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The first annual Interfaces of Global Change (IGC) Graduate Research Symposium will be held on Friday, April 22, 2016 in Fralin Hall.
[/vc_column_text][vc_tta_accordion active_section=”” collapsible_all=”true”][vc_tta_section title=”Abstract & Poster Guidelines” tab_id=”1538577375464-f5b871fd-f2c6″][vc_column_text]All IGC fellows are encouraged to present their work at the symposium. First-year students will give posters on their proposed research/study design; second- and third-year students have the option of presenting either a poster or a talk. Awards will be given for best talks.
Please submit your abstracts to Gloria Schoenholtz (schoeng@vt.edu) by March 28, 2016. Each abstract should contain 1) Title, 2) Authors and affiliations (e.g., Dept and University), and 3) an abstract not to exceed 250 words in length.
For posters: maximum poster size is 40″ x 60″. An easel and backboard will be provided.[/vc_column_text][/vc_tta_section][/vc_tta_accordion][vc_tta_accordion active_section=”” collapsible_all=”true”][vc_tta_section title=”Schedule” tab_id=”1538577640247-91072c23-5331″][vc_column_text]Friday, April 22, 2016
8:30-10:30 a.m. IGC IGEP Breakfast Forum with
Dr. Josh Tewksbury; Preston’s, Inn at Virginia Tech
11:15 a.m Poster setup; Fralin Hall Atrium
12:15 p.m Coffee & Posters (students by posters)
1:00 p.m. Welcome (Dr. Bill Hopkins); Fralin Auditorium
1:05 p.m. Opening Remarks (Vice President and Dean Karen DePauw)
1:30 p.m. Session 1 (S1); Session Chair: Laura Schoenle
1:30 p.m. S1 Talk 1 Corinne Diggins
1:45 p.m. S1 Talk 2 Jon Doubek
2:00 p.m. S1 Talk 3 Tamara Fetters
2:15 p.m. S1 Talk 4 Cathy Jachowski
2:30 p.m. Coffee Break w/ posters
3:00 p.m. Session 2 (S2); Session Chair: Tamara Fetters
3:00 p.m. S2 Talk 1 Ryan McClure
3:15 p.m. S2 Talk 2 Daniel Medina
3:30 p.m. S2 Talk 3 Laura Schoenle
3:45 p.m. S2 Talk 4 Ben Vernasco
4:00 p.m. S2 Talk 5 Carl Wepking
4:15 p.m. Poster Reception (students by posters)
6:00 p.m. Platform Award Announcements
6:30 p.m. Symposium Adjourns
DOWNLOAD SCHEDULE (pdf)[/vc_column_text][/vc_tta_section][/vc_tta_accordion][/vc_column][/vc_row][vc_row][vc_column][vc_column_text][heading_horizontal type=”h3″ margin_bottom=”10px”]ORAL PRESENTATIONS[/heading_horizontal][/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]
Platform Session 1 1:30 – 2:30 p.m.
Session Chair: Laura Schoenle
Comparison of survey techniques on detection probability of northern flying squirrels: Live trapping, camera traps, and ultrasonic acoustics
Authors: Corinne A. Diggins1, L. Michelle Gilley2, Christine A. Kelly3, and W. Mark Ford4
Affiliations: 1. Virginia Polytechnic Institute and State University, Blacksburg, Virginia, 24061 (CAD); 2. Mars Hill University, Mars Hill, NC, 28754 (LGM); 3. North Carolina Wildlife Resources Commission, Asheville, North Carolina, 28806 (CAK); 4. U.S. Geological Survey Virginia Cooperative Fish and Wildlife Research Unit, Blacksburg, Virginia, 24060 (WMF)
The ability to detect a species during surveys or monitoring is important for conservation and management, especially if the species is rare or endangered. Traditional methods can be labor intensive, invasive, and produce low detection rates. Technological advances may provide opportunities to efficiently survey for a species, while reducing field effort. We conducted a comparison study of one traditional technique (live trapping) and two novel non-invasive techniques (camera trapping and ultrasonic acoustic surveys) on detection rates of the Glaucomys sabrinus coloratus at Roan Mountain Highlands in North Carolina. We established three 5 x 5 trapping grids (6.5 ha) with four camera traps and four acoustic detectors systematically embedded in each grid. All three techniques were surveyed simultaneously over two 4-day survey periods. We compared techniques by assessing probability of detection (POD) and latency to detection (LTD), as well as survey effort and cost. Acoustics had the highest POD (0.37±0.06 SE), followed by camera traps (0.30±0.06), and live traps (0.01±0.005). Acoustics had a significantly lower LTD than camera traps (p=0.017), detecting flying squirrels during the first survey night at 75% of survey units. Total field effort was highest with live traps (111.9 hrs) versus acoustics (8.4) and camera traps (9.6), although laboratory effort for data analysis non-invasive techniques made overall effort similar between the three methods. Our study demonstrates that both non-invasive methods are a better rapid-assessment technique of Carolina northern flying squirrel detection compared to live traps. However, protocol for both non-invasive techniques needs further development prior to widespread application.
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Hypoxia-induced trade-offs on zooplankton vertical distribution and community structure in reservoirs
Authors: Jonathan P. Doubek1, Kevin A. Bierlein2, Alexandra B. Gerling3, Kathleen D. Hamre1, Ryan P. McClure1, Zackary W. Munger4, Cayelan C. Carey1
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA; 2. Hydros Consulting Inc., Boulder, CO; 3. American Water Works Association, Denver, CO; 4. Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA
As a result of global change, hypolimnetic hypoxia is increasing in lakes and reservoirs worldwide. Hypoxia can have many detrimental effects on freshwater ecosystem functioning, such as increased internal nutrient and metal loads from bottom sediments. Although the effects of hypoxia on nutrient release has been well-studied, less is known about how hypoxia impacts plankton communities, especially zooplankton. Typically, zooplankton migrate to the dark bottom waters (hypolimnion) during the day to escape visual fish predation in the surface waters (epilimnion). However, due to the physiologically-stressful conditions of hypoxic hypolimnia, zooplankton may remain in the epilimnion during daylight, trading oxic stress for increased predation risk. We sampled five reservoirs weekly to biweekly in southwestern Virginia from May-September 2014 to examine how hypolimnetic oxygen concentrations impact the vertical distribution, abundance, and community composition of zooplankton. These reservoirs varied on a gradient of hypolimnetic oxygen concentrations, from hypoxic to oxic at the sediment-water interface during most of the thermally-stratified period. We also conducted a 36-h sampling campaign on a reservoir with a hypoxic hypolimnion to examine how zooplankton were vertically distributed over an entire day. In hypoxic conditions, zooplankton were predominately found in the epilimnion, and had overall lower abundances than in reservoirs with oxic hypolimnia. Because of the critical role zooplankton play in lakes and reservoirs as the dominant grazers of phytoplankton, it is vitally important to better understand how they may respond to hypoxia, and what the resulting impacts are for lake and reservoir water quality.
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Variation in thermal tolerance in an invasive lizard (Anolis sagrei)
Authors: Tamara L. Fetters1, William Hopkins1, Joel McGlothlin1
Affiliations: 1. Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Biological invasions allow researchers to assess phenotypic responses to novel environments in a natural setting. Anolis sagrei is a tropical lizard that has successfully invaded geographic ranges with climatic variables that differ substantially from its native range. A climate niche shift in this species has been observed between its native range in the Caribbean and its invasive range in the southeastern United States. This shift is expected to lead to population differences in thermophysiological traits such as thermal tolerance between these two ranges. This study provides data on thermal traits from native and invasive populations of A. sagrei across a latitudinal gradient, and examines how metabolic and locomotive performance varies across different temperatures and populations. In conjunction with previous work on invasive populations of A. sagrei, our results will be important in further understanding the phenotypic adjustments that occur in populations exposed to new environments.
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Demography of Eastern Hellbenders (Cryptobranchus alleganiensis) Along a Land Use Gradient
Authors: Cathy M. Bodinof Jachowski1 and William A. Hopkins1
Affiliations: 1. Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Habitat loss due to deforestation is one of the greatest threats to freshwater biodiversity. Many studies have linked land use to changes in abundance and occurrence of freshwater biota. However, few studies have described how land use acts on demographic rates to elicit population level effects. We used mark-recapture data collected between 2007 and 2015 to describe demography of eastern hellbender (Cryptobranchus alleganiensis alleganiensis) populations in six stream reaches stratified across a land use gradient. We tested the hypotheses that loss of forest cover negatively affects hellbender density and population growth rates due to reduced recruitment (evidenced from demographic structure) and/or reduced adult survival. We also investigated relationships between forest cover and potential mechanisms (water quality and substrate) linking land use to hellbender demography. Mean sub-adult/adult densities in 2014-2015 were three- to 9-fold higher in reaches with ≥ 65% forest in riparian areas throughout the catchment relative to reaches with 53-64% forest. Apparent survival of adults did not vary with forest cover. However, population structure reflected a decline in recruitment as riparian forest decreased and populations composed of relatively few (≤ 10% of the population) young adults declined during our study. Water temperature, salinity and predominance of fine substrates increased as riparian forest cover decreased. Our findings suggest hellbender population viability is sensitive to loss of forest cover in riparian areas and that alterations to water quality, substrate or some other correlate of riparian land use acts specifically on demographic rates that determine recruitment to the adult population.
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Platform Session 2 3:00 – 4:15 p.m.
Session Chair: Tamara Fetters
Greenhouse gases respond to whole-ecosystem oxygenation and thermal stratification manipulations in a eutrophic reservoir
Authors: Ryan P. McClure1, Jon P. Doubek1, Kate D. Hamre1, Zack W. Munger1, Barbra R. Niederlehner1, & Cayelan C. Carey1
Affiliations: 1. Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Climate models predict increased air and water temperatures for many regions, thereby increasing the magnitude of freshwater hypoxia and thermal stratification in waterbodies. Simultaneously, the frequency of intense storms is rising, resulting in intermittent periods of oxygenated, mixed conditions and hypoxic, stratified conditions. Changing oxygen concentrations and thermal stratification could significantly alter the production of greenhouse gases, particularly carbon dioxide (CO2) and methane (CH4), and the redox conditions leading to their production in freshwaters. To examine the effects of these climate change impacts, we directly manipulated hypolimnetic oxygen concentrations and thermal stratification at the whole-ecosystem level and explored the responses of carbon dioxide (CO2) and methane (CH4), as well as the electron acceptor pathways that lead to carbon mineralization. We mixed the epilimnion of a small, eutrophic reservoir and intermittently oxygenated the reservoir’s sediments during the summer of 2015. Throughout the summer, we observed dissolved CH4 concentrations ~7500X higher than atmospheric levels. Interestingly, these high CH4 concentrations occurred at the metalimnion during periods of hypolimnetic oxygenation, after epilimnetic mixing events ended. During hypolimnetic oxygenation, CO2 concentrations increased to >13,000 ppm near the sediments, likely due to stimulated aerobic respiration. In the anoxic metalimnion, we observed shifts in the availability of electron acceptors that coincided with the initiation of methanogenesis. Our preliminary data suggest that altered thermal stratification and hypolimnetic oxygen conditions will considerably alter greenhouse gas production in eutrophic reservoirs. Given the global increase in reservoir construction, it is vital that we understand how greenhouse gas production in these ecosystems will respond to a changing climate.
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Context-dependency of amphibian-Bd-microbiome interactions in the Neotropics: implications for future ecological research and conservation
Authors: Daniel Medina1, Myra Hughey1, Matthew Becker1, Jenifer Walke1, Thomas Umile2, Elizabeth Burzynski2, Anthony Iannetta2, Kevin Minbiole2 and Lisa Belden2
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. Department of Chemistry, Villanova University, Villanova, Philadelphia, Pennsylvania
Dramatic declines in amphibian diversity have been documented throughout the Neotropics, in part, due to the skin disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd). Studies suggest that amphibian skin bacterial communities can alter the outcome of the amphibian-Bd interaction, and that Bd might be posing a selective pressure upon these communities in wild populations. However, an understanding of how environmental conditions impact the function of these bacterial communities is scarce. Variable functions of these symbiotic bacteria under different contexts might explain why experiments testing potential amphibian probiotics have obtained mixed results. Given the variation in chytridiomycosis outbreaks across elevations, we aimed to determine how the diversity, structure and function of these symbiotic bacterial communities changes with elevation. We collected skin swab samples in Panamá from three high and three low elevation populations of Silverstoneia flotator. Skin bacterial communities and metabolite profiles were assessed using 16S rRNA gene amplicon sequencing and HPLC-MS, respectively. Our results indicate that across high and low elevations, individuals harbor similar skin bacterial communities, although one lowland site appeared to differ from the others. The metabolite profiles suggest that there is significant variation among frog populations (i.e. sites) and between elevations. Overall, these results suggest that while the frogs have similar bacterial community structure, the local environment might be shaping the metabolites profiles, which indicate a potential functional plasticity that could influence the interaction with Bd. Thus, it is critical to consider the context-dependence of amphibian-microbe-Bd interactions to inform amphibian conservation efforts in the Neotropics.
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The physiological consequences of infection with Haemosporidian parasites
Authors: Laura Schoenle1, Meredith Kernbach1, Fran Bonier1,2, and Ignacio Moore 1
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. Biology Department, Queen’s University, Ontario, Canada
Haemosporidian parasites, including those responsible for avian malaria, can have substantial, negative fitness consequences for their hosts. In areas where the parasites have been recently introduced, infection can be deadly. For example, in Hawaii, malaria has contributed to the extinction of up to twenty species of honeycreeper. Where the parasites are endemic, infection does not appear to have immediate effects, but chronic infection can reduce both annual survival and reproductive success. Although most infected birds experience chronic infections, the effects of long-term exposure to the parasites on host physiology are unknown. We investigated the physiological consequences of infection in adult male red-winged blackbirds (Agelaius phoeniceus) from a population where about 95% of individuals are infected with Haemosporidian parasites. Using both an observational field study and an anti-malarial treatment experiment in an aviary, we examined the effects of Haemosporidian infection on 1) cellular damage, 2) tissue repair, and 3) immune activation. In free living birds, higher parasite burdens were correlated with a decrease in hematocrit and an increase in red blood cell production. The aviary experiment confirmed the relationships found in free-living birds, and additionally showed that infection causes a reduction in mass. We detected no effect of infection on immune function or oxidative damage. The physiological costs of Haemosporidian infection can be substantial and are likely related to the replacement of damaged red blood cells. These results provide a mechanism that could underlie the fitness costs of Haemosporidian infection found in other studies.
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Understanding the drivers of temporal variation in wood thrush post-fledging survival
Authors: Ben Vernasco1, T. Scott Sillet2, Peter Marra2, and Thomas B. Ryder2
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. Migratory Bird Center, Smithsonian Conservation Biology Institute, Washington, D.C.
Between leaving the nest and recruiting into the breeding population the following year, songbirds experience multiple life stages (e.g., post-fledging period, dispersal) with different inherent risks. The post-fledging period is an important period because many songbirds suffer high mortality. Although post-fledgling survival (PFS) has been quantified for a large number of passerines, the drivers of both spatial and temporal variation in survival remain poorly understood. In this study, we used radio telemetry to track fledgling Wood thrush, a declining Neotropical migrant, at 12 sites across 4 years in Southern Indiana. We built competing known-fate survival models to quantify the temporal structure of PFS and to understand which abiotic and biotic factors (i.e., nest parasitism, precipitation and natal habitat characteristics) affect survival probability. Our results show that PFS did not vary within each year (i.e., over the course of the breeding season), but did show substantial variability between years. Models suggest that annual variation in survival is linked to weather, with birds having the lowest survival during droughts. The effect of precipitation deficits showed that young birds that have just fledged the nest are disproportionately impacted in dry years. In contrast, our results did not show a strong effect of either natal habitat characteristics or nest parasitism on survival probability. Overall, this research broadens our understanding of the spatial and temporal drivers of variation in PFS and highlights the impact of region-wide droughts on PFS and subsequent recruitment patterns.
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Increased antibiotic resistance – effects on microbial communities and ecosystem function
Authors: Carl Wepking1, Bethany Avera2, Brian Badgley3, John E. Barrett1, Josh Franklin1, Katharine F. Knowlton4, Partha P. Ray4, Crystal Smitherman3, Michael S. Strickland1
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. Department of Ecosystem Science and Sustainability, Colorado State; 3. Department of Crop & Soil Environmental Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 4. Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
In the United States nearly 80% of all antibiotics are used in the livestock industry. This use has become a major health concern given the potential for increased antibiotic resistance in human pathogens. While such concerns have obvious human health implications, the impact of increased antibiotic resistance on soil microbial communities and the ecosystem processes they regulate is unknown. At a national scale, we compare soil microbial communities from paired sites receiving either high or low inputs of dairy cattle manure. Given high antibiotic (i.e. cephapirin, a β-lactam antibiotic) excretion rates in manure, we expected that 1) the composition of soil microbial communities, particularly bacteria, would shift toward taxa with demonstrated resistance to these compounds; 2) concentrations of antibiotic resistance genes (ARGs) would increase; and 3) increasing maintenance demands in response to antibiotic additions would lead to decreased microbial efficiency (i.e. greater mass specific respiration). The abundance of the β-lactam resistance gene ampC was 5.2-fold greater in the high input sites, likely due to the use of cephapirin in dairy herds. Additionally, bacterial communities in high input sites differed from those in low input sites, driven primarily by a 25-fold increase in Acinetobacter, an opportunistic pathogen known for β-lactam resistance. Finally, ampC abundance was positively correlated with indicators of microbial stress (i.e. qCO2), and microbial mass specific respiration, which increased 2.1-fold under high inputs. These results demonstrate that antibiotic residues and resistance are not just of human health concern but alter soil microbial communities and the ecosystem processes they regulate.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_column_text][heading_horizontal type=”h3″ margin_bottom=”10px”]POSTERS[/heading_horizontal][/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]
The Influence of Social Behavior and Stability on Disease Transmission in a Songbird Host
Authors: Matt Aberle1 and Dana Hawley1
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Social interaction in animals has been shown to have lots of fitness benefits, like cooperation in foraging and sharing of resources. However, species that have lots of social interaction are also at a much higher risk of transmitting infectious diseases. Therefore, it is important to study not only social behavior itself, but the structure and stability of social groups as well. Past studies have shown that not only does social stability and behavior change an animal’s exposure to disease, but it can impact physiological factors influencing disease susceptibility through both stress responses and changes in hormones as well. A relatively new method for analyzing social behavior and disease transmission is through contact network modeling. Contact networks show the interactions between individuals within a population and can be created using technology like radio-frequency or GPS. These networks can also give information on how interactions are changing over time as well making them a dynamic tool. Since the early 1990s house finches have been subject to a highly infectious bacterium causing conjunctival pathology. Finches form flocks outside of the breeding season and congregate at bird feeders where the majority of transmission takes place, thus they are an ideal system to test hypotheses relating to social behavior, stability, structure and the impacts of those behaviors on disease transmission. I plan to do my dissertation research on this system utilizing RFID technology placed on feeders to see how manipulations of house finch social behavior and stability affects disease transmission, prevalence, and severity.
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The Two Towers: An ecosystem story as told by the atmosphere
Authors: Ben Ahlswede1, Quinn Thomas1, Tom O’Halloran1
Affiliations: 1. Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
How do we combat climate change? One potential solution is to change our source of energy, from fossil fuels to bio-fuels. Biofuels, have a shorter carbon cycle than fossil fuels, allowing for complete reabsorption of burned fuel within a hundred years as opposed to ten thousand. However, sources of biofuel such as Switchgrass and Loblolly pine have other effects on climate besides absorbing carbon. They also affect the planetary energy balance by altering the reflectivity of the Earth’s surface, and altering how energy is distributed through the atmosphere. These processes have the ability to affect local and regional temperature and can counteract any benefit derived from reduced CO2 in the atmosphere. We have partnered with Sweet Briar College and the Global Change Center to set up two eddy flux covariance systems on the Sweet Briar campus, one over a loblolly stand, and one over a switchgrass field. These paired systems will independently measure fluxes of carbon and water, as well as incoming and outgoing radiation, photosynthetically active radiation, temperature, humidity, precipitation, soil temperature, soil moisture, and energy absorbed by the ground. These measurements will allow us to compare these systems as potential biofuels in a complete accounting of how they affect climate. In addition, data from these towers can be used to inform and constrain future work investigating the effects of implementing a biofuel program on a regional and global scale.
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Identifying local strains of Nile tilapia Oreochromis niloticus that are adapted to future climate conditions
Authors: Gifty Anane-Taabeah1,2, Emmanuel Frimpong1, Stephen Amisah2, Akwasi Ampofo-Yeboah3, and Eric Hallerman1
Affiliations: 1. Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. Department of Fisheries and Watershed Management, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, 3. Department of Fisheries and Aquatic Resources Management, University of Development Studies, Nyankpala Campus, Ghana
This study was conducted to synthesize information on the ambient water quality (temperature, dissolve oxygen and salinity) for the Nile tilapia, an important commercial species, compare wild populations in the Volta basin and the selectively bred Akosombo strain from the basin used in fish farming in Ghana under current and future climate conditions, and develop predictive models delineating the boundaries of the species’ range. A combination of literature survey, field and laboratory methods provided data for meta-analysis, growth and genetic analysis, as well as distribution models. We found variations in water temperature along the latitudinal gradient in Ghana; and temperature was the most informative variable in terms of characterizing the adaptive range and ambient water quality for the species. The results of the growth studies showed no evidence of superior performance of the Akosombo strain over the wild strains under current or predicted future climatic conditions of temperature, dissolved oxygen, or salinity. Significant Fst values from the genetic analysis suggested that the Akosombo strain was well differentiated from all the wild populations (Aframso, Sabare and Binaba) studied. The combined results of the field, growth and genetic studies show that at least one wild population from the Oti River (Sabare) may possess the traits for superior performance under high temperature and low DO conditions. Further studies should concentrate on comparing the Sabare strain with the Akosombo strain under different experimental conditions and increase replications to confirm the suggested differences and the heritability of those performance traits for selective breeding.
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What’s Bugging the Bugs? Commonalities in Benthic Stressors across the United States
Authors: Heather Govenor1, W. Cully Hession1, Leigh-Anne Krometis1
Affiliations: 1. Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Biological monitoring of invertebrate communities is a key component of stream monitoring under the Clean Water Act in nearly all states, and is one approach used to determine if the biological integrity of state waters is being protected. Monitoring methods, interpretation of field data, and metrics used to evaluate invertebrate communities vary widely across the county, and flexibility in reporting requirements results in inconsistencies in how invertebrate-based impairments are reported to the EPA. Further, states differ in the specific approaches used to determine Total Maximum Daily Loads (TMDLs) to address the stressors associated with impairments. The objective of this research was to determine the pollutants most commonly associated with invertebrate-based stream impairments in the U.S. Through discussions with EPA and state regulators, and evaluation of over 1000 approved TMDL reports written since the initiation of the TMDL program, we confirm a long-thought but formerly undemonstrated assumption that sediment is the most commonly identified stressor associated with invertebrate-based stream impairments nationwide. The variety of approaches used to identify sediment TMDLs are discussed.
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Millipedes Under Our Feet: Taxonomic Revisions of the Common North American Millipede Genera Pseudopolydesmus(Polydesmida: Polydesmidae) and Nannaria (Polydesmida: Xystodesmidae)
Authors: Derek A. Hennen1 and Paul. E. Marek1
Affiliations: 1. Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Much progress in North American millipede taxonomy has been made over the past three decades, stabilizing nomenclature and providing identification resources. However, much work remains, particularly with regards to alpha-taxonomy and revisions of poorly-understood groups. In eastern North America, the two genera Pseudopolydesmus (Polydesmida: Polydesmidae) and Nannaria (Polydesmida: Xystodesmidae) are among the most commonly encountered millipedes, with 12 and 23 described species, respectively. However, species level classification in Pseudopolydesmus is fuzzy and in need of revision. Nannaria has many undescribed species represented in museum collections, and may even double the number of currently known species. To remedy this, molecular and morphological studies are being conducted to revise the genera and describe new species. Collecting is being done in areas throughout the eastern United States to obtain fresh specimens for molecular analysis and to search for new species, and museum specimens are being examined for morphological analysis. As a result of these studies, photographs and identification keys will be produced, and new species and their ranges will be described.
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Effects of social environment on the development and maintenance of behavioral strategies for coping with stress.
Authors: Kaan Kerman1 & Kendra Sewall1
Affiliations: 1. Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Coping styles are consistent behavioral differences in how individuals respond to stressful conditions. Proactive individuals are more likely to engage with potential dangers, while reactive individuals tend to avoid a threatening stimuli. Understanding the proximate mechanisms behind these contrasting strategies is an active area of research. In this dissertation project, we will explore one aspect of these proximate processes: mediating role of social environment on the development and expression of coping styles in a model species, the Zebra Finch (Taeniopygia guttata). Using behavioral responses in three different assays to characterize coping styles in our population, we will investigate how exposure to social stress in early development impact the emergence of coping styles later in life, and how social position within a group influence the expression of coping styles in adulthood. We predict that, exposure to stressful social conditions during development, as simulated by artificial injection of stress hormones in egg and hatchling stages (i.e. CORT), causes differential expression of two types of stress hormone receptors in the brain, which leads to a more reactive response later in life. In adulthood, we predict that individuals with strong associations within a flock, and higher dominance status, will be buffered from potential risks in an environment, resulting in a more proactive response even though their coping style is strongly shaped with early life social conditions. This study will have important implications on understanding the emergence of coping with stress as an interplay between epigenetic effects in early life and social conditions in adulthood.
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Impacts of mining effluent on fishes in the Clinch River and Powell River watersheds
Authors: Zachary Martin1, Serena Ciparis1, Don Orth1, and Paul Angermeier1,2
Affiliations: 1.Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. U.S. Geological Survey, Virginia Cooperative Fish and Wildlife Research Unit, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Mining coal in Appalachia has profoundly changed landscapes and impacted >1,900 km of headwater streams. Mining activities can increase instream sedimentation and elevate concentrations of total dissolved solids and trace elements (e.g. selenium) above tolerances of stream fishes. We are evaluating the fish response to mining effluent across a mining-intensity gradient in 16 headwater streams in the upper Powell River and the upper Clinch River watersheds. We expected conductivity, fine sediments, major ion concentrations and [Se] to be elevated in streams on the high-impact end of the gradient. Further, we expected to find fish responses such as shifts in community assemblage, reduced spawning performance, and reduced individual-level health at high-impact sites. Water quality, physical habitat, fish community, and fish tissue samples were collected August – October 2015. There were strong correlations between our mining gradient and measured specific conductivity and concentrations of HCO3–, Ca, Mg, Na, K, and SO42-. Seventeen fish species were collected and individual-fish data were gathered on two species, Etheostoma flabellare and Rhinichthys obtusus. A hierarchical cluster analysis characterizing species composition at sites identified two groups: widespread species (Campostoma anomalum, Rhinichthys obtusus, Etheostoma flabellare, and Semotilus atromaculatus) and patchily distributed species (all others). Although E. flabellare was widespread, it was absent from assemblages at four high-impact sites. Future interpretation of community data will be paired with physical habitat and water quality data. This spring we are also processing fish tissue samples to describe changes in individual-level health and conducting spawning surveys of E. flabellare across our mining-impact gradient.
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Behavior and Impact of Spathius galinae and Spathius agrili on Emerald Ash Borer in Virginia
Authors: Max Ragozzino1, Scott Salom1
Affiliations: 1. Department of Entomology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Emerald ash borer (EAB), Agrilus planipennis Fairemaire (Coleoptera: Buprestidae) is a wood-boring beetle native to Asia introduced to Michigan in 2002. In both its native range and in North America, EAB primarily feeds on ash trees (Fraxinus sp.). In North America, ash tree stands suffer complete mortality within 6 years of infestation, and it is estimated to kill 38 million ash trees by 2019. EAB larvae are frequently predated by native woodpeckers (Picidae), accounting for up to 39% of all EAB larvae in some areas. Four hymenopteran parasitoids have been identified in Asia and introduced to the U.S. as biological control agents against EAB. This study will focus on two larval parasitoids, Spathius agrili Yang (Hymenoptera: Braconidae), and Spathius galinae Belokobylskij and Strazenac (Hymenoptera: Braconidae). Neither parasitoid is established in Virginia. We plan to study competitive interactions between both parasitoid species, including multiparasitism and adult competition to determine the best course of action for establishment. We will release both parasitoids across Virginia at a variety of ash dense forest locations, and monitor their activity using a variety of methods including sentinel logs and total larval counts. Once establishment occurs, we will exclude woodpeckers from infested ash trees in order to determine the effect of woodpecker predation on the parasitoids.
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Climate Change, Coups, and Critically Endangered Species: First Aerial Drone Surveys of Madagascar’s Lemurs
Authors: Brandon P Semel and Sarah M Karpanty
Affiliations: Fish and Wildlife Conservation Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Lemurs are found only in Madagascar and are earth’s most threatened mammals. Hunting, habitat loss, government instability, and climate change all pose serious threats to lemur species. Establishing baseline population estimates and enacting long-term population and habitat monitoring efforts to guide conservation strategies are critical to their survival. However, traditional survey methods are labor intensive, expensive, and can facilitate resource extraction. Novel technologies, such as aerial drones, will help to overcome these obstacles. Population estimates and threat quantification for diurnal species in northern Madagascar will be obtained summer 2016, including critically endangered golden-crowned sifakas (Propithecus tattersalli) and endangered crowned (Eulemur coronatus) and Sanford’s brown (E. sanfordi) lemurs. Prior to conducting drone surveys, lemur behavioral responses to their presence will be assessed so that surveys are performed in a way that minimizes animal stress. A cost-benefit analysis comparing line transects and aerial drone surveys will be conducted, fragments with extirpated lemur populations will be identified for future translocation, and land cover change will be mapped to aid in conservation prioritization and to establish a habitat baseline for future climate change studies. Partnering with Malagasy conservation initiatives will ensure continued long-term monitoring. Pilot data will facilitate my doctoral work investigating how lemurs in this region will respond to climate change-induced environmental change and aid in local conservation efforts in a global biodiversity hotspot. Results will be broadly applicable to wildlife management and conservation around the world.
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Modeling Freshwater Salinity for Aquatic Biodiversity Management
Authors: Tony Timpano1, Stephen Schoenholtz1, David Soucek2, and Carl Zipper3
Affiliations: 1. Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. Illinois Natural History Survey, U. Illinois Urbana-Champaign; 3. Crop and Soil Environmental Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Human activities like agriculture and resource extraction can increase the dissolved inorganic ion concentration (i.e., salinity) in waterbodies, creating toxic conditions for life adapted to dilute freshwater. This salinization of freshwaters is a global threat to aquatic biodiversity. In the USA, mountaintop coal mining contributes to salinization of headwater streams in the Appalachian region, a biodiversity hotspot. Recently, water quality managers have sought to mitigate the biotic effects of salinization by determining the limits of salinity tolerable to freshwater organisms. To date, limits have been based on salinity-biota relationships observed in field surveys that measured salinity only once per year. However, because salinity can vary with seasonal stream flow, effective management will require understanding the temporal patterns. Toward that end, we measured the salinity surrogate electrical conductivity continuously for three years in 25 minimally-disturbed headwater streams across a gradient of salinity in the Appalachian coalfields of Virginia and West Virginia. We found that salinity changed throughout the year, in a distinct seasonal pattern in nearly all streams, regardless of mean annual salinity level. We modeled the pattern using a sine-cosine linear model and found moderate to strong fits. The models indicated that annual minimum salinity occurred in spring and annual maximum salinity occurred in autumn. Averaged across all sites, seasonal deviations from mean annual salinity reached approximately 20% in spring and autumn. Our models indicate substantial, yet predictable seasonal variation in salinity, which should improve salinity management to achieve aquatic biodiversity goals.
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Subtle variation in incubation temperature may have long-term effects on immune function and sexually-selected traits of an altricial model, the zebra finch
Authors: J. Wagner1, M. Beck2, E. Joseck3, W. Hopkins1
Affiliations: 1. Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 2. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia; 3. Department of Animal and Poultry Science, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
Avian incubation temperature plays an important role in offspring development and is affected by the interaction between parental behavior and environmental variables. Numerous studies have indicated its importance to a suite of phenotypic traits in offspring, yet we have a fairly limited understanding of how variation in incubation temperature affects individuals throughout adulthood. The literature has identified numerous traits that are affected in altricial nestlings prior to fledging and in precocial birds (chickens and ducks), but whether or not incubation temperature has long-lasting impacts on individuals, possibly affecting their lifetime phenotypic trajectory, is unknown. We investigated how growth, immune function, and ornamental plumage was influenced by variation in incubation temperature by incubating eggs at two biologically-relevant temperatures (36.5 and 37.5°C) and measuring endpoints on nestlings and adults. We found no differences in growth or immune function in young birds across the two incubation temperatures. However, compared with 37.5°C individuals, those incubated at 36.5°C had a lower cell-mediated immune response as adults (40 days post-hatch) and males had lower brightness and intensity ornamental plumage coloration at sexual maturity (~100 days post-hatch). This study demonstrates how subtle differences in the conditions experienced during embryonic development may have a crucial and long-lasting influence on individual phenotype.
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A Comparison of Intraspecific Aggression in Populations of the Lizard, Anolis sagrei, at Varying Stages of Species Invasion
Authors: Julie M. Wiemerslage1 and Joel McGlothlin1
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
It is important to asses how invasive species are able to thrive in novel environments in order to predict and prevent future invasions. Additionally, the study of invasive species allows a unique opportunity to assess how species adapt to novel conditions, which are often created by current global changes. Invasive species often undergo phenotypic divergence from their native counterparts because they must adjust to novel conditions to persist outside of their native range. Behavior is a key determinant of success for invasive animals because it can facilitate rapid responses to novel conditions, so it is likely that behavioral divergence occurs in species invasions. Anolis sagrei is an invasive territorial lizard in the Southeast United States that is native to the Caribbean. For A. sagrei and other territorial species, increased territorial aggression may be selected for when their ranges expand into areas that contain closely related species. This study investigates the differences in aggressive behavior between populations of A. sagrei at different stages of invasion. One-on-one aggressive encounters were staged between males in order to assess differences in aggressive behavior between different populations. We had two competing hypotheses: 1. lizards at the front of the range are more aggressive than other populations because aggression allows them to outcompete species in their new range, and 2. lizards at the front of the range are less aggressive than other populations because there is lower population density there, thus less competition.
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Population biology, life history, and ecology of the Bahama Swallow (Tachycineta cyaneoviridis): informing conservation of an endangered bird in the northern Bahamas
Authors: Maya Wilson1 and Jeffrey Walters1
Affiliations: 1. Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
The Bahama Swallow (Tachycineta cyaneoviridis) is an endangered bird species that is endemic to the northern Bahamas. This doctoral research project focuses on three central questions:
- What are the features of the current Bahama Swallow population biology? Available population estimates indicate a sharp decline in population abundance, and there is currently no information regarding distribution and dispersal. I am conducting surveys and using capture-recapture to estimate abundance and distribution, and taking genetic samples to assess the dispersal of populations between islands.
- What are the life history characteristics of the Bahama Swallow? The life history data for this species are limited, and I am expanding these data by monitoring active nests during several consecutive breeding seasons.
- What are the potential agents of decline of Bahama Swallow populations? (A) Habitat loss and degradation: Bahamian pine forests were heavily logged, and continued loss and degradation of pine forests poses an ongoing threat. I am conducting habitat surveys to assess the availability of suitable breeding habitat. (B) Competition for nesting cavities: The Bahama Swallow may face competition for cavities with other cavity-nesting bird species. I am identifying the species that excavate and utilize the same types of nesting cavities as Bahama Swallows, and designing a cavity nest web illustrating the interactions of these species. (C) Predation: Increased abundance of nest predators could pose a threat to the Bahama Swallow. I am monitoring active nests to determine whether the rates of depredation are sufficiently high to contribute significantly to population declines.
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