Life Sciences Commons^™

Challenging And Diagnosing Structured Population Models By Testing Predictions From Stochastic Demography, Stephen P. Ellner, Robin E. Snyder, Daniel T. Blumstein, Dylan Z. Childs, Joshua C. Fowler, Christina M. Hernández, Julien G. A. Martin, María Paniw, Yngvild Vindenes

Biological Sciences Faculty Publications

1. Structured population models are parameterized to accurately project expected population sizes, stage/state distributions and population growth rates, but they also predict the variation in outcomes among individuals, such as the variance and skewness of lifetime reproductive output (LRO) and lifespan, the probability of never reproducing, and many other life-history metrics.

2. Testing such predictions about individual outcomes can be very useful model 'stress tests', because they depend on how components of the model (e.g. submodels for survival and fecundity) interact over multiple time steps, not just on the accuracy of the submodels. Because data on among-individual variation is rarely …

Evaluating Benthic Macroinvertebrate Communities In Streamside Management Zones In Private, Working Forests, Haley Vaglienti

College of Graduate Studies: Theses & Dissertations

Forestry operations can alter riparian vegetation and increase sediment and nutrient inputs to streams, affecting water quality and aquatic biota. Forestry best management practices (BMPs) including streamside management zones (SMZs) are designed to mitigate those effects by reducing sediment delivery and moderating temperature, flow, and nutrient regimes. We assessed ecological integrity at 24 intermittent stream sites with SMZs in private, working forests across the Piedmont and Southeastern plains of Georgia. At each site, we conducted physical habitat evaluations and characterized benthic macroinvertebrate assemblages. Sites represented a gradient of habitat conditions, SMZ widths, and pine stand ages, allowing for comparisons of …

Monograph Available: Best Practices For Managing Human–Beaver Conflicts In North America: Balancing Ecological Benefits And Human Interests

Human–Wildlife Interactions

This is an announcement about the published monograph titled "Best Practices for Managing Human–Beaver Conflicts in North America: Balancing Ecological Benefits and Human Interests." This publication, part of the HWI Monograph Series, is online and open access.

Machine Learning-Based Spatio-Temporal Modeling Of Climate Dynamics And Desertification In The Sahara–Sahel Region, Stephen M. Tivenan

Theses and Dissertations

Arid climate classifications are threshold-dependent and easily interpretable mappings that are widely used in ecological, agricultural, and climate-related studies. These classifications inform scientific understanding, support policy and land management decisions, and provide an intuitive summary of environmental conditions. Despite their usefulness, traditional arid climate classifications often fail to quantify uncertainty, incorporate spatial context, or account for complex relationships among relevant environmental variables. Existing approaches to uncertainty assessment have largely relied on comparing classifications across multiple datasets or alternative formulas, but these methods generally overlook important spatial dependence and latent structure in the data.

This dissertation develops three machine learning-based statistical …

Climate, Biogeography, And Dispersal: A Unifying Framework For Ameri-Caribbean Dry Forests, Pablo Lopez Bustamante

Theses and Dissertations

Seed dispersal is a crucial ecological function that enables plants to alter their distributional range, avoid intense competition and natural enemies near the parent plant, and recover from disturbances. These processes shape species and functional composition of forests. Wind has traditionally been considered the dominant dispersal mechanism in Ameri-Caribbean dry forests, yet growing evidence suggests that other dispersal mechanisms also play significant roles in this ecosystem, responding differently to biotic and abiotic conditions. Still, how dispersal syndrome composition influences plant communities, the ecological drivers underlying these patterns, and the effects of climate change on dispersal syndrome dominance remain poorly understood. …

Hybridization And Introgression In Marine Invertebrates: Population Genomics Of Phymactis Papillosa And Asterias Sea Stars, Christopher J. Dookie

Dissertations and Theses

Hybridization and introgression are evolutionary significant processes in marine invertebrates (Sanford & Kelly,2011) yet genome-wide investigations of gene flow in these taxa remain limited relative to vertebrate systems (Marchi et al., 2021). This thesis presents genomic analyses of hybridization and introgression in two marine invertebrates occupying contrasting oceanographic settings and characterized by contrasting genomic datasets: restriction-site associated DNA sequencing (RADseq) SNP data for the eastern Pacific sea anemone Phymactis papillosa and whole genome sequencing (WGS) data for the North Atlantic sea stars Asterias rubens and Asterias forbesi. For each system, I applied coalescent-based species tree inference using CASTER (Zhang …

Viral Diversification And Host-Specific Fitness Of Powassan, Heartland, And Bourbon Viruses In New York State, Rachel E. Lange

Electronic Theses & Dissertations (2024 - present)

This dissertation reports important progress for our understanding of emerging and re-emerging tick-borne viruses circulating in North America including Powassan, Deer Tick, Heartland, and Bourbon viruses. Chapter 2 describes important tools for these viruses including multiplex assays for viral and bacterial pathogens in field-collected ticks and mammals, development of full genome sequencing assays and bioinformatic pipelines for evolutionary analysis, and establishment of tick-specific tools for viral isolation and characterization. Chapter 3 focuses on the disease focality of Deer Tick virus, reporting transovarial transmission in nature in Ixodes scapularis for the first time, further evidence to incriminate shrews as potential Deer …

Compositional And Functional Shifts In Fish Community Structure In Response To Low-Head Dam Removals, Joshua D. Bruegge

Masters Theses

Low-head dams serve as intermittent barriers to aquatic connectivity and directly alter both upstream and downstream habitats and biotic communities. In 2018 and 2019, two low-head dams in the Vermilion River watershed of eastern Illinois were removed, reconnecting over 1,700 kilometers of upstream habitat within the basin. To determine the impacts of these dam removals, fish community surveys were conducted at 12 fixed sites across three reaches in two rivers from 2012-2022. This study assessed reach-specific temporal responses of the fish community and habitat characteristics. I linked trait expressions within the fish community to abiotic variables using the co-inertia RLQ …

Complexity Theory And Environmental Conservation Management: A Case Study With Coyote And Red Wolf Hybridization, Gretchen E. Mahalic

Honors Undergraduate Theses

Conservation biology and invasion biology are value-led scientific disciplines founded on environmental advocacy, operating at the intersection of research and action. Though these disciplines are known for their scientific veracity, unexamined values are often promulgated without scrutiny and drive decisions that work against good ecological outcomes. A case in point is that coyotes migrating into southeastern territory are framed as the greatest threat to the conservation of the endangered red wolf because hybridization is seen as diminishing their species integrity. Applying Val Plumwood’s ecofeminist account of dualistic frameworks, I will use this case to show how the vilification of the …

Sex In Plants: Birth, Death, And Trying To Survive In Changing Climates, Elena M. Meyer

Theses and Dissertations

Plant mating systems are key determinants of fitness. Angiosperms exhibit a wide variety of reproductive strategies, including self-fertilization (or selfing), outcrossing, and mixed mating. It has been estimated that up to 43% of plant species are capable of selfing, and selfing has been hypothesized to provide reproductive assurance where opportunities for mating may be limited, such as in marginal environments. However, questions regarding the overall distribution of selfing rates across angiosperms, the maintenance of mixed mating in the face of inbreeding depression, and the impact of self-fertilization on diversification rates remain incompletely resolved. Here, we explore the dynamics of self-fertilization …

Nutritional Niche Separation Amongst Sympatric Threatened Lemurs: The Role Of Micronutrients In Food Selection And Implications For Physiological Health, Maire K. O'Malley

Graduate Research Theses & Dissertations

Madagascar’s biodiversity is heavily affected by anthropogenic change and consequently, conservation management plans need to reflect current research to protect biodiversity. Primate nutritional ecology offers valuable insights into ecology, evolution, health, habitat requirements, social behavior, and conservation management strategies. Macronutrients (fat, carbohydrates, and protein) provide consumers with energy whereas micronutrients (vitamins and minerals) are essential to metabolic processes but are frequently overlooked. This study provides a novel examination of dietary niche separation by comparing mineral consumption between three sympatric species differing in feeding strategies: 1) Grey Bamboo lemur (Hapalemur griseus), a bamboo specialist, 2) Diadema sifaka (Propithecus diadema), a folivore, …

Layers Of Biodiversity: Linking Urban Garden Plants And Arthropods, Chenyang Su

Dartmouth College Ph.D Dissertations

Diverse arthropods play essential roles in urban agriculture, while urban agriculture provides food and habitat that support arthropod biodiversity in fragmented urban landscapes. In urban community gardens, a form of urban agriculture characterized by allotment-style gardens, arthropods interact with plants and green space across multiple spatial scales of management, from individual gardeners' plots to broad urban landscapes. Understanding how plant communities in urban community gardens and urban landscapes shape arthropod biodiversity and interactions across scales can inform both agricultural management and urban biodiversity conservation. In this thesis, I conducted a series of field studies on ecologically and economically important arthropods …

Evaluating Planting Methods For Native Seed Production And Exploring Granivory In The Northern Great Plains, Allison Dollen

Electronic Theses and Dissertations

Temperate grasslands have faced immense losses due to land use change in the last 150 years and less than half of the overall grasslands that once covered North America remain today. A portion of historic and remaining U.S. grasslands are located within the northern Great Plains (NGP) region which is home to over 1,600 species of native plants and provides many ecosystem services and economic benefits. Initiatives to restore grasslands and their ecosystem services are currently underway, but barriers such as limited native seed supply and granivory hinder restoration efforts. My first chapter addresses knowledge gaps in planting methods for …

Non-Native Seagrass, Halophila Stipulacea, Reaches Northern Caribbean, Elizabeth R. Whitman, Elizabeth W. Stoner, Stephanie K. Archer

Gulf and Caribbean Research

Halophila stipulacea, a seagrass native to the western Indian Ocean, has become an established invader throughout the western Atlantic, where it often outcompetes native seagrass species across diverse environmental conditions. Here, we report its presence in the northern Bahamas, ca. 2300 km northwest of the first Caribbean record in Grenada and 304 km northeast of the recent observation in Florida, USA. This range expansion represents the northernmost Caribbean record to date and highlights the species’ capacity for long-distance dispersal and continued spread within the region. Our observation underscores the need for coordinated monitoring efforts to track the trajectory of …

Manatee Dock Sign Distribution And Its Influence On Publicly-Sourced Sighting Reports In Alabama, Daniela Payán Arias, Sophia C. Corde, Ruth H. Carmichael

Gulf and Caribbean Research

No abstract provided.

A Novel 3d Imaging Approach To Study Evolutionary Innovations In Solanaceae Inflorescences, Devin L. Jackson, Joonseog Kim, Wenheng Zhang Dr.

UROP Posters

Understanding the relatedness of angiosperms and the evolution of their inflorescence remains challenging, as these structures are highly modified and prone to convergent evolution. The current research describing inflorescence architecture, whether genetically or morphologically focused, typically relies on text based explanations, 2D images, or 3D based models created with CAD modeling software. This creates a disparity in the reader's understanding of these models since descriptions rely heavily on the author's interpretation of the inflorescence. The goal of our study is to bridge this disconnection by producing anatomically and color-correct 3D inflorescence models using Solanaceae flowers that readers can explore directly, …

Seasonal And Lunar Patterns Of Peach Blossom Jellyfish (Craspedacusta Sowerbii) In Michigan, Claire Kozal

Master's Theses and Doctoral Dissertations

The peach blossom jellyfish (Craspedacusta sowerbii) is the only freshwater medusa found in the United States, yet its distribution, abundance, and mechanisms of dispersal remain poorly understood. Given its uncertain status, understanding the ecology of this species is a priority. To characterize population dynamics during the medusa season, surface water temperature and medusa abundance were surveyed at six inland lakes in Michigan. Occurrence records of C. sowerbii in Michigan were then used to compare co-occurrence patterns with nine aquatic invasives as a window into potential dispersal mechanisms and to create a regional ecological niche model. Medusae were observed in one …

From Nesting To Emergence: Environmental Drivers Of Hatchling Success In Blanding’S Turtles And Implications For Management In Southeast Michigan, Morgan Boyer

Master's Theses and Doctoral Dissertations

Blanding’s turtles (Emydoidea blandingii) are long-lived turtles whose populations are highly sensitive to juvenile recruitment. We used intensive nest monitoring, microclimate logging, soil measurements, and local weather data at two Southeast Michigan sites to quantify how nest placement, incubation environments, and substrate conditions influence emergence success and hatchling condition. Nesting females were morphologically similar in size and produced average clutch sizes for the species (8 ± 2 eggs). Nest sites were found on relatively open, disturbed uplands with sandier soil substrates. Emergence success was generally high (≈ 70-80%) in nests protected from predation. Sandy loam had the highest success rates …

From Theory To Ecosystems: Exploring Biodiversity And Ecosystem-Function In Pitcher Plant (Darlingtonia Californica) Microbial Communities, Gavin Sutter

Cal Poly Humboldt theses and projects

The relationship between biodiversity and ecosystem-function (BEF) has been a central focus of ecological research for the last three decades, yet the role of space in shaping BEF relationships remains relatively unknown. Research has shown that community diversity and composition can strongly influence productivity, nutrient cycling, and decomposition, but much of this work treats communities as spatially isolated, leaving open how dispersal and other spatial processes shape BEF at broader scales. To begin addressing this gap, I used microbial communities inhabiting Darlingtonia californica pitcher plant leaves to evaluate how spatial organization and successional change shape biodiversity and ecosystem-functioning. I quantified …

End-To-End Modeling For The Ross Sea Region Marine Protected Area: A Review Of Available Tools For Conservation Objectives, James R. Lovvorn, Cara Nissen, Alexis A. Bahl, Erik Behrens, Cassandra M. Brooks, Katy Christensen, Michael S. Dinniman, Lilian A. Dove, Alice K. Duvivier, Eileen E. Hofmann, Hayley Kwasniewski, Young Shin Kwon, Sharon E. Stammerjohn, Lei Xing

CCPO Publications

The challenge of protecting marine ecosystems, including biodiversity and manifold interactions in changing environments, has encouraged development of end-to-end models linking physical drivers through entire food webs to upper-level predators. Ideally such models should have temporal and spatial resolution adequate to capture important small-scale processes, while including scales large enough to encompass local food webs and movements of wide-ranging consumers. The need for component submodels to be manipulated and upgraded independently by scientists from different disciplines, and used selectively depending on questions addressed, favors modular structure allowing linkage of different submodels with varying strengths and weaknesses. As an example, this …

Ecological Feedbacks In The Earth System, Eugene J. Murphy, Jessica J. Williams, Isla H. Myers-Smith, Vivienne P. Groner, David M. P. Jacoby, Lester Kwiatkowski, Jess Melbourne-Thomas, Emma Ransome, Cristina Banks-Leite, Laurent Bopp, Marion Gehlen, Eileen E. Hofmann, Babette Hoogakker, Nadine M. Johnston, Yadvinder Malhi, Emma L. Cavan

CCPO Publications

Ecological feedbacks are fundamental features of the Earth system, affecting physical processes and chemical cycles. Our understanding of the interactions underlying these feedbacks at different spatial and temporal scales and the extent to which feedbacks affect Earth system functioning remains limited. Climate change and other anthropogenic pressures are already negatively affecting ecological processes in marine, freshwater, and terrestrial ecosystems. These will most likely be amplified in the coming decades under our current warming and socioeconomic pathways. The knock-on impacts on ecological feedbacks have the potential to cause rapid perturbations to the Earth system, and may significantly impact the structure and …

Geographic Distribution: Pseudacris Sierra (Sierran Treefrog). Usa: Florida: Escambia Co., Justin A. Anto, Logan P. Cutts, Jakira A. Davis, Dyrana N. Russell, Renee M. Shiska, Kayla L. O. Walker, Louis A. Somma

Papers in Herpetology

No abstract provided.

Enhancing The Recovery Of Threatened And Endangered Shorebird And Plant Species In Southampton, New York: A Structured Policy Analysis Approach, Joann Smith

Electronic Theses & Dissertations (2024 - present)

Settled on the eastern end of the most human populated island in North America, Long Island, New York, is the Town of Southampton. The Towns’ Board of Trustees are responsible for the management of federal or state listed species, which they carry out through their Threatened and Endangered Species Program (T&E program). Currently the program manages two listed shorebirds and two listed seabeach plants; the Piping plover (Charadrius melodus), a federally threatened species, and the Least Tern (Sternula antillarum), a New York State threatened species, Seabeach amaranth (Amaranthus pumilus), both federal and state threatened, and …

Chesapeake Bay Water Clarity: Challenges And Successes, Jessica S. Turner, Carl T. Friedrichs, David B. Parrish, Kelsey A. Fall

OES Faculty Publications

The Chesapeake Bay is a large estuarine system spanning multiple jurisdictions and serves as a model for estuarine health worldwide. Historically, nutrient loading degraded water quality, prompting the need for regulation. Water clarity, one component of water quality, is vital for benthic communities and serves as a key indicator of overall ecosystem health. Here, physical resuspension and salinity gradients, nutrient and sediment inputs, production of organic detritus by phytoplankton, and benthic communities all interact to drive clarity patterns, with high spatial variability. Trends over the last 50 years show improvement, though with a temporary increase in organic detritus in response …

Modeling Upper Ocean Ecosystem Dynamics In Response To Interannual Sea-Ice Variability In The Western Antarctic Peninsula, Catherine R. Czajka, Jessica S. Turner, Sharon Stammerjohn, Heather H. Kim, Oscar Schofield, Benjamin T. Saenz, Scott C. Doney

OES Faculty Publications

In the Western Antarctic Peninsula (WAP), marine plankton dynamics are tightly linked to the interannual variability in environmental conditions, including phenological shifts in sea-ice seasonality. To explore these linkages, we use a 1-dimensional vertical ocean-ice-ecosystem model (KPP-Eco-Ice, or KEI) that simulates physical and ecosystem conditions at a continental shelf mooring location in the Palmer Long Term Ecological Research program sampling grid. KEI allows for year-round examination of the ecosystem in a region where in situ observations on the shelf are limited to January. Comparisons are made between seasonal sea-ice retreat, mixed layer depth, primary productivity, and phytoplankton relative abundance, grazing, …

Microbial Mats In Dinosaur Ichnocoenoses, Nora Noffke, Paul C. Murphy, Roger C. Buntin, Martin G. Lockley

OES Faculty Publications

Until now, the significance of microbial mats in preservation of dinosaur tracks and in reconstructing the palaeoenvironment in which dinosaurs roamed was rarely studied. Dinosaur tracks are commonly found close to ancient aquatic bodies where moist sediment had once allowed footstep registration. At such sites, epibenthic or endobenthic microbial mats may have developed as well and may have led to exquisite track preservation. Microbial mats in coastal, lacustrine or flood plain environments cause 'microbially induced sedimentary structures—MISS', which are micobialites found in sandy or evaporitic settings. The microbial structures record environmental parameters including meteorological conditions that existed at the time …

Microplastics Suppress Copepod Grazing Of The Harmful Algal Bloom-Forming Dinoflagellate, Alexandrium Catenella, Megan Ladds, Christopher Gobler

OES Faculty Publications

While harmful algal blooms (HABs) are prominent occurrences in coastal zones where microplastic concentrations are maximal, the manner in which microplastics may influence food webs and HABs is poorly understood. This study explored how polystyrene microplastics affected copepod grazing of the saxitoxin-synthesizing harmful dinoflagellate, Alexandrium catenella, as well as a non-toxic dinoflagellate, Gymnodinium aureolum. Experiments were performed using multiple densities of microplastics (250 – 10,000 mL^–¹) of differing sizes (4 and 10 µm), as well as multiple densities of microalgae in microplates. The addition of 10 µm microplastics at densities of 1000 – 10,000 beads mL^{– …}

Water Mass Dynamics Drive Nitrogen Fixation Rates And Diazotroph Community Composition In The Coastal Region, Katherine E. Crider, Corday R. Selden, Kimberly Powell, Sing-How Tuo, Michael Muglia, Patterson Taylor, Margaret R. Mulholland, P. Dreux Chappell

OES Faculty Publications

Although significant N₂ fixation rates (NFRs) have been observed throughout mid-Atlantic coastal waters, studies have been limited in their temporal coverage, and the methods used to detect nitrogen fixers (diazotrophs) and their findings have varied. This study investigated NFRs and diazotroph communities in a dynamic coastal setting between Nags Head and Pea Island, North Carolina, USA, during a monthly time series from June 2019 to August 2020, and an August 2019 cruise. We observed movement of the Cape Hatteras Front and distinct NFRs and diazotroph communities in the Mid-Atlantic Bight, South-Atlantic Bight, Chesapeake Bay and Oregon Inlet plume waters, and …

Interactive Effects Of Bti Larviciding And Predation On Culex Pipiens And Its Ephemeral Pond Communities, Jaclyn S. Everly

Theses and Dissertations

Populations of adult vector mosquitoes can be controlled by reducing larval mosquito abundances in aquatic habitats. This can be achieved via predation by introduced or naturally-occurring enemies (i.e., biocontrol or conservation control) or by applying pesticides to larval mosquito habitats (i.e., larviciding). The larvicide Bacillus thuringiensis israelensis (Bti) is commonly applied to ephemeral ponds to control populations of Culex pipiens mosquitoes that vector West Nile virus. However, there is concern that Bti may directly or indirectly harm non-target organisms such as dragonfly and damselfly naiads, which provide a natural source of mosquito biocontrol. Bti or predators may also induce positive …

Managing Multi-Drug Resistance: An Evolutionary Game Theory And Optimal Control Approach, Shukhrat Nasrulloev

Theses and Dissertations

Multi-drug resistance is an evolutionary process in which treatment eliminates sensitive cells, allowing resistant clones to dominate. This thesis investigates this process using a framework integrating population dynamics, evolutionary game theory, and optimal control theory. We develop a two-population logistic growth model describing competition between drug-sensitive and drug-resistant cells under treatment, construct dose-dependent payoff matrices and replicator dynamics to characterize evolutionary competition, and derive a critical drug level D_crit = (r_S - rR)/(dS - d_R) at which resistant cells gain a fitness advantage. An optimal control problem is formulated via Pontryagin's Maximum Principle to identify schedules …