Ecology and Evolutionary Biology Commons^™

Host Densities And Parasitism Rates In A Forest Defoliator Across A Rural-Urban Landscape, Abigail J. Nelson

Theses and Dissertations

Fall cankerworm (FCW) outbreaks have recently increased in frequency and intensity in the mid-Atlantic region of the United States, especially around cities of Charlotte, NC and Richmond, VA. This study evaluated the effects of two landscape features associated with urbanization, impervious surface and forest cover, on population patterns of FCW and its parasitoids across eastern Virginia. Forest cover was positively related to parasitism rates while impervious surface was positively related to FCW abundance, suggesting that FCW outbreaks may be amplified in urban areas. FCW abundance declined over the two-year period of this study, but parasitism rate increased at most sites. …

Communicating The Overall Experience Of Research Through Various Approaches Using Art: A Case Study Of The Prothonotary Warbler, Hannah Huddle, Lesley P. Bulluck, Sarah E. Faris

Rice Rivers Center Research Symposium

Recommended Citation

In general, scientific research has publication of data as the end goal. The process and experience, which are of great importance in art disciplines, is not necessarily represented or valued. However, science has an inherent element of art to it, which deserves to be shown. I have been studying Prothonotary Warblers with a team from the VCU Biology Department to learn how I can reinterpret the research in a way that bridges the gap between the experience and typical scientific products. The research team measured spatial and temporal variation in warbler prey abundance (caterpillars and mayflies) and assessed …

Emergent Non-Consumptive Predator Effects Alter Habitat Colonization By Mosquitoes, Ethan G. Staats, Salvatore J. Agosta, James R. Vonesh

Rice Rivers Center Research Symposium

Top-down consumptive control (suppression) is an important driver of populations and communities of prey organisms. Diverse predator assemblages often yield non-linear suppression with respect to constituent species' effects (emergence); most often diversity enhances suppression. Predators also affect prey organisms non-consumptively through changes in prey physiological, physical, spatial, temporal, and behavioral responses to predators. Role of predator diversity in non-consumptive response by prey is relatively un-studied. Role of predator diversity in shaping prey populations and communities through habitat colonization is a novel question.

Vegetation Structure Of Mangrove Ecosystems In Panama, Christopher L. Arrington, Cole Gandee, Spencer R. Parkinson

Rice Rivers Center Research Symposium

Mangroves provide important habitat for terrestrial and marine wildlife. They buffer shorelines from flooding and sequester excess nutrients and pollutants in runoff before reaching rivers and oceans. Mangroves provide a wintering habitat for migratory bird species. These habitats are being rapidly lost to coastal development. This research focused on assessing the vegetation structure of mangrove ecosystems in Panama.

Algal Toxins In The Food Chain – A Comparative Study Of Chesapeake Bay And Baltic Coastal Food Webs, Spencer Tassone, Jūratė Lesutienė, Zita Gasiūnaitė, Linas Ložys, Renata Pilkaitytė, Žilvinas Pūtys, Paul A. Bukaveckas

Rice Rivers Center Research Symposium

Microcystin (MC) is a hepatotoxin produced by cyanobacteria (blue-green algae) which is found globally in eutrophic waters including lakes, lagoons and estuaries (Paerl and Paul 2012). The presence of MC in food webs is of concern due to adverse effects on biota and exposure to humans via commercial and recreational fisheries (Paerl and Otten 2013). Little is known regarding the factors which determine MC accumulation in food webs. We hypothesized that dietary exposure would be determined in part by sources of organic matter supporting the food web. We undertook a comparative study of the James River Estuary, a sub-estuary of …

A Baseline Study Of Edaphic Characteristics, Vegetation Structure, And Recruitment Of Native Baldcypress (Taxodium Distichum (L). Rich. Var. Distichum) In The Newly Restored Wetland Of The Vcu Rice Rivers Center, Melissa J. Davis, Matthew S. Schibner

Rice Rivers Center Research Symposium

In theory, the ideal of ecological restoration is to reestablish a completely functioning ecosystem, however restoration success is often elusive (Stanturf et al. 2001). There is a significant gap in the current research on the impacts of restoration management of restored wetlands on ecosystem functions, especially biogeochemical cycling (Bernal & Mitsch 2013). Furthermore, there are many questions about management techniques when it comes to ecological engineering versus self-design (Bernal & Mitsch, 2013). However, we do know that it is critical to understand the species' life history, habitat template, and spatio temporal scope when attempting to re-establish populations (Lake et al. …

Using The Past To Restore The Future: Quantifying Historical Vegetation To Assist In Tidal Freshwater Wetland Restoration Former Lake Charles At The Vcu Rice Rivers Center, Christopher D. Gatens, 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.

Behavioral Observations: Foraging And Aggression Of Neotropical Migrants And Resident Birds In Panama, Jessica M. Johnston, Samuel B. King, Ryan A. Levering

Rice Rivers Center Research Symposium

Lyons suggests that foraging data in songbirds can be an indicator of food abundance, with higher attack rate= higher habitat quality; higher foraging speed= lower habitat quality (2005). Territorial behavior such as interspecific aggression among songbirds may also be related to food availability. Previous studies have documented variation in the extent of territorial and aggressive behaviors among resident and Neotropical migratory species on tropical wintering grounds. This research gathered foraging and aggression data at two coastal angroves sites in central Panama, one on the Caribbean Coast (Galeta) and one on the Pacific Coast (Juan Diaz-East). Foraging data was used an …

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

UROP Posters

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 damming and filling. Both occurred along Kimages Creek in Charles City County, VA during the 19^th and 20^th centuries. In 2010 the Lake Charles dam was partially removed, restoring the creek’s tidal communication with the James River. Upon the recession of the body of water, numerous woody stumps were revealed. We studied these stump remnants in an attempt to assess …

The Effects Of Hydropeaking On Lotic Benthic Macroinvertebrate Assemblages, Andrew L. Garey

Theses and Dissertations

The term hydropeaking refers to anthropogenically induced, short-duration, high-magnitude discharge pulses that are generated in lotic systems for electricity production. The practice of hydropeaking produces the largest source of renewable energy worldwide, and its use is projected to increase through the year 2040. The primary objective of this work was to evaluate the effects of hydropeaking on benthic macroinvertebrate assemblages, which are important components of lotic ecosystems. Results of this work show that, across a wide range of impacted systems worldwide, the consistently observed patterns of elevated benthic macroinvertebrate drift in response to hydropeaking pulses are primarily related to the …

The Export Of An Algal Toxin Into Terrestrial Predators Via Emerging Aquatic Insects, Nicholas J. Moy

Theses and Dissertations

Algal blooms are directly related to human-caused nutrient enrichment of water bodies. The cyanobacteria Microcystis aeruginosa produces microcystin (MC), a toxin that has been linked with mortalities and illness of many organisms. We show that MC is not constrained by the aquatic-terrestrial ecotone. MC was detected in a primary consumer and emerging aquatic invertebrate (Hexagenia Mayfly), a terrestrial insect and predator of emerging aquatic invertebrates (Tetragnathidae Spider), and a vertebrate consumer (Prothonotary Warbler). Mayfly and spider MC levels varied across the blooming period. MC levels in prothonotary warbler livers varied by age class; nestlings having the highest levels. MC levels …

Emergent Non-Consumptive Predator Effects Alter Habitat Colonization By Dipteran Prey, Ethan G. Staats

Theses and Dissertations

When ovipositing, prey organisms avoid habitat patches containing predator cues because predators consume, and negatively affect the fitness of their prey. Richness of predator species often enhances the strength of consumptive predator effects, but little is known about how multiple predators combined affect prey non-consumptively. We quantified dipteran colonization in aquatic mesocosms in response to varied predator richness. Multiple predator species combined reduced oviposition by Culex mosquitoes, chironomid midges, and the general colonizing dipteran community more than predicted by the effects of the independent predator species. Previous research which quantifies effects of multiple predators on prey as prey abundance, but …

Expanding Eco-Visualization: Sculpting Corn Production, Jennifer E. Figg

Theses and Dissertations

This dissertation expands upon the definition of eco-visualization artwork. EV was originally defined in 2006 by Tiffany Holmes as a way to display the real time consumption statistics of key environmental resources for the goal of promoting ecological literacy. I assert that the final forms of EV artworks are not necessarily dependent on technology, and can differ in terms of media used, in that they can be sculptural, video-based, or static two-dimensional forms that communicate interpreted environmental information. There are two main categories of EV: one that is predominantly screen-based and another that employs a variety of modes of representation …

Behavioral Responses Of Male Parasitic Wasps To Plant Cues: A Comparison Of Two Host-Plant Complex Sources Of Cotesia Congregata (Say), Megan Ayers

Theses and Dissertations

Prior exposure to plants cues can enhance assortative mating in insects. We hypothesized that, as previously reported for females, males of Cotesia congregata would display inherent responses to plant cues that could be modified by postemergence experience and further, that males originating from two different host-plant complexes (HPCs) would display different behavioral responses to these HPCs. In no-choice contact assays with a non-host plant, searching responses of males and females increased sharply at Day 2 and remained stable through Day 4. In no-choice assays with potential host plants, males searched longer on catalpa than tobacco; responses were not modified by …

Speed And Resolution In The Age Of Technological Reproducibility, Shawn Taylor

Theses and Dissertations

The rate of acceleration of the biologic and synthetic world has for a while now, been in the process of exponentially speeding up, maxing out servers and landfills, merging with each other, destroying each other. The last prehistoric relics on Earth are absorbing the same oxygen, carbon dioxide and electronic waves in our biosphere as us. A degraded .jpeg enlarged to full screen on a Samsung 4K UHD HU8550 Series Smart TV - 85” Class (84.5” diag.). Within this composite ecology, the ancient limestone of the grand canyon competes with the iMax movie of itself, the production of Mac pros, …

Consequences Of Vine Infestation: Linking Abiotic Influences And Biotic Interactions To Successional And Structural Changes In Coastal Communities, Spencer N. Bissett

Theses and Dissertations

Located at the interfaces of terrestrial and marine environments, coastal habitats are inherently vulnerable to the effects of global change. Barrier island systems in particular serve not only as protective buffers against storm events, but also as sentinel ecosystems for observation of the impacts of sea level rise, and of increasing storm frequency and intensity. In the mid-Atlantic region, shrub thickets of Morella species compose the dominant forest community. The often monospecific nature of these plant community assemblages is advantageous to ecological studies and cross-scale applications; the relatively low diversity facilitates transitions between scales. My objective was to investigate the …

Effects Of Constant Vs. Fluctuating Temperatures On Performance And Life History Of The Herbivorous Pest Lymantria Dispar (Lepidoptera: Eribidae), Brendan E. Sostak

Theses and Dissertations

The role of temperature variation in organismal performance is understudied, but is critically important for understanding the response of biodiversity to climate change. To address this issue in herbivorous insects, I studied the direct and interactive effects of thermal regime (constant vs. fluctuating temperatures) and nutrition (dietary nitrogen) on gypsy moth (Lymantria dispar) performance under laboratory conditions. Predictions for differences between constant and fluctuating thermal conditions were derived from Jensen’s inequality, and artificial diets of differing nutritional quality were made by modifying nitrogen (casein) content. Larvae were reared in the laboratory under four temperature regimes (22°C constant, 22°C …

Responses Of The Catalpa Sphinx, Ceratomia Catalpae, And Its Primary Parasitoid, Cotesia Congregata, To Varying Levels Of Iridoid Glycosides In Catalpa, Jessica L. Bray

Theses and Dissertations

The catalpa sphinx, Ceratomia catalpae, is a specialist on Catalpa trees, which produce iridoid glycosides (IGs). Whereas some trees are defoliated every year, others escape herbivory. Caterpillar populations are either heavily parasitized by the braconid wasp, Cotesia congregata, or remain unparasitized. We hypothesized that these patterns could be explained by variable IG concentrations among trees and insect responses to these chemicals. IG concentrations varied among trees. Percent defoliation was positively related to IG concentration. In comparisons of insect responses to relatively high or low IG concentrations, moths preferred to oviposit on trees with high IG concentrations. Caterpillars did …

Physical And Biological Constraints On The Abundance Of Cyanobacteria In The James River Estuary, Brendan C. Trache

Theses and Dissertations

The tidal-fresh James River experiences recurring blooms of toxin-producing cyanobacteria, including Microcystis aeruginosa. However, cyanobacteria cell densities in the James are relatively low. Our purpose was to identify key factors suppressing cyanobacteria growth in the face of eutrophication. A mesocosm experiment was designed to test the effects of light, mixing and grazing on cyanobacteria abundance, with nutrients held constant. We predicted that toxic cyanobacteria would be most abundant under stagnant conditions, with enhanced light, with no bivalve grazers present. Abundances of indicator gene copies and phytoplankton counts supported this hypothesis. However, chlorophyll-a, phycocyanin, and the toxin microcystin were all …

Coarse Woody Debris And The Carbon Balance Of A Moderately Disturbed Forest, Amy V. Schmid

Theses and Dissertations

Landscapes are comprised of multiple ecosystems shaped by disturbances varying in severity and source. Moderate disturbance from weather, pathogens, insects, and age-related senescence, in contrast to severe disturbances that fell trees, may increase standing woody debris and alter the contribution of coarse woody debris (CWD) to total ecosystem respiration (R_E). However, woody debris dynamics are rarely examined following moderate disturbances that substantially increase standing dead wood stocks. We used an experimental manipulation of moderate disturbance in an upper Great Lakes forest to: 1) examine decadal changes in CWD stocks through a moderate disturbance; 2) quantify in situ CWD …

Regional And Scale-Specific Effects Of Land Use On Amphibian Diversity [Poster], James R. Vonesh, David Marsh, J. J. Apodaca, Karen H. Beard, Jane M. Bell, Christine Bozarth, Derrick Carper, Julie Charbonnier, Bradley J. Cosentino, Andreia Dantas, Elizabeth A. Forys, Miranda Foster, Jaquelyn General, Kristen S. Genet, Macie Hanneken, Kyle Hess, Shane Hill, Faisal Iqbal, Kara Jones, Nancy E. Karraker, Eran Kilpatrick, Tom A. Langen, James Langford, Katherine Lauer, Alison J. Mccarthy, Joseph Neale, Saumya Patel, Austin Patton, Cherie Southwick, Nathaniel Stearrett, Nick Steijn, Mohammad Tasleem, Joseph Taylor

Biology Presentations

Background/Question/Methods

Habitat loss and degradation influence amphibian distributions and are important drivers of population declines. Our previous research demonstrated that road disturbance, development and wetland area consistently influence amphibian richness across regions of the U.S. Here, we examined the relative importance of these factors in different regions and at multiple spatial scales. Understanding the scales at which habitat disturbance may be affecting amphibian distributions is important for conservation planning. Specifically, we asked: 1) Over what spatial scales do distinct landscape features affect amphibian richness? and 2) Do road types (non-rural and rural) have similar effects on amphibian richness? This is …

On The Challenges Of Modeling The Net Radiative Forcing Of Wetlands: Reconsidering Mitsch Et Al. 2013, Scott C. Neubauer

Biology Publications

Wetlands play a role in regulating global climate by removing carbon dioxide (CO2) from the atmosphere and sequestering it as soil carbon, and by emitting methane (CH4) and nitrous oxide (N2O) to the atmosphere. In a recent article in this journal (Mitsch et al. Landscape Ecol 28:583–597, 2013), CO2 sequestration and CH4 emissions were modeled for several freshwater wetlands that vary in vegetation type, climate, and hydrology. The authors of that study made significant errors that caused them to underestimate the importance of wetland CH4 emissions on climate dynamics. Here, I reanalyze the Mitsch et al. dataset and show that …

Aquatic Priming Effects In The York River Estuary And Implications For Dissolved Organic Carbon Mineralization, Thomas M. Dunlap

Theses and Dissertations

The priming effect (PE), characterized as the enhanced microbial processing of bio-recalcitrant organic matter with the addition of labile substrates, has been hypothesized to moderate carbon (C) cycling in aquatic systems. In this study, aquatic PEs were evaluated through bacterial respiration and dissolved organic C consumption in incubations of water collected from three locations along the York River estuary. Incubations from White’s Landing on the Pamunkey River, a tidal freshwater tributary of the York, and from Croaker Landing in the middle of the estuary, displayed positive PEs when amended with labile C. In contrast, amended incubations from Gloucester Point, near …

Non-Lethal Effects Of Dragonfly Predators On The Interactions Between The Tadpoles Of Two Neotropical Hylid Frogs [Poster], Zacharia Costa, James R. Vonesh

Biology Presentations

Background/Question/Methods

Prey frequently alter their phenotype in response to perceived predation risk in order to reduce vulnerability. Differences in the costs and benefits of such plastic responses to predators can lead to differences in non-consumptive predator effects. Such differences can occur between taxa or through ontogeny for a given species, and may alter interactions between prey and other species in the food web. Less vulnerable prey may respond less to predator cues compared to vulnerable prey and thus may have higher performance in risky environments. Here we build upon previous research on the tadpoles of two hylid treefrogs, Agalychnis callidryas …

Interactions Between Competition And Predation Shape Early Growth And Survival Of Two Neotropical Hylid Tadpoles [Poster], Sergio C. Gonzalez, Justin C. Touchon, James R. Vonesh

Biology Presentations

Background/Question/Methods

Recent literature reviews reveal that competition typically has stronger effects on growth than the presence of predators, while predation has larger effects on survival. Further, past studies show that predators typically lessen the negative effect of competition on growth and also make interspecific competition beneficial for the survival of focal species. We examine the independent and combined effects of competition and predation for survival and growth of the tadpoles of two co-occurring Neotropical hylid frogs (Agalychnis callidryas and Dendropsophus ebraccatus). Our experiment crossed tadpole species composition (single and mixed at single total density) with the presence or absence of …

Terrestrial Predators And Abiotic Conditions Affect Hatching Survival Of Arboreal Frog Eggs: Implications For Aquatic Food Web Dynamics [Poster], Jessica Hite, James R. Vonesh

Biology Presentations

Background/Question/Methods
Recent work in food web studies has highlighted the importance of terrestrial and aquatic linkages and the trait and density-mediated effects of predators and abiotic conditions. Many studies have focused on species with complex life histories (amphibians and aquatic insects) because they encompass a variety of trophic levels and form important linkages between terrestrial and aquatic food webs. For example, red-eyed treefrog, Agalychnis callidryas eggs are deposited on vegetation overhanging ponds and risk mortality from a variety of terrestrial predators and abiotic stressors. Red-eyed treefrog embryos, however, exhibit phenotypic plasticity in hatching time in response to these terrestrial stressors. …

Life-Centered Ethics And The Human Future In Space, Michael Noah Mautner

Chemistry Publications

In the future, human destiny may depend on our ethics. In particular, biotechnology and expansion in space can transform life, raising profound questions. Guidance may be found in Life-centered ethics, as biotic ethics that value the basic patterns of organic gene/protein life, and as panbiotic ethics that always seek to expand life. These life-centered principles can be based on scientific insights into the unique place of life in nature, and the biological unity of all life. Belonging to life then implies a human purpose: to safeguard and propagate life. Expansion in space will advance this purpose but will also raise …

Seeding The Universe With Life: Securing Our Cosmological Future, Michael Noah Mautner

Chemistry Publications

Life is unique in Nature, and for us, it is precious. Life is unique in its complex patterns, and in its purposeful self-continuation. We belong to life and share its drive for self-propagation. Belonging to life then implies a human purpose to secure, expand and propagate our family of gene/protein life.

This purpose is best achieved in space, where life has an immense future. We can start now to secure this future, by seeding with life new solar systems. New species can develop there into intelligent beings who will further expand life in the galaxy. Filling the universe with life …

Planetary Bioresources And Astroecology 1. Planetary Microcosm Bioassays Of Martian And Carbonaceous Chondrite Materials: Nutrients, Electrolyte Solutions, And Algal And Plant Responses, Michael Noah Mautner

Chemistry Publications

The biological fertilities of planetary materials can be assessed using microcosms based on materials in martian and carbonaceous chondrite meteorites. Their biological fertilities are rated based on soluble electrolyte nutrients, on the growth of mesophile and cold-tolerant algae, and of plant tissue cultures. The Murchison CM2 carbonaceous chondrite meteorite and DaG 476 martian shergottite contain high levels of water-extractable Ca, Mg, and SO4–S. The martian meteorites DaG 476 and EETA 79001 also contain high levels of extractable nutrients NO3–N (0.013–0.017 g kg⁻¹) and PO4–P (0.019–0.046 g kg⁻¹). The yields of most of the water-extractable …

Space-Based Genetic Cryoconservation Of Endangered Species, Michael Noah Mautner

Chemistry Publications

Genetic materials of endangered species must be maintained, for cryoconservation, permanently near liquid nitrogen temperatures below 77 K. Due to the instability of human institutions, permanent safety is best provided at storage sites that maintain passively the needed low temperatures, and provide barriers to access. The required conditions are available in permanently shaded polar lunar craters with equilibrium temperatures of 8 to 40 K, on the moons of Saturn, and unshielded storage satellites. A genetic depository can be incorporated readily into planned lunar programmes.