Population Biology Commons^™

Effects Of Litter Biomass And Soil Stoichiometry On Leaf Litter Amphibian And Reptile Density, Biomass, And Community Structure In Tropical Wet Forests, Alondra Medina Charriez

Masters Theses, 2020-current

Understanding the mechanisms behind patterns of diversity and abundance is a major goal of ecology. Research on nutrient stoichiometry has revolutionized the way ecologists understand the patchy distribution of mega-diverse invertebrate taxa that live at the soil surface and leaf litter in tropical wet forests. In this study, I studied the importance of soil nutrient concentrations and stoichiometry, habitat structure, and invertebrate biomass for patterns of amphibian and reptile density, biomass and community structure in two lowland wet tropical forests. I used data from study sites in Los Amigos Biological Station in Peru and two sampling occasions at La Selva …

Causes And Consequences Of Lasr Mutant Selection In Pseudomonas Aeruginosa Populations, Dallas L. Mould

Dartmouth College Ph.D Dissertations

Change is the only constant in life, and these changes, though random in nature, can have consequences. Quorum sensing is heterogeneous in phenotype and prone to negative selection. In P. aeruginosa, the regulator LasR is frequently non-functional in phylogenetically diverse isolates. Through repeated experimental evolution and mathematical modeling, we show that differences in growth enable lasR mutant evolutionary success and this requires a system enabling metabolic choices, known as carbon catabolite repression (or catabolite repression). The differences in catabolite repression between wild type and lasR mutants enable altered metabolite preferences, and the resulting differences in metabolic states enable intraspecies …

Aspects Of Distribution, Abundance, Habitat, And Life History Of The Caddo Madtom (Noturus Taylori), A Narrow Endemic Of The Ouachita Highlands, Brittany L. Mccall, Brook L. Fluker

Southeastern Fishes Council Proceedings

The Caddo Madtom, Noturus taylori, is a small catfish endemic to the Ouachita Mountain ecoregion in Arkansas, with habitat altered by land use practices and reservoir dams. We examined aspects of distribution, abundance, habitat, and life history of N. taylori during seasonal sampling from winter 2016 through fall 2017. Our sampling data were concordant with previous studies that suggested N. taylori is more widespread and has higher catch per unit effort in the Caddo River drainage when compared to the upper Ouachita River drainage. We did not detect N. taylori in the Little Missouri River drainage, where it is …

Du Undergraduate Showcase: Research, Scholarship, And Creative Works, Caitlyn Aldersea, Justin Bravo, Sam Allen, Anna Block, Connor Block, Emma Buechler, Maria De Los Angeles Bustillos, Arianna Carlson, William Christensen, Olivia Kachulis, Noah Craver, Kate Dillon, Muskan Fatima, Angel Fernandes, Emma Finch, Colleen Cassidy, Amy Fishman, Andrea Francis, Stacia Fritz, Simran Gill, Emma Gries, Rylie Hansen, Shannon Powers, Jacqueline Martinez, Zachary Harker, Ashley Hasty, Mykaela Tanino-Springsteen, Kathleen Hopps, Adelaide Kerenick, Colin Kleckner, Ci Koehring, Elijah Kruger, Braden Krumholz, Maddie Leake, Lyneé Alves, Seraphina Loukas, Yatzari Lozano Vazquez, Haley Maki, Emily Martinez, Sierra Mckinney, Audrey Mitchell, Kipling Newman, Audrey Ng, Megan Lucyshyn, Andrew Nguyen, Stevie Ostman, Casandra Pearson, Alexandra Penney, Julia Gielczynski, Tyler Ball, Anna Rini, Christina Rorres, Simon Ruland, Helayna Schafer, Emma Sellers, Sarah Schuller, Claire Shaver, Kevin Summers, Isabella Shaw, Madison Sinar, Claudia Pena, Apshara Siwakoti, Carter Sorensen, Madi Sousa, Anna Sparling, Alexandra Revier, Brandon Thierry, Dylan Tyree, Maggie Williams, Lauren Wols

DU Undergraduate Research Journal Archive

DU Undergraduate Showcase: Research, Scholarship, and Creative Works

Community And Population Dynamics Of Diatoms In Recovering Agricultural Stream And Ubiquitous Taxon In Low-Impact Sites Across Southeastern United States, Sydney Brown

Biology Theses

Streams play vital roles to surrounding communities and provide essential ecosystem services. The protection of streams is important, legally protected under the Clean Water Act (CWA) and can be monitored through the continuous analyses of biological data, like algal or other aquatic communities. Diatoms are a group of algae characterized by rigid glass cell walls and ubiquitous distribution. They are typically identified using the morphological species concept and an ever-varying range of sizes may pose challenges in the identification process. However, when identified and applied correctly, diatoms are robust bioindicators. This research identifies and analyzes low-impact sites across the Southeastern …

Assessing The Appropriateness Of Free-Roaming Cat Management Strategies Based On Resident Perspectives In A Small Pennsylvania Municipality, Brianna Marks

Electronic Theses and Dissertations

The popularity and mismanagement of free-roaming cats has resulted in invasive populations responsible for over-predation of birds and small mammals and increased disease transmission to humans and animals (Bies, 2014; Crowley et al., 2020). Management effectiveness fluctuates between communities due to varying opinions of free-roaming cats by governments and the public, which can influence management development and success (Deak et al., 2019). This research assesses the relationship between community perspectives of free-roaming cats and management. A survey of residents in a small Pennsylvania municipality was conducted with questions pertaining to free-roaming cats and management preferences in the community. Over 50% …

Striped Blenny (Chasmodes Bosquianus) Presence And Behavior Between Sunrise And Sunset At Oyster Landing, South Carolina, Madeline Schuetze

Honors Theses

Lunar and diel cycles of fishes can help to interpret their behaviors during their reproductive season. Temperate estuaries are used by many benthic fishes for shelter and reproduction. This study examined the behavior and presence of striped blennies (Chasmodes bosquianus) during diel and lunar cycles. PVC pipe shelters were placed to mimic oyster shell nests, a natural habitat for blennies, and cameras were placed to monitor these shelters in April, May, and June 2022, during the striped blenny reproductive period. Video footage was reviewed and analyzed for the presence and behavior of both male and female blennies. Male presence …

Effect Of Temperature On The Microbiome Of A Laboratory Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna Mitchell

Poster Presentations

Honors research poster.

Haemaphysalis longicornis is a species of tick native to eastern Asia, including eastern China, Japan, eastern Russia, and Korea. To date, it has invaded and has now established its existence in Australia, New Zealand, and several of the Pacific Islands. This species of tick has recently been introduced to the United States, having a confirmed sighting in November 2017 on a sheep farm in New Jersey and since establishing populations in 18 states along the east coast and Appalachia. Based on the existing locations of H. longicornis in its native regions, as well as in the United …

Species Diversity Of Coleoptera Populations In An Urban Garden In Chattanooga, Tennessee, Mallory Anderson

Honors Theses

Insects are an essential part of the function of ecosystems. The majority of entomological faunistic research has been conducted primarily in rural areas due to high diversity, space for bulky traps, and less outside influence from human activities. However, the need for time-series insect biodiversity data, in rural areas and urban areas alike, is paramount in the wake of our current sixth mass extinction event. Previous research has shown that the greater Chattanooga area is comprised of a diverse population of insects in the Coleoptera (beetles) order, and as shown in the University of Tennessee at Chattanooga’s (UTC) Insect Collection. …

Past And Present Patterns Of Neutral And Adaptive Genetic Diversity In Wild Mandrills (Mandrillus Sphinx), Anna Weber

LSU New Orleans Theses and Dissertations

Although primates have fascinated researchers and the public alike for generations, one species that has remained enigmatic is the mandrill (Mandrillus sphinx), a large Cercopithecine monkey endemic to Central Africa. Mandrills are currently in decline due to bushmeat hunting, urbanization, and habitat loss. Neutral and adaptive genetic diversity are important tools for understanding evolutionary history and future viability, since diversity influences a species’ ability to adapt to a changing environment. However, thus far, minimal genetic information has been available for wild mandrills. Because of the dense vegetation in their tropical forest habitat, studying wild mandrills has proven to …

Effect Of Temperature On The Microbiome Of A Laboratory-Reared Colony Of Haemaphysalis Longicornis Ticks, Brianna L. Mitchell

Honors Theses

Haemaphysalis longicornis ticks are invasive to the United States with potential to transmit several tick-borne pathogens that are native to the United States. Based on existing locations of H. longicornis in its native regions in Asia, as well as its invasive populations that are established in the United States, several geographic range prediction models have been produced to help understand future range expansion and distribution of this invasive tick in North America. Unfortunately, these models do not all agree and there is uncertainty associated with the potential geographic range expansion of H. longicornis ticks in North America. Climate can affect …

Optimal R&D Investment In The Management Of Invasive Species, William Haden Chomphosy, Dale T. Manning, Stephanie A. Shwiff, Stephan Weiler

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive alien species (IAS) threaten world biodiversity, ecosystem services, and economic welfare. While existing literature has characterized the optimal control of an established IAS, it has not considered how research and development (R&D) into new removal methods or technologies can affect management decisions and costs over time. R&D can lower the costs of control in a management plan and creates an intertemporal trade-off between quick but costly control and gradual but cheaper removal over time. In this paper, we develop and solve a continuous time dynamic optimization model to study how investment in R&D influences the optimal control of an …

Assessing The Dynamics Of The Southeast Florida Shark Community From 2013-2019 Via Catch Per Unit Effort And Stable Isotope Analysis, Alexandra Barth

All HCAS Student Capstones, Theses, and Dissertations

Sharks, as well as other top predators, are in drastic decline worldwide. As apex and near-apex predators, species such as nurse, lemon, and tiger sharks maintain balanced marine ecosystems by enacting top-down trophic control. However, this cascading effect is diminished with exploitation via commercial and recreational fishing. Sharks are generally long-lived, mature late, have long reproductive cycles, and produce few offspring. Much remains to be learned about the community structure, population trends and conservation statuses of shark populations worldwide. Comprehensive studies on the composition of the shark community in Southeast Florida north of Miami have been limited. This study assessed …

Cats Of Unl: An Investigation Into The Human-Feral Cat Relationships On A University Campus In Nebraska, Jacey Skoda

Honors Program: Senior Projects (Public)

At the University of Nebraska-Lincoln (UNL), there exists a population of feral cats that is monitored and cared for by a group known as Husker Cats. As the cats wander the sidewalks and gardens of the university, they may appear non-threatening and pleasant to have around. However, a feral cat presence could have detrimental impacts on the surrounding ecosystem, property, and community. The first component of this project, a survey of individuals on UNL campus, ultimately seeks to understand what those in the UNL community know about the feral cats, how they feel about the feral cats, and how they …

Senesced Leaves Of An Invasive Species (Lonicera Maackii) Alter Community Composition And Ecosystem Function In Experimental Wetlands, Cy Mott

2023 Midwest Ecology & Evolution Conference

Secondary compounds produced by terrestrial invasive plants can cross terrestrial-aquatic boundaries via senesced leaves, leading to altered patterns of aquatic biodiversity and ecosystem functioning. Prior attempts to examine the impacts of invasive leaves on wetland communities have primarily employed the use of leaf leachates and focal taxa inhabiting relatively low trophic positions, and additional studies are needed to examine impacts on higher-order consumers and potential additive/synergistic effects of leachates and leaf decomposition. Using cattle-tank mesocosms across multiple experiments, we observed that the addition of senescent leaves of Amur Honeysuckle (Lonicera maackii) to native leaves resulted in mass mortality …

Comparison Of Channel Catfish Populations In Two Northeast Kansas Impoundments, Ethan Thompson

2023 Midwest Ecology & Evolution Conference

In the summer of 2022, we sampled Channel Catfish populations at Brown State Fishing Lake and Sabetha City Lake, both located in Northeast Kansas. These impoundments are similar only in latitude and size with several differences in their fish populations, specifically with Channel Catfish. One is stocked annually with 200 mm intermediate Channel Catfish and the other is not. Surprisingly, the impoundment that is not stocked has a higher density of fish than the impoundment that is. This poster will present age, growth, length, and weight information and make inferences on the impacts of population density on those metrics.

Evaluating Anti-Predator Behavior In A Captive Elk (Cervus Canadensis) Herd, Jordan L. Tandy

2023 Midwest Ecology & Evolution Conference

Predator-prey interactions drive decisions of either counterpart, meaning predators and the presence of perceived dangers, such as scent markings or calls, are capable of altering an organism’s behavior. On a spatial scale, risk and cost-benefit tradeoffs related to predation pressures create a landscape of fear (LOF), where prey avoid areas they associate with risk. Certain periods of time, such as birthing seasons, pose even greater risk to prey species. Research suggests that captive and/or historically captive animals tend to respond less effectively to predation than native populations that regularly experience threats of predation. I have gathered behavioral data on a …

Adaptive Plasticity Of Coloration In Response To Environmental Change, Karissa Coffield

2023 Midwest Ecology & Evolution Conference

When rapid environmental changes occur, different selective forces can create phenotypic trade-offs in which a trait can provide fitness benefits or costs under different environmental conditions. Amphibians are particularly vulnerable to environmental change, and previous research has revealed that some species will plastically respond to variation in temperature and ultra-violet radiation (UVR) by altering their coloration. Divergent selection on coloration may change with elevation and climate induced shifts in temperature because high temperatures are likely to result in lighter color morphs but as elevation increases, UVR exposure increases leading to the prediction that darker color morphs will be more common. …

How Accurately Structure Can Identify Hybrids When Comparing Different Numbers Of Species And Marker Types And Numbers, Chloe Hendrikse

2023 Midwest Ecology & Evolution Conference

Hybridization is a common problem in conservation. It can be difficult to identify hybrid individuals but doing so is often necessary in order to make conservation recommendations. For example, botanical gardens and seed banks want to identify if individuals are hybrids of two or more species to determine if offspring could be used for conservation or restoration, and to analyze the risk of possible extinction via introgression. Our project looks at how well the program STRUCTURE can detect and cluster hybrids, their parent species, and other pure species, which we created using simulations. We build on past studies, which typically …

Sexual Selection, Female Body Size, And Fecundity In Drosophila Melanogaster, Calvin Herrick

2023 Midwest Ecology & Evolution Conference

In Drosophila melanogaster it is well established that male sexual preference emphasizes high fecundity in females and females with larger body sizes. It is hypothesized that male preference for large females is due to a positive correlation between body size and fecundity. Here, we take advantage of a long-running experiment, where lineages of flies were made significantly larger (L-lineages) and smaller (S-lineages) during 400+ generations of artificial selection. In the first part of this study, we measured female Drosophila fecundity, based only on differences in evolved size and found substantial differences in fecundity. In the second part of this study, …

Habitat Characteristics And Winter Use Of Woodpecker-Excavated Tree Cavities, Adrianna Yoder

2023 Midwest Ecology & Evolution Conference

Avifauna are in decline in North America, including red-headed woodpeckers (Melanerpes erythrocephalus). Red-headed woodpeckers are negatively impacted by urbanization, which has decreased their ideal habitats of oak-savannas and through the management of urban trees there has been a reduction in the amount of tree decay, a necessary feature of suitable trees that woodpeckers can make cavities in. Cavities are created and used as nests in the breeding season (spring/summer) and as roost-sites in the non-breeding season (fall/winter). In the Chicagoland region, during the fall some red-headed woodpeckers migrate while others do not and remain overwinter, making them facultative …

Forest Recruitment Dynamics Within The Southern Boreal-Temperate Ecotone, Kiley M. Chernicky

2023 Midwest Ecology & Evolution Conference

Understanding how global climate change will alter future forest composition is especially challenging in forest communities where tree species have long co-occurred, but their competitive balance may be altered due to changes in climate. Of particular concern with increasing global temperatures are boreal forest communities that lie on the southern boreal-temperate forest ecotone, where the boreal forest is particularly vulnerable. The aim of my research is to investigate shifts in recruitment dynamics due to climate change near the southern range limit of two historically co-occurring boreal forest conifer species, white spruce (Picea glauca) and balsam fir (Abies …

Spatiotemporal Patterns Of Ticks And Tick-Borne Disease Dynamics At Neon Sites Across A Sub-Continental Scale., Ana Sofia Rivera

2023 Midwest Ecology & Evolution Conference

At local scales, dynamics of ticks and tick-borne diseases such as Lyme disease are driven by resource pulses, such as mast seeding in forest trees, that creates increases in tick hosts. Tick-borne diseases in humans have nearly doubled between 1940 and 2004 and understanding the dynamics of infectious diseases has long been of interest for ecologists. The family Ixodidae is the most capable of transmitting pathogens to humans and tick-borne diseases are the most common vector of illness in the United States. The objective of this research is to characterize the spatiotemporal dynamics of ticks and tick-borne diseases, which may …

Host Size Reduction In Response To Parasitic Infection Fuels Trophic Cascades, Lauren Albert

2023 Midwest Ecology & Evolution Conference

Outbreaks of disease epidemics continue to erupt in host populations. Within these populations, parasites drive top-down effects. For example, when parasites kill their hosts, they can indirectly increase the hosts’ resource density, causing trophic cascades. This phenomena arises in a diversity of parasite-host-resource systems; however, the mechanisms of parasite-driven trophic cascades remain less clear. A straightforward density-mediated mechanism occurs when parasites increase host mortality, depressing host density. Alternatively, host traits such as body size could be affected, depressing host resource regulation. To disentangle connections between parasites and trophic cascades, we must measure mechanisms operating at both the population (density) and …

Polyploidy’S Impact On Plant-Herbivore Dynamics: Evidence From Experiments With Water-Lily Aphids And Greater Duckweed, Hannah R. Assour

2023 Midwest Ecology & Evolution Conference

Polyploidy, or whole-genome duplication, is a widespread mutational process in plants with a myriad of phenotypic and genotypic consequences. In addition to consequences incurred by the plant, polyploidy can potentially cascade to alter species interactions. Yet, knowledge of whether ploidy-induced variation has effects on plant-herbivore dynamics is scarce. Here, we test whether aphid herbivores exhibit preference for a diploid or polyploid host cytotype and whether ploidy impacts plant resistance and tolerance to aphids, measured as aphid and plant performance respectively. To answer these questions, we evaluated aphid choice and compared the effects of the water-lily aphid (Rhopalosiphum nymphaeae) …

Coyote Occupancy And Movement In Hanover County, Virginia, Richard S. Groover

Virginia Journal of Science

Although the coyote (Canis latrans) is native to North America, we have limited understanding of its presence in Virginia. Coyote range expansion is linked to anthropogenic factors, including habitat fragmentation and the extirpation of apex predators. Information on coyote adaptations to Virginia habitats is scarce, and eastern coyotes may have unique adaptations for colonizing an area. Anecdotal evidence suggests that coyotes are abundant in Hanover County (north of Richmond, VA), but this has not been confirmed. This study was conducted over an 18-month period with multiple survey sites throughout Hanover County, each equipped with game camera stations and …

Highly Pathogenic Avian Influenza A(H5n1) Virus Outbreak In New England Seals, United States, Wendy Puryear, Kaitlin Sawatzki, Nichola Hill, Alexa Foss, Jonathon J. Stone, Lynda Doughty, Dominique Walk, Katie Gilbert, Maureen Murray, Elena Cox, Priya Patel, Zak Mertz, Stephanie Ellis, Jennifer Taylor, Deborah Fauquier, Ainsley Smith, Robert A. Digiovanni, Adriana Van De Guchte, Ana Silvia Gonzalez-Reiche, Zain Khalil, Harm Van Bakel, Mia K. Torchetti, Kristina Lantz, Julianna B. Lenoch, Jonathan Runstadler

United States Department of Agriculture Wildlife Services: Staff Publications

We report the spillover of highly pathogenic avian influenza A(H5N1) into marine mammals in the northeastern United States, coincident with H5N1 in sympatric wild birds. Our data indicate monitoring both wild coastal birds and marine mammals will be critical to determine pandemic potential of influenza A viruses.

Cell Volume As A Determinant Of Virus-Mediated Population Growth In Ciliates, Jace Miller, John Paul Delong Phd

Honors Program: Senior Projects (Public)

Many protists and other small aquatic organisms consume virus particles, a behavior known as virovory. Some species of protists, such as the ciliate Halteria grandinella, can grow and divide using viruses as their sole food source. Other ciliate species have previously been shown to consume large quantities of viral particles, but it is unclear if they are able to support population growth with viruses alone. Because large ciliates have a higher energy demand, we hypothesize that they will be unable to support population growth on a virus-only diet. We fed nine ciliate species a diet of chloroviruses and found …

Annual Treasurer's Report For 2022, Jan Johnson

Nebraska Bird Review

No abstract provided.

The Nebraska Bird Review: A Magazine Of Ornithology Of The Nebraska Region. Volume 91, Number 1. March 2023, Nebraska Ornithologists’ Union

Nebraska Bird Review

Winter Field Report, Dec. 2022 - Feb. 2023 by W. Ross Silcock

Annual Color Photo Section

Annual Treasurer's Report for 2022 by Jan Johnson

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