydrology types influence juvenile performance, I conducted an in-situ enclosure experiment in the Fox River watershed of Kachemak Bay, Southcentral Alaska, measuring age-0 coho salmon (Oncorhynchus kisutch) growth across four hydrologic types: a glacial and snow-fed natal creek, a groundwater-fed natal creek, a non-natal …

Environmental Change In The Northeast Pacific: Climate Impacts On Phenology, Life History, And Population Dynamics In Marine And Aquatic Populations, Genoa Sullaway

Fisheries

Climate change is rapidly transforming Northeast Pacific ecosystems and fundamentally altering environmental conditions that drive species' survival, growth, and life histories. This dissertation examines relationships between environmental change and population-level processes across Northeast Pacific marine and freshwater ecosystems. This dissertation focuses on understanding the influence of environmental change on foundational zooplankton communities in the Bering Sea and Pacific salmon populations, specifically Yukon River Chum salmon and Bristol Bay Sockeye salmon. This research addresses knowledge gaps in zooplankton systems modeling, zooplankton phenology, and salmon population dynamics. First, this dissertation evaluated the performance of a systems model that utilizes climate and physical …

Plant Community Responses To Wildfire, Timber Thinning, And Bison Reintroduction On The Northern Great Plains, Ethan H. Van-Derpoel

All Theses

The Northern Great Plains (NGP) is one of the largest intact grasslands remaining in the world. These two studies examine a few of the ecological concerns on the NGP today. First, the woody encroachment of conifers into grasslands and the effects of wildfires. Second, the effects of bison (Bison bison) reintroduction on plant communities. In Chapter 1, this study aims to examine the effects of wildfire and mechanical timber thinning, using a two-by-two factorial design, on plant community responses and forage quality in the Bull Mountains area of central Montana, USA. We found that our treatments had varying …

Soundscapes Of Alaska's Arctic Coastal Plain: Implications For Wildlife, Maxwell Plichta

Biological Sciences

Passive acoustic monitoring is an effective tool for collecting baseline acoustic data in remote locations and for advancing our understanding of soundscapes, the sound that emanates from a landscape. Terrestrial Arctic soundscapes remain understudied. The Arctic Coastal Plain (ACP) of northern Alaska is an ecologically, culturally, and economically significant region, containing a mix of land-uses and management practices. This study leverages a spatially large (~8,000 km2), multi-year dataset of acoustic recordings and paired images collected across the ACP to investigate how natural and anthropogenic factors influence the soundscape (Chapter 2), and how acoustic metrics influence the behavior of caribou (Rangifer …

Testing For Local Adaptation In Sympatric Monkeyflowers Growing In Serpentine Seeps And Adjacent Rock Outcrops, Avin Niknafs

Master's Theses

Divergent selection across heterogeneous environments can drive ecological differentiation and the evolution of locally adapted populations, even when gene flow occurs. We tested for local adaptation between two sympatric monkeyflowers, Erythranthe guttata and E. serpentinicola (formerly Mimulus), which co-occur on the central coast of California. Erythranthe guttata is a perennial species primarily found in moist serpentine seeps, whereas E. serpentinicola is an annual species restricted to adjacent serpentine rock outcrops. Using a reciprocal transplant experiment with second-generation, greenhouse-derived seed, we quantified germination, survival, and reproductive success across contrasting microhabitats. We further evaluated the relative contributions of species, lineage, …

Robustness Of Network Inference Algorithms Under Network Class Misspecification, Roberto Ceja

Electronic Theses, Projects, and Dissertations

Inferring phylogenies in the presence of hybridization remains a difficult problem. As a result, many current methods for reconstructing phylogenetic networks are restricted to a simple class of networks known as level-1. This restriction arises from theoretical considerations rather than empirical evidence, with real data possibly arising from complex networks. In this work, we evaluate the robustness of two level-1 network inference methods, SNaQ and NANUQ+, through a simulation study, when the input data originates from a more complex network. Specifically, we investigate whether these methods can accurately recover important features of the true species network, such as the circular …

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 …

Spotted Seal Coastal Haul Out Behavior In Arctic Alaska, Maeghan Connor

Biological Sciences

Hauling out - the act of exiting the water to rest, molt, breed, and pup on solid surfaces - is a key behavior of pinnipeds worldwide. Unlike other ice seals (i.e., ice-associated phocid species), spotted seals (Phoca largha) in Alaska frequently use terrestrial substrates to haul out during the summer and fall open-water period in the Chukchi and Beaufort Seas. Despite being a core aspect of spotted seal ecology, their terrestrial haul out behavior remains understudied. To address this, we analyzed data collected from 2020 - 2022 near two known haul out sites in Dease Inlet, Alaska, including time-lapse camera …

Exploring Phenological Mismatch And The Role Of Aquatic Insects For Olive-Sided Flycatchers (Contopus Cooperi) Breeding In Boreal Alaska, Ian Kwit

Biological Sciences

Migratory insectivorous birds are an increasingly threatened group worldwide. These birds rely on an ephemeral resource of insects during a short window in which they arrive at breeding territories to rear young. Climate change has the potential to create a phenological mismatch between the timing of bird breeding and the availability of key insect prey. This study investigates the potential for such a phenological mismatch in a population of olive-sided flycatchers (Contopus cooperi). We used data on breeding phenologies and the composition of insect communities around nests in three regions of Alaska, Anchorage, Fairbanks, and Tetlin National Wildlife Refuge, to …

The Ecology Of Arthropod Rain In A Tropical Forest., Andrew Robert Seiler

Electronic Theses and Dissertations

Tropical forests are structured by complex vertical linkages and nutrient exchanges between canopy and understory habitats. These linkages include the downward flux of organisms, the movement of canopy fauna, and the recycling of nutrients through litter and organic matter deposition. This dissertation investigates arthropod rain and its role in connecting the canopy and forest floor processes in a lowland tropical forest in Panama. Chapter 2 quantifies “arthropod rain”, the fall of canopy arthropods into the understory. Using pan and pole traps, I measured the composition, abundance, and biomass of arthropods falling from the canopy and assessed environmental drivers of the …

Population Genomics Of Pacific Herring Spawning Aggregations In The Eastern Bering Sea, Sydney A. Almgren

Fisheries

Pacific herring (Clupea pallasii) is a critical forage fish to the marine environment, economy, and culture of Alaska. However, despite the importance of Pacific herring in Alaska and throughout the North Pacific, knowledge gaps exist for foundational genomic characteristics of the species, including genetic population structure and the basis of genetic sex determination. In this thesis, I addressed these knowledge gaps using low coverage, whole genome sequencing. I assessed population structure and genetic diversity across seven sampling sites and found three genetic populations: Unalaska, the farthest south sampling location, Kotzebue, the farthest north, and a third group unassociated with geographic …

Margalefidinium Polykrikoides Group Iii Va, Usa Strain Growth And Sac-Like Pellicle Cyst Dynamics, Eduardo Pérez Vega

OES Theses and Dissertations

Margalefidinium polykrikoides is a harmful cosmopolitan dinoflagellate that blooms in coastal waters. The effect of temperature and salinity on the growth of M. polykrikoides VA strain was examined using microscopy and growth models. M. polykrikoides Group III VA strain grew better at warmer temperatures and lower salinities than M. polykrikoides Group III NY strain, Group I Korea strain, and Japan strain (unknown group). Modelers need to use the temperature and salinity growth responses from M. polykrikoides Group III VA strain to better simulate and predict M. polykrikoides blooms in the Chesapeake Bay.

Dinoflagellates produce cysts as a strategy to withstand …

Ogallala Fall Field Days, Janis Paseka

Nebraska Bird Review

The 2025 NOU Fall Field Days were held in Ogallala on September 26–28, with about 80 in attendance. The programs were held at the Quality Inn, and the meeting was planned by Boni Edwards, Dave Cunningham, and Paul Pearson. Field trips were led by Tobin and Keegan Brown, Jacob Cooper and UNK ornithology students, Joel Jorgensen and Stephen Brenner, T. J. Walker, and Thane Dinsdale. Destinations included various sites around Lake McConaughy, Lake Ogallala, Cedar Point Biological Station, Sutherland Reservoir SRA, Ash Hollow State Historical Park, Crescent Lake NWR, Arthur Co and various Sandhills lakes. The total species count was …

Integrating Manager Perspectives Into The Evaluation Of Wetland Revegetation Strategies, Loren F. Taylor

All Graduate Theses and Dissertations, Fall 2023 to Present

Ecological restoration is the process of assisting the recovery of an ecosystem that has been degraded and is dependent on complex and context-specific decisions. The decision-making process influencing restoration is rarely examined alongside ecological processes. There is a need for research that incorporates the social, economic, institutional, and logistical considerations that shape real-world practices, as well as ecological processes. Decisions made by restoration practitioners and land managers (hereon “manager”) are challenged by the lack of information shared regarding the practical constraints (e.g., cost, labor, specialized equipment) they face. Revegetation, particularly in wetlands, poses challenges due to site conditions and degradation …

Impacts Of Halophila Stipulacea Invasion On Organic Matter Dynamics In Thalassia Testudinum Dominated Seagrass Meadows, Puerto Rico, Jonathan D. Herald

Master's Theses

Halophila stipulacea (Forsskål & Niebuhr) is a tropical seagrass native to the Red Sea, Persian Gulf, and Indian Ocean. In 2002, invasive populations of H. stipulacea were identified in the Caribbean Sea where it now forms large meadows, displaces native seagrasses, alters invertebrate and fish communities, and potentially affects organic matter dynamics in invaded meadows. This study investigated differences in organic matter dynamics between meadows of H. stipulacea and native Thalassia testudinum within the Jobos Bay National Estuarine Research Reserve (JBNERR) on the southern coast of Puerto Rico. From March 2023-March 2024, sampling was conducted across four sites to investigate …

Effects Of Urbanization On The Population Genetics And Morphology Of The White-Footed Mouse (Peromyscus Leucopus) Across An Urban–Rural Gradient, Sydney A. Morton

Master's Theses

Urbanization alters landscapes in ways that can reshape wildlife populations by changing habitat connectivity, resource availability, and selective pressures. To investigate how urbanization influences both genetic differentiation and morphology in small mammals, I examined Peromyscus leucopus (PELE) across an urban–rural gradient in northern Georgia. Using RADseq SNP data from PELE individuals across 13 sites, I quantified pairwise genetic differentiation (F_ST) and tested how various environmental variables, including impervious surface cover, human population density, and tree canopy cover, predict genetic differentiation after accounting for geographic distance. Genetic differentiation increased with geographic distance and, after controlling for isolation by …

Multiple Aspects Of Environmental Temperature Have Complex Interactions With Avian Parental Behavior To Influence Offspring Outcomes, William H. Kirkpatrick

Graduate Theses and Dissertations

Anthropogenic climate change is projected to shift not only average temperatures across the globe, but also the amount of thermal variation experienced in the natural environment. Exposure to shifts in averages and a wider range of thermal experiences will cause shifts in wildlife behavior. In avian species, behaviors exhibited during reproduction have implications for the well-being of their offspring. Here, I explore specific incubation behaviors in four species: Scaled Quail (Callipepla squamata), Northern Bobwhite Quail (Colinus virginianus), Tree Swallows (Tachycineta bicolor), and Eastern Bluebirds (Sialia sialis). I examined constancy, or the percentage of time on the nest, and off-bout duration, …

What Limits Dryland Ecosystems? Patterns Of Soil Fertility And Resource Limitation In The Chihuahuan Desert, Dylan Stover

Open Access Theses & Dissertations

Human activities are substantially altering global resource cycles with widespread implications for biogeochemistry and ecosystem functioning globally. Drylands, regions where precipitation is outweighed by water losses, are especially sensitive to these large shifts in resource cycles due to their inherently low and variable resource availability. In these regions, resource availability and biological activity are often concentrated around plants – or fertile islands – and predominantly driven by pulses of water. However, our knowledge of the processes influencing biological productivity in drylands – patterns of soil fertility and resource limitation – remains lacking, and their unique biogeochemical and biological processes create …

Drivers Of Faunal Communities In Isolated Wetlands: Local And Landscape Determinants Of Assemblages, Joshua Holbrook

All Dissertations

Ecological interactions such as predation are vital to shaping the distribution of organisms. For interactions to occur, organisms must undertake movement, such as dispersal, that places them in proximity to the organisms with which they may interact. Geographically isolated wetlands (GIW) are productive and biodiverse ecosystems, but little is known on broad geographic scales about the determinants of their fauna. Fishes have difficulty colonizing GIW, whereas amphibians and macroinvertebrates are adept overland dispersers – though they may be sensitive to top-down control by fishes. To better understand these phenomena, I sampled 10-20 wetlands each at nine regions in North and …

Exploring Life History Trade-Offs In The Facultative Eusocial Bee Megalopta Genalis, Ana Gutiérrez Zuluaga

All Graduate Theses and Dissertations, Fall 2023 to Present

Organisms face many trade-offs in how to invest in these traits. One example is the trade-off between reproduction and longevity. Queens of social insects seem to escape this trade-off, producing thousands of eggs daily, despite having a longer lifespan than their workers. Some hypotheses have been proposed to explain this phenomenon, such as an evolutionary change in the molecular pathways that regulate queen investment in maintenance, growth, and reproduction. An alternative hypothesis suggests that the tradeoffs are rarely observed in queens due to the extensive resources provided by the help of workers. While these hypotheses have supporting evidence, they have …

Golden Eagle Predation Of Greater Sage-Grouse On Diamond Mountain Plateau, Victoria E. Thorpe

All Graduate Theses and Dissertations, Fall 2023 to Present

Predation and the perceived risk of predation can have major impacts on prey populations. Golden Eagles are considered one of the main predators of adult greater sage-grouse. Sage-grouse populations have been declining for decades throughout the West and wildlife managers are concerned about the impacts of golden eagles on sage-grouse. We investigated the nonconsumptive effects of golden eagles on sage-grouse by conducting observational surveys for golden eagles, sage-grouse, and other predators at sage-grouse lek sites near Vernal, Utah during the sage-grouse breeding season from 2022–2024. Additionally, we examined the prevalence of sage-grouse in golden eagle diet using DNA metabarcoding of …

Explaining The Association Between Kittlitz's Murrelets (Brachyramphus Brevirostris) And Tidewater Glaciers: Which Habitat Factors Influence Spatial Distribution?, Brendan Higgins

Marine Biology

The Kittlitz’s Murrelet (Brachyramphus brevirostris) is a rare and cryptic seabird species that inhabits Alaska and Eastern Siberia. Populations of Kittlitz’s Murrelets that occur in areas with tidewater glaciers are tightly associated with tidewater glaciers and are only found in close proximity to them. The Kittlitz’s Murrelet is a species of conservation concern, but specific habitat associations are poorly understood. I conducted a multidisciplinary investigation to better understand associations between Kittlitz’s Murrelets and tidewater fjord physical structure. I used remotely sensed spectral indices to model change in abundance of suitable nesting habitat, and a long-term oceanographic dataset to quantify changes …

Organic Matter Sources And The Seasonal And Spatial Trophic Dynamics In Arctic Lagoon Food Webs, Sydney Wilkinson

Marine Biology

The rapid loss of sea ice, warming waters, and increasing freshwater inputs are altering Arctic coastal lagoons, ecosystems that support diverse invertebrate communities, fishes, and subsistence harvests. To resolve how trophic interactions in these systems function under strong seasonal and spatial variability, I applied multiple biochemical tracers, specifically bulk δ13C and δ15N, compound-specific stable carbon isotopes of essential amino acids, and fatty acids to characterize organic matter sources and better understand the trophodynamics of benthic invertebrates and fishes in Beaufort Sea lagoons. I first established local biomarker baselines for terrestrial, microalgal, and macroalgal producers, showing that no single tracer could …

Decision Support To Meet Objectives For Water And Fisheries Management In Large River And Estuarine Systems, Phaedra Elizabeth Budy

Funded Research Records

No abstract provided.

Immunological Surveillance Against Cancer Across Mammals, Orsolya Vincze, Piotr Minias, Alexandre Corthay, Fernando Colchero, Jean-François Lemaître, Louise Maille, Tamás Malkócs, Justus Hagemann, Dalia A. Conde, Samuel Pavard, Antoine M. Dujon, Beata Ujvari, Frédéric Thomas, Amy M. Boddy, Carlo C. Maley, Damien Chevallier, Tuul Sepp, Thomas Pradeu, Mathieu Giraudeau

Presidential Fellows Articles and Research

Contrary to expectations based on their higher cell numbers, larger and longer-lived species do not face dramatically increased risk of cancer. This strongly suggests that evolution has fashioned natural cancer resistance mechanisms, yet our knowledge remains limited on what these mechanisms might be. The cancer immunological surveillance hypothesis, proposed by Burnet and Thomas in the 1950s, highlights immunity as a key factor determining species-specific cancer resistance. Here we address the original, evolutionary interpretation of this hypothesis by investigating the relationship between cancer mortality risk and markers of efficient antigen presentation. Our results show that the expansion of the MHC class …

The Effect Of Noise Pollution On The Diversity And Abundance Of Bird Species At Different Locations At Warner Parks, Nashville, Tn, Jeremy T. Little, Wyatt L. Fooks, Darlene Panvini, Jackson Whiteside

Science University Research Symposium (SURS)

Noise pollution is a significant abiotic factor that can alter bird biodiversity and abundance of birds in urbanized areas. A new road is proposed through a relatively untouched area of Warner Parks in Nashville, TN, which may affect the bird community. Acoustic Song Meters were used to monitor bird sounds and soundscapes in the proposed road site and two areas of the park with different levels of noise pollution (roadside=high noise; isolated=low noise) for three weeks. Recordings were analyzed to determine bird species and abundance at each site to predict how increasing noise pollution may affect bird diversity in the …

Surviving The Seasons: Climate And Time Effects On Native Songbirds, Essence Donaldson, Todd Hoskinson, John Niedzwiecki

Science University Research Symposium (SURS)

Bird populations across North America have declined sharply in recent decades due to habitat loss, climate change, and changes in food availability. As bird numbers fall, ecosystems lose essential pollinators, seed dispersers, and insect predators. Long-term monitoring of bird populations is vital for understanding how environmental changes influence their survival and abundance. This study examines capture data from a long-term bird banding station at Percy Warner Nature Center in Nashville, Tennessee, focusing on five native species: Northern Cardinal (NOCA), American Robin (AMRO), American Goldfinch (AMGO), Tufted Titmouse (TUTI), and Carolina Chickadee (CACH), from fall 1983 to fall 2023. We analyzed …

Macrophyte Community Analysis Of The Tennessee-Tombigbee Waterway, The Pearl River, And The Pascagoula River, Samuel A. Schmid, Nicholas J. Engle-Wrye, Gray Turnage

Research Data

The macrophyte Tennessee-Tombigbee Waterway, Pearl River, and Pascagoula River were surveyed using point surveys. Data collected from these surveys were used to determine differences in species composition among macrophyte communities, how latitude affected species richness, and how the presence/absence of introduced species was affected by native richness. Differences in species composition were measured using NMDS, and the latitude-richness and introduced-native relationships were modeled using linear modeling methods. This record includes the data and code used for these analyses.