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"The EU is carrying out a once-in-a-decade review of its common fisheries policy. John Harris joins fisherman John Griffin on his boat off Hastings, East Sussex, and discovers that quotas put in place under the auspices of conservation are being allocated to bigger interests at the expense of locals who have been fishing for generations." The Guardian
Grand Coulee Dam in Washington State is the largest U.S. Bureau of Reclamation dam and reservoir in the Columbia River Basin. It was completed in 1942.
Washington State University researchers have documented an underappreciated suite of players in global warming: dams, the water reservoirs behind them, and surges of greenhouse gases as water levels go up and down.
Bridget Deemer, a doctoral student at Washington State University-Vancouver, measured dissolved gases in the water column of Lacamas Lake in Clark County and found methane emissions jumped 20-fold when the water level was drawn down. A fellow WSU-Vancouver student, Maria Glavin, sampled bubbles rising from the lake mud and measured a 36-fold increase in methane during a drawdown.
Methane is 25 times more effective than carbon dioxide at trapping heat in the atmosphere. And while dams and the water behind them cover only a small portion of the earth's surface, they harbor biological activity that can produce large amounts of greenhouse gases. There are also some 80,000 dams in the United States alone, according to the U.S. Army Corps of Engineers National Inventory of Dams.
"Reservoirs have typically been looked at as a green energy source," says Deemer. "But their role in greenhouse gas emissions has been overlooked."
Deemer and Glavin's findings will be on display this week in a poster session at the national meeting of the Ecological Society of America in Portland.
Their efforts are part of a larger attempt to appreciate the role of lakes, reservoirs and streams in releasing greenhouse gases. A study published last year in the journal Science conservatively estimated that the ability of terrestrial ecosystems to act as carbon sinks, storing greenhouse gases, could be one-fourth less than estimated once emissions from reservoirs are considered.
The WSU-Vancouver work is the first to actually demonstrate and quantify the relationship between water-level drawdowns and greenhouse gas releases, says John Harrison, Deemer and Glavin's advisor and an assistant professor of Earth and Environmental Sciences.
The research could lead to different ways of managing drawdowns, he says, as emissions may be higher in summer months, when warmer temperatures and low oxygen conditions in bottom waters stimulate the microbial activity that produces greenhouse gases.
"We have the ability to manage the timing, magnitude and speed of reservoir drawdowns, which all could play a role in how much methane gets released to the atmosphere," Harrison says.
Managers can also consider the optimal time to take out a dam, Deemer says. While a dam removal may lead to some greenhouse gas emissions initially, she says it will be a one-time occurrence, while emissions can recur with regular drawdowns. The ability of soils and plants to store greenhouse gases could also make reservoir decommissioning a net sink, she says, but researchers "simply don't know at this point."
With Army Corps of Engineers funding, Deemer now plans to look at three other reservoirs in Oregon and northern California's Klamath basin.
Contact: Eric Sorensen
eric.sorensen@wsu.edu
206-799-9186
Washington State University
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Virginia Tech Associate Professor of Wildlife Conservation Sarah Karpanty has conducted biodiversity research in Madagascar since 1998. Credit: Virginia Tech |
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The 14 years of wildlife studies in and around Madagascar's Ranomafana National Park by Sarah Karpanty, associate professor of wildlife conservation at Virginia Tech's College of Natural Resources and Environment, and her students are summarily part of a paper on biodiversity published July 25 by Nature's Advanced Online Publication and coming out soon in print.
As human activities put increasing pressures on natural systems and wildlife to survive, 200 scientists around the world carved up pieces of the puzzle to present a clearer picture of reality and find ways to mitigate the destructive forces at work.
Titled "Averting biodiversity collapse in tropical forest protected areas," the paper was coordinated by William F. Laurance of the Smithsonian Tropical Research Institute and James Cook University's Centre for Tropical Environmental and Sustainability Science and School of Marine and Tropical Biology. Nature is the prestigious international weekly journal of science that focuses on the natural environment.
The study, which looked at more than 30 different categories of species, from butterflies to large predators, within protected areas across the tropical regions of the Americas, Africa, and Asia, concludes that many of the world's tropical protected areas are struggling to sustain their biodiversity.
"But some of the arks are in danger of sinking, even though they are our best hope to sustain tropical forests and their amazing biodiversity in perpetuity," Laurance said.
The scientists estimated how these species groups had changed in numbers over the past two to three decades, while identifying environmental changes that might threaten the reserves, such as the deforestation advancing rapidly in tropical nations. Calling the tropical forests the biologically richest real estate on the planet, the team found many nature reserves acted like mirrors — partially reflecting the threats and changes in their surrounding landscapes.
Karpanty's role was to provide an expert review of her research in Madagascar since 1998, with attention on the state of the wildlife she studied, the threats to both the wildlife and the park, and how changes outside the park boundary impact wildlife inside the park.
In particular, the College of Natural Resources and Environment researcher contributed data on raptor, carnivore, and lemur populations in Ranomafana National Park. Assisting her in the research were master's students Brian Gerber and Mary Kotschwar, both of whom received their degrees in fisheries and wildlife sciences from Virginia Tech in 2010.
"This is a uniquely comprehensive, up-to-date, and honest assessment about the role of protected areas in saving biodiversity in the tropics," Karpanty said of the entire Nature paper. "The large project was a collaborative effort by scientists from around the world to contribute their data and insight to the question of whether nature and wildlife parks can save the world's biodiversity."
The answer? While most reserves were helping to protect their forests, about half were struggling to sustain their original biodiversity, including old-growth trees, big predators and other large-bodied animals, many primates, stream-dwelling fish and amphibians, and other wildlife. The researchers found that reserves that were suffering most were those that were poorly protected and suffered encroachment from illegal colonists, hunters, and loggers.
"The take-home point," Karpanty emphasized, "should not be viewed in a negative light, in terms of thinking that hope is lost for biodiversity in the tropics. We need to be as aggressive in eliminating threats outside of park boundaries as we are in establishing new parks or maintaining existing ones. In many ways, the findings are common sense. However, sometimes 'we,' meaning society, need a wake-up call about the obvious."
Contact: Helen Thompson
davisl@vt.edu
540-231-6157
Virginia Tech
Diseased trees in forests may be a significant new source of methane that causes climate change, according to researchers at the Yale School of Forestry & Environmental Studies in Geophysical Research Letters.
Sixty trees sampled at Yale Myers Forest in northeastern Connecticut contained concentrations of methane that were as high as 80,000 times ambient levels. Normal air concentrations are less than 2 parts per million, but the Yale researchers found average levels of 15,000 parts per million inside trees.
"These are flammable concentrations," said Kristofer Covey, the study's lead author and a Ph.D. candidate at Yale. "Because the conditions thought to be driving this process are common throughout the world's forests, we believe we have found a globally significant new source of this potent greenhouse gas."
The estimated emission rate from an upland site at the Yale forest is roughly equivalent to burning 40 gallons of gasoline per hectare of forest per year. It also has a global warming potential equivalent to 18 percent of the carbon being sequestered by these forests, reducing their climate benefit of carbon sequestration by nearly one-fifth.
"If we extrapolate these findings to forests globally, the methane produced in trees represents 10 percent of global emissions," said Xuhui Lee, a co-author of the study and Sara Shallenberger Brown Professor of Meteorology at Yale. "We didn't know this pathway existed."
The trees producing methane are older—between 80 and 100 years old—and diseased. Although outwardly healthy, they are being hollowed out by a common fungal infection that slowly eats through the trunk, creating conditions favorable to methane-producing microorganisms called methanogens.
"No one until now has linked the idea that fungal rot of timber trees, a production problem in commercial forestry, might also present a problem for greenhouse gas and climate change mitigation," said Mark Bradford, a co-author and Assistant Professor of Terrestrial Ecosystem Ecology at F&ES.
Red maple, an abundant species in North America, had the highest methane concentrations, but other common species, including oak, birch and pine were also producers of the gas. The rate of methane emissions was 3.1 times higher in the summer, suggesting that higher temperatures may lead to increasing levels of forest methane that, in turn, lead to ever-higher temperatures.
"These findings suggest decay in living trees is important to biogeochemists and atmospheric scientists seeking to understand global greenhouse gas budgets and associated climate change," said Covey.
The other co-authors of the paper, "Elevated Methane Concentrations in Trees of an Upland Forest," are Stephen Wood, a Ph.D. student at Columbia University, and Robert Warren, former postdoctoral researcher at Yale and now an assistant professor at Buffalo State (SUNY).
Citation: Covey, K. R., S. A. Wood, R. J. Warren II, X. Lee, and M. Bradford (2012), Elevated methane concentrations in trees of an upland forest, Geophys. Res. Lett., doi:10.1029/2012GL052361, in press.
Contact: David DeFusco
david.defusco@yale.edu
203-436-4842
Yale University
A survey of teachers from the United States and Canada found that one out of four educators who used live animals as part of their science curriculum released the organisms into the wild after they were done using them in the classroom.
Yet only 10 percent of those teachers participated in a planned release program, increasing the likelihood that the well-intentioned practice of using live organisms as a teaching tool may be contributing to invasive species problems.
The study was presented today (Aug. 7) in Portland at the national meeting of the Ecological Society of America.
"Live organisms are a critical element for learning and we don't want to imply that they should not be used in the classroom," said Sam Chan, an Oregon State University invasive species expert and a principal investigator on the study. "But some of our schools – and the biological supply houses that provide their organisms – are creating a potential new pathway for non-native species to become invasive.
"We need to work through the whole chain and educate both the teachers and suppliers about the potential damages – both environmental and economic – that invasive species may trigger," added Chan, a Sea Grant Extension specialist and former chair of the Oregon Invasive Species Council.
The study surveyed nearly 2,000 teachers in Florida, New York, Indiana, Illinois, Oregon, Washington, California, Connecticut, British Columbia and Ontario. Conducted primarily by Sea Grant researchers, it also included focus groups and interviews with teachers, curriculum specialists and biological supply house owners and managers.
The researchers found as many as 1,000 different organisms utilized by the teachers, and many frequently listed species were known or potential aquatic invasive species including elodea, crayfishes, amphibians, mosquito fish, red-eared slider turtles and other aquatic plants and snails.
Crayfish, Chan said, provide an interesting case study.
"Oregon teachers who have ordered crayfish that originate in the Pacific Northwest have found that their mortality is extremely high, so many have taken to ordering crayfish from distributors who get their supply from Louisiana," Chan said. "The problem is that we have no idea whether those crayfish may carry diseases or parasites that may be problematic if those animals are released into the wild here."
Funded by the National Oceanic and Atmospheric Administration, the study also pointed to the dilemma that teachers face over what to do with the animals after the curriculum section has been completed.
"Teachers are evenly split over the idea of euthanasia," Chan said. "In some cases, it may be the only option. We don't recommend what teachers would do, but suggest they consult a local veterinarian. Our goal as researchers is to make the teachers and biological supply houses aware that releasing organisms into the wild may cause problems and to think about using native species in lessons whenever possible."
One problem, Chan acknowledged, is that biological supply house managers don't see this as their issue. About 50 percent of the animals used by teachers came from pet stores or aquariums; the others from supply houses.
"More than one of them told us 'it isn't our job to educate the teachers,'" Chan said. "On the flip side, there were some who said they would be willing to work with us to try to provide more local organisms."
Chan and his colleagues say the project provides a rare opportunity to study an invasive species pathway along the entire chain, from the wholesaler to the release of organisms into the wild. Educating the teachers and the suppliers about invasive species issues is the first step toward changing behavior, the OSU researcher points out.
"Many of the teachers were mortified when we pointed out they may be exacerbating the invasive species problem," Chan said. "They want to be part of the solution, not part of the problem. But it is a complex issue. We don't want to discourage the use of live organisms in teaching because they can provide focus, enhance student interest, and foster responsibility and care.
"But there are consequences to using them and both teachers and suppliers should consider what will become of these organisms when the classroom lessons are over," he added.
Contact: Sam chan
samuel.chan@oregonstate.edu
541-737-1583
Oregon State University
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Kaveh Madani is a former postdoctoral research scholar in the Water Science and Policy Center at UC Riverside. Credit: Madani Lab, University of Central Florida |
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California's hydropower is vulnerable to climate change, a University of California, Riverside scientist has advised policymakers in "Our Changing Climate," a report released July 31 by the California Natural Resources Agency and the California Energy Commission (CEC).
"Climate change is expected to affect the quantity and timing of water flow in the state," explained Kaveh Madani, a former postdoctoral research scholar in UC Riverside's Water Science and Policy Center (WSPC), who led a research project on climate change effects on hydropower production, demand, and pricing in California. "Under dry climate warming, the state will receive less precipitation, with most of it as rain instead of snow, impacting hydropower supply and operations."
On average, 15 percent of California's electricity comes from hydropower, a cheap and relatively clean energy source. About 75 percent of this hydropower comes from high-elevation units, located above 1,000 ft. The state has more than 150 high-elevation units, with most of them located in Northern California and the Sierra Mountains. The majority of the high-elevation reservoirs are small in terms of their storage capacity, being built only for hydroelectricity production and no other benefits, such as water supply and flood control.
"If California loses snowpack under climate warming, these high-elevation reservoirs might not be able to store enough water for hydropower generation in summer months when the demand is much higher and hydropower is priced higher," said Madani, currently an assistant professor of civil, environmental, and construction engineering at the University of Central Florida. "California might, therefore, lose hydropower in warmer months and hydropower operators may lose considerable revenues."
Madani, who led UCR's only research team for CEC's third climate change assessment studies, explained that the major cause of revenue loss is that hydropower prices are expected to decrease in colder months of the year and increase in warmer months.
"The big problem is that hydropower will be less available when it is most needed and expensive: in the summer months," he said. "A warmer California needs more electricity for cooling in summer months and less electricity for warming in winter months. This means that hydropower pricing patterns will be affected by climate change. It is important to analyze climate change effects on this renewable energy source early on to figure out what strategies are available to adapt to the new conditions and thereby minimize the potential negative impacts of climate change on hydropower."
Madani explained that, on average, California could lose up to 20 percent of its hydropower generation under dry climate change, which can result in 8 to 18 percent reduction in hydropower revenues for producers.
"Our results do not yet suggest that we need to build more dams in California for hydropower generation," said Madani, who was recently selected as one of the 10 New Faces of Civil Engineering in 2012 by the American Society of Civil Engineering. "But they suggest that hydropower, a highly valuable energy source, may be less available. So we have to look for clean replacements and we have to reduce our energy demands as much as we can."
Madani began his research on climate change effects on California's hydropower as a graduate student at UC Davis, where, along with a colleague, he developed an "Energy-Based Hydropower Optimization Model" (EBHOM) that covers more than 150 high-elevation hydropower units in California. An optimization model, EBHOM prescribes the best operation policies in response to the changes in climatic conditions.
A new version of the model that Madani developed can estimate changes in hydropower pricing and demand in response to temperature changes.
"It helps us consider the effects on supply and demand simultaneously," Madani said of the model's new version. "But modeling studies have limitations that need to be addressed as more data become available and the science improves. Future studies need to have a closer look at the environmental side of this problem. Changes in operations of the high-elevation systems should be done after careful consideration of all possible environmental damages."
Madani's research at UCR was funded by CEC. As the principal investigator of the research project, he worked with fellow-researchers at Lund University, Sweden; the University of Central Florida; and the Bourns College of Engineering at UCR.
Madani's postdoctoral research took place during 2009-2010 at the WSPC, where he closely worked with Ariel Dinar, its director.
"I am an engineer and Ariel is an economist," Madani said. "We talk different languages and sometimes might think differently about the same problem. The different views helped me learn many new things and gave me the ability to think out of the engineering thinking box. Working at the WSPC was thus a true interdisciplinary research and education experience for me."
The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 20,500 students. The campus will open a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.
Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California - Riverside
Even temporary rises in local temperatures significantly damage long-term economic growth in the world's developing nations, according to a new study co-authored by an MIT economist.
Looking at weather data over the last half-century, the study finds that every 1-degree-Celsius increase in a poor country, over the course of a given year, reduces its economic growth by about 1.3 percentage points. However, this only applies to the world's developing nations; wealthier countries do not appear to be affected by the variations in temperature.
"Higher temperatures lead to substantially lower economic growth in poor countries," says Ben Olken, a professor of economics at MIT, who helped conduct the research. And while it's relatively straightforward to see how droughts and hot weather might hurt agriculture, the study indicates that hot spells have much wider economic effects.
"What we're suggesting is that it's much broader than [agriculture]," Olken adds. "It affects investment, political stability and industrial output."
Varied effects on economies
The paper, "Temperature Shocks and Economic Growth: Evidence from the Last Half Century," was published this summer in the American Economic Journal: Macroeconomics. Along with Olken, the authors are Melissa Dell PhD '12, of Harvard University, who was a PhD candidate in MIT's Department of Economics when the paper was produced, and Ben Jones PhD '03, an economist at Northwestern University.
The study first gained public attention as a working paper in 2008. It collects temperature and economic-output data for each country in the world, in every year from 1950 through 2003, and analyzes the relationship between them. "We couldn't believe no one had done it before, but we weren't really sure we'd find anything at all," Olken says.
By looking at economic data by type of activity, not just aggregate output, the researchers concluded there are a variety of "channels" through which weather shocks hurt economic production — by slowing down workers, commerce, and perhaps even capital investment.
"If you think about people working in factories on a 105-degree day with no air conditioning, you can see how it makes a difference," Olken says.
One consequence of this, borne out in the data, is that the higher temperatures in a given year affect not only a country's economic activity at the time, but its growth prospects far into the future; by the numbers, growth lagged following hot years.
To see why, Olken suggests, first think of a dry year for vegetables in your backyard garden: The bad weather would hurt the plants, but if the weather is reasonable the following year, the backyard crop would return to its normal level. Now contrast that with problems that affect, say, industrial and technological development, and capital investment; temperature shocks limiting those activities can compound over time.
"If you think about economic growth, you build on where you were last year," Olken explains. For longer-term industrial or technological projects, he adds, "If it's that kind of activity that's lost, then it affects the country's long-run growth rate, [and it's] not a one-off hit."
Political change in the weather
Olken, Dell and Jones also integrated data about forms of government into the study, and found that temperature shocks are associated with an increase in political instability. A 1-degree-Celsius rise in a given year, they found, raises the probability of "irregular leader transitions," such as coups, by 3.1 percentage points in poor countries. In turn, the authors write, "poor economic performance and political instability are likely mutually reinforcing."
As Olken observes, the study does not try to account for all the possible problems that could be generated by long-term climate change, such as rising oceans, floods or increased storms. Still, he adds, the paper does suggest some general points about the economic impact of a warming atmosphere. It is vital, he says, to "think about the heterogeneity of the impact between the poor and rich countries" when leaders and policymakers map out the problems the world may confront in the future.
"The impacts of these things are going to be worse for the countries that have the least ability to adapt to it," he adds. "[We] want to think that through for the implications for future inequality. It's a double whammy."
Written by Peter Dizikes, MIT.
Contact: Caroline McCall
cmccall5@mit.edu
Massachusetts Institute of Technology
Plains bison are an iconic symbol of America on everything from coins to state flags. Now scientists writing in Conservation Biology are exploring how the cross-breeding of bison with domestic cattle in the late 1800s may still have unwanted effects on modern populations of the species.
"The plains bison are an iconic symbol of rugged individualism and the will to survive," said Professor James Derr from Texas A&M University. "The population crash and the spectacular recovery over the last 125 years is a classic example of the resilience of this species and the success of science based wildlife conservation."
Plains bison (Bison bison bison) once numbered in the tens of millions, but they were driven to the brink of extinction in the late 1880's during America's westward expansion. A small population of wild bison survived in Yellowstone National Park, while 5 herds remained in the hands of private ranchers. It is estimated that less than 100 surviving bison became the common ancestors of today's herds.
In some of these privately held herds, bison were crossed with domesticated cattle in an attempt to introduce the hardy bison traits into beef producing animals. While this effort failed to produce new and improved beef breeds, some hybrids were created, and with the use of molecular technologies, these scientists have discovered there remains a legacy of small amount of cattle genetic contamination in most bison herds in North America.
"Looking at the long-term recovery of the bison it is important to find out if this small amount of cattle genetics in an otherwise normal bison can really have a biological effect," said Derr. "We brought together researchers from Arizona, California, Montana and Texas to find out."
The team recorded size measurements for over 900 bison from a nutritionally harsh environment for bison on Santa Catalina Island in California and a nutritionally rich environment on a ranch in Montana.
The results revealed that bison with a particular domestic cattle genetic trait, mitochondrial DNA, were consistently smaller and lighter than animals with true bison mitochondrial DNA in both environments.
"We have found that this cattle ancestry affects phenotypic traits and most likely fitness of bison in herds which are maintained for both production and species conservation," concluded Derr. "Long term management efforts with bison, and possibly other species with a history of hybridization, must carefully consider the importance of genome integrity in order to preserve what is the foundation and essence of these species, their genomes."
Reference: Phenotypic Effects of Cattle Mitochondrial DNA in American Bison,JAMES N. DERR, PHILIP W. HEDRICK, NATALIE D. HALBERT, LOUIS PLOUGH, LAUREN K. DOBSON, JULIE KING, CALVIN DUNCAN, DAVID L. HUNTER, NOAH D. COHEN, DENNIS HEDGECOCK. Article first published online: 2 AUG 2012. DOI:10.1111/j.1523-1739.2012.01905.x
Contact: Ben Norman
Sciencenewsroom@wiley.com
44-012-437-70375
Wiley
Greening vacant lots may make neighborhood residents feel safer and may be associated with reductions in certain gun crimes, according to a new study from the Perelman School of Medicine at the University of Pennsylvania. Results show that residents living near greened vacant lots feel safer than those near non-greened sites. Additionally, researchers noted that incidents of police-reported crimes may be reduced after greening. The results expand upon previous studies and are the next step in helping researchers understand the full impact of vacant lot greening on crime, safety, and health. Full results of the study were published online this week in Injury Prevention.
"Vacant lot greening changes the physical environment of a neighborhood from one that may promote crime and fear to one that may reduce crime and make people feel safer," said lead author Eugenia C. Garvin, MD, a resident in the Department of Emergency Medicine at the Perelman School of Medicine. "Our theory is that transforming vacant lots from a space overgrown with vegetation and filled with trash to a clean and green space may make it difficult for people to hide illegal guns and conduct other illegal activities such as drug use in or near the space. Additionally, green space may encourage community cohesion."
The study is the first to use a randomized controlled trial design - the gold standard in scientific research - to examine the effects of vacant lot greening. Researchers randomly selected two clusters of vacant lots – one cluster which was later greened, and one control cluster which was not. The team worked with members of the Pennsylvania Horticultural Society who performed greening of select vacant lots by removing debris, planting grass and trees, building fences, and performing regular maintenance every two weeks.
"Philadelphia LandCare has helped transform thousands of vacant lots in key neighborhoods across the city," said Bob Grossmann, director of the Pennsylvania Horticultural Society's vacant land program. "We know that these improvements help neighborhoods and residents in a number of ways, but studies like the one led by Dr. Garvin help us to determine very specifically how we're impacting the city so we can continue to drive change where it's needed most and in the way that will have the most positive effects."
Twenty one residents living near both sites were interviewed before and after the greening. Survey results show that residents living near the greened vacant lots felt significantly safer at the three-month follow-up visit compared to those near the control site. Additionally, the research team analyzed police reported crime data from three months before and three months after the greening. Total crime, as well as assaults with and without a gun, was less after the greening.
Results from two other portions of the interview are still being analyzed: an in-depth qualitative interview about the impact of the physical environment on health, and a walking interview around the neighborhood, in which residents' heart rates were monitored. The goal of the walking interview was to explore a link between the environment and heart rate, a physiologic marker for stress. Data from the interviews will be published at a later time.
"We know health can be affected by the environment of one's neighborhood, but we know very little about what causes the impact," said Garvin. "One theory is that chronic stress from the neighborhood environment can lead to poor health outcomes, but there are few studies that examine the physiologic basis for this link. By monitoring the participants' heart rate during the walking interview, we hope to get a better idea of how the body reacts to the environment, and how vacant land might influence a resident's health."
Until now, few studies have examined vacant lot interventions to reduce violence and improve health. The results of the new study expand upon a 2011 study led by Charles Branas, PhD, associate professor of Epidemiology at Penn Medicine and senior author on the current study, in which a quasi-experimental, decade-long comparison of thousands of greened and non-greened vacant lots documented significant before-and-after reductions in gun assaults around vacant lots that were greened compared with those which were not.
Randomized controlled trials of vacant lot greening such as the present study provide the next level of statistical evidence needed to provide the best information to urban planners and city officials interested in greening as a strategy to prevent violence and encourage safety. A significantly larger randomized controlled trial examining hundreds of vacant lots is currently under way.
Carolyn C. Cannuscio, ScD, Department of Family Medicine and Community Health also co-authored the study. Funding for the study was supported by a grant from the Robert Wood Johnson Health and Society Scholars Educational Fund.
Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $4.3 billion enterprise.
The Perelman School of Medicine is currently ranked #2 in U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $479.3 million awarded in the 2011 fiscal year.
The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania -- recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report; Penn Presbyterian Medical Center; and Pennsylvania Hospital — the nation's first hospital, founded in 1751. Penn Medicine also includes additional patient care facilities and services throughout the Philadelphia region.
Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2011, Penn Medicine provided $854 million to benefit the local community.
Contact: Katie Delach
katie.delach@uphs.upenn.edu
215-349-5964
University of Pennsylvania School of Medicine
Feral Cat on Tilos Island, Dodecanese, Greece.Analysis of this feral cat’s stool gave us the following information about its diet: Scolopendra sp. 1.8%, Carabinadae 19.6%, Teleostei indet. 1.8%, Alectoris chukar 1.8%, Passer sp. 1.8%, Passeriformes indet. 10.7%, Aves indet. 1.8%, Apodemus mystacinus 7.1%, Rattus rattus 23.2%, Mus domesticus 30.4%. Credit: Constantine Alexander. All Rights Reserved.
There is no question that birds are better off when cats stay indoors. Exact numbers are unknown, but scientists estimate that every year in the United States alone, cats kill hundreds of millions of birds, and more than a billion small mammals, including rabbits, squirrels, and chipmunks. Feline predators include both domestic cats that spend time outdoors and stray cats that live in the wild, sometimes as part of a colony.
A new study of house cats allowed to roam outdoors finds that nearly one-third succeeded in capturing and killing animals. The cats, which wore special video cameras around their necks that recorded their outdoor activities, killed an average of 2.1 animals every week they were outside, but brought less than one of every four of their kills home. Of particular interest, bird kills constituted about 13 percent of the total wildlife kills. Based on these results, American Bird Conservancy and The Wildlife Society estimate that house cats kill far more than the previous estimate of a billion birds and other animals each year.
The study was carried out by scientists from the University of Georgia and the National Geographic Society's Crittercam program.
“The results were certainly surprising, if not startling,” said Kerrie Anne Loyd of the University of Georgia, who was the lead author of the study. “In Athens-Clarke County, we found that about 30 percent of the sampled cats were successful in capturing and killing prey, and that those cats averaged about one kill for every 17 hours outdoors or 2.1 kills per week. It was also surprising to learn that cats only brought 23 percent of their kills back to a residence. We found that house cats will kill a wide variety of animals, including: lizards, voles, chipmunks, birds, frogs, and small snakes.”
Loyd and her colleagues attached small video cameras (dubbed Crittercams or KittyCams) to 60 outdoor house cats in the city of Athens Georgia, and recorded their outdoor activities during all four seasons. Loyd said the cats were outside for an average of 5-6 hours every day.
“If we extrapolate the results of this study across the country and include feral cats, we find that cats are likely killing more than 4 billion animals per year, including at least 500 million birds. Cat predation is one of the reasons why one in three American bird species are in decline,” said Dr. George Fenwick, President of American Bird Conservancy, the only organization exclusively conserving birds throughout the Americas.
“I think it will be impossible to deny the ongoing slaughter of wildlife by outdoor cats given the videotape documentation and the scientific credibility that this study brings,” said Michael Hutchins, Executive Director/CEO of The Wildlife Society, the leading organization for wildlife professionals in the United States. “There is a huge environmental price that we are paying every single day that we turn our backs on our native wildlife in favor of protecting non-native predatory cats at all cost while ignoring the inconvenient truth about the mortality they inflict.”
Volunteer cat owners were recruited through advertisements in local newspapers, and all selected cats were given a free health screening. Each cat owner downloaded the footage from the camera at the end of each recording day.
The new study does not include the animals killed by feral cats that have no owners. A University of Nebraska study released last year found that feral cats were responsible for the extinction of 33 species of birds worldwide, that even well fed cats in so-called “managed” cat colonies will kill, that feral cats prey more on native wildlife than on other invasive creatures, and that most feral cats (between 62 and 80 percent) tested positive for toxoplasmosis (a disease with serious implications for pregnant women and people with weakened immune systems).
This study was collaboration between Kerrie Anne Loyd and Dr. Sonia Hernandez from the University of Georgia, and Greg Marshall, Kyler Abernathy, and Barrett Foster of National Geographic’s Remote Imaging Department and was funded in part by the Kenneth Scott Charitable Foundation.
American Bird Conservancy (ABC) is a 501(c)(3) not-for-profit membership organization whose mission is to conserve native birds and their habitats throughout the Americas. ABC acts by safeguarding the rarest species, conserving and restoring habitats, and reducing threats, while building capacity in the bird conservation movement.
The mission of The Wildlife Society is to represent and serve the professional community of scientists, managers, educators, technicians, planners, and others who work actively to study, manage, and conserve wildlife and habitats worldwide.
Contact: kloyd@uga.edu or shernz@uga.edu.
