The study took place in China’s Wolong Nature Reserve, which houses one-tenth of the world’s wild giant pandas. As part of a conservation program, more than 1,000 households monitored about 40,100 hectares of the reserve for illegal activities such as logging. Groups of one to 16 households were assigned to look after different sections of the forest.

Mid-sized groups of eight to nine households put the most effort per household into monitoring, the team reports in Proceedings of the National Academy of Sciences. Their forest parcels also performed the best; when overseen by a nine-household group, forest cover increased by 15.8 percent from 2001 to 2007.

Larger groups probably have more “free riders,” or members who don’t pull their weight, the researchers say. And smaller groups may not be able to exert enough social pressure on their members to contribute. — Roberta Kwok | 17 June 2013

Source: Yang, W. et al. 2013. Nonlinear effects of group size on collective action and resource outcomes. Proceedings of the National Academy of Sciences doi: 10.1073/pnas.1301733110.

Image © Robert Kneschke | Shutterstock.com

The effectiveness of wildlife corridors “remains surprisingly unknown,” the study authors write in Conservation Biology. The crossings are intended to help animals navigate fragmented habitat. But these structures are expensive to build, and skeptics wonder whether the investment is worth it.

In Canada’s Banff National Park, 25 wildlife corridors criss-cross an area with a four-lane highway, golf course, and ski resorts. The team set out barbed wire on 20 of the crossings to catch hair samples from the bears. Then the researchers conducted genetic tests on the samples to figure out how many individual bears had passed through.

From 2006 to 2008, 15 grizzlies and 17 black bears traversed the corridors, the team reports. Grizzlies preferred the open crossings, such as overpasses, while the black bears were also comfortable with small culverts. The authors estimate that at least 15-20 percent of the grizzly population and 11-18 percent of the black bear population used the corridors. — Roberta Kwok | 14 June 2013

Source: Sawaya, M.A. et al. 2013. Demographic connectivity for ursid populations at wildlife crossing structures in Banff National Park. Conservation Biology doi: 10.1111/cobi.12075.

Image © Heidi Brand | Shutterstock.com

The researchers examined the populations of 366 metropolitan areas, which contain at least 50,000 people, and 576 “micropolitan” areas, which contain 10,000 to 50,000 people. The smallest urban area evaluated was Tallulah, Louisiana, and the biggest was the New York area. The team also analyzed each county’s CO₂ emissions for 1999 to 2008.

When the number of people living in a city increases by 1 percent, CO₂ emissions rise by 0.93 percent, the study authors estimate. This “near-linear relationship… suggests that large urban areas in the U.S. are only slightly more emissions efficient than small ones,” they write. — Roberta Kwok | 13 June 2013

Source: Fragkias, M. et al. 2013. Does size matter? Scaling of CO₂ emissions and U.S. urban areas. PLOS ONE doi: 10.1371/journal.pone.0064727.

Image © IM_photo | Shutterstock.com

Rich countries often import products associated with high CO₂ emissions from poor countries. The study authors wanted to find out of this trend applied to regions within a country as well. So they studied trade patterns for 57 types of products across 30 regions in China.

In the rich Beijing-Tianjin, Central Coast, and South Coast regions, about one-half to three-quarters of the CO₂ emissions linked to products used by residents took place outside those areas. In other words, “higher levels of household consumption in more developed coastal regions are being supported by production and associated emissions occurring in less developed neighboring regions,” the team writes in Proceedings of the National Academy of Sciences.

The poorer regions tend to rely on old, inefficient technologies and are “heavily dependent on coal,” the authors note. If these provinces don’t improve their infrastructure, they could have trouble meeting their emissions reduction targets. — Roberta Kwok | 11 June 2013

Source: Feng, K. et al. 2013. Outsourcing CO2 within China. Proceedings of the National Academy of Sciences doi: 10.1073/pnas.1219918110.

Image © Vepar5 | Shutterstock.com

By Jason G. Goldman

It was just after six o’clock in the evening on an autumn day in Kenya’s Samburu National Reserve. A researcher watched a female elephant known as Eleanor collapse. She was a matriarch, an elder within female-dominated elephant society. Her swollen trunk dragged on the ground. One of her tusks was broken, evidence of another recent fall. Another matriarch, Grace, ran toward her and tried to stabilize the ailing pachyderm with her tusks. But Eleanor’s back legs were too weak to support her massive body, and she fell again. The rest of her herd had continued their journey, but Grace stayed with Eleanor as day turned into night.

By eleven o’clock the next morning, Eleanor was dead. Over the next few days, no fewer than five other elephant groups visited Eleanor’s carcass. Several of these, like Grace, were completely unrelated to her. They poked at her lifeless body, sniffed it, and felt it with their feet and with their trunks. Did they know that they were touching death? Do elephants grieve?

This story is well known among animal cognition researchers, and it is one that Virginia Morell beautifully—almost poetically—recounts in her book Animal Wise. “Her six-month-old calf never left its mother’s side, even after park rangers cut out her tusks to make sure they did not fall into the hands of poachers,” she writes. By the calf’s ninth month, researchers had lost track of it and assumed it was “probably killed by a predator.” Like us, elephants are lost without their mothers.

But we’ve only just come to recognize this. Comparative cognition laboratories have historically relied upon just three animals. Morell recounts a conversation with one cognitive scientist who pointed out that decades of research were built upon “rats, pigeons, and college sophomores—preferably male.” It’s laughable now, but this is the thinking that dominated the fields of psychology and cognition for so long. Cognitive scientists have since adopted other species into their research programs, examining critters more familiar to anthropologists, ethologists, or evolutionary biologists.

Take dolphins and chimpanzees. On the surface, they’re tremendously different. But they are both, like humans, highly social. By comparing them, scientists can understand the evolution of sociality—and in doing so, might better grasp what it means to be human. Or consider Fido. Dogs are sensitive to human social cues in a way that even our closest cousins, the bonobos, are not. The list goes on: songbirds tell us about the evolution of language. Ants and bees teach us about group decision making. Fish are being used to investigate emotion.

Animal Wise by Virginia Morell, Crown, 2013

The practical uses of knowledge derived from animal cognition research should be obvious, though perhaps it became so only in recent years. “It was very common in the last century,” Morell writes, “to manage wild animals almost as if they were vegetable crops. Even today, whale populations are referred to as ‘stocks,’ implying that they are farmed.” But a pod of whales is not like a field of carrots, an elephant herd is not like an apple orchard, a chimpanzee family is not a sheaf of wheat. It takes more than sunlight and water to build a bonobo.

Recent history has proven that husbandry and management programs are more successful when they’re informed by a species’ natural feeding habits, navigation skills, mating, parenting, and other social behaviors. But Morell leaves the reader with a very different sort of argument, one that appeals to our emotions—the very same emotions we share with other animals.

In a chapter on emotion and fish, Morell describes a study conducted by biologist Victoria Braithwaite. She injected a bit of bee venom into the lips of some trout. The fish behaved in a way that “suggested discomfort.” They rocked back and forth, which is unusual for trout but is also eerily similar to something distressed primates do. For three hours, the fish avoided food. Other trout, which had been injected with a harmless saline solution and had therefore felt the same needle-prick, “ate with as much gusto as did a group of untreated fish.” So the trout weren’t reacting in a simple, mindless, reflexive way to the injection.

If fish can feel pain, Morell pointedly asks, should we practice catch-and-release sport fishing? It is here that her narrative comes a bit too close to an animal-rights call to arms. Animals “cannot argue for their rights or how they might best be treated or farmed or managed,” she says. “Most animals have no voice that we can hear, unless we speak up for them.” What seems absent from this argument is a discussion about animal rights versus animal welfare. (Braithwaite provides one answer: it is more ethical to use barbless hooks.) But this is a small quibble with an otherwise compelling book.

“What do the minds of animals tell us about ourselves?” Morell asks in the final chapter of Animal Wise. She responds that “they have moments of anger, and sorrow, and love. Their animal minds tell us that they are our kin.” Instead of simply relying on animal cognition research to drive better or more effective conservation efforts, Morell argues, by studying animal cognition we will better understand our own place within the broader animal kingdom.

Animals grieve for their dead. Animals play. Animals teach. Some animals even seem to imagine. By peering into the minds of crows, monkeys, dolphins, or dogs, will we see our own reflections staring back? And if we do, will that spur us to treat our nonhuman cousins with empathy and compassion?

Humans are quick to draw superficial distinctions between groups within their own species in order to justify or rationalize the poor treatment of others. Can we expect better of our species when it comes to the way we treat other taxa? I’m not sure. ❧

Jason G. Goldman received his PhD in Developmental Psychology at the University of Southern California. His research focuses on social cognition in animals. He writes “The Thoughtful Animal” blog on the Scientific American blog network.

Art: “Love Rat” by Banksy

In the battle to scale up intermittent energy sources such as wind and solar, the team with the best storage strategy wins. While many companies are banking on new battery technologies to fill the gaps when the wind dies and the sun sets, a few are working on storing energy using a cheap, abundant resource—the very air around us.

Compressed air energy storage, or CAES, is elegant and simple in concept: use excess power from the electricity grid to compress some air, then let it expand and turn a turbine when you need the electricity back. “It’s a pretty simple idea,” says Steve Crane, the CEO of LightSail Energy, one company refining compressed air technology with the hope of making a dent in the storage market soon. “Like a lot of simple ideas, it is easy to describe, and it is fiendishly difficult to actually implement.”

It’s an idea long touted as a transformative energy-storage method. But early attempts at CAES have been held back in part by those pesky laws of thermodynamics: compressing air into a tighter space than it would prefer generates heat—a lot of heat. The heat losses translate into low efficiency—you need to put a lot of energy in to get just a bit of energy out, with the rest lost as heat.

To deal with the heat, technologies from new companies including LightSail, SustainX, and General Compression keep the compressing air at a near-constant temperature with the simple addition of a fine water mist. Water heats up far more slowly than air; instead of an increase of around 1,000 degrees Celsius with just air, the temperature may go up by only 40 degrees or so. And with that, CAES is no longer too hot to handle.

When it’s time to send electricity back to the grid, compressors run backward to expand the cool air, using the slightly warmed water to help the process. The expanding air then runs a generator or turns a turbine, and the electricity grid can send power off to homes just as it would from a power plant.

Another factor limiting CAES development in the past has been geology. To date, industry has managed to build only two full-scale compressed air facilities—one in McIntosh, Alabama, and one in Huntorf, Germany. In both cases, the air is stored in large underground caverns, salt formations from which the salt has been leached. Such geologic formations aren’t uncommon, but they are not evenly distributed around the world; just because you’re building a wind farm somewhere—say, Iowa—doesn’t mean you’ll find a handy cavern nearby. Alabama’s plant was built specifically because of the suitability of the salt formation underground, not because any particular power source was nearby.

LightSail and SustainX address the siting issue with modularity. Instead of using one big underground storage cavern, they store the air in smaller tanks or pipes which can be added or deleted as needed. The Alabama and Germany facilities both exceed 100 megawatts in size, whereas the new companies’ systems start in the one- or two-megawatt range and can build up from there. As it turns out, smaller storage units may be better suited to the needs of many renewable-energy projects. “We think for a 100-megawatt wind farm, 10 to 20 megawatts of storage capacity is probably the right place to be,” says Richard Brody, SustainX’s vice president of business development. “It provides firmer, more schedulable power to the grid.”

Despite their size, the modular tanks pack a bigger punch with higher energy density, a measure of how much electricity they can store in a given volume. In fact, the densities achieved in the newer systems can rival those of some expensive batteries.

General Compression’s version of CAES is something of a middle ground between the massive caverns and the megawatt-scale, pipe-and-tank systems. In December 2012, they commissioned a two-megawatt facility in West Texas that combines the new, water-based methods of keeping temperatures down with the older idea of using caverns (which happen to be abundant in the region). Company founder David Marcus says they are still ramping up to full capacity, but all is running smoothly so far.

Other creative compressed air solutions are taking off as well. For example, Thin Red Line Aerospace, a company that also makes shielding materials for spacecraft, wants to store air deep under water—in balloons.

CAES has drawn significant attention over the past few years. LightSail has received funding from some impressive sources, including PayPal cofounder Peter Thiel, Bill Gates, and other high-profile venture capitalists, while SustainX has attracted money from General Electric and the Department of Energy, among others. General Compression has raised around $100 million from a variety of sources. All three companies are aiming to start selling the technology to clients within the next year or so.

CAES backers think the technology might fit into a very sweet spot when it comes to energy storage. Batteries have their place, but they tend to be expensive and can cycle only a few thousand times before needing to be replaced. Other storage ideas all have significant drawbacks, from siting requirements to stubbornly high costs. CAES systems using common industrial air compressors would last at least 20 years, much more in line with the needs of the grid, and costs are likely to be very reasonable once the technology is mature. Research out of Sandia National Laboratories in 2011 found CAES was “the least expensive long-duration storage,” given “an appropriate geologic site.” Remove the geology requirement, and CAES may be on its way. ❧

—Dave Levitan

By Jim Sterba

It is very likely that in the eastern U.S. today, more people live in closer proximity to more wildlife than anywhere else on Earth at any time in history. There are greater concentrations of wildlife elsewhere in the world, and they have been even greater in the past—but with fewer people around them. Likewise, human population densities are obviously higher in other places, but those densities have taken their toll on the wildlife in their midst.

In a world full of eco-woes, the wildlife abundance in the eastern U.S. should be wonderful news—unless, perhaps, you are one of more than 4,000 drivers who will hit a deer today, or your child’s soccer field is carpeted with goose droppings, or feral cats have turned your bird feeder into a fast-food outlet, or bears are looting your trash cans. In just a few decades we have turned a wildlife comeback miracle into a mess that’s getting messier, and costlier.

How did this happen? The simple answer: Forests grew back over the past two centuries, wildlife came back over the past century, and people sprawled across the landscape over the past half-century.

Reforestation began in nineteenth-century New England, when farmers started abandoning marginal pastures. Later, petroleum-based fertilizers and gasoline-powered machinery made Midwestern farming more productive and draft animals obsolete, freeing up 70 million acres that were being used to feed them. Many farmers, meanwhile, opted for jobs in town. Trees took back much of their land and, after World War II, nonfarmers began moving onto it.

Today, the eastern third of the country has the largest forest in the contiguous U.S., as well as two-thirds of its people. Since the nineteenth century, forests have grown back to cover 60 percent of the land within this area. In New England, an astonishing 86.7 percent of the land that was forested in 1630 had been reforested by 2007, according to the U.S. Forest Service. Not since the collapse of Mayan civilization 1,200 years ago has reforestation on this scale happened in the Americas, says David Foster, director of the Harvard Forest, an ecology research unit of Harvard University.

Before Columbus arrived, for example, a few million Native Americans and perhaps 30 million white-tailed deer lived in the eastern forests. Today in the same region there are more than 200 million people and 30 million deer, if not more.

Still, the idea of wildlife overabundance is difficult for many people to accept. Generations of Americans have grown up with a narrative of environmental loss. There are thousands of environmental and animal protection charities tugging at the heartstrings, and the narrative of loss spills out of virtually every envelope and email containing an appeal for funds. To look at a desktop full of these appeals is to come away convinced that the world is doomed.

It may well be. Make no mistake: All sorts of worthy battles are being fought to save the landscape and its wild inhabitants from the relentless growth of the human population; the natural resources it devours; the air, land, and water it befouls; and the climate it changes. The global environment has been seriously degraded in recent decades by increased human consumption of food, fresh water, timber, fiber, and fuel.

But a new kind of nature war has broken out that early conservationists never saw coming. While it is fashionable to say that most conflicts between people and wildlife are the result of human encroachment into wildlife habitat, it’s also true that critters have encroached right back—even species thought to be people-shy, such as wild turkeys and coyotes. (In Chicago alone, there are an estimated 2,000 coyotes.)

American communities are full of what writer Paul Theroux calls “single species obsessives.” I call them species partisans—people who choose a particular group or flock, or even individual animals, to defend. Each species has a constituency, be it geese, deer, bears, turkeys, beavers, coyotes, cats, or endangered plovers. Many people, of course, want to save all species. But often advocates for one creature square off against the saviors of another. Feral cat defenders, for example, belittle arguments of bird defenders who assert that cats kill native songbirds just to exercise their killing skills. Strange alliances form. Bird lovers side with hunters and trappers on the need for lethal control of cats, foxes, and other bird predators. Deer lovers and bow hunters join hands to keep out sharpshooters. Trappers align themselves with local governments, lobbying to reinstate outlawed traps to limit mounting damage by beavers.

For species partisans, these battles can be exciting, and they are often fought with self-righteous conviction. Arguments become shouting matches or lawsuits. Fights get nasty.

When officials in Clarkstown, New York, decided to rid their village of hundreds of Canada geese a while back, demonstrators turned up with TV crews to protest a pending “goose Holocaust.” When Princeton, New Jersey, hired sharpshooters to cull its deer population, the mayor’s car was splattered with deer guts, and the township’s animal control officer began wearing a bulletproof vest after finding his dog poisoned and his cat crushed to death. When coyote sightings in Wheaton, Illinois, increased dramatically and a resident’s dog was mauled by a coyote and had to be euthanized, the town divided into pro-coyote and anti-coyote factions. A nuisance wildlife professional, hired by the city council, discovered that a few residents were feeding the coyotes. He trapped and shot four of the animals, then began receiving voice-mail death threats. A brick was tossed through a city official’s window, and council members received threatening letters. The FBI was called in.

Ironically, the solution to our current predicament could be to manage nature more, not less. The default mode for many environmental activists has been to leave nature alone. In our new arrangement of man, beast, and tree, we need to find novel ways to manage our ecosystems for the good of all inhabitants—including people. ❧

Adapted from Nature Wars by Jim Sterba. Copyright ©2012 by Jim Sterba. Published by Crown, a division of Random House, Inc.

Illustration: “Burst” by Josh Keyes

Last summer, behavioral ecologist Charles Brown noticed something odd. He had been collecting road-killed cliff swallows in southwestern Nebraska for three decades, and the number of carcasses seemed to be dropping. “I began to think, you know, we’re not finding as many dead birds as we used to,” says Brown, who is at the University of Tulsa in Oklahoma.

The finding led Brown to discover that these swallows have evolved shorter wings over the past 30 years, helping them dodge oncoming cars. The study, published in Current Biology, suggests that at least some animals can adapt to urban threats relatively quickly.

Brown and a colleague started surveying cliff swallows in Nebraska in 1982 to study why the animals live in colonies. The birds nest under bridges, in highway culverts, and on buildings, and the team often found road-killed swallows while driving from site to site. Brown didn’t intend to analyze road-kill trends, but he always stopped for the dead birds and, if they were in good condition, saved them as specimens.

When he realized last year that road-killed swallows seemed to have become less common, he checked his specimens and found that the number per year had indeed dropped since the early 1980s, by roughly 90 percent. Decreased traffic couldn’t explain the trend, since traffic had, if anything, gone up. The number of scavengers that might pick up the carcasses hadn’t risen. And the number of cliff swallows in the area had actually increased.

Brown wondered whether natural selection might be weeding out swallows with characteristics that made them more vulnerable to car collisions. One of the easiest properties to measure is wing length, so he compared the wings of birds killed on the roads and birds that had accidentally died in mist nets. The road-killed birds’ wings were on average 3.5 millimeters longer, he found. And the wing length of the overall population dropped by about 5 millimeters over the study period.

Shorter wings allow birds to be more maneuverable, says Brown. A short-winged swallow could fly upward more easily to avoid a car. Other factors may have contributed to the change in wing length as well. Many cliff swallows died from starvation in 1996 when a cold snap killed the insects the birds usually eat, and the surviving birds had shorter wings. The extra maneuverability might have enabled those swallows to catch the remaining insects, Brown speculates. ❧

—Roberta Kwok

Brown, C.R. and M.B. Brown. 2013. Where has all the road kill gone? Current Biology doi:10.1016/j.cub.2013.023.

Photo courtesy of University of Tulsa

People in Miami can now feel slightly less guilty for using air conditioning in the summer. According to a new study, cooling down hot cities in the U.S. is far less energy-intensive than warming up cold cities.

There’s no question that AC eats up a lot of energy. But “the energy demand from living in a cold climate such as the Midwest or Northeast is frequently taken for granted,” writes study author Michael Sivak of the University of Michigan Transportation Research Institute in Ann Arbor, Michigan.

Sivak decided to compare Miami, the hottest major U.S. city, to Minneapolis, the coldest. First, he calculated how often and by how much the cities’ temperatures strayed from 18 degrees Celsius. He also accounted for the efficiency of furnaces, boilers, air conditioners, and power plants.

Data from: Sivak, M. 2008. Cities doi:10.1016/j.cities.2008.09.001

The amount of annual heating that Minneapolis requires is higher than the annual cooling that Miami requires, Sivak reports in Environmental Research Letters. And that heating takes more energy than does cooling, since furnaces and boilers are only about one-quarter as efficient as central air conditioners.

Overall, Minneapolis’s energy requirements for climate control are 3.5 times higher than Miami’s, Sivak estimates. He speculates that since people “are generally more tolerant of heat than of cold,” Miami’s energy usage might be even lower than his study suggests. ❧

—Roberta Kwok

Sivak, M. 2013. Air conditioning versus heating: Climate control is more energy demanding in Minneapolis than in Miami. Environmental Research Letters doi: 10.1088/1748-9326/8/1/014050.

Photo ©Steve Wisbauer/Getty

For David Nowak, making urban nature a policy priority requires hard, dollars-and-cents data. Cool interactive maps help, too. Nowak, a research forester with the U.S. Forest Service in Syracuse, New York, is out to provide both. After conducting comprehensive assessments of trees in half a dozen major cities, he’s now in charge of iTree, a suite of open-source software introduced in 2006 to model the ecosystem services provided by urban trees.

Anyone, from city planners to curious citizens, can enter some basic information about a tree—its size, species, location—and iTree quantifies what the tree contributes to pollution removal, carbon storage, and mitigation of building heating and cooling costs. It scales up, too: enter data on a citywide sampling of trees, and the program computes the value of the urban forest as a whole. Ecosystem services provided by street trees in Minneapolis, for example, are worth $15.7 million per year.

With those kinds of numbers, city leaders are taking notice: iTree data have inspired cities including New York and Baltimore to set ambitious tree-planting goals. About 10,000 copies of iTree have been downloaded so far. Environmental consultants, university students, local governments, and nonprofits have used the software in projects across the U.S. and in Canada and Australia, too. Novak’s team is tweaking the model so it can handle data from Colombia and Brazil.

“iTree is basically a calculator right now,” Nowak says, but he has even bigger goals. A new module, for example, links to Google Maps to help homeowners and landscape architects see the effects a tree would have if planted in a certain place on a specific lot. In the next version of the software, to be released in 2014, Nowak wants to enable modeling of trees and their ecosystem services 30 to 50 years into the future—for example, projecting how climate change may shift the distribution of different tree species and guiding planners to plant trees now that will continue to do well under future climate conditions. If the preliminary data are any indication, the return on investment will be pretty good. ❧

—Sarah DeWeerdt

Art: Digital Tree ©Astralsid

Airplane passengers flying over the North Atlantic will experience more turbulence by mid-century, according to a study in Nature Climate Change.

The link between climate change and bumpy flights may not seem immediately obvious. But global warming is expected to strengthen the jet stream, a channel of fast-flowing air about 30,000 feet high. Paul Williams, an atmospheric scientist at the University of Reading in the U.K., and a colleague wanted to find out how this change would affect airplane turbulence. “Astonishingly, no one had thought of trying to answer this question before,” he says.

The team studied clear-air turbulence, which occurs when planes are flying above the clouds. Passengers often have their seatbelts unbuckled during this time, increasing the risk of injuries. And airlines have no good way to detect clear-air turbulence, although they do their best to predict it by relying on turbulence reports from previous flights and running computer models with atmospheric data.

Williams’s team ran simulations to estimate turbulence under two conditions: pre-industrial carbon dioxide levels and carbon dioxide levels expected to be reached by about 2050. The researchers focused on the transatlantic flight corridor, one of the most heavily trafficked parts of airspace. They also limited their analysis to data for December through February because clear-air turbulence is usually strongest in winter.

The team found that clear-air turbulence would likely become ten to 40 percent stronger in the second scenario, and the frequency of significant clear-air turbulence encounters would increase by 40 to 170 percent. Devising better ways to predict turbulence would allow airplanes to fly around bumpy patches. But taking circuitous paths will require more fuel. “If airlines do have to fly more wiggly routes rather than straight lines and use more fuel, it’s going to cost airlines more, which is a cost ultimately that could be passed down to the passengers,” says Williams. Moreover, airplane emissions will increase, contributing to even more warming. ❧

—Roberta Kwok

Williams, P.D. and M.M. Joshi. 2013. Intensification of winter transatlantic aviation turbulence in response to climate change. Nature Climate Change doi:10.1038/nclimate1866.

Artist Adrien Segal has transformed cold, hard data about snow into an undulating wood sculpture. Segal started with 31 years of snowpack measurements recorded by a SNOTEL sensor at Ebbetts Pass in California’s Sierra Nevada Mountains. The SNOTEL (short for “snowpack telemetry”) network, operated by the USDA’s National Water and Climate Center, calculates the amount of water contained in the snowpack of mountains in the western U.S.; the data are used to forecast water supplies in the face of a changing climate. Segal designed her Snow Water Equivalent Cabinet with each drawer representing one year of data. The height of each layer is proportional to that year’s total precipitation. The sculpted plywood front acts as a graph of snow water equivalents throughout the year and highlights the first snow, maximum snowpack, and last melt. Visit adriensegal.com for more about her work. ❧

Images courtesy of Adrien Segal

Around the world, hunters are emptying tropical forests of wildlife. Gorillas, chimpanzees, leaf monkeys, and gibbons all have fallen prey to people’s hunger for meat.

Now, two new studies show that bushmeat hunting affects not just the animals but also the plants they leave behind. While forests may seem intact at first glance, the disappearance of wildlife has triggered subtle shifts in tree composition. “Many conservationists look at a forest and see these giant trees and say, ‘Oh, it’s fine,’” says Stuart Davies, a forest ecologist at the Smithsonian Tropical Research Institute. “But there’s a silent sort of killer going on underneath.”

Many hunted animals play an important role in the forest. They spread seeds by carrying fruit away from the tree and dropping the seed, by spitting it out, or by eating it and leaving it in their feces.

Ecologist Ola Olsson of Lund University in Sweden and his colleagues wanted to find out how the loss of these animals affected the trees. The team trekked to three pairs of forest sites in Nigeria, each of which included a well-protected area and an area where protection from hunting was lax. The researchers surveyed animals such as gorillas and chimpanzees, as well as young and mature trees.

The protected sites had more than twice as many primate groups as the unprotected sites, the team reports in Proceedings of the Royal Society B. While mature trees were similar in both types of forests, the researchers saw a stark difference in the type of seedlings. In the hunted areas, seedlings had shifted away from plant species dispersed by primates toward those that depend on other types of animals or on wind for seed dispersal.

These changes could ultimately thwart efforts to restore primates to the forest. “Once the fruit trees are gone, it will be really difficult for a monkey to live in it,” says Olsson.

Davies and his colleagues found similar patterns when they monitored a site in northwest Borneo for 15 years. Analyses of more than 470,000 trees showed that the number of new saplings from animal-dispersed species dropped as hunting pressure rose, the team reports in Ecology Letters. And the seedlings clustered more tightly together, which lowers their chances of survival because they’re more likely to pass pathogens to each other.

The studies suggest that tropical trees face threats that are more insidious than logging. “These forests are bound to change, whether we cut any trees in them or not,” says Olsson. ❧

—Roberta Kwok

Effiom, E.O. et al. 2013. Bushmeat hunting changes regeneration of African rainforests. Proceedings of the Royal Society B. doi:10.1098/rspb.2013.0246.
Harrison, R.D. et al. 2013. Consequences of defaunation for a tropical tree community. Ecology Letters doi:10.1111/ele.12102.

Art: Henri Rousseau. Tropical Forest with Apes and Snake (1910)

Oil and gas companies drilled a total of 1,365 “unconventional” natural gas wells . . . just in Pennsylvania . . . just in 2012. “Unconventional” means the controversial practice of hydraulic fracturing, or fracking, was used—which means the drillers sent gallons and gallons of the mystery chemical soup known as fracking fluid down underneath the Pennsylvania countryside. And that means 1,365 possible new sources of groundwater contamination.

But with natural gas production booming, questions surrounding water contamination remain unsettled. What if there were a reliable way to prove that some of the nasty stuff sent a mile down a well does or does not migrate into the water table? A few enterprising teams are starting to emerge with some low-cost methods that do just that.

BaseTrace, a startup led by CEO Justine Chow, is synthesizing individualized DNA molecules that can be used as tracers in fracking fluid. DNA has countless numbers of unique sequences, so BaseTrace can create tiny bits of the stuff that serve as a kind of fingerprint for individual drilling operations. Drillers add a bit of their unique DNA tracer to their fracking fluid. If someone’s water gets contaminated, testers can look for a DNA sequence that can pinpoint the exact source. Chow says the DNA tracer is detectable on a parts-per-quadrillion scale and only a thimbleful of the tracer would be needed for the several million gallons of water used in every fracking job.

Another idea, spun out of research by Andrew Barron and others at Rice University into a company called FracEnsure, involves a totally different type of tracer: magnetic nanoparticles. Barron describes the particles as resembling rust, but with other naturally occurring metals added in varying amounts to create a unique signature. To test for contamination, he can run a water sample through a magnetic separator that would find the tiny particles and identify specifically which well or set of wells they came from.

“When you have a water source you think is contaminated, the concentration of these particles is going to be tiny,” says Barron. “How do you find a needle in a haystack? You take a magnet and you wander around the haystack and the needle will fly out.”

Both ideas are getting close to commercialization, potentially dropping down wells by the start of 2014. Both tracers are themselves harmless (unlike some existing tracer tech, such as that involving radioactivity) and would add only minimal costs to a frack job. Industry is interested, since it could help them prove they are not responsible for water contamination. Of course, if the opposite proves true, these clever tracers might help send the natural gas industry packing. ❧

—Dave Levitan

Photo: ©Duskbabe/Dreamstime

Researchers have found another potential downside to climate change: warmer waters could make fish accumulate more mercury, increasing the health risk to people who eat seafood.

As small fish eat tiny marine organisms, a chemical called methylmercury builds up in their bodies. The methylmercury then gets passed up the food chain to bigger fish, reaching higher and higher concentrations. Mercury has been linked to all kinds of human health problems, including heart attacks and brain development issues.

The team studied killifish in salt marsh pools along the coast of Maine. Some of the pools were naturally warmer than others. The researchers also exposed killifish to different temperatures in the lab, ranging from 15 to 27 degrees Celsius.

The fish in warmer pools had higher methylmercury levels in their tissues, the researchers report in PLOS ONE. And the fish kept at 27 degrees Celsius in the lab also accumulated more methylmercury than those kept at lower temperatures.

The authors suggest that this pattern emerged because fish in warmer waters “ate more and grew less than fish exposed to lower temperatures.” The extra mercury could eventually travel up the food chain to fish on people’s dinner plates, they add. ❧

—Roberta Kwok

Dijkstra, J.A. et al. 2013. Experimental and natural warming elevates mercury concentrations in estuarine fish. PLOS ONE doi:10.1371/journal.pone.0058401.

By Paul Bogard

The Isle of Sark rises abruptly from the English Channel, 300-foot cliffs topped by dark hedgerow lines and sloping checkerboard greens, looking as if chipped from England and floated out to sea. But that is Sark in daylight; at night, in the dark, Sark nearly disappears. With no streetlights, no cars or trucks, no gas stations lit to daylight—just the pubs, farms, and homes of its 600 residents, Sark emits almost no light of its own. Seventy miles south of England and just half that north of France, Sark itself covers only two square miles; but it soon may have an impact beyond its size as the world’s first International Dark Sky Island.

Until about a year ago, I had never heard of Sark. My guess is most of the world’s nearly 7 billion people could say the same. But at least a few more know about this tiny island now, thanks to its recognition in 2010 by the International Dark-Sky Association. The IDA began its International Dark Sky Places program in 2001 with its designation of Flagstaff, Arizona, as the world’s first International Dark Sky City. That category—Dark Sky City—has since been changed to Dark Sky Community and has been joined by such designations as Dark Sky Parks and Dark Sky Reserves. And not that the IDA has cornered the market on such designations, as similar programs exist elsewhere. In Canada, the Royal Astronomy Society has its own system of Dark Sky Preserves, for example, and the United Nations Educational, Scientific and Cultural Organization (UNESCO) has initiated its own Starlight Reserves program, too. Although each varies slightly in its approach, the different programs are working toward the same general goal: protecting darkness in a world of ever-increasing artificial light.

What makes Sark especially compelling is that people actually live there, with their fears of the dark, their concerns for safety, their desire for “progress.” As important as it is to protect areas of wild pristine sky, it’s the protection of darkness in places where people actually live that will ultimately change attitudes toward light and darkness.

“If you only want to slap patches on very dark places, you can do that to your heart’s content, cover the world with dark sky parks,” says Steve Owens, the Scotsman who helped walk Sark through a two-year process with the IDA. “But it wouldn’t affect one single light. Whereas Sark, they had to do some light work.” By “light work,” Owens means that in order to qualify for the IDA recognition, the community of Sark had to take action—inventory its existing lights, change those lights that were causing excessive glare and sky glow, and promise that any new lights would conform to anti–light pollution regulations. In doing so, they conformed to the IDA’s definition
of an International Dark Sky Community: “a town, city, municipality, or other legally organized community that has shown exceptional dedication to the preservation of the night sky through the implementation and enforcement of quality lighting codes, dark sky education, and citizen support of dark skies.”

“They actually want the places that are on the borderline,” Owens explains of the IDA, “the places that should be good but aren’t, and can get good by doing some work on the lighting. They’re not so much interested in places that are already exemplary, because it doesn’t achieve their goal of improving lighting.” A Dark Sky Community, then, acts as an example to help people understand that darkness—and good lighting—isn’t something just for National Parks or communities near observatories, but something to which everyday communities could aspire.

Born and raised in Inverness, Scotland, at the edge of the famed Loch Ness, Steve Owens grew up interested in astronomy, ran a science-show theater “where people blow stuff up and set fire to things,” and now makes part of his living helping communities develop their dark sky identities. His first success came when the IDA declared Galloway Forest Park in southwestern Scotland the first Dark Sky Park in Europe. Galloway is the first in what Owens hopes will be a long list of parks in the U.K. to become dark sky reserves. “I don’t think that’s excessive,” he says. “Mainly because the national parks in the U.K. are called ‘Britain’s breathing spaces,’ and the measurement they take of their success in that is a measure of tranquility. They’ve done study upon study of what people think tranquility means, and always in the top three is a good, clear night sky and no light pollution.”

As important as official designations may be, Owens believes that ultimately dark sky areas will succeed only if they are supported by local communities. When astronomy programs began to take off in Galloway Park, for example, and people who lived in or near the park started to hear others saying Galloway was one of the best places in Europe for stargazing, their reaction was, Owens says with a smile, “‘Oh, I didn’t know that. Do I live in one of the best places in Europe for stargazing? That’s quite good.’ And that filtered through eventually, and people got excited.

“It’s all about education,” says Owens. “It’s about making sure that people are aware of dark skies. Most people, up until relatively recently, weren’t. I think the real sea change, the massive step forward, has come through the Dark Sky Parks. The Galloway Forest Park might affect hundreds of thousands of people over the next few years as they visit the park. And more than that, 160 million people worldwide heard about this effort. Certainly in the U.K. media, that elevated light pollution to a different level.”

The popularity of the dark sky places idea stems from their focus on the positive, Owens believes. “The media definitely were interested in reporting a good-news story that was about environmentalism and economics and tourism and astronomy.”

To value darkness would be to follow Aldo Leopold’s desire for us to enlarge the boundaries of our community. Ecologically this is vital: If we truly value nocturnal and crepuscular creatures, for example, then we won’t allow our artificial lights to destroy their habitat. Leopold’s thinking applies, too, in that the values of darkness aren’t always economically obvious. How do we quantify the value of the darkness that provides passage for migrating sea turtles or shorebirds?

Leopold believed the reason humans are so shortsighted in our treatment of the natural world is that we do not see ourselves as part of a community with it. He argued that, while humans have made great strides over the centuries toward expanding our notion of the human community to include a wider ranger of race, gender, and ethnicities, we have not made the same adjustment for the land. “All ethics so far evolved rest upon a single premise: that the individual is a member of a community of interdependent parts,” he wrote. “The land ethic simply enlarges the boundaries of the community to include soils, waters, plants, and animals, or collectively: the land.”

Working in the desert Southwest during the first decades of the century, Leopold would have known fantastic darkness. Even after he moved to Wisconsin in 1924, he would have known real night while at “the shack,” his retreat 40 miles outside Madison. Darkness doesn’t show up explicitly in his writing, but I can’t help but think that Leopold would have understood the costs of losing it. ❧

Paul Bogard teaches creative nonfiction at James Madison University. He is the editor of the anthology Let There Be Night: Testimony on Behalf of the Dark.

This essay is excerpted from the book The End of Night by Paul Bogard. Copyright © 2013 by Paul Bogard. Reprinted with permission of Little, Brown and Company.

Invasive species are usually the bad guys in conservation. But an invasive crab is helping restore salt marshes on Cape Cod by forcing out more destructive crabs, a new Ecology study suggests.

Along the New England coast, fishing has left many marshes bereft of predatory animals. As a result, marsh crabs that would otherwise have been eaten by the predators have multiplied. The marsh crabs have gobbled cordgrass along creek banks, making the land erode more easily.

Enter the European green crab, which invaded North America a couple of hundred years ago and has settled on Cape Cod. Researchers studied ten recovering marshes in the area last summer and discovered that the more green crabs they found at a site, the more the cordgrass had regrown.

The team wondered whether green crabs were stealing the marsh crabs’ homes. So they performed experiments in which they placed a green crab and a marsh crab into an enclosure with one burrow. In other experiments, they put a marsh crab alone into the enclosure.
Nearly all the lone marsh crabs staked out the burrow as their home. But when a green crab was present, none of the marsh crabs was able to settle into the burrow, and more than 85 percent of them were killed by the green crabs.

Finally, the team placed green crabs into enclosures with marsh crabs and cordgrass. After a month, the amount of cordgrass left was several times higher than in enclosures without green crabs. “These results suggest that invasive species can contribute to restoring degraded ecosystems,” the team concludes. ❧

—Roberta Kwok

Bertness, M.D. and T.C. Coverdale. 2013. An invasive species facilitates the recovery of salt marsh ecosystems on Cape Cod. Ecology doi:10.1890/12-2150.1.

When most people think of backyard wildlife, they imagine squirrels and sparrows. But researchers have discovered much more imposing neighbors living among people in India: wild leopards. The animals frequent many of the same paths taken by humans and often sit in fields of tall crops such as sugarcane.

“There are people working around them, but the people don’t realize that the leopard is sitting maybe 20 or 30 meters from them,” says Vidya Athreya, a wildlife biologist at the Wildlife Conservation Society–India who is based in Pune.

The team set up heat-triggered camera traps on paths near houses and throughout fields in Ahmednagar, a district about 250 kilometers from Mumbai. The area is largely agricultural, with abundant livestock and a few hundred people per square kilometer. The team saw five adult male leopards and six adult females, two of which had cubs with them. Since the animals mainly come out at night, they haven’t had many conflicts with humans in that district.

The results, reported in PLOS ONE, contradict a popular belief that leopards found near villages have wandered there from the forest. The prevalent idea is that “these animals are strays,” says Athreya. “What we found is they’re resident, they’re reproducing, and they’re living there among people.”

Seeing the leopards as strays could end up endangering humans. Often, people catch leopards and move them to the forest, on the assumption that they’re returning the animals to their home. But if the leopards are used to living in human-dominated areas, such territory will be unfamiliar to them—and they could be more likely to attack people in nearby villages.

The results also suggest that wildlife managers should look beyond protected areas. “We need to think about the policy and management of animals that are living among people,” says Athreya. ❧

—Roberta Kwok

Athreya, V. et al. 2013. Big cats in our backyards: Persistence of large carnivores in a human dominated landscape in India. PLOS ONE doi:10.1371/journal.pone.0057872.

Photo ©Project Waghoba

Conservation biologists want in on the 3-D printing revolution.

John Barnes of Australia’s national science agency CSIRO is designing and printing titanium fish tags to help marine biologists study big fish such as marlin, sharks, and tuna. The tags the biologists had been using before were rather crude, one-size-fits-all devices. Now, 3-D printing can customize tags quickly and cheaply with minimal waste.

Materials engineer Barnes and his team have printed a dozen different variations on a fish tag for the biologists to try out, making the tags progressively smaller and more streamlined. They also added subtly textured spots where a fish’s tissue might grow into the tag, helping it stay in place over time.

After all, if you were standing on the deck of a boat off the coast of Tasmania to plunge a satellite-tracking tag into the body of a shark, using a long-handled spear, you’d want that tag to be as easy to insert as possible. And you’d want that tag to stay in place as firmly as possible, just to minimize the amount of time spent standing on the deck of a boat and spearing a shark.

“You can build all the intricate detail you want into it,” Barnes says. With 3-D printing, “That detail comes relatively free.” But the customized tags would be almost impossible to create using traditional manufacturing processes.

The CSIRO team is working with titanium, an ideal material to use for fish tags since it doesn’t corrode in saltwater and is nontoxic to living tissues. Also, says Barnes, who heads the agency’s titanium-research group, “Titanium is a perfect material to do 3-D printing because it’s expensive and it’s difficult to machine.” Three-D printing minimizes waste and circumvents traditional manufacturing constraints.

Barnes says 3-D printing technology could aid many different ecological research projects, which often need very specific devices in small numbers on a shoestring budget. In the future, for example, the team may produce slightly different tags for each species of fish. “It can be as perfect as you want it to be,” Barnes says. ❧

—Sarah DeWeerdt

Photo ©CSIRO/Simon Hunter

“Pity the banana. Despite its unmistakably phallic appearance, it hasn’t had sex for thousands of years,” wrote Fred Pearce in his 2008 feature story about declining genetic diversity among bananas (“The Sterile Banana,” Fall 2008). As it turns out, some people are, in fact, now taking pity on the faltering fruit. This past February, The Hindu reported that the National Research Centre for Banana (NRCB) in Tamil Nadu, India, is working to rejuvenate two endangered native banana varieties. Many bananas in the Tamil Nadu region have fallen victim to pests and bunchy top virus, which often prevents fruit production and requires destruction of the plant. According to The Hindu, the NRCB aims to develop tissue cultures for the endangered bananas, distribute seedlings and growing kits to farmers, and educate farmers about propagation and biodiversity conservation. ❧

Wildlife biologist and grazing guru Allan Savory continues to garner attention on the global stage. In the pages of this magazine, Judith Schwartz covered his concept of holistic management of grasslands with the strategic use of cattle (“Greener Pastures,” Summer 2011). His method for moving grazing animals helps sequester carbon in the soil and fight back desertification. Schwartz’s profile of Savory led her to investigate other ways that cows can be an environmental boon, and her work culminated in a new book titled Cows Save the Planet (Chelsea Green, 2013). As for Savory himself, he presented at the TED2013 conference in Long Beach, California, this past February. His talk received rave reviews, with influential food writer and meat-minimalist Michael Pollan touting it as a TED highlight (“Eat MORE meat?”).

Not everyone was so quick to embrace Savory’s ideas. Agriculture expert and Conservation contributor James McWilliams noted in Slate how the talk failed to consider issues of scaling up the holistic management idea. For example, McWilliams points out that not all rangelands are created equally and that the grazing methods have not helped the prairie rangelands of North America. And even if we could scale up, eating more meat still may not be an option on the table; most grass-fed cows are led to slaughter at just 15 months. ❧

Above: Allan Savory at TED2013. Photo by James Duncan Davidson

Mead, C. et al. 2013. Environmental Science & Technology doi:10.1021/es303940p.

Jim Denevan’s large-scale sand art makes a big visual impact—not an environmental one. Denevan often walks miles to create a single drawing. That it will get washed away by the next tide is part of its beauty and appeal; it’s art that’s at the same time both colossal and humble. His work has been featured in a Range Rover commercial and in an exhibit at MoMA PS1 in Long Island City, New York. In addition, Denevan is a chef and the founder of a traveling farm-dinner series. See more of his work on beaches, deserts, and frozen lakes around the world at jimdenevan.com. ❧

Photos from San Mateo County, California (large), and Cape Cod, Massachusetts (small), courtesy of Jim Denevan

Once a common bird across western Europe, the house sparrow has been squeezed out of its habitat within the past couple of decades. In response to such rapid population declines, Dutch design students Micaela Nardella and Oana Tudose have devised a way to create more space in the urban environment for the crack-dwelling birds. They’ve handcrafted a plaster building material, which they call the Brick Biotope, with strategically shaped nooks and crannies for nesting as well as for water collection and vegetation growth. And the habitat-creating bricks can be built right into an ordinary masonry wall. With this simple innovation, having wildlife nesting in the walls isn’t such a bad thing. ❧

Photo ©Micaela Nardella and Oana Tudose