Life Sciences Commons^™

The Perfect Pairing: Early Stand Dynamics In Conventional Aspen And Mixedwood Forests In Northern Minnesota, Usa, Chelsea C. Semper, John M. Zobel, Sawyer S. Scherer, Michael R. Reinikainen, Matthew B. Russell, Tyler S. Gifford, Marcella A. Windmuller‑Campione

Aspen Bibliography

In North America, mixedwood management is being increasingly considered by natural resource managers as an alternative to single species management for a variety of ecological, economic, and cultural reasons. In northern Minnesota, USA, natural resource managers are increasingly using treatments to establish mixedwood forests in aspen (Populus tremuloides Michx, Populus grandientata Michx) dominated ecosystems by planting white spruce (Picea glauca (Moench). However, little quantitative information is known regarding differences between stand structure and composition in conventional aspen and aspen-white spruce during early stand development. To provide greater clarity for managers, we sampled 40 aspen stands across a chronosequence …

Crayfish Microhabitats Provide A Close Association With Benthic Microbiomes To Support Cleaning Symbionts., Kyle J. Harris, John Hoverson, Matthew Becker, Matthew M. Cooke Mr

NEXUS: The Liberty Journal of Interdisciplinary Studies

Stream ecosystems promote variable microhabitats along a longitudinal gradient. These microhabitats support dynamic biotic assemblages. One such microhabitat in freshwater streams involves the external surface of crayfish. We investigated the microbiome of crayfish exoskeletons and the surrounding environment (water and substrate) in association with the presence and abundance of crayfish cleaning ectosymbionts (branchiobdellidans). These ectosymbionts actively consume the biofilm on crayfish as they live and reproduce in association with crayfish microhabitats. Sequenced microbes of the environment and crayfish were compared for dominant taxa. While the sample types (water, substrate, and crayfish) had significantly different microbiomes, there was not a significant …

Using Stomach Content Analysis To Determine The Trophic Ecology Of Omosudis Lowii, A Deep-Sea Predator In The Gulf Of Mexico, Claire De Noyo

USF Tampa Graduate Theses and Dissertations

Little is known about the feeding dynamics of deep-sea communities, despite their significant ecological importance. Deep-pelagic communities contribute to marine biodiversity and ecosystem stability while directly offsetting climate change via carbon sequestration. Omosudis lowii is an understudied, deep-sea fish found in temperate and tropical waters worldwide, including the Gulf of Mexico. Omosudis lowii have large jaws and distensible stomachs, allowing them to capture prey items larger than their body size. The present seminal study used stomach content analysis to quantitatively describe the O. lowii trophic ecology, providing baseline data regarding diet composition, feeding selectivity, and factors that impact prey selection. …

Exploiting Genomics To Advance Genetic Gain For Reproductive Traits In Sheep, Mujibur Rahman

ORBioM (Open Research BioSciences Meeting)

Poor reproductive performance has a negative impact on the profitability of sheep production systems with the number of lambs reared highlighted as a key driver of farm profitability. Nevertheless, the genetic improvement of reproductive traits in sheep has been constrained by their low heritability and pleiotropic nature. Understanding the underlying genetic architecture can improve genomic prediction estimates and enhance genetic gain.

This study will utilize large-scale genomic and phenotypic datasets to enhance genetic gain in sheep reproductive traits through four approaches: 1) to determine the effect of inbreeding depression on reproduction, 2) to identify causal variants impacting reproductive performance through …

Analyzing Human - Nonhuman Primate Conflict Mitigation Techniques In Mto Wa Mbu, Northern Tanzania, Lil Adams

Undergraduate Theses, Capstones, and Recitals

Human-wildlife conflict is a widespread challenge faced by those living in regular contact with wildlife that can have profound impacts on livelihood outcomes for humans, wildlife, and their shared environment (Barua et al., 2013; Blackie, 2023). Human – non-human primate conflict is particularly crucial due to primates’ high capacity to live among human populations (Chapman & Chapman, 1990; Alberts & Altmann, 2006; Reader et al., 2011; Sinha & Vijayakrishnan, 2017), and is currently on the rise due to increasing contact between human and non-human primates (Hockings, 2016; Uddin et al., 2020). To characterize and analyze techniques currently being used to …

Evolutionary Dynamics Of Artificial Agents: Exploration And Learning In Games, Brian Mintz

Dartmouth College Ph.D Dissertations

The natural world abounds with examples of complex behavior in humans and many other species. Evolutionary game theory is a powerful mathematical framework to understand the origins of many such behaviors like cooperation. Since these behaviors are often selected against initially, understanding why they are so widespread has been a longstanding question. Rather than assuming agents' rationality, like in traditional game theory, this approach studies the mutation and selection of strategies themselves. However most behavior is neither perfectly rational nor entirely determined by genetics. This dissertation works to bridge the gap between these two perspectives by analyzing models where individuals …

More Equal Than Others: Taxonomic Bias In Animal Management, Barrett L. Christie

Animal Sentience

Oldfield & Bonano (2024) point out not only the scarcity of research on fish welfare but also significant taxonomic bias in broader research on these species. This bias extends to the management practices of aquaria and zoos, where the focus is on higher vertebrates. More resources need to be allocated to research to address this disparity. We also need to develop welfare constructs that recognize the inherent differences between aquatic and terrestrial species, taking into account the unique ecological contexts and behavioral patterns of fishes.

Influence Of Increasing Fires On Mixed Conifer Stand Dynamics In The U.S. Southwest, Simon D. Baker, Kristen M. Waring, David Auty, Nicholas Wilhelmi

Aspen Bibliography

(1) Stand-replacing fires may threaten the continued stability of mixed conifer forests in the U.S. Southwest. Increasing fire frequency and severity have made post-fire forest recovery trajectories uncertain for many coniferous species, potentially leading to long-term shifts in forest structure and composition. (2) The purpose of this study was to examine post-fire stand dynamics over a 10-year period, using a network of permanent plots established prior to wildfire events across Arizona and New Mexico. We assessed changes in over story composition, regeneration, and fuel loading across different fire severities. (3) High severity fire caused near-total over story mortality, with little …

Bat Occurrence And Microclimatic Conditions Of The Sima Del Órgano Cave, Mexico, Luis A. Hernández, Jaime E. Gómez, Cyntia Reyes

International Journal of Speleology

Caves represent an important type of shelter for many species of bats, particularly in karstic regions. In Mexico, about 60 bat species regularly use caves as roosts. The microclimate of a cave is a key component of the overall cave ecosystem. So, an adequate microclimate can minimize the energetic costs of bats associated with thermoregulation, gestation, embryonic development, parental care, lactation and social interaction. Cave environments are among the least known and most threatened on the planet, which is why we aimed to determine the monthly occurrence of bat species in the Sima del Órgano Cave, estimate the population size …

Experiments To Enhance Post-Fire Aspen Seedling Survival And Growth, Larissa L. Yocom, Mark R. Kreider, Owen T. Burney, Tammy Parsons, Ryan T. Choi, Emily K. Liese, Karen E. Mock

Aspen Bibliography

Aspen forests provide wildlife, watershed, and aesthetic value, and the potential for reduced fire occurrence, behavior, and severity. There is interest in planting aspen to achieve various management objectives. However, few studies have investigated the optimal conditions for aspen seedlings in the western US. We conducted two experiments to address this knowledge gap. First, we tested the effects of shading structures (i.e., logs) and biochar on the survival and growth of 960 outplanted aspen seedlings in three exclosures in a recent fire footprint. Second, we tested whether experimentally placing logs near 120 naturally-occurring post-fire aspen seedlings affected survival or growth. …

Colonization-Persistence Trade-Offs In The Human Microbiome, Liam F. Nokes

Environmental Studies Senior Theses

Understanding how diverse microbial taxa coexist in the human body without competitively excluding one another remains a key challenge in microbiome ecology. One proposed explanation is the colonization-persistence trade-off, where species with high colonization ability are poor persisters, and vice versa. We test for this trade-off across human associated microbial communities among many individuals and in multiple body sites using a large-scale participant-level meta-analysis of longitudinal microbiome datasets curated from the MGnify database. We applied island biogeography-based models to calculate effective colonization and persistence rates for microbial families and genera across 606 individuals over twenty-six studies. Regression of the log-transformed …

Distribution And Habitat Use Of Sounders Gray Whales From 1990 To 2023, Sara N. Mach

Honors Projects

Abstract: Every spring, a small subgroup of gray whales (Eschrichtius robustus), referred to as “Sounders,” migrate to northern Puget Sound (NPS), Washington State, to forage on small crustaceans, particularly during years of low prey availability in the Arctic, the primary foraging habitat for gray whales. In contrast to gray whales in other locations, Sounders primarily forage on ghost shrimp (Neotrypnea californiensis) while in NPS. These small crustaceans live in the sediment in the intertidal to shallow subtidal zones, so gray whales must wait for higher tides to feed. Gray whale abundance in NPS and time spent …

Patterns Of Late Holocene And Historical Extinctions On Madagascar, Laurie R. Godfrey, Zachary S. Klukkert, Brooke E. Crowley, Robin R. Dawson, Peterson Faina, Benjamin Z. Freed, Evon Hekkala, Cortni Borgerson, Harimanjaka A. M. Rasolonjatovo, Patricia C. Wright, Stephen J. Burns

EKU Faculty and Staff Scholarship

Around 1000 years ago, Madagascar experienced the collapse of populations of large vertebrates that ultimately resulted in many species going extinct. The factors that led to this collapse appear to have differed regionally, but in some ways, key processes were similar across the island. This review evaluates four hypotheses that have been proposed to explain the loss of large vertebrates on Madagascar: Overkill, aridification, synergy, and subsistence shift. We explore regional differences in the paths to extinction and the significance of a prolonged extinction window across the island. The data suggest that people who arrived early and depended on hunting, …

Changes In Morphology, Phenology, And Demography Of Several Avian Species Over 18 Years At A Restored Grassland, Ashley Mcmahon, Katie Stumpf

Georgia Journal of Science

In response to a changing climate and the loss of habitat, avian species are displaying changes in body size, migration phenology, and demography. Several species have adhered to Allen’s and Bergmann’s rules by displaying increased wing length and decreased mass, respectively, over time in response to higher temperatures. Climate change has also resulted in earlier spring migration and depending on species, either earlier or later fall migration. Finally, species affected by habitat loss often display male-skewed sex ratios and juvenile skewed age ratios. Our goal was to determine how body size, migration phenology, and demography have changed for grassland birds …

Prescribed Fire Leads A Pine Flatwoods Specialist Tree Frog To Seek Local Refugia, Ian Biazzo, Pedro F. Quintana-Ascencio

Faculty Publications

Pine savannas of the southeastern United States evolved with frequent low-intensity wildfires. Today, land managers use prescribed fires to restore this ecological process while also controlling vegetative fuel accumulation. Given the ubiquitous application of this management tool, studies should consider impacts on target and nontarget taxa in these systems. During fires, animal populations persist in the landscape when individuals emigrate to unburned areas or seek refugia within the burn zone; otherwise, they experience local extirpation. We examined the effect of prescribed fires on a pine flatwoods specialist frog, the pinewoods treefrog Dryophytes femoralis, in a frequently burned pine landscape. …

Allelopathy Of Western Red Cedar, Douglas Fir, And Western Hemlock On Seed Germination, Lainey E. Mendoza Ms.

Honors Projects

Understanding the allelopathic interactions of native Pacific Northwest conifers, Douglas Fir, Western Hemlock, and Western Red Cedar is crucial to understanding the interactions of each species within their ecological niche. As of now there is little research on allelopathy of PNW conifers, specifically how different damaged states of the conifer tissue could impact the germination rates and radicle growth of a model organism. Analyzing these allelopathic interactions may be crucial to help predict forest regeneration of the PNW in the future. Presented here is the analysis of Douglas Fir, Western Hemlock, and Western Red Cedar tissue that is undamaged, damaged, …

The Ecophysiology Of The Enigmatic Namib Succulent, Lithops Ruschiorum, Garrett Macleod Althausen

Environmental Studies Senior Theses

Water availability is the primary constraint for plant survival and reproduction in hyper-arid ecosystems. In such environments, plant fitness depends on an alignment between physiological traits and limited water resources. The Namib Desert of Namibia exemplifies this extreme selection pressure. Within the Namib Desert, Lithops ruschiorum, a succulent endemic to the gravel plains, exhibits habitat specificity and numerous physiological adaptations to cope with the hyper-aridity.

This research explores the intersection of two fitness strategies for L. ruschiorum: habitat selection and exploitation of alternative moisture sources. The first chapter explores the population dynamics and micro-site habitat conditions preferred by …

An Unusual Trumpeter Swan (Cygnus Buccinator) In Nebraska: Albinism Or Leucism?, Jacob C. Cooper, Peggy M. Huss, Eugene A. Huryn, Cody Mcgregor

Nebraska Bird Review

On 26 January 2025, we observed a large mixed flock of Trumpeter Swans (Cygnus buccinator) and Tundra Swans (C. columbianus) at Hansen Reservoir ca. 7 miles (11 km) NNW of North Platte along the east side of Nebraska Highway 97. The flock of 158 swans consisted of 4 “Whistling” Tundra Swans (C. c. columbianus), 153 typical Trumpeter Swans, and one individual that we were not immediately able to identify. Our unknown swan was in the company of a family group of Trumpeter Swans but immediately stood out due to its broad yellow base of …

Nebraska Ornithologists' Union Tri-State Meeting With Iowa Ornithologists' Union And South Dakota Ornithologists' Union, South Sioux City, Nebraska, May 16-18, 2025

Nebraska Bird Review

The NOU Spring Meeting was held at the Salvation Army Western Plains Camp in South Sioux City, Nebraska, in conjunction with the IOU and SDOU, with approximately 180 attending. The organizers of the meeting included Chris Anderson and Mark Schmidtbauer from South Dakota, Tyler Harms and Kevin Murphy from Iowa, and Ruth Stearns, Joel Jorgenson, and Paul Pearson from Nebraska.

A scientific poster session featuring the work of 9 ornithological researchers from UN-Kearney, USD-Vermillion, and Hitchcock Nature Center was held Friday evening. Thanks to Dr. Jacob Cooper from UNK, Dr. David Swanson from USD, and the students who participated.

Field …

Nou Tri-State Meeting—South Sioux City [Spring 2025 Nou Meeting Species Tally]

Nebraska Bird Review

Bird species tally (185) for the Spring 2025 NOU Tri-State Meeting, South Sioux City (Nebraska Ornithologists’ Union Tri-State Meeting with Iowa Ornithologists’ Union and South Dakota Ornithologists’ Union, South Sioux City, Nebraska, May 16–18, 2025)

Abstracts Of Posters Presented At South Sioux City Nou Meeting

Nebraska Bird Review

A scientific poster session featuring the work of 9 ornithological researchers from UN-Kearney, USD-Vermillion and Hitchcock Nature Center was held Friday evening. Thanks to Dr. Jacob Cooper from UNK, Dr. David Swanson from USD, and the students who participated.

Wandering from the River: On- and Off-River Abundance of Interior Least Terns along the 59-Mile Reach of the Missouri National Recreational River. Zoe Donelan, Hannah Slattery, Kyle Jorgensen, and David L. Swanson, University of South Dakota, Department of Biology.

Preliminary Results of Raptor Migration Monitoring at Hitchcock Nature Center. Kellie Hayden, Jerry Toll, and Sandy Reinken, Hitchcock Nature Center, Pottawattamie Conservation, …

Spring Field Report, March–May 2025, W. Ross Silcock

Nebraska Bird Review

Perhaps the most important takeaway this spring is the continuing phenomenon of large numbers of species with early spring arrival dates. Although about half as many as 2024, there were 64 examples of either tied or new early arrival dates, most obviously of insectivores such as swifts, flycatchers, vireos, swallows, pipits, longspurs, and 10 warbler species. Among these, record or near-record early were Whip-poor-will, Black-necked Stilt, Marbled Godwit, Black Tern, Olive-sided Flycatcher, Purple Martin, Rock Wren, Gray Catbird in central, Spotted Towhee in north and west, and Hooded Warbler.

Following along logically perhaps with early arrival dates were a number …

The Nebraska Bird Review (June 2025) 93(2), Whole Issue

Nebraska Bird Review

Spring Field Report, March–May 2025, by W. Ross Silcock

NOU Spring Field Days and Annual Meeting in South Sioux City, May 16–18, 2025

Abstracts of posters presented at Spring 2025 NOU Meeting

Spring 2025 NOU Meeting Species Tally

An Unusual Trumpeter Swan (Cygnus buccinator) in Nebraska: Albinism or Leucism? by Jacob C. Cooper, Peggy M. Huss, Eugene A. Huryn, and Cody McGregor

Subscription and Organization Information

When Trees Disappear: Understory Successional Implications Of Sudden Oak Death And High-Severity Wildfire In Big Sur, California, Sam J. Balthazard

Master's Theses

The rapidly emerging disease sudden oak death, caused by the non-native pathogen Phytophthora ramorum, is transforming coastal California forests by driving extensive mortality of tanoak (Notholithocarpus densiflorus) and increasing fire severity. As a novel disturbance, sudden oak death and its interaction with wildfire may catalyze unexpected shifts in successional trajectories and reconfigure forest understory communities. Furthermore, how tanoak influences the forest understory and how its decline might reshape understory dynamics remain poorly understood. We hypothesize that disease alone and the compounding disturbances of disease and wildfire alter successional dynamics, and that the potential functional extinction of N. …

Belowground Biomass Shifts Along A Temperate Forest Edge, Lara Holbrook Roelofs

Dartmouth College Undergraduate Theses

Anthropogenic land use change and development has caused widespread global forest fragmentation, resulting in a greater proportion of forests at or near a forest edge. Temperate forests are the most fragmented forest biome, and forests in the Northeastern U.S. are particularly fragmented due to a history of intense land use and development pressure. Nearly a quarter of these forests are now within 30 meters of a forest edge. These edge ecosystems have distinct abiotic and biotic gradients that differentiate them from forest interiors, including increased light, temperature, and exposure to wind and other disturbances, as well as decreases in humidity …

Woofs And Warbles: The Influence Of Urban Dog Walking On Birdsong, Grace Phillips

University Honors Theses

Recreational activity in natural areas can disrupt songbird singing during critical learning or courtship periods, increasing the risk of fitness and population declines in sensitive species. Local data on birdsong disturbance caused by recreation can guide management efforts protecting wildlife, such as signage, leash laws, and dog walking bans. This study assessed bird vocalization responses to groups with and without dogs in urban greenspaces. Surveys were conducted in Fall 2024 at three parks in Portland, Oregon, with varying rates of dog and human presence. Throughout two-hour observation periods, bird vocalization activity of seven songbirds was recorded at five-minute intervals and …

United Seas For Resilient Reefs: A Blueprint For Coral Conservation Through International Cooperation, John J. Bohorquez, Maoz Fine, Dana I. Grieco, David A. Gill, Ali Al-Swalimih, Jacqueline Padilla-Gamino, Isaiah W. Bolden, Margaux Hein, Callum Backstrom, Melanie Mcfield, Raphael Martinez, Benjamin Midberry, Fahd Al-Guthmy, Ellen K. Pikitch, Natalia Benejam, Chen Azulay, Britt Ronen, Oren Levy, Anne Mcelroy, Karine Kleinhaus

School of Marine & Atmospheric Sciences Faculty Publications

Coral reefs are one of Earth’s most vital and threatened ecosystems. They protect coastlines, generate billions of dollars of tourism revenue, support valuable fisheries, and contribute to the development of vital medicines. Yet half of the world's coral reefs have been lost in the last 50 years, and 90% of remaining reefs are projected to die off by the middle of this century, mainly due to warming seas from climate change.

Despite these challenges there is reason for hope. Some coral reefs – such as in the northern Red Sea and Gulf of Aqaba – have demonstrated remarkable resilience to …

Individual, Social, And Environmental Factors Associated With Patterns Of Parasitic Infection In Capuchin Monkeys (Cebus Imitator), Megan C. Henriquez

Dissertations, Theses, and Capstone Projects

Parasites, and the infectious diseases they carry, are thought to have significantly impacted our evolutionary trajectory for millennia. Exploring how parasites are acquired and transmitted by their hosts in wild, natural populations is integral to understanding how similar processes may have shaped host-parasite co-evolutionary relationships over time. However, parasitological studies in humans and in non-human primates have produced inconsistent results, highlighting the dynamic, nuanced, and unique relationships individual parasites have with their hosts. These relationships are largely regulated by variation in factors at host, social, and environmental levels. Characteristics unique to the host (e.g., age and sex), factors pertaining to …

Decoding The Plant Metabolome: A Metabolomics Approach To Guereza (Colobus Guereza) Feeding Ecology In Kibale National Park, Uganda, Emma Grace Thurau

Dissertations, Theses, and Capstone Projects

Plant metabolites, an elusive and diverse group of plant chemicals, represent a complex chemical interplay between plants and herbivores. Plants contain essential nutrients necessary for herbivore survival, yet herbivore consumption results in negative fitness consequences to a plant. This relationship has triggered a coevolutionary arms race in which plants have evolved chemical defenses to prevent herbivore consumption and herbivores, in response, have evolved their own counter-adaptations. This arms race has led to the diverse numbers of herbivores and plants observed today; therefore, these plant metabolites act as a signature of evolution through their influence on herbivore adaptations. Plant metabolites are …

Disturbance And Diversity: Lichens In Changing Landscapes, Laura Boggess

Dissertations, Theses, and Capstone Projects

Disturbance is a fundamental ecological force that shapes biodiversity, community composition, and ecosystem function. Human-driven disturbances—such as habitat fragmentation, deforestation, and air pollution—are increasing worldwide, altering ecosystems at unprecedented rates. While ecological research has illuminated many effects of disturbance, significant knowledge gaps remain for underappreciated but ecologically vital organisms, such as lichens. Lichens are obligate symbioses between at least one fungus and one alga or cyanobacterium. As such, they are sensitive bioindicators of environmental change, offering unique insights into ecosystem health due to their responses to stressors such as poor air quality, habitat fragmentation, and deforestation. Yet, their responses to …