Category: New Publications

Researchers examine how the laws of physics impact evolution

Post author By jcoker
Post date September 18, 2018

Think about the fast sprint of a cheetah or the rapid undulation of a swimming fish.

All biological motion is dependent on the rules of mechanics, which is a branch of physics that deals with the motion of material bodies and the forces exerted upon them.

But, how do the static laws of physics impact the dynamic process of evolution? Do stronger relationships between a morphological trait and swimming speed, for example, facilitate or hinder evolution? Virginia Tech and Duke University researchers answer this question with their most recent research.

Using various biomechanical systems in animals, the researchers have demonstrated that mechanical relationships in the structural traits of animals impart distinct, predictable footprints on biological diversity. Specifically, morphological traits that more strongly impact the way an animal moves also evolve faster.

Martha Muñoz, an assistant professor of biological sciences in the College of Science

“Our study demonstrates that evolution is shaped by the general laws of physics. We have long known that there are fundamental laws of motion that shape performance space for organisms. But, the laws of mechanics don’t just define the parameter space that organisms can occupy. Mechanical laws also shape the process of evolution itself by guiding the rate of morphological evolution as well as shaping its pattern throughout evolutionary history,” said Muñoz, an assistant professor of biological sciences in the College of Science at Virginia Tech.

Muñoz did much of this research as a post-doctoral fellow in the lab of Sheila Patek, a professor of biology at Duke University. Their findings were recently published in the journal eLife.

“Our findings provide a compelling case for a strong influence of biomechanics on the pace of evolutionary change. We know that physics and biomechanics are central to evolutionary diversification, and our finding of a consistent increase in the rate of evolutionary change in the most tightly correlated parts of the system is surprising and exciting,” said Patek.

Their evolutionary finding opens up numerous possibilities across different organisms and different mechanical systems. The evolutionary footprints that Muñoz and Patek have discovered may be widespread in biological motion.

With the help of researchers from the University of Rhode Island and University of Illinois, Urbana-Champaign, Muñoz chose to focus on four-bar linkages, a simple movable closed chain linkage common in nature that is comprised of four levers connected in a loop by four joints. Examples of four-bar linkages in human-engineered systems include the pedaling of a bicycle or the movement of a pair of locking pliers.

Examples of four-bar linkages in the pedaling of a bicycle and locking pliers

Muñoz’s research on these linkages focuses on four biological systems: wrasses, cichlids, sunfish, and mantis shrimp.

“In order to conduct evolutionary analyses, I needed biomechanical and morphological data from numerous species and a good working phylogeny, or evolutionary history, to be available. With these requirements in mind, I was able to study three independent evolutions of four-bar linkage systems: the oral four-bar (wrasses and cichlids), the opercular four-bar (sunfish), and the raptorial four-bar (mantis shrimp),” said Muñoz, an affiliated faculty member of the Global Change Center, an arm of the Fralin Life Science Institute.

Each of these four-bar systems represents an independent evolutionary experiment in a common mechanical system — the same laws of mechanics apply to all of these four-bars, but each one is used in a different ecological context. Mantis shrimp use their raptorial four-bar to rapidly strike at prey, whereas fish use their four-bar linkages to suction food into their mouths. Thus, Muñoz was able to examine whether similar laws of mechanics result in similar evolutionary patterns in various independently evolved mechanical systems.

In multiple groups of fishes and mantis shrimp, the researchers discovered that four-bar linkages evolve in predictable ways: links that impact mechanical output of the system the most evolve the fastest.

This recent study establishes the connection between mechanical sensitivity and evolutionary rate. Muñoz’s next question is how natural selection factors into the equation.

“Are links of high mechanical effect experiencing strong directional selection, or are links of weak mechanical effect experiencing strong stabilizing selection? In other words, I’ve documented an evolutionary pattern, and I’d like to next examine the underlying evolutionary process.” said Muñoz.

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CONTACT:

Kristin Rose

(540) 231-6614

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Study: Genetic variation can leave long-lasting stamp on evolutionary patterns

Post author By jcoker
Post date September 18, 2018

From VT News

[Featured image: An Anolis evermanni lizard, photo courtesy Edmund D. Brodie III.]

A new study from Virginia Tech takes on the decades-old battle of which has more impact on evolution: genetic variation or natural selection.

In a study published in the latest issue of Evolution Letters, Virginia Tech researcher Joel McGlothlin has found that genetic variation can leave a much longer-lasting stamp on evolutionary patterns than was previously thought. Started when McGlothlin was a post-doctoral researcher at the University of Virginia, the study focuses on Anolis lizards, which McGlothlin and other scientists say are “icons” of adaptive radiation, an evolutionary pattern involving the origin of group of related species that differ in appearance and ecological role.

“Different anoles species have evolved different traits that allow them to live in different habitats such as in treetops or on tree trunks,” said McGlothlin, an associate professor in the Department of Biological Sciences, part of the Virginia Tech College of Science. “During the past 40 million years or so, species with body types fitting them into these habitats have evolved several times across different islands in the Caribbean. This suggests that natural selection has had similar effects on evolution under similar conditions.”

However, scientists know that natural selection doesn’t always push a species in the optimal direction, McGlothlin said. Because natural selection works with existing genetic variation, evolution can be “constrained” by genetics. For example, if some traits are not as heritable as others, they may evolve more slowly. Also, when traits are correlated with each other — such as arm length and leg length — it may be more difficult for them to evolve on their own, he added. Although these constraints are important over a few generations, whether they are important over millions of years of evolution is more controversial.

McGlothlin and his team sought to disentangle the roles that natural selection and genetic constraints played in the evolution of body shape among anoles. “What we found was the species become differentiated from each other in ways predicted not only by their habitat, but also by patterns of genetic variation,” McGlothlin said. “Traits that were more genetically variable showed greater evolutionary changes across species. We were really surprised that we still saw this pattern when looking across 40 million years of evolution.”

In the study, McGlothlin and his team — which included Edmund “Butch” Brodie III, a professor at the University of Virginia and McGlothlin’s former postdoctoral mentor, and Jonathan Losos, a professor of biology at Washington University in St. Louis, Missouri — measured patterns of genetic variation for body-shape traits in seven different species of anoles and compared it to how traits evolved across species. The team also included several undergraduate students from several universities.

They collected adult lizards from Puerto Rico, Jamaica, and the Bahamas and bred them in the lab to produce thousands of offspring. Measuring traits, such as head shape and limb length, in these offspring allowed the researchers to measure how much trait variation was due to heritable differences that could be passed down from parent to offspring.

The team found another surprising result: The relationship between genetic variation and evolution was maintained even though the genetic variation they measured also changed across evolutionary time. Their analysis suggests that that genetic variation isn’t just passive material for natural selection. Instead, it seems to co-evolve with the traits themselves, perhaps changing in response to selection.

“When we began this study, we thought we might be able to provide strong evidence favoring either selection or constraint, but instead, we may have demonstrated just how difficult they are to separate,” McGlothlin wrote in a blog post for Evolution Letters. “At least in anoles, constraint shapes the evolutionary response to selection, but also evolves in response to selection in such a way to keep the two entwined. Perhaps it’s this never-ending creative dance that makes evolution so interesting in the first place.”

The study of these lizards can help scientists understand the evolution of other species, said McGlothlin, who is an affiliated member of the Fralin Life Science Institute’s Global Change Center. “Our results are pretty general, and I wouldn’t be surprised if we saw similar patterns if we looked genetic variation in humans and our closest relatives,” he added.

McGlothlin is continuing to research the role of genetic variation in evolution. “Now, we are asking some similar questions using a single species, the brown anole,” McGlothlin added. “In that species, males and females are really different, and we’re trying to apply what we’ve learned about the evolution of different species to understand how males and females evolve to become different in appearance.”

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Researcher settles decades-old evolutionary biology question by examining Caribbean lizards

Snakes in evolutionary arms race with poisonous newt

CONTACT:

Steven Mackay

540-231-5035

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New Publications News Research

Disaster aid: new research uses analytics to improve placement of supplies

Post author By jcoker
Post date September 12, 2018

From VT News

When disaster strikes, having relief supplies in the right place to be deployed swiftly is critical.

Humanitarian relief agencies often position such supplies in advance to help ensure ready availability but lack a good way to gauge the effectiveness of such preparations.

It’s difficult to know what quantities of supplies will be needed and where they should be placed to be most effective, particularly given the uncertainty about where and when a disaster may occur, said Chris Zobel, professor of business information technology in the Pamplin College of Business.

In a recent research project, Zobel used analytics to develop a new approach to help the Red Cross address the challenges of more effectively pre-positioning resources that are needed to help open emergency shelters.

Zobel and co-researcher Andy Arnette, who received a Ph.D. from Virginia Tech and now teaches at the University of Wyoming, worked with the Red Cross in Wyoming and Colorado to build a model for allocating assets to prepare for multiple possible disasters in a region.

Effectively managing supply chains in humanitarian aid and disaster relief can be extremely complex due to demand uncertainty, shifting needs and priorities, and nontraditional objectives, Zobel noted. “This complexity means there is both a significant need and an opportunity to develop new analytic approaches for improving humanitarian supply-chain operations.

“Our project with the Red Cross is based on the organization’s data and its actual operations, resulting in a model that has practical applications and real potential to assist disaster response efforts for other relief organizations also,” he said.

“Not only will our approach allow assets to be more accurately pre-positioned to reduce immediate suffering, it also will save time and resources that can then be put towards other types of disaster response and relief activities.”

Their model can also be adapted to a variety of problems that involve exposure of a vulnerable population to a hazard, the impacts of which can be diminished through appropriate and equitable allocation of different assets. These problems include flooding and wind damage resulting from hurricanes.

Citing some other examples, Zobel said the model could be useful to such agencies as the U.S. Forest Service and CAL FIRE, which frequently pre-position mobile cache vans to support operations bases for fighting forest fires in the Western U.S., or to organizations, like the New York State Office of Health Emergency Preparedness, that pre-position medical emergency caches to mitigate the spread of infectious diseases, such as anthrax.

Despite the growing frequency and severity of disasters, the Red Cross lacked a systematic, analytical approach for determining the most effective locations to place its caches and trailers — the two types of assets stocked with the supplies needed for opening emergency shelters, Zobel said.

The computer model Zobel and Arnette created incorporates a risk-based formula that uses the likelihood of different hazards and the exposure and vulnerability of the population to determine the extent to which a given resource allocation can reduce disaster risk.

“Our approach helps ensure that such allocations will be made equitably, based on addressing risk, not just demand,” Zobel said. “In particular, if two populations have the same hazard likelihood and level of exposure, the more vulnerable population will be assigned more resources to offset its increased risk.”

Their approach, he said, also allows agencies to quantify the value of mobile assets in offsetting risk in adjacent locations, giving them important flexibility: “Lower-risk areas can have their needs covered by adjacent assets and more direct relief can be provided to the more vulnerable and higher-risk locations.”

An article by Zobel and Arnette on their work, “A Risk-based Approach to Improving Disaster Relief Asset Pre-Positioning,” will be published in Production and Operations Management journal.

The full story on their research will appear in the forthcoming fall 2018 issue of Virginia Tech Business, the magazine of the Pamplin College of Business.

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CONTACT:

Sookhan Ho

540-231-5071

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Climate Change Conservation New Publications News Pollution Research

Land use and pollution shift female-to-male ratios in snapping turtles, raising conservation concerns

Post author By jcoker
Post date September 7, 2018

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From VT News

Most of us know that our biological sex is decided by the pairing of X and Y chromosomes during conception.

However, for many wildlife species, sex of offspring is determined after fertilization and often influenced by environmental factors, such as temperature. The sex of reptiles, for example, is based on temperatures in the nest while eggs incubate.

Current research shows that increasing global temperatures as a result of climate change are expected to produce more female turtles since their offspring are influenced by the nest’s temperature. But now, a team of Virginia Tech biologists has found that the nesting environment of turtles in agricultural habitats, which can ultimately lower nesting temperatures, can actually produce more males.

To make matters worse, the researchers found that the effect of agricultural activities on sex ratios was exacerbated by the presence of mercury pollution. While it’s known that mercury can impact reproduction in reptiles, this study provides the first documentation that mercury can influence sex determination. The common and pervasive environmental pollutant, when transferred from mother to offspring, was found to increase the number of male offspring even more.

The findings, which were published in the journal Biological Conservation in June, shed new light on predictions about temperature and sex determination in the snapping turtle, Chelydra serpentina, and many other reptilian species. By examining the impacts of agricultural land use, both independently and interactively with mercury pollution, the research builds new understanding for the complexity of climate-related predictions.

“Our work illustrates how routine human activities can have unexpected side effects for wildlife,” said William Hopkins, professor of wildlife conservation in the College of Natural Resources and Environment and lead researcher of the Wildlife Ecotoxicology and Physiological Ecology Lab at Virginia Tech, who oversaw the study. “We found strong masculinizing shifts in sex ratios caused by the interaction of two of the most common global changes on the planet, pollution and crop agriculture.”

The team worked along the South River in Virginia, where large amounts of mercury persist in the river and floodplain due to leaks from a nearby manufacturing plant into the river from 1929 to 1959. Field experiments were replicated simultaneously in the laboratory using high-resolution temperature profiles to confirm results from the field.

In the field, temperature probes placed in each nest recorded temperature at one-hour intervals throughout the incubation period, mid-May through September. Every eight days, samples were collected to determine soil moisture content, and vegetation growth was monitored for height, density, and ground cover surrounding the nests.

[/vc_column_text][vc_gallery type=”nivo” interval=”3″ images=”25122,25127,25134,25126,25125,25130,25128″ img_size=”400×400″][vc_column_text]Snapping turtles, they found, favor agricultural sites for nesting because they naturally select sun-exposed areas with loose soil, sand, and vegetation debris in which to dig their nests. Females are attracted to the open and sunny agricultural fields in the early summer; the sites quickly become shaded and cooled as dense, monoculture crops grow throughout the season. Cooler incubation temperatures in the nest mean more male offspring are produced.

“Our results indicate that turtles are attracted away from natural nesting habitat into agricultural habitats, and this decision has undesirable consequences for their reproductive success,” said Hopkins. “Turtle populations are sensitive to male-biased sex ratios, which could lead to population declines. These findings are particularly alarming because freshwater turtles are one of the most endangered groups of vertebrates on earth.”

The team also analyzed mercury levels from maternal blood collected in the field as well as one random egg from each nest sampled. They found that higher concentrations of mercury in the mother turtle correlated with the development of more male offspring, and turtles exposed to both mecury and agricultural shade produced the most male offspring.

“These unexpected interactions raise new, serious concerns about how wildlife respond to environmental changes due to human activities. They also add an extra layer of complexity to current projections of climate change,” said Hopkins.

A general best practice for conservation management, according to the researchers, is to incorporate periods of uncultivation for fields in areas known to support a high number of turtle nests. For species of special concern, such as the wood turtle in Virginia, working with landowners to rotate periods of crop growth, implement predator guards, and exercise caution with machinery near identified nests could prevent over-shading and nest damage.

Lead author Molly Thompson, who earned her master’s in fisheries and wildlife sciences at Virginia Tech in 2017, now works as a wildlife biologist at Yosemite National Park. Additional co-authors include Robin Andrews, professor emerita of biological sciences in the College of Science; Brittney Coe, who earned bachelors’ degrees in biological sciences and chemistry in 2009 and a master’s in fisheries and wildlife sciences in 2012 at Virginia Tech; Dean Stauffer, professor of wildlife conservation in the College of Natural Resources and Environment; Daniel Cristol, Chancellor Professor at the College of William & Mary; Dane Crossley, an associate professor of biological sciences at the University of North Texas; and William Hopkins, professor of wildlife conservation at Virginia Tech and director of the Global Change Center at Virginia Tech, a branch of the Fralin Life Science Institute.

This research is supported by the U.S. Fish and Wildlife Service in cooperation with the E.I. DuPont de Nemours and Company.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column][vc_separator][/vc_column][/vc_row]

Conservation New Publications News Outreach

Personal outreach to landowners is vital to conservation program success

Post author By jcoker
Post date April 6, 2018

From VT News

April 5, 2018 | Virginia Tech College of Natural Resources and Environment research published in the scientific journal PLOS ONE shows that private landowners trust conservation agencies more and have better views of program outcomes when they accompany conservation biologists who are monitoring habitat management on their land.

Engaging private landowners in conservation and sustaining that interest is critically important, particularly in the eastern United States, where more than 80 percent of land is privately owned. Outreach from conservation professionals can connect private landowners with voluntary conservation programs, such as those administered by the U.S. Department of Agriculture’s Natural Resources Conservation Service (NRCS) and could also help keep landowners involved in conservation.

Federal conservation programs funded through the Farm Bill, such as Working Lands for Wildlife and the Regional Conservation Partnership Program, provide private landowners with financial and technical assistance to conduct conservation on their lands. Since 2012, efforts through these two programs have helped landowners create young forest habitat to benefit wildlife, such as the at-risk golden-winged warbler.

cnre-forestlandowners — Left to right: USDA Natural Resources Conservation Service District Conservationist Brad Michael and Emily Heggenstaller, a golden-winged warbler biologist, meet with private landowners Mike and Laura Jackson to discuss young forest habitat management on their property. Photo by Justin Fritscher.

According to lead author Seth Lutter, a master’s student in fish and wildlife conservation, the goal of the research was to understand how effective these habitat programs are from a social perspective. The researchers were interested in evaluating how outreach could influence landowners’ program experiences and possibly their future management for wildlife on their land.

Lutter worked with Ashley Dayer, assistant professor of human dimensions in Virginia Tech’s Department of Fish and Wildlife Conservation, to survey landowners to supplement a wider NRCS Conservation Effects Assessment Project (CEAP) assessment. The CEAP assessment, led by Jeffery Larkin, professor of biology at Indiana University of Pennsylvania and forest bird habitat coordinator with the American Bird Conservancy, evaluates the effectiveness of young forest management in creating quality habitat for the golden-winged warbler and other wildlife species.

The phone survey was conducted with a group of landowners who had participated in NRCS programs to manage young forest since 2012. These landowners had voluntarily allowed biological technicians onto their properties to monitor bird populations and vegetation regrowth as part of the assessment project. Some landowners accompanied these technicians on site visits, while many chose not to. In addition, some landowners received another form of outreach — personalized mailings that described the birds detected on the monitored property.

The survey investigated landowners’ experiences with the habitat program and what they thought the effects of management were for their land and its wildlife. The researchers then compared responses from landowners who had received additional outreach with those from landowners who had not.

Landowners who had accompanied technicians expressed higher trust of the agency and better perceptions of program outcomes. Meanwhile, the mailings contributed to increased landowner knowledge about birds, but did not improve landowner trust of the agency or perceptions of program outcomes.

These findings suggest that outreach, particularly in-person interactions, can have a significant effect on shaping landowner experiences with conservation programs. At a time when funding for agency outreach is tight, these results are particularly important.

“This study shows the value of investing in face-to-face interactions and relationship building,” Lutter explained. “Further, the results show an important and unexpected role that biological monitoring technicians can play in building landowner trust with the agency delivering conservation programs.”

Dayer and Lutter hope their results will help agencies like NRCS focus their efforts on effective outreach strategies, including training technicians and field staff on landowner interactions, encouraging site visits, and providing feedback to landowners on management outcomes.

“This study gives NRCS a unique perspective on how landowners perceive the conservation planning help we provide them to manage sustainable working lands and emphasizes the importance of including landowners when assessing outcomes of conservation efforts,” said Charlie Rewa, the NRCS biologist coordinating CEAP’s wildlife component.

Dayer added, “Private landowners are critical to the health of our nation’s wildlife populations. Ensuring that conservation programs are designed and delivered in a way that works for landowners and fosters their continued interest in conservation is essential.”

Moving forward, Lutter and Dayer will further explore the experiences of landowners in programs to manage young forest in an effort to understand what causes some of them to manage habitat after incentives from conservation programs have ended. This research will build on a literature review about management persistence after conservation programs that Dayer and Lutter published last year.

Dayer, who is affiliated with the Global Change Center housed in Virginia Tech’s Fralin Life Science Institute, will also follow up on this study’s findings with research into the effects of outreach in the context of biological monitoring for eastern hellbender salamanders in Southwest Virginia.

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Accolades Conservation Ideas New Publications News

Human-centered design is key to forming partnerships for large-scale conservation success

Post author By jcoker
Post date March 23, 2018

From VT News

March 22, 2018 | To recruit more fishers to help with marine conservation, cast a wider net.

This is the conclusion of a new study by Virginia Tech researchers who examined participation in a payment for ecosystem services program. The study modeled preferences of fishers in Chile in creating and monitoring marine protected areas inside their fishing management zones.

Lead author Michael Sorice, an associate professor of conservation social science in the College of Natural Resources and Environment, and his colleagues found that more fishers voted in favor of adopting the program when it was designed to incorporate their preferences and when they had a reasonable expectation of good outcomes for the fishery.

“We call this approach where participants’ needs are given the same weight as the resource’s needs during the design phase of the program, ‘human-centered design,’” said Sorice, who is also affiliated with the university’s Global Change Center, an arm of the Fralin Life Science Institute. “It can help minimize costs by building programs that are seen as desirable at the outset.”

Boats by a harbor — Small-scale fishers mainly use diving gear and these deckless boats to harvest inshore finfish, benthic invertebrates, and algae. Photo courtesy Mike Sorice.

The findings, published in PLOS ONE on March 9, question previous assumptions in the field that the payments themselves are the most effective motivator of participation.

“Similar to the way consumers make purchasing decisions, voluntary conservation programs are value propositions,” said Josh Donlan, founder and director of Advanced Conservation Strategies and co-author on the study. “While payments are important, fishers also consider other costs and benefits they expect to occur and then decide whether their overall wellbeing would be improved.”

The human-centered design approach works by attracting fishers who may be otherwise uncertain or unenthusiastic about the payment program. Their study found that desirable programs were better able to attract fishers who thought the program was a good idea, but who might have low trust that the conditions exist to make it happen. They also found that fishers who were not sure it is a great idea were more willing to participate based on program adjustments like shorter enrollment periods.

Kevin Boyle, co-author and a professor of agricultural and applied economics in the College of Agriculture and Life Sciences at Virginia Tech, said that these results indicate that small program design changes that reduce fisher uncertainty are keys to successfully casting the wider net.

The team surveyed a total of 168 fishers across 12 fishing associations in central Chile, all of which have functioning territorial user rights (TURFS) assigned by the Chilean government. The TURF-reserve program was described to respondents as a marine biodiversity conservation program in which businesses, organizations, and agencies interested in protecting marine biodiversity, either for philanthropic purposes or to offset environmental impacts elsewhere, would provide the fishing association with an annual cash payment to set aside 15 hectares of their fishing territory as a no-take protected area.

Fishers were informed that an independent nonprofit organization would be created to administer the program, and that, while the fishing association would actually receive the cash payment, each member would receive a portion.

“For a lot of these fishers, fishing is more than money, it’s a way of life. Programs that provide a better fit to their way of life will be more likely to be successful and grow,” said Stefan Gelcich, a co-author on the study and professor of natural resource management at the Center of Applied Ecology and Sustainability at Pontificia Universidad Católica de Chile.

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New Publications

Dude…Where’d this weed come from?

Post author By jcoker
Post date November 29, 2017

Globalization and other human activities such as domestication can influence population structure of the earth’s flora and fauna, having broad implications for biodiversity. For example, Cannabis sativa (a.k.a. hemp/marijuana) has been used by humans for diverse purposes including medicine, spirituality, entertainment, and as a source of fiber for thousands of years. Because of its broad utility, this plant has been subject to extensive cultivation, artificial selection, and global trade. As a result, the origins and historical patterns of genetic diversity of marijuana remain ambiguous.

Using state of the science genetic tools, Drs. David Haak, Aure Bombarely, and their colleagues from the University of Tehran have revealed patterns of genetic structure of C. sativa from Iran. Their work shows that cultivation of hemp for fiber originally arose from marijuana strains grown for medicinal/spiritual purposes. The findings have broad implications for identifying pools of genetic diversity, and the influence of human activities on this diversity, that may be important to a growing global multi-billion dollar industry.

Read the full paper: Assessment of Genetic Diversity and Population Structure in Iranian Cannabis Germplasm

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New Publications Research

Even small amounts of oil made birds sick near Deepwater Horizon spill

Post author By jcoker
Post date November 1, 2017

From VT News

Photos from the Deepwater Horizon Oil Spill on April 20, 2010, show heartbreaking images of deceased or soon-to-be-deceased sea life—birds, fish, sea turtles, and mammals coated in thick, black grime.

However, even small amounts of oil exposure affected the health of birds in the Gulf of Mexico, according to a Virginia Tech research team. Their findings were published Oct. 12 in the journal Environmental Toxicology and Chemistry.

The team examined samples shipped to them from hundreds of birds — a mix of American oystercatchers, black skimmers, brown pelicans, and great egrets — in the months following the spill. Blood samples taken by first responders showed that individuals exposed to small amounts of oil from the spill suffered from hemolytic anemia, a condition that occurs when toxins enter the bloodstream and damage red blood cells that carry oxygen to tissues. Anemia can affect growth, alter organ function, reduce reproductive success, increase risk of disease, and even cause death in birds.

The research team’s findings could not be published until now because they were used in the legal settlement that was finalized in 2016, in which the oil company BP was ordered to pay state and federal natural resource agencies $8.8 billion for restoration efforts.

“Our findings suggest that adverse effects of oil spills on birds are much more widespread than estimates based on avian mortality or severe visible oiling,” said co-author William A. Hopkins, a professor of wildlife in the College of Natural Resources and Environment and director of the Global Change Center at Virginia Tech. “Because remarkably small amounts of oil exposure injured birds in the gulf, our research changes the way we think about ecological damage from oil spills and influences how we document adverse effects after future spills.”

Hopkins is an expert in wildlife ecotoxicology, studying how environmental stressors impact animals’ physiological processes, such as reproduction, thermoregulation, and immune function. His past research has examined adverse effects of environmental pollutants on the physiology of diverse wildlife species. His work involves collaboration with state and federal agencies, as well as industry, and includes numerous high-profile chemical spills and natural resource damage cases, including the historic Tennessee Valley Authority coal fly ash spill in nearby Tennessee and a massive release of mercury from an industrial site in the Shenandoah Valley.

Jesse Fallon spent countless hours in the laboratory analyzing blood samples as they were shipped to Blacksburg from the Gulf of Mexico. Photo by Nicole Newman.

Jesse Fallon, of Morgantown, West Virginia, a doctoral student in Hopkins’ lab in the Department of Fish and Wildlife Conservation, was the first author on the paper. Fallon is also a practicing veterinarian who received his D.V.M. from the Virginia-Maryland College of Veterinary Medicine before pursuing his Ph.D. with Hopkins. He determined which physiological parameters would be most valuable to quantify in exposed birds during early development of the project, developed the sampling protocols, and trained teams on proper sample collection and handling. Fallon spent countless hours in the laboratory analyzing blood samples as they were shipped to Blacksburg from the Gulf of Mexico.

“Even birds with relatively limited exposure to oil from the Deepwater Horizon spill sustained damage to circulating red blood cells and had evidence of anemia,” Fallon said. “Our results help scientists, industry, and government agencies understand the far-reaching effects of the Deepwater Horizon spill and will inform future damage assessment efforts.”

The research represents a coordinated collaborative effort with the federal government, as well as with first responders, animal rehabilitation facilities, and research teams from other institutions that were encountering oiled birds. Other co-authors include Eric P. Smith, a professor in the Department of Statistics at Virginia Tech; Nina Schoch, James D. Paruk, Evan A. Adams, and David C. Evers, from the Biodiversity Research Institute; Patrick G.R. Jodice with the U.S. Geological Survey’s South Carolina Cooperative Fish and Wildlife Research Institute and Clemson University; Christopher Perkins with the Center for Environmental Sciences and Engineering at the University of Connecticut; and Shiloh Schulte with Manomet.

The research was funded by the U.S. Fish and Wildlife Service.

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Story by Lindsay Key

New Publications Research

Sterling Nesbit finds early dinosaur cousin had a surprising croc-like look

Post author By jcoker
Post date April 13, 2017

From VT News

For decades, scientists have wondered what the earliest dinosaur relatives looked like. Most assumed that they would look like miniature dinosaurs, be about the size of a chicken, and walk on two legs.

A Virginia Tech paleobiologist’s latest discovery of Teleocrater rhadinus, however, has overturned popular predictions. This carnivorous creature, unearthed in southern Tanzania, was approximately seven to 10 feet long, with a long neck and tail, and instead of walking on two legs, it walked on four crocodylian-like legs.

The finding, published in the journal Nature today, fills a critical gap in the fossil record. Teleocrater, living more than 245 million years ago during the Triassic Period, pre-dated dinosaurs.

It shows up in the fossil record right after a large group of reptiles known as archosaurs split into a bird branch (leading to dinosaurs and eventually birds) and a crocodile branch (eventually leading to today’s alligators and crocodiles). Teleocrater and its kin are the earliest known members of the bird branch of the archosaurs.

“The discovery of such an important new species is a once-in-a-lifetime experience,” said Sterling Nesbitt, an assistant professor of geosciences in the College of Science.

He and Michelle Stocker, a co-author and also an assistant professor of geosciences in the College of Science, will give a free public talk at 7 p.m. Thursday in 4069 Derring Hall, folllowed by a fossil viewing session at the Virginia Tech Museum of Geosciences on the second floor of Derring Hall.

Teleocrater fossils were first discovered in Tanzania in 1933 by paleontologist F. Rex Parrington, and the specimens were first studied by Alan J. Charig, former Curator of Fossil Reptiles, Amphibians and Birds at the Natural History Museum of London, in the 1950s.

Largely because the first specimen lacked crucial bones, such as the ankle bones, Charig could not determine whether Teleocrater was more closely related to crocodylians or to dinosaurs. Unfortunately, he died before he was able to complete his studies.

The new specimens of Teleocrater, found in 2015, clear those questions up. The intact ankle bones and other parts of the skeleton helped scientists determine that the species is one of the oldest members of the archosaur tree and had a crocodylian look.

Nesbitt and co-authors chose to honor Charig’s original work by using the name he picked out for the animal, Teleocrater rhadinus, which means “slender complete basin” and refers to the animal’s lean build and closed hip socket.

“The discovery of Teleocrater fundamentally changes our ideas about the earliest history of dinosaur relatives,” said Nesbitt. “It also raises far more questions than it answers.”

Scientists at dig site
Ken Angielczyk of the Field Museum of Natural History, Sterling Nesbitt, an assistant professor of geosciences in the College of Science, and Michelle Stocker, an assistant professor of geosciences in the College of Science, work at the the Teleocrater dig site in Tanzania moments before the discovery was made by Roger Smith. Photo by Christian Sidor.
“This research sheds light on the distribution and diversity of the ancestors of crocodiles, birds, and dinosaurs,” said Judy Skog, program director in the National Science Foundation’s Division of Earth Sciences, “and indicates that dinosaur origins should be re-examined now that we know more about the complex history and traits of these early ancestors.”

Teleocrater and other recently discovered dinosaur cousins show that these animals were widespread during the Triassic Period and lived in modern day Russia, India, and Brazil. Furthermore, these cousins existed and went extinct before dinosaurs even appeared in the fossil record.

The team’s next steps are to go back to southern Tanzania this May to find more remains and missing parts of the Teleocrater skeleton. They will also continue to clean the bones of Teleocrater and other animals from the dig site in the paleontology preparation lab in Derring Hall.

“It’s so exciting to solve puzzles like Teleocrater, where we can finally tease apart some of these tricky mixed assemblages of fossils and shed some light on broader anatomical and biogeographic trends in an iconic group of animals,” said Stocker.

Stocker and Nesbitt are both researchers with the Global Change Center at Virginia Tech. Other co-authors on the paper include: Richard J. Butler with the University of Birmingham; Martin D. Ezcurra with Museo Argentino de Ciencias Naturales; Paul M. Barrett with the Natural History Museum of London; Kenneth D. Angielczyk with the Field Museum of Natural History; Roger M. H. Smith with the University of the Witwatersrand and Iziko South African Museum; Christian A. Sidor with the University of Washington; Grzegorz Niedzwiedzki with Uppsala University; Andrey G. Sennikov with Borissiak Paleontological Institute and Kazan Federal Univeristy; and Charig.

The research was funded by the National Science Foundation, National Geographic Society, a Marie Curie Career Integration Grant, a National Geographic Society for Young Explorers grant, and the Russian Government Program of Competitive Growth of Kazan Federal University.

More information is available through the Paleobiology & Geobiology Research Group at Virginia Tech website.

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Story by Lindsay Key, Communications Director, Fralin Life Science Institute