Ecology and Evolutionary Biology Commons^™

A Comparative Analysis Of Geometric Morphometrics Across Two Pseudemys Turtle Species In East Central Virginia, Kristin C. Dillard

Theses and Dissertations

The phylogeny of the turtle genus Pseudemys is poorly understood. In Virginia, many turtles have been found with indicator traits of both eastern river cooters (Pseudemys concinna concinna) and northern red bellied cooters (Pseudemys rubriventris). This study explores morphological evidence for hybridization between the two species across three riverine sites in east central Virginia.

Museum voucher groups for each species were analyzed for relative shell height and plastron length. The shape of the plastral scutes and upper jaw were analyzed using landmark-based morphometric software. These metrics were compared with measurements taken from 188 field-caught Pseudemys specimens. …

A Range-Wide Assessment Of Migratory Connectivity For The Prothonotary Warbler Using Stable Hydrogen Isotopes, Jessica Reese

Theses and Dissertations

Populations of many species of migratory birds are declining, and an understanding of how populations are linked between the breeding and nonbreeding grounds is necessary in order to determine drivers of declines. While all current tracking technologies to study the movements of small songbirds are limited by their coarse resolution, tracking birds by measuring stable isotopes in keratin offers an advantage because it requires only a single capture and is cost-effective, which leads to robust sample sizes. While this tracking method is accurate, stable hydrogen isotope values measured in feathers (δ²H_f) are known to be variable …

Quantifying Current Sediment Deposition, Legacy Sediments, And Pre-Impoundment Vertical Accretion And Carbon Dynamics Following Dam Removal In A Recently Restored Tidal Freshwater Wetland, Melissa J. Davis

Theses and Dissertations

Damming disrupts natural sediment flow to downstream resulting in legacy sediment accumulation. Legacy sediments have been well investigated in streams throughout the Piedmont region; however, there is no research of legacy sediments following dam removal in low-gradient Coastal Plain streams. Research objectives were to: characterize legacy sediments in a low-gradient stream restoration, quantify pre-impoundment accretion and carbon dynamics, and assess current sediment deposition rates via ¹⁴C analyses within sediment cores and sediment collection tiles. Carbon accumulation and accretion rates of modern tidal sediment have reached that of the tidal relic benchmark and current sediment deposition rates are similar between …

The Effect Of Chronic Nutrient Addition From Wastewater On Forest Ecosystems At The Rice Rivers Center, Michael Beck

Theses and Dissertations

Wastewater application to land can be a useful tool for mitigating impacts of nutrient enrichment on aquatic systems. A land application treatment system at VCU’s Rice Rivers Center in Charles City County, VA provided an opportunity to study the impact of wastewater addition on the biogeochemistry of forests representative of the Mid-Atlantic Coastal Plain. Nutrient concentrations in throughfall and leachate were measured at Treatment and Control sites to assess differences in nutrient deposition and retention. Wastewater amended plots from the Walter L. Rice education building received 20-fold (N) and 6-fold (P) higher inputs relative to Control plots and plots located …

Anticipating Elimination Of Mosquito-Borne Diseases, Suzanne M. O'Regan, Jonathan Lillie, John M. Drake

Biology and Medicine Through Mathematics Conference

No abstract provided.

The Influence Of Temperature Variation On Dengue Fever: A Model-Based Investigation, Michael A. Robert, Paula D. Weber, Rebecca C. Christofferson, Christopher N. Mores, Helen J. Wearing

Biology and Medicine Through Mathematics Conference

No abstract provided.

Dynamics Of Two Pathogens In A Single Tick Population, Alexis White

Biology and Medicine Through Mathematics Conference

No abstract provided.

Growth Dynamics For Pomacea Maculata, Lihong Zhao, Karyn L. Sutton, Jacoby Carter

Biology and Medicine Through Mathematics Conference

No abstract provided.

Spatial Patterning In The York River Tidal Marshes Through The Interaction Of Cordgrass, Mussels And Sediment, Sofya Zaytseva, Leah Shaw, Rom Lipcius, Junping Shi

Biology and Medicine Through Mathematics Conference

No abstract provided.

Movement And Dynamics Of Norway Rats In An Urban Landscape, Rosalyn Rael, Caz Taylor

Biology and Medicine Through Mathematics Conference

No abstract provided.

Characterization Of Current And Historical Variations In Sediment Accretion And Carbon Dynamics At The Rice Rivers Center Kimages Creek Wetland Restoration, Melissa J. Davis, Christopher D. Gatens, Edward R. Crawford, Arif Sikder

Rice Rivers Center Research Symposium

Current research of freshwater wetland soils have assessed and reported smaller stocks of soil organic carbon in restored wetlands compared to reference natural wetlands. However, a majority of these studies focus on sites restored from agricultural draining of non-tidal depressional wetlands,whereas carbon and accretion dynamics in tidal freshwater wetlands restored via dam removal is poorly understood. The U.S. Army Corps of Engineers estimates over 80,000 dams greater than 6 feet and tens of thousands of smaller dams pepper the U.S., of which the majority are unsafe, old or no longer serve their intended purpose. Damming disrupts the natural flow of …

An Analysis Of Particulate Matter In Central Virginia, Elizabeth Garrett, Arif Sikder

Rice Rivers Center Research Symposium

Virginia is consistently rated as a state with high rates of asthma (Asthma and Allergy Foundation 2014). Although this respiratory disease has many causes, certain air pollutants can be a trigger. The EPA currently identifies, monitors, and regulates seven types of air pollutants. One of these pollutants, particulate matter, can occur both naturally and culturally. The primary anthropogenic cause of particulate matter is fly ash, which is formed during fossil fuel combustion. Different technology installed in the power plant can capture some of the fly ash but these methods are not entirely effective.

This study focused on estimating the ratio …

Assessing How Disruption Of Methanogenic Communities And Their Syntrophic Relationships In Tidal Freshwater Marshes Via Saltwater Intrusion May Affect Ch4 Emissions, David J. Berrier, Scott C. Neubauer, Rima B. Franklin

Rice Rivers Center Research Symposium

Tidal freshwater wetlands (TFW), which lie at the interface of saltwater and freshwater ecosystems, are predicted to experience moderate salinity increases due to sea level rise. Increases in salinity generally suppress CH4 production, but it is uncertain to what extent elevated salinity will affect CH4 cycling in TFW. It is also unknown whether CH4 production will resume when freshwater conditions return. The ability to produce CH4 is limited to a monophyletic group of the Euryarchaeota phylum called methanogens (MG), who are limited to a small number of substrates (e.g., acetate, H2, and formate) produced from the breakdown of fermentation products. …

Effects Of Olfactory Cues On The Foraging Behavior Of A Carabid Beetle, Calosoma Wilcoxi, A Predator Of A Forest Defoliator., Kennesha J. Myrick-Bragg, Karen Kester, Derek M. Johnson

Rice Rivers Center Research Symposium

Arthropod predators use environmental cues such as kairomones to locate herbivore prey. Several species have been shown to be attracted to volatiles emitted by herbivore host plants, as well as olfactory cues produced by the herbivore. Calosoma wilcoxi is a voracious predator that specializes on lepidopteran larvae often found in the forest canopy, showing a preference for the fall cankerworm. It is unknown whether C. wilcoxi uses olfactory cues associated with prey or their host plants to locate foraging sites.

The objective of this study is to use fall cankerworm frass, caterpillars, damaged oak leaves, and conspecifics to determine if …

Using The Past To Restore The Future: Quantifying Historical Vegetation To Assist In Tidal Freshwater Wetland Restoration, Christopher D. Gatens, Richard Ward, Edward R. Crawford

Rice Rivers Center Research Symposium

Wetlands have been providing humans with critical natural ecosystem services throughout our time on Earth. Nevertheless, these invaluable ecosystems have been habitually altered as a cost of human progression. Two of the most common alterations to wetlands are hydrologic, in the form of damming, and filling. Both occurred along Kimages Creek in Charles City County, VA during the 19th and 20th centuries. In 2010 the Lake Charles dam was partially removed, restoring the creek's tidal communication with the James River and beginning tidal forested freshwater wetland restoration. Upon the recession of the body of water, numerous woody stumps were revealed.

Greenhouse Gas Emissions Over A Tidal Cycle In A Freshwater Wetland, Joseph C. Morina, Rima B. Franklin

Rice Rivers Center Research Symposium

Tidal freshwater wetlands are located at the interface of non-tidal freshwater riverine systems and estuarine tidal systems. These habitats experience freshwater tides, creating unique redoximorphic soil characteristics while simultaneously presenting an opportunity for hydrologic nutrient transport into the system. Because of this periodic flooding and draining, tidal freshwater wetlands are systems of intense biogeochemical transformations, which are microbially mediated. Several microbial transformations (e.g., methanogenesis, incomplete denitrification, and nitrification) result in the production of greenhouse gases (CO2, CH4, and N2O) at globally-significant levels. For example, wetlands are one of the greatest sources of methane on Earth, accounting for 20-33% of the …

Tower-Based Greenhouse Gas Fluxes In A Restored Tidal Freshwater Wetland: A Shared Resource For Research And Teaching., Ellen J. Stuart-Haëntjens, Scott C. Neubauer, Christopher M. Gough

Rice Rivers Center Research Symposium

The goals of this study are: 1) to use an eddy-covariance system to continuously measure wetland-atmosphere CO2 and CH4 exchange in a restored forested wetland, 2) to quantity C sequestration in plant biomass and soils in restored (Kimages Creek watershed) and old-growth (Harris Creek watershed) forested wetlands, and 3) to establish a shared long-term, shared research and teaching platform centered on eddy-covariance tower measurements. Since the old-growth forest wetland has had longer to accumulate C, the current C stocks are likely much larger than those of the restored wetland; however, the rate of C accumulation (i.e., C sequestration or net …

Wood Frog And Spotted Salamander Abundance Across Pool Types And Wetland Networks At Fort A.P. Hill, Va, Logan Mcdonald, Will Fields, Katelyn Horn, James R. Vonesh, Kristine Grayson

Rice Rivers Center Research Symposium

Effective management of pond breeding amphibians requires identifying suitable breeding habitat and its use by different species. Suitable breeding habitat is largely characterized by pool type, physical habitat, and position within the landscape. Parameters such as vegetative cover, hydrology, and water chemistry are known to influence amphibian occupancy of vernal pools. While seasonal vernal pools have been the focus of conservation efforts, pools that are an artifact of anthropogenic disturbance, such as road ruts, may be an important component of the landscape for amphibians. The role of wetland isolation within a landscape has been well studied, but less consideration has …

Upper Thermal Limits Differ Among Component Species In A Host-Parasitoid-Hyperparasitoid System, Kanchan A. Joshi

Theses and Dissertations

Among the predicted impacts associated with global climate change, warming is of special interest because the rates of physiological processes are temperature-dependent. Insects and other ectotherms are likely to be affected due to their limited ability to control body temperature. In this study, I measured the tolerance to extreme high temperatures, i.e., critical thermal maximum (CT_max), of component species in a tri-trophic system, including an herbivore (Manduca sexta), a primary larval parasitoid (Cotesia congregata) and a hyperparasitoid (genus Silochalcis). For wild insects, the parasitoid had the lowest CT_max, the hyperparasitoid had …

From Seed To Sky: Impacts Of Explosive Compounds On Vegetation Across Spatial And Developmental Scales, Stephen M. Via

Theses and Dissertations

Explosive compounds are broadly distributed across the globe as a result of nearly two centuries of munitions use in warfare and military activities. Two explosive compounds have seen disproportionate use; RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2-methyl- 1,3,5-trinitrobenzene), being the most commonly found explosives in the environment. The effects of explosives on biota have been studied in great detail; however, there is a general lack of understanding with regard to broader ecological impacts of these contaminants. My dissertation objective was to follow the impacts of explosive compounds on vegetation across scales. Impacts on vegetation at the species scale alter community composition via …

Independent Origination Of Floral Zygomorphy, A Predicted Adaptive Response To Pollinators: Developmental And Genetic Mechanisms, Ghadeer Bukhari, Wenheng Zhang

Theses and Dissertations

Observations of floral development indicate that floral organ initiation in pentapetalous flowers more commonly results in a medially positioned abaxial petal (MAB) than in a medially positioned adaxial petal (MAD), where the medial plane is defined by the stem and the bract during early floral development. It was proposed that the dominant MAB petal initiation might impose a developmental constraint that leads to the evolution of limited patterns of floral zygomorphy in Asteridae, a family in which the floral zygomorphy develops along the medial plane and results in a central ventral (CV) petal in mature flowers. Here, I investigate whether …

Seasonal Variation Of Fish And Macroinvertebrate Biomass Spectra In Southern West Virginia Streams, Andrew J. Kirk

Theses and Dissertations

The biomass size spectrum - the power-law scaling relationship between average individual size and total biomass - has often been studied in lake and marine ecosystems, but rarely in lotic systems. The objective of this study was to test for characteristic biomass spectra in small temperate streams. Seasonal fish and macroinvertebrate data, including population abundance and biomass estimates, were collected in three wadeable, southern West Virginia streams from October 2013 to May 2015. Fish abundances were estimated with 3-pass electrofishing (depletion) surveys and individuals were weighed in the field. Macroinvertebrates were collected with a Hess sampler and returned to the …

Differential Response Of Barrier Island Dune Grasses To Species Interactions And Burial, April Harris

Theses and Dissertations

Dune grasses are integral to biogeomorphic feedbacks that create and alter foredunes and barrier island stability. In a glasshouse study, Ammophila breviligulata Fern. and Uniola paniculata L. were planted together and subjected to sand burial to quantify morphological and physiological response. Ammophila breviligulata physiological and morphological performance declined when planted with U. paniculata but U. paniculata was not affected when planted with A. breviligulata. Burial had a positive effect on A. breviligulata and U. paniculata as indicated by electron transport rate and total biomass at the end of the experiment. Due to their different growth strategies, A. breviligulata and …

Emergent Interactions Influence Functional Traits And Success Of Dune Building Ecosystem Engineers, Joseph K. Brown

Theses and Dissertations

Stability of coastal systems are threatened by oceanic and atmospheric drivers of climate change. Sea-level rise compounded with increased frequency and intensity of storms emphasizes need for protection of inner island systems by dune formations. Dune building processes are affected by interactions between growth of ecosystem engineering dune grasses and environmental factors associated with disturbance such as sand burial and salt spray. Climate change may also cause latitudinal expansion of some species, resulting in emergence of competitive interactions that were previously absent. Topographic structure of coastlines, traditionally influenced by sand burial, could change as a result of competition emergence. My …

The Microbiome In Light Of Host Evolution, Alexander M. Waldrop Jr.

Theses and Dissertations

Recent advances in sequencing technologies have provided an unprecedented window in the unseen biological world. Accompanying this revolution is a growing appreciation for the ubiquity and diversity of beneficial interactions between animals and the microbes they carry. Given the symbiotic roles of microbes in host nutrition, immunity, behavior, development, and nearly every other facet of host biology, it is becoming increasingly clear that any understanding of hosts and their evolution would be incomplete without also considering the microbial dimension. Yet despite the growing body of evidence that many of these partnerships are rooted deep in evolutionary time, the majority of …

Genome Wide Epigenetic Analyses Of Araptus Attenuatus, A Bark Beetle, Chitra Seshadri

Theses and Dissertations

Phylogeographic studies have relied on surveying neutral genetic variation in natural populations as a way of gaining better insights into the evolutionary processes shaping present day population demography. Recent emphasis on understanding putative adaptive variation have brought to light the role of epigenetic variation in influencing phenotypes and the mechanisms underlying local adaptation. While much is known about how methylation acts at specific loci to influence known phenotypes, there is little information on the spatial genetic structure of genome-wide patterns of methylation and the extent to which it can extend our understanding of both neutral and putatively adaptive processes. This …

The Effects Of Tidal Forcing On Nutrient Fluxes In The Tidal, Freshwater James River Estuary, Va, Dana L. Devore

Theses and Dissertations

A 12-month study (January to December 2015) focused on the effects of tidal forcing on nutrient fluxes in the tidal, freshwater segment of the James River Estuary (JRE). Discrete sampling of nutrient chemistry and continuous monitoring of tidal discharge were used to determine the volume and timing of the tides, and differences in nutrient concentrations between incoming and outgoing tides. The goal of this study was to improve understanding of tidal influence on nutrient fluxes and their role in nutrient transport to the lower estuary. Results suggested that differences in nutrient concentrations between incoming and outgoing tides were small throughout …

Influence Of Historic Landscapes And Contemporary Species Management On Chesapeake Bay Bald Eagles And Osprey, Catherine B. Viverette

Theses and Dissertations

Influence of historic landscapes and contemporary species management on Chesapeake Bay Bald Eagles and Osprey

Catherine B. Viverette

Co-distributed species with well documented demographic histories can provide good models for testing alternative hypotheses about the impact of evolutionary history, contemporary landscapes, and species management on current distribution and population structure. The Osprey (Pandion haliaetus) and Bald Eagle (Haliaeetus leucocephalus) have been extensively studied, managed and monitored across their North American breeding range, particularly in the Chesapeake Bay. We used a combination of ecological niche modelling, diet reconstruction, and population genetic modeling to understand the role of …

The Curiosity Of Con, Petrified Breath, And An Accident Known As Blue., Steven Randall

Theses and Dissertations

My thesis installation emerged from an interest in visualizing breath. The resulting work came to exist at the intersection between art, biology, and performance.

The unicorn tapestries were used as a generative point of departure to explore the preservation and transformation of images through time, by time, and with time. Reproductions of the six tapestries were each etched into paper and then submerged into solutions of Phenol Red dye, Ferric Ferrocyanide (also known as Prussian Blue), and various forms of sodium chloride. Exhaled breath was used to encrust these images of the tapestries into physical objects which gradually crystallized and …

Forest Stand Structure And Primary Production In Relation To Ecosystem Development, Disturbance, And Canopy Composition, Cynthia M. Scheuermann

Theses and Dissertations

Temperate forests are complex ecosystems that sequester carbon (C) in biomass. C storage is related to ecosystem-scale forest structure, changing over succession, disturbance, and with community composition. We quantified ecosystem biological and physical structure in two forest chronosequences varying in disturbance intensity, and three late successional functional types to examine how multiple structural expressions relate to ecosystem C cycling. We quantified C cycling as wood net primary production (NPP), ecosystem structure as Simpson’s Index, and physical structure as leaf quantity (LAI) and arrangement (rugosity), examining how wood NPP-structure relates to light distribution and use-efficiency. Relationships between structural attributes of biodiversity, …