Ecology and Evolutionary Biology Commons^™

Quantifying Insect Emergence In Tidal Freshwaters And The Importance Of Aquatic Prey In Wetland-Dependent Songbird Diet, Samantha L. Rogers

Theses and Dissertations

Insectivorous birds and their arthropod prey are experiencing widespread population declines, driven largely by anthropogenic disturbance and climate change. For wetland-dependent insectivores that consume a mixture of terrestrial and aquatic insects, understanding the availability, consumption, and nutritional qualities of aquatic diet subsidies is important for conservation. I use prothonotary warblers (Protonotaria citrea) as a model species throughout this work, because their breeding season aligns with aquatic insect emergence and they include aquatic insects when provisioning nestlings. In the first chapter, I estimate aquatic insect emergence from tidal freshwaters, which are understudied compared to nontidal systems. Using continuous field …

Plant Trait Effects On Tidal Wetland Methane Emission, Adam M. Dunn

Theses and Dissertations

High rates of carbon (C) sequestration exhibited by coastal wetlands is an important natural climate solution to global environmental change. At the same time, however, wetlands are the largest natural source of methane (CH₄) to Earth’s atmosphere, a potent greenhouse gas that influences the global climate. Wetland CH₄ emissions display high degrees of uncertainty in accounting for spatial and temporal variations in emissions due to the complex interactions between biotic and abiotic factors that influence methane production and transport, in addition to simultaneous influences from climate-driven effects on wetlands such as rapid sea level rise and increased …

Stage-Structured Predator-Prey Interactions In A Warming World: A Case Study In Riverine Rock Pools, Andrew T. Davidson

Theses and Dissertations

Warming can impact predator-prey interactions through a variety of mechanisms. For example, warming can both alter the rate at which predators consume prey and the rate prey develop through vulnerable life stages. Thus, the overall effect of warming on consumer-resource interactions will depend upon the strength and asymmetry of warming effects on predator and prey performance. Here, we describe the consequences of these asymmetrical responses to temperature by first developing a simple stage-structured modeling framework, then applying that framework to predation of American rock pool mosquito larvae, Aedes atropalpus, by several common predators in riverine rock pools. We then …

Salinization Impacts On Heterotrophic Respiration, Ecosystem Respiration, And Plant Productivity In Tidal Freshwater Marshes, Kelsie J. Moses

Theses and Dissertations

Tidal freshwater marshes have preserved substantial stocks of soil carbon, which represents carbon dioxide that is no longer in the atmosphere. There is conflicting evidence in the literature about how disturbances such as sea level rise and associated wetland salinization impact the accumulation and long-term stability of this stored carbon. The goal of this experiment was to quantify how salinization impacts total ecosystem respiration and its component parts, autotrophic and heterotrophic respiration. This was a microcosm experiment using a C4 plant (Spartina cynosuroides) grown in soil derived from C3 plant matter and exposed to different salinities (0 to …

Population Demography Of A Neotropical Migratory Songbird In The Face Of A Changing Climate, Adele Balmer

Theses and Dissertations

This dissertation investigates the population dynamics and demographic trends of the Prothonotary Warbler (Protonotaria citrea), a migratory songbird that breeds in North America during the spring and summer and overwinters in Central and northern South America. The primary objective of this dissertation is to examine the combined implications of variation in weather and individual traits on demographic traits and to project the effects of climate change on population trajectories of the Prothonotary Warbler.

The analyses conducted in this dissertation centered around female Prothonotary Warblers; however, visual identification of a nestling’s sex is impossible in most altricial bird species, …

Epidemiological Assessment Of Wolbachia-Based Biocontrol For Reduction Of Dengue Morbidity, Olga Vasilieva, Oscar E. Escobar, Hector J. Martinez, Pierre-Alexandre Bliman, Yves Dumont

Biology and Medicine Through Mathematics Conference

No abstract provided.

De-Coupling Cell-Autonomous And Non-Cell-Autonomous Fitness Effects Allows Solution Of The Fokker-Planck Equation For The Evolution Of Interacting Populations, Steph J. Owen

Biology and Medicine Through Mathematics Conference

No abstract provided.

Gene Drives And The Consequences Of Over-Suppression, Cole Butler

Biology and Medicine Through Mathematics Conference

No abstract provided.

Parameter Estimation Using Nudging On The Logistic Growth Equation, Susan Rogowski

Biology and Medicine Through Mathematics Conference

No abstract provided.

Bioeconomic Analysis In A Predator-Prey System With Harvesting: A Case Study In The Chesapeake Bay Fisheries, Iordanka Panayotova, Maila Hallare

Biology and Medicine Through Mathematics Conference

No abstract provided.

Coupled Structure-Function Responses To Disturbance: High Structural Complexity Resistance Supports Primary Production Resistance, Kerstin M. Niedermaier

Theses and Dissertations

The capacity of forests to resist structural change and retain material legacies–the biotic and abiotic resources that persist through disturbance–is crucial to sustaining ecosystem functioning after disturbance. However, the role of forest structure as both a material legacy and feature supporting carbon (C) cycling stability following disturbance has not been widely investigated. We used a large-scale disturbance manipulation to ask whether LiDAR-derived canopy structures as material legacies drive 3-year responses of NPP to a range of disturbance severity levels. As part of the Forest Resilience Threshold Experiment (FoRTE) in northern Michigan, USA we simulated phloem-disrupting disturbances at a range of …

Advancing Forest Structure-Function Relationships: Linking Above- And Belowground Structure To Soil Respiration, Laura J. Hickey

Theses and Dissertations

Variation in the soil-to-atmosphere C flux, or soil respiration (Rs), is influenced by a suite of biotic and abiotic factors, including soil temperature, soil moisture, and root biomass. However, whether canopy structure is tied to soil respiration through its simultaneous influence over these drivers is not known. We assessed relationships between measures of above- and belowground vegetation density and complexity, and evaluated whether Rs is linked to remotely sensed canopy structure through pathways mediated by established biotic and abiotic mechanisms. Our results revealed that, at stand-scale, canopy rugosity–a measure of complexity–and vegetation area index were coupled to soil respiration through …

Biotic Characteristics Of Managed And Unmanaged Coastal Dunes In The Outer Banks, North Carolina, Andrew E. White

Theses and Dissertations

Under future climate change and sea level rise scenarios, Natural and Nature-Based Features (e.g., dunes) that protect coastal habitat and infrastructure will be exposed to increased wave energy and storm surge. Understanding how these forces will impact coastal dunes is necessary for their continued use as protective features. Coastal dunes develop through feedback between vegetation and sediment deposition, a process complicated by species-specific growth rates and responses to burial. Wave flume studies have tested the effects of dune vegetation on erosion and found multiple plant organs across several functional types to be important for resisting erosion. Although dune building and …

Quantifying Contributions Of Climate, Geography, And Gene Flow To Divergence: A Case Study For Three North American Pines, Constance E. Bolte

Theses and Dissertations

Long-lived species of trees, especially conifers, often display weak patterns of reproductive isolation, but clear patterns of local adaptation and phenotypic divergence. Discovering the evolutionary history of these patterns is paramount to a generalized understanding of speciation and the processes that confer population persistence versus those that compromise adaptive potential under rapidly changing environments. Forest trees have long generation times and low migratory potential making them especially vulnerable to population fragmentation and reductions of genetic diversity due to insufficient tracking of niche optima and adaptational lags. Within clades of the genus Pinus, evolutionary histories appear to be riddled with hybridization …

Evaluating Population Genetic Structure And Potential Genomic Signals Of Natural Selection In A Migratory Songbird (Protonotaria Citrea), Tyler A. Hohenstein

Theses and Dissertations

In this study I attempted to further resolve the population genetic structure in the Prothonotary Warbler (Protonotaria citrea), and conducted an outlier SNP analysis and exploratory gene ontology analysis to investigate potential ongoing natural selection in the species. This analysis of population structure confirms previous work by DeSaix et al. (2019), where weak population structure was observed between eastern sites along the Atlantic Coastal Plain, and western sites in the Mississippi Alluvial Valley, possibly due to a genetic discontinuity across the Appalachian Mountains. I conducted two forms of outlier SNP analyses, a principal component analysis (PCA)-based approach to identify SNPs …

Identifying The Human Homologs Of Yeast Rab Proteins Ypt10 & Ypt11 And A Global-Scale Louse Endosymbiont Genome Variation, Nathaniel P. Smith

Theses and Dissertations

Amyotrophic lateral sclerosis (ALS) is a late-onset fatal neurodegenerative disease that causes loss of upper and/or lower motor neurons, and currently has no treatment or cure available. Over 90% of cases occur spontaneously with unknown causes, highlighting the complexity of the disease, and only 10% of cases are linked to heritable genetic mutations. Numerous ALS-linked genes are conserved through evolution, and model organisms may therefore provide opportunities to understand disease pathology at a molecular or cellular level, proving instrumental in identifying therapeutic targets. ALS subtype 8 (ALS8) is caused by an autosomal dominant P56S mutation in the VAPB gene that …

Phenotypic Characterization Of Table Mountain (Pinus Pungens) And Pitch Pine (Pinus Rigida) Hybrids Along An Elevational Gradient In The Blue Ridge Mountains, Virginia, Alexander L. Brown

Theses and Dissertations

Hybridization has played a long-standing role in the evolution of both plant and animal species and allows for the sharing of genetic information between lineages. Here, potential hybridization of a species endemic to the Appalachian Mountains, Table Mountain pine (Pinus pungens), and pitch pine (Pinus rigida) was investigated along an elevational gradient, through the use of phenotypic measurements: cone length, cone width, and needle length. Phenotypes were used to identify hybrids in a three-tiered elevational sampling method at two sites in Shenandoah National Park with the use of linear discriminant analysis. It was found that hybridization …

Searching For Gold: Using A Novel Land Cover Classification To Identify Multiscale Drivers Of Site Occupancy By A Flagship Species For Early-Successional Habitat Conservation, Baron Lin

Theses and Dissertations

Understanding habitat selection at multiple scales is an important step in guiding conservation programs and reversing species declines. This, however, is difficult for species that occupy early-successional habitats (ESH) due to a lack of accurate representation of shrub cover in publicly available land cover data. The Golden-winged Warbler (Vermivora chrysoptera; GWWA) is a threatened species of conservation concern and a flagship for ESH conservation. We used a novel, LIDAR-derived land cover classification that accurately identifies shrubs at a fine resolution (1m) to investigate how habitat composition and configuration influence GWWA site occupancy. We aggregated this same land cover …

Plant Communities In Dynamic Systems: How Disturbance Influences Coastal Plant Community Structure And Function, Joseph K. Brown

Theses and Dissertations

As the climate continues to change it is difficult to predict how barrier island function will respond to global change drivers accompanying predicted climate change. Disturbance frequency and nutrient enrichment in coastal regions are drivers of plant community change that increase with climate change. Plant communities on barrier islands are not only tightly connected to barrier island function but are also some of the first communities affected by environmental change, making them a critical piece in understanding how current drivers of global change will impact the future of barrier islands. The objective of my dissertation was to observe and manipulate …

Movement, Home Ranges, And Population Estimates Of Spotted Turtles (Clemmys Guttata) During A Rainy Breeding Season In Virginia, Lauren J. Jurczak

Theses and Dissertations

Spotted turtles (Clemmys guttata) use a complex of wetland and terrestrial habitats for survival and reproduction. Precipitation expands and creates larger and more numerous ephemeral pools available to spotted turtles on the landscape. In this study, I investigated the effects of precipitation on movement patterns and ephemeral pool usage by spotted turtles in southeastern Virginia. I conducted a 4-month capture-mark-recapture study alongside a telemetry study to estimate population size and to quantify movement of spotted turtles across the landscape during the breading season. A change point analysis was used to detect discrete changes in turtle behavior and whether …

Effects Of Abiotic And Biotic Factors On Hornworm Distributions, Emelia O. Kusi

Theses and Dissertations

Determining the drivers of species occurrences is a central topic in ecology. Both abiotic and biotic factors are important predictors of species distributions, yet most species distribution models consider abiotic variables only. In this study, the influence of abiotic and biotic factors on current distributions of herbivores, Manduca sexta, and Manduca quinquemaculata, their major cultivated and wild host plants, and a parasitoid, Cotesia congregata, was quantified using an ensemble of three models (generalized linear model, maximum entropy, and random forest). The predictive ability of abiotic-only, biotic-only, and abiotic-biotic models was evaluated. Winter temperatures and precipitation (i.e., precipitation of …

Water Clarity At The River-Estuary Transition Zone: A Comparative Study Of The James, Mattaponi, And Pamunkey Sub-Estuaries, Rachel Henderson

Theses and Dissertations

Water clarity is a key parameter for monitoring water quality and often used to assess habitat suitability for submerged aquatic vegetation (SAV). Light attenuation, a measure of water clarity, is impacted by colored dissolved organic matter (CDOM), and by suspended particulates which include living and non-living components. We anticipated that the relative importance of these factors in regulating light attenuation would vary among the upper portions of three sub-estuaries differing in morphometry, hydrology, and degree of human influence. The James is characterized by eutrophic conditions and high algal abundance, whereas the Mattaponi and Pamunkey exhibit lower phytoplankton production. The Mattaponi …

A Spatiotemporal Assessment Of Fish Assemblage Response To Land-Use Change And The Evaluation Of Edna Metabarcoding For Describing Diverse Fish Communities, Timothy M. Owen

Theses and Dissertations

Fish assemblages are often assessed as a biological proxy for environmental health. While humans value healthy environments for the ecosystem services and recreational opportunities they provide, it is increasingly evident that such resources can be paradoxically degraded by anthropogenic activities. In this investigation, we studied the relationship between different intensities of anthropogenic land-use change and habitat-driven fish assemblage response across multiple spatiotemporal scales. Secondarily, we explored the efficacy of eDNA metabarcoding against conventional electrofishing techniques for the purpose of describing complete fish communities. This study was conducted in the Tuckahoe Creek basin near Richmond, Virginia. This James River tributary serves …

Successional Changes In Carbon Storage Are Sustained In A Temperate Forest Across Different Initiating Disturbances, Cameron Clay

Theses and Dissertations

Managing forests for carbon (C) sequestration requires an understanding of how disturbance history shapes C pools and fluxes over successional time. At the University of Michigan Biological Station, we examined how two stand establishing disturbances influenced C pools and fluxes over 100+ years of succession, comparing these secondary forests with “legacy” late-successional stands encompassing ages and compositions that would be present in the absence of region-wide stand-replacing disturbance. Our work utilized measurements taken between 2014 and 2020 from separate experimental forest chronosequences initiated following clear-cut harvesting only or clear-cut harvesting and fire, along with three >130-yr-old late successional stands comprising …

The Mechanisms And Consequences Of Shrub Encroachment On The Virginia Barrier Islands, Lauren K. Wood

Theses and Dissertations

Shrub encroachment is a global phenomenon driven by direct and indirect anthropogenic influence which alters plant communities and ecosystem function. Many studies have investigated drivers and consequences of woody plant establishment, but mesic landscapes are underrepresented in the literature. My objective was to assess the mechanisms of Morella cerifera encroachment into coastal mesic grassland, the potential for self-reinforcement, and consequences on community composition, nutrients, and landscape productivity. I studied temperature and water microclimate modification by Morella cerifera presence and removal to understand ecosystem engineering and community composition changes. Additionally, I examined the influence of shrubs on surrounding grassland species traits …

Density-Dependent Development Impacts The Success Of Wolbachia-Based Mosquito Control Programs, Alyssa Petroski, Lauren M. Childs, Michael Andrew Robert

Biology and Medicine Through Mathematics Conference

No abstract provided.

A Mathematical Approach To Understanding Eurasian Watermilfoil Growth, Spread, And Control, Diana White, Jonathan Martin, Isabel Dengos

Biology and Medicine Through Mathematics Conference

No abstract provided.

Modeling Vaccination Strategies To Control White-Nose Syndrome In Little Brown Bat Colonies, Eva Cornwell, David Elzinga, Shelby R. Stowe, Alex Capaldi

Biology and Medicine Through Mathematics Conference

No abstract provided.

Statistical Inference Of Adaptation At Multiple Genomic Scales Using Supervised Classification And A Hidden Markov Model, Lauren A. Sugden

Biology and Medicine Through Mathematics Conference

No abstract provided.

Eco-Evolutionary Dynamics Of Microbial Communities, Lihong Zhao

Biology and Medicine Through Mathematics Conference

No abstract provided.