October-December 2008 / Vol. 9 No. 4

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Discussion Questions

• The traditional view of parasites is as pests that decrease the health of ecosystems. What does recent work by ecologists tell us about this interpretation? What are the implications for conservation?
• Regardless of the effect on ecosystems, in some cases parasites are detrimental to the health and well-being of some species, including some threatened and endangered species. Additionally, in some cases the degree of disturbance is correlated with increased parasite load. Can you reconcile this with the information given in the article?
• What do you predict for trends in parasites in ecosystems affected by global change?

Websites for Further Information

• The American Society of Parasitology
• United States Geological Survey—Using Parasites to Monitor Ecosystem Health

Parasites and Ecosystems in the News

• A Troubled Outlook for Parasites (The New York Times, November 15, 2005)
• Parasites’ Impact Goes Beyond Host To Affect Ecosystem (Science Daily, May 15, 2007)
• Parasites And Global Change: Past Patterns, Future Projections (Science Daily Nov. 3, 2008)

Peer-reviewed Literature (in addition to the citations listed in the article)

• Gillespie, T.R., and C.A. Chapman. 2006. Prediction of parasite infection dynamics in primate metapopulations based on attributes of forest fragmentation. Conservation Biology 20:441-448
• May, R.M. 2007. Parasites, people and policy: infectious diseases and the Millenium Development Goals. Trends in Ecology and Evolution 22:497-503.
• Stireman, J.O. III, L. A. Dyer, D. H. Janzen, M. S. Singer, J. T. Lill, R. J. Marquis, R. E. Ricklefs, G. L. Gentry, W. Hallwachs, P. D. Coley, J. A. Barone, H. F. Greeney, H. Connahs, P. Barbosa, H. C. Morais, and I. R. Diniz. 2005. Climatic unpredictability and parasitism of caterpillars: Implications of global warming. Proceedings of the National Academy of Sciences 102:17384-17387.

Key Concepts

•    Food webs
•    Trophic levels
•    Ecosystem health
•    Emerging infectious disease

October-December 2008 / Vol. 9 No. 4

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Discussion Questions

• Is genetics relevant to conservation? How is this article an example of an application to conservation?
• Why is accurate species naming important when tracking wildlife consumption? What will likely happen to global fish stocks if we can’t track the consumption of individual species? What will happen to the more rare species? Why is Dr. Peter Marko – quoted in the article – so concerned? What percentage of fillets his students sampled turned out to be something other than as named?
• How does the global food market contribute to this problem? What role do regulations play? When you go to the grocery store, do you know where your food is coming from? What are the advantages and disadvantages both environmentally and economically, for a global food supply?
• What role do corporations play in this? How could certification help? What specific companies could you write to for more information on their policies towards accurate labeling of wild caught fish?
• What role does consumer preference play in all of this? If people were more willing to eat a “Slimehead,” do you think that this problem would go away? Could you design an educational campaign to make people aware of the importance of accurate naming for conservation?
• What role did students such as your selves play in these labeling studies? Is it inspiring to think that you could do such groundbreaking science?

Websites for Further Information

• Seafood Watch Guide from Monterey Bay Aquarium (download region-specific seafood buying guides)
• Website of biologist and writer Carl Safina-Song of the Blue Ocean and other books
• Whole Foods Seafood Department

Food labeling in the News

• At long last, food labeling law is set to take effect (MSNBC, September 30, 2008)
• Small type and large loopholes in new labeling law (New York Times, October 7, 2008)
• Try the Slimehead? Delicious! (The Tyee, October 20, 2008):

Peer-reviewed Literature (in addition to the citations listed in the article)

• Avise, J.C. 1998. Conservation genetics in the marine realm. The Journal of Heredity 89:377-382.
• Hutchings, J.A., and J.D. Reynolds. 2004. Marine fish population collapses: Consequences for recovery and extinction risk. BioScience 54:297-309.
• Jaquet, J.L., and D. Pauly. 2007. The rise of seafood awareness campaigns in an era of collapsing fisheries. Marine Policy 31:308-313.

Key Concepts

• Collapse of marine fisheries
• Consumer preferences
• Genetics

October-December 2008 / Vol. 9 No. 4

Read the article >>

Discussion Questions

• The author suggests a link between sexual reproduction and maintainance of genetic diversity, both naturally and culturally, to fight off pests and diseases.  What is that link?
• If the lack of genetic diversity puts the banana and other crop species at risk from novel environmental threats, how have they managed to survive the many thousands of years since their domestication?
• How might the technology for genetic engineering be used to help preserve landraces of crops that are at risk of extinction?
• One of the major social trends of the 20th century was increased globalization of trade and the economy relative to previous centuries.  In what ways has globalization hurt efforts to maintain landraces of crops species?  In what ways has globalization helped?

Websites for Further Information

• Global Crop Diversity Trust
• Food and Agriculture Organization
• Community Food Security Coalition
• Center for New Crops and Plant Products, Purdue University
• Bioversity International

Food Security in the News

• U.N. food meeting ends with a call for “urgent” action (New York Times, June 6, 2008)
• U.N. says food plan could cost $30 billion a year (New York Times, June 4, 2008)
• Near Arctic, seed vault is a Fort Knox of food (New York Times, February 29, 2008)

Peer-reviewed Literature

• Craenen, K., and R. Ortiz. 1998. Influence of black Sigatoka disease on the growth and yield of diploid and tetraploid hybrid plantains. Crop Protection 17:13-18.
• Frison, E. 2003. Rescuing the banana. New Scientist 177:26.
• Padulosi, S., and P. Ayton. 2000. Ripe for revival. New Scientist 167:42-45.

Key Concepts

• Agriculture
• Fruit
• Asexual reproduction
• Genetic diversity
• Genetically modified organisms
• Food security
• Landrace

In a new book from Oxford University Press, two Harvard physicians look at one of the least-talked about casualties of environmental destruction: medical research. In addition to describing imperiled ecosystems that may hold solutions for human health problems, they delve into fascinating examples—ranging from “denning” bears that recycle, instead of excrete, waste and could serve as models in kidney failure research to a sea slug yielding a compound now in tests for cancer treatments. Here’s an excerpt about the extraordinary wood frog.

For centuries, people have dreamed of being frozen so that they might be thawed at some point in the future. Some have even paid high prices to be stored post mortem in this way, hoping that scientists will someday figure out how to bring them back to life. While frogs cannot return to being alive after dying, frozen or not, at least five frog species—the wood frog (Rana sylvatica), gray tree frog (Hyla versicolor), spring peeper (Pseudacris crucifer), chorus frog (Pseudacris triseriata), and Cope’s tree frog (Hyla chrysoscelis)—can survive after being frozen solid. In The case of a wood frog, upon its first exposure to ice in the fall, it undergoes a remarkable transition, worthy of a science fiction novel, to a dormant state in which its heart ceases to beat for up to several weeks and the water that surrounds its cells turns to ice. The contact with ice first sets off a modified fight-or-flight response (the body’s way of preparing for acute stress, which includes an increased heart rate, dilated pupils, and mobilized energy stores) that yields an enormous outpouring of sugar into its bloodstream (as much as 4,500 milligrams per deciliter has been recorded—more than ten times the level needed to diagnose diabetes mellitus in humans, and more than enough to kill us) in addition to other substances that together act as antifreeze. These substances are taken up by the wood frog’s cells, while at the same time proteins are released into its blood that promote the formation of ice. Thus, the cells are protected—if ice crystals were to form inside the cells rather than in the extracellular spaces, they would be torn apart. Come spring, wood frogs reverse the process, though they do so from the inside out. In a somewhat inconceivable turn of events, despite warmer temperatures outside, they manage to thaw their brains and hearts first. The frog’s ability to survive freezing has drawn the attention of many, including those involved in organ transplantation, who are trying to apply some of what the frogs do to prolong the viability of organs for eventual transplantation. ❧

From: Sustaining Life: How Human Health Depends on Biodiversity
Edited by Eric Chivian and Aaron Bernstein, Oxford University Press, 2008

Here’s a good one: what links the U.S. mortgage crisis and West Nile disease? Answer: one of the world’s most invasive alien species.

As we all know, unwise dealing by U.S. financial institutions has caused a lot of people to default on mortgages. A lot of this has been happening in the parts of the U.S. people want to move to—sunny places such as Arizona or California, where swimming pools are common.

But when those people lose their mortgages, and their homes, the pools lie abandoned.

And a stagnant, unfiltered pool is a perfect breeding ground for mosquitos. This is more than a nuisance—since 1999 North American mosquitos have carried West Nile virus, which can be fatal in the elderly. So civic authorities in the western U.S. are scanning neighborhoods for the tell-tale green of algae-filled abandoned pools and dumping mosquito fish into them. These small relatives of the guppy gobble
the mosquito larvae. Problem gone. They’re even calling them the foreclosure fish.

The problem is, these fish (Gambusia species) are native to streams around the Gulf of Mexico. Outside their ancestral waters, they wreak havoc with local wildlife.

Starting in the 1920s, they were transported all over the world to control mosquitos in one of the first big efforts at biological control. In most cases, they ate local wildlife in addition to mosquito larvae and often didn’t even do a better job of mosquito control than local fish were already doing. Some wildlife experts hate them so much they call them “Damnbusia.”

In Europe, the fish developed a taste for everything but mosquito larvae and have displaced native fish. In Australia Gambusia caused extinctions of native fish and amphibians. In California they have decimated native species—yet civic authorities will give you a bag of them free if you have a mosquito problem. It may not seem risky to put them into a plastic-and-concrete pool, but the fish are champion escape artists and can travel in water that is only three millimeters deep.

So which is worse? A nasty, invasive—and face it: ugly—little fish that is, however, already out there in much of the world? Or mosquitoes?

The flying nuisances can carry other nasties: malaria is always threatening to expand its range, and the chikungunya virus has escaped from Africa to Asia to Europe. Maybe it would be better not to have created a lot of deserted pools in the first place. ❧

Debora MacKenzie has worked for the New Scientist since 1984. Based in Geneva and Brussels, she focuses on  issues of global stability, infectious disease, food production, arms control, and fish.

©New Scientist, Reed Business Information Ltd. www.newscientist.com

Richard Ellis’s paean to tuna begins as a celebration but ends more like a Greek tragedy. After describing the tuna’s impressive anatomy and physiology and the romantic history of sport fishing for tuna, replete with larger-than-life heroes, from Hemingway to Zane Grey, Ellis delves deep into the darker side of our modern obsession with the big fish. From sushi to Chicken of the Sea®, global demand for tuna has brought us perilously close to destroying the object of our love. Ellis reveals the loopholes and political dealings that have allowed mass slaughter of bluefins to continue despite recognition of their imperiled status. His discussions of tuna ranching and issues surrounding mercury levels in tuna are enough to make any conscientious consumer squirm. The one bright spot in what is a depressingly bleak picture has been recent attempts at large-scale, land-based aquaculture of bluefins. ❧

—Margaret Pizer

Ichthyo
The Architecture of Fish
Chronicle Books, 2008

In stark white images on black backgrounds, the x-rays of hundreds of fish are laid out to make art in the new book Ichthyo. Reminiscent of fine prints in a gallery, a collection of fish from the Smithsonian Institution is exposed and aesthetically arranged to highlight their structural beauty. ❧

—Judy Wexler

The Endless City
The Urban Age Project by the London
School of Economics and Deutsche Bank’s
Alfred Herrhausen Society
Phaidon, 2008

With photographs, statistics, essays, and graphs, this comprehensive volume delves into the social, political, and economic factors that affect the “built environment” of housing, buildings, transportation, streets, and public spaces.

—Judy Wexler

The Superorganism
By Bert Hölldobler and E.O. Wilson
W.W. Norton and Company, 2008

Almost 20 years after publishing their comprehensive, Pulitzer-winning tome The Ants, Bert Hölldobler and E.O.Wilson have followed up with an ambitious volume— focusing on the emergent properties and evolution of insect social groups. Like its predecessor, The Superorganism is, at its core, a scholarly book complete with theoretical discussions of multilevel selection and literature reviews on bee communication, ant nest-building, and the genetics of caste determination. The authors skirt controversies over sociobiology, selfish genes, and group selection. Hölldobler and Wilson’s stance on these issues is clear from their histories and from their choice of title. Indeed, The Superorganism may reawaken the sleeping ghosts of acrimonious conflicts between Wilson and Dawkins, Gould, Lewontin, and others. But the text itself is understated, relying mainly on the accumulation of scientific data—much of it collected by the authors themselves over the course of their long and distinguished careers—rather than on polemics to make its point that selection has shaped the “beauty, elegance, and strangeness of insect societies.” ❧

—Margaret Pizer

Russ G.R. et al. 2008. Rapid increase in fish numbers follows creation of world’s largest marine reserve network. Current Biology 18(12):514-515.

In mid-2004, the Australian government set up the largest network of no-fishing zones in the world by prohibiting fishing across one-third (114,000 square kilometers) of the Great Barrier Reef Marine Park. Two years later, the coral trout populations in the no-take zones had increased as much as 68 percent in some places, according to a recent study led by Gary Russ at James Cook University in Australia.

The trout are one of the target species of the government program as well as one of the species prized by fishermen, who bitterly opposed the program. The results of Russ’s study show that, as politically charged as creating no-take zones can be, they work on a large scale.

The researchers believe that the increase of trout in the no-take zones will also likely boost fish production everywhere else in the park as the fish larvae migrate from the no-take zones to other parts of the reef. ❧

—John Weier

Betts, M.G. et al. 2008. Social information trumps vegetation structure in breeding-site selection by a migrant songbird. Proceedings of the Royal Society B 275(1648):2257–2263.

Much like people, birds looking to raise children like to settle down in neighborhoods that already have plenty of families. For years, scientists have believed that birds identify those “neighborhoods” (i.e., nesting sites) based solely on their vegetation. But a new paper in Proceedings of the Royal Society, Series B, threatens to upend this belief by finding that some songbirds’ nesting decisions are driven by the sounds they hear, not the plants they see.

Matthew Betts, the Oregon State University ecologist who led the study, first suspected a few years ago that conventional wisdom might be off base. “I noticed many species of songbird living in a way that couldn’t be explained by vegetation alone,” he said. “There seemed to be an inherent clustering, like we see people clustering in towns.”

Betts thought the birds might be selecting nest sites based on whether the songs of other birds indicated they had bred successfully. So he concocted a rather devious experiment involving the black-throated blue warbler. He and his team made recordings of the birds’ shrill song, then set up speakers along with decoy warblers at a number of spots across New Hampshire. Only one-third of these sites had good warbler habitat, which consists of plenty of shrubs and mature trees. Another third had mediocre habitat with mostly shrubs, and the final, lousy, third didn’t have any shrubs at all—easy pickings for predators.

Betts’s team set timers at all sites to broadcast the songs of successful breeders across the speakers at regular intervals from late July through August, when empty-nesters scope out breeding sites. Betts then packed his bags and headed back to the west coast for the winter. He returned to New Hampshire in May and found that nearly 60 percent of the sites with mediocre and lousy warbler vegetation were settled. “After we had this response I felt slightly guilty” for duping the birds, Betts says, “but this is not an endangered species. There are millions of them.”

Overall, Betts discovered that male warblers were four times more likely to set up camp in places where they heard bird songs, compared to sites with good vegetation alone. Betts believes that this behavior allows warblers and perhaps all territorial songbirds to quickly adapt to their surroundings. As global warming begins to alter the habitat of songbirds around the world, all that may be needed is a few pioneering souls to find alternative places to nest. Betts also thinks his technique could be used to draw certain birds away from areas where they are being a nuisance or are in danger. ❧

—John Weier

Reed, S.E. and A.M. Merenlender. 2008. Quiet, nonconsumptive recreation reduces protected area effectiveness. Conservation Letters 1(3):146–154.

Conservationists often hail nature-based recreation and ecotourism as critical tools in the fight to preserve wild lands. This support is based on the assumption that many recreational activities have little impact on parks and other natural areas. But a study in Conservation Letters suggests that even the least-disruptive activities can upset ecosystems and diminish biodiversity.

Led by Sarah Reed and Adina Merenlender of the University of California, Berkeley, the study investigates how hiking, mountain biking, and other quiet, nonmotorized activities affect the presence of carnivores in parts of Northern California. The researchers spent four months surveying populations of bobcats, red foxes, and other predators in 14 parks and preserves that permit limited recreation. As a control, they conducted similar surveys in protected areas where recreation is barred.

Reed and Merenlender found that densities of coyotes and bobcats were roughly five times lower in the areas permitting recreation. Those areas were also home to domestic dogs and cats, which were absent in the areas that did not permit recreation.

The researchers infer that even seemingly benign forms of recreation scare off key carnivores, thereby removing predators that keep domestic animals in check. In turn, those domestic animals can decimate populations of birds and small animals, setting off a cascade that reduces biodiversity.

This leaves conservation advocates and policy makers with a dilemma. Recreation users are often some of the strongest proponents of protecting public lands, and their support is critical to new conservation proposals. The challenge, Reed and Merenlender argue, is to preserve this support while developing management strategies that minimize recreation’s impact. ❧

—Justin Matlick

Barton, B.T. and J.D. Roth. 2008. Implications of intraguild predation for sea turtle nest protection. Biological Conservation 141:2139–2145.

Raccoons (Procyon lotor) love loggerhead turtle (Caretta caretta) eggs, as do ghost crabs (Ocypode quadrata). Unfortunately, the often-used conservation measure of controlling raccoons at turtle nesting beaches lets the ghost crabs off the hook. But raccoons are also partial to the odd crustacean for dinner. A study published recently in Biological Conservation suggests that leaving at least some raccoons might actually benefit the beleaguered turtles, because they suppress predation levels by crabs. Yale researcher Brandon Barton’s field study found the highest ghost crab numbers—and highest overall turtle nest predation—occurred where there were the fewest raccoons. ❧

—Nick Atkinson

Swaddle, J. and S. Calos. 2008. Increased avian diversity is associated with lower incidence of human West Nile infection: Observation of the dilution effect. PLoS ONE 3(6):e2488.

Incidence of West Nile virus in humans tends to be lower in areas with a diverse array of bird species, according to a new paper in PLoS ONE. Led by John Swaddle of the University of California, Santa Barbara, the study is in line with previous research showing that higher species diversity slows the spread of Lyme disease from animals to humans due to the so-called “dilution effect.”

The driving force behind the effect is that the relative abundance of the species most likely to transmit disease goes down when more species are present. This in turn decreases the likelihood that the disease-carrying species will spread their infections to humans. Swaddle and his colleagues set out to determine whether this effect applies to West Nile virus.

They compared data on avian diversity in the eastern United States with human incidence of the disease in 2002, when the West Nile epidemic was in full swing.

While controlling for other factors, the study found a strong link between higher bird diversity and reduced human infection. This is likely because crows, jays, and other common West Nile hosts tend to flourish when avian biodiversity is low. But when bird diversity is high, those host populations remain in check, hindering their ability to spread disease.

The dilution effect may also apply to avian flu, bubonic plague, and other infectious diseases. From a conservation standpoint, Swaddle believes the research underscores the need for land-management policies that increase biodiversity, thereby providing a buffer against future disease outbreaks. ❧

—Scott Norris

Gratwicke, B. et al. 2008. Attitudes toward consumption and conservation of tigers in China. PLoS ONE 3(7):e2544.

When it comes to endangered tigers, consumers’ buying habits clash with their conservation values, according to a recent study led by Brian Gratwicke of the National Fish and Wildlife Foundation in Washington, D.C.

In a survey of 1,880 people living in China, Gratwicke’s team found that 93 percent of respondents believed the country’s 1993 law forbidding the sale of tiger bones should remain on the books. Forty-three percent, however, admitted to consuming ground-up tiger bones as a treatment for arthritis and other conditions. Perhaps most disturbingly, 71 percent of those who ate the bones preferred products from wild tigers vs. tigers raised in farms.

In a study published in PLoS ONE, the researchers argue that the survey illustrates the need for a continued ban on the sale of all tiger-bone products in China despite outcries by Chinese tiger breeders to legalize farmed products. The fear is that, if sales from tiger farms are legalized, poachers will use the farmers’ distribution networks to get wild tiger parts into customers’ hands. The study’s authors believe this could make it easier for China’s 1.4 billion consumers, some of whom are suddenly flush with cash, to finish off the world’s endangered wild tiger populations.❧

—John Weier

Boersma, P.D. 2008. Penguins as marine sentinels. BioScience 58(7):597–607.

Dee Boersma has spent over 20 years studying Magellanic penguins in Punta Tombo, Argentina—long enough to suspect that their dramatic decline signals a more ominous truth: oceans are in trouble.

In a new paper in Bioscience, Boersma, of the University of Washington, recounts how penguins are going 60 kilometers farther to find food than they did a decade ago. The number of breeding Magellanic pairs at Punta Tombo has dropped roughly 22 percent between 1987 and 2006. And they aren’t alone in their struggles.

From Africa to Antarctica, penguin populations are declining due to a conspiracy of human-induced environmental problems—including climate change, overfishing, and pollution—that have degraded penguin habitat, disrupted breeding grounds, and made it harder for the flightless birds to find food.

Boersma argues that penguins’ problems are a key bellwether indicating that the marine environment is changing in ways that could threaten a vast number of today’s species. That’s bad news not only for penguins, but also for people. ❧

—Justin Matlick

Wittemyer, G. et al. 2008. Accelerated human population growth at protected area edges. Science 321:123–126.

Human populations in areas adjoining nature reserves grow faster than in other areas. And, in a surprising twist, this growth is not due to people moving out of newly protected areas and then populating their boundaries. Rather, the parks may offer previously unforeseen benefits to other local residents, enticing them to move closer.

In a paper in Science, a team led by George Wittemyer and Justin Brashares of the University of California, Berkeley reached this conclusion by analyzing population-growth data. The researchers focused on growth occurring within 10 kilometers of 306 reserve areas from 1960 to 2000.  In 38 of 45 countries, human numbers increased faster in park buffer zones than in other rural areas with similar ecological characteristics.

Buffer zones are attractive because they offer new economic opportunities associated with conservation investment by outside donors, the researchers say.  They also provide access to ecosystem services like firewood, bushmeat, and clean water that may be scarce elsewhere.

The findings help answer the longstanding argument that reserve establishment is often detrimental to local communities.  But the researchers note that as human populations become concentrated around reserves, goals of habitat and biodiversity protection become more difficult to achieve. ❧

—Scott Norris

Miller-Rushing, A.J. et al. 2008. Bird migration times, climate change, and changing population sizes. Global Change Biology 14:1959–1972.

One of the most visible biological consequences of global warming is the earlier spring arrival of many migratory songbirds.  But measuring the extent to which spring arrival dates have actually shifted for any given species is extremely complicated.  A new report in Global Change Biology suggests that many previous studies have drawn erroneous conclusions because changes in migration time are often masked or distorted by changes in population size.

Biologists have long noted that shifts in first arrival dates—the date on which the first individual of a species is observed each year—may not accurately reflect species migratory patterns as a whole.  Nonetheless, first arrival dates have commonly been used in studies reporting earlier migration times.  A team led by Abraham Miller-Rushing of Boston University and the Rocky Mountain Biological Laboratory set out to quantify the bias associated with the use of first arrival dates versus average arrival dates.

According to Miller-Rushing, one problem with using first arrival dates is that they usually suggest that more-abundant species arrive earlier than less-abundant ones.  This is true because of the larger range of variation present in larger populations and also because earlier-than-average arrivals of abundant species are more likely to be detected. In other words, declining species appear to be arriving later than they really are.

To test this, Miller-Rushing’s team embarked on a study using a 33-year record of songbird capture data from the Manomet Center for Conservation Sciences in Massachusetts. The study reports that eight of the 32 species studied showed a significant shift toward earlier spring migration, as measured by their average arrival date.  First arrival dates for all eight, however, showed no significant change.

The researchers argue that using average arrival dates could become increasingly important as bird populations struggle. As a species declines in number, it will tend to be detected later—potentially obscuring any actual shift toward earlier migration.❧

—Scott Norris

Move over, Flipper. Southern elephant seals (Mirounga leonina) have been drafted into the fight against climate change and are helping scientists unravel key mysteries about the most remote waters on earth.

As detailed in Proceedings of the National Academy of Sciences, a team of international researchers, including Jean-Benoît Charassin of the Paris Natural History Museum and Mark Hindell of the University of Tasmania, has started outfitting the seals with a device that turns them into mobile monitoring stations. Glued to the animals before they leave on months-long foraging journeys, the cell phone-sized device contains sensors that monitor a seal’s location, keep track of how deep it dives, and record data on water temperature and salinity.

Because the elephant seals cover thousands of square kilometers each winter, sometimes diving hundreds of meters below the Antarctic ice sheets, their forays deliver information on areas that can be impossible for ships or buoys to penetrate. For instance, frigid polar conditions have prevented scientists from accurately measuring how much sea ice forms during a particular year—a critical question because the ice reflects sunlight back into space. The salinity data gathered via the seals can be used to infer sea-ice quantities, establishing baselines that will help measure future increases or declines.

Now, the researchers plan to extend their work to the Arctic regions and have set their sights on using additional seal species in order to maximize the territory they cover.

— Justin Matlick

Researchers have spent years hunting for a more efficient way to track targets that travel underwater. While methods such as tagging dolphins or dispatching boats to take water samples are effective, they’re also expensive and labor-intensive. Now, the University of Washington’s Kristi Morgansen may have found a better solution: autonomous, robotic fish that could be dispatched to monitor everything from whales to pollution spills.

Still in the development phase, the so-called “robofish” measure about two feet in length, use a unique fishtail design for propulsion, and are being programmed to work together without being directed by humans. This would allow them to perform functions a single robot couldn’t do alone, such as tracking groups of animals or locating the boundaries of undersea chemical clouds.

Morgansen says challenges remain—she has struggled to come up with a wireless communication system that doesn’t overtax the robots’ batteries—but she is making progress.  In a recent test, the robofish successfully moved together as a group, laying the groundwork for more sophisticated assignments. In fact, Morgansen has already cooked up their next mission: tail a remote-control shark. ❧
—Judy Wexler

Cow belches, one of the strangest contributors to global warming, may have an even stranger cure: low-burp grass. Cows’ digestive systems contain special microbes that help break down grass, allowing the animals to subsist on an all-grass diet. But this digestion process also produces methane, a powerful greenhouse gas, which is released when the cows belch. The burps are so potent that the livestock sector accounts for more than one-third of all methane released by human industries, according to the US Environmental Protection Agency.

Scientists at the Australian biotech firm Gramina Pty Ltd may have found a way to slash this contribution. Led by plant geneticist German Spangenberg, Gramina is modifying certain grasses so they are easier for cows to digest. The key is to engineer the grass to produce less lignin, a particularly indigestible fiber.

Although the research is still in its early stages—the low-fiber grasses won’t hit the market for several years—the firm has already produced prototypes and believes the new grass could eventually reduce cows’ methane emissions by as much as 20 percent. This could be a significant step in the fight against climate change. And it might even improve pasture etiquette. ❧

—Rachel Tompa

When Kevin McGarigal started studying marbled salamanders, he ran into a problem that left him feeling cross-eyed. A biologist at the University of Massachusetts, McGarigal needed to track individual salamanders as they moved between vernal pools. But the spotted creatures are hard to tell apart, so McGarigal’s team would spend painstaking hours poring over photographs, trying to determine whether a salamander that appeared in one pool was the same creature seen in another.

Now, McGarigal has teamed up with Sai Ravela of MIT to develop a computerized solution that makes it easier to identify individual animals and could help researchers understand how species use habitat.

Dubbed “multi-scale analysis” (MSA), the new computer program is similar to the facial-recognition technology police use to pick known criminals out of a crowd. Just as people have unique facial features, individual animals have distinct markings. MSA breaks pictures of these markings down into patterns, then searches for those same patterns in other photos.

In a recent test, the program identified salamanders with 90 percent accuracy, saving researchers more than 400 hours. And McGarigal says MSA can be applied to any species with unique markings. This could add a new layer to conservation approaches by helping monitor animals that use dispersed patches of habitat. “Conservation has been very locally oriented,” McGarigal said, “but it’s the connection between habitats that allows [some populations] to exist.” ❧

—Courtney Humphries

Alexei Vyssotski’s search for a new way to monitor animal brain waves began in 2002 when he was trying to figure out how homing pigeons, Columba livia, navigate.  A researcher at the University of Zurich, Vyssotski wanted to see how the birds’ brain activity changed when they encountered landmarks.  But he needed a device that could be attached to free-flying birds, and existing brain-wave monitors were too cumbersome.

Six years later, Vyssotski is perfecting a solution: a small high-tech device that is portable enough to monitor everything from tigers to mice and can provide valuable new information about how animals interact with their environment.

Dubbed the “neurologger,” the apparatus weighs around two grams and contains a tiny memory card.  To use it, researchers immobilize an animal and then attach electrodes, the neurologger, and a locator beacon to its body.  The device then records how brain waves change as the animal moves through its habitat. When the batteries run out, the researchers recapture the animal, retrieve the memory card, and sift through the data.

The neurologger has been tested on pigeons and is ready to be used in a variety of experiments, including one to determine whether frigate birds, Fregata minor, sleep during long-distance flights.  According to Vyssotski, understanding this and other behaviors will help scientists see not only how animals operate but also what environmental conditions are necessary for them to flourish. ❧

—Judy Wexler

It’s the perfect storm. Climate change, poverty, and the fact that there are so many of us on the planet mean that millions of people are being forced into ever more marginal and vulnerable areas. According to Oxfam International, natural disasters and their associated humanitarian impacts marked 2007 as one of the worst years on record. (1) Africa’s biggest floods in three decades hit 23 countries and affected nearly 2 million people. Nepal, India, and Bangladesh were hit by the worst flooding in living memory, affecting more than 41 million people. Greece and Eastern Europe witnessed heat waves and forest fires that affected more than 1 million people. All told, 254 million people are affected by natural disasters each year. This is up from 174 million 20 years ago. (2) The projections only get worse, so where will all these people go?

Sources: 1. Oxfam International “From Weather Alert to Climate Alarm.” November 2007. 2. International Federation of Red Cross and Red Crescent Societies “World Disaster Reports 2004-6.” Graph reproduced with permission from the United Nations International Strategy for Disaster Reduction (UN/ISDR) “Disaster Risk Reduction: Global Review 2007” http://www.preventionweb.net/english/hyogo/gar/global-review; data from EM-DAT: The OFDA/CRED International Disaster Database www.em-dat.net and analysis by P. Peduzzi, UN/ISDR.

By Carl Zimmer
October-December 2008 (Vol. 9, No.4)

Every science has its icon. Genetics has the double helix of DNA. Particle physics has the spiraling tracks of electrons and protons. And if you had to sum up modern ecology in a single picture, it would be the dense mesh of arrows and circles that represents the food web.

The food web’s structure helps ecologists unravel how ecosystems function—whether species go through wild population swings or stay relatively stable. On the Serengeti, for example, acacia trees and grasses form the base of the web, with arrows rising to plant-eaters such as grasshoppers, mice, and gazelle. Each herbivore is in turn eaten by its own set of predators. You don’t have to be an ecologist to recognize the lion’s place in the food web. It’s the king of the jungle, the top predator.

Or is it? Ecologists are beginning to understand that the traditional picture of the food web is missing a vast menagerie of invisible creatures—creatures that might exercise far more control over an ecosystem than even the top predators. Every ecosystem is loaded with tiny parasites—viruses, bacteria, protozoans, fungi, and animals—invisibly feeding on just about every living thing. The Serengeti’s lions, for example, are the sole host to 31 species of worms and flukes, along with two species of bacteria, two arthropods, six protozoans, and ten viruses. In fact, a recent study in Nature found parasites to be so plentiful that, in terms of biomass, they actually outweigh predators in some ecosystems—sometimes by a factor of 20. (1)

Now, for the first time in the history of ecology, a few forward-thinking scientists are pulling parasites out of the shadows and incorporating them into food webs. When they do, the webs then take on a dramatically new look. Parasites are often regarded as a scourge on nature, but—as counterintuitive as it may seem—they may actually keep ecosystems healthy. They may control how top predators coexist with their prey. And when ecosystems begin to suffer, parasites are often the first ones to feel the effects—leading some scientists to believe the tiny creatures could form an early warning system for ecosystems in trouble.

Ecologists first began to draw food webs in the early 1900s. The pictures served mainly to summarize what they knew about who ate whom in a particular ecosystem. But in recent years, scientists have turned food webs from pretty pictures into scientific tools for understanding how species work together as ecosystems.

One of the main challenges to understanding how food webs behave is drawing the web in the first place. Ecologists need to observe which species are eating which. In some cases, a single species of prey may be the main source of food for a predator; other predators may prefer to liven up their diet with many species. But a perfect picture of a food web would be too difficult to assemble and too difficult to analyze. So ecologists have had to decide how much detail they can live without. Until the 1990s, they universally agreed that parasites could be ignored. Parasites seemed like little more than hangers-on, with no significant effect on the food web of their hosts.

Then, in 1997, two Canadian biologists, David Marcogliese and David Cone, published a paper titled “A Plea for Parasites.” (2) Parasites, they argued, might well play a pivotal role in food webs. Some of them were deadly, thus controlling populations of predators and prey alike. Others didn’t kill their hosts but lived inside them, feeding on their food and diverting energy that might produce more hosts. And many parasites needed to live in more than one species of host throughout their life cycle—in other words, they moved through the food web. To say parasites didn’t matter to food webs seemed absurd.

Marcogliese and Cone knew it wouldn’t be easy to rectify the problem. Parasites may be the most successful life form on Earth, but scientists know relatively little about them because they’re so hard to study. Documenting parasites requires years of dissections, of careful study with microscopes, of experiments. “It’s an enormous amount of work,” Marcogliese says.

Given how little we know about parasites, answering Marcogliese’s plea might have seemed like an impossible task. Unless your name is Kevin Lafferty. Lafferty, who runs a marine lab at the University of California, Santa Barbara, is a marine ecologist with the US Geological Survey’s Western Ecological Research Center. When he read Marcogliese and Cone’s paper, he did not think it folly. He thought, “We can do that.”

Lafferty—blond, tan, lean—looks like a California surfer. That’s because he is—he’s been surfing the California coast since he was a teenager and still tries to catch a wave most days, now that he’s a professor. And when Lafferty wasn’t surfing as a kid, he was exploring tide pools, snorkeling, and scuba diving. It was then that he became fascinated by food webs, from grazing sea slugs to top predator sharks.

But when Lafferty started graduate school at Santa Barbara, his vision was radically changed by a class on parasitology. Armand Kuris, then his teacher and now his collaborator, revealed to him the vast, complex world of marine parasites that Lafferty could not see on his dives.

Spurred by Kuris, Lafferty set out to understand the parasites in a single ecosystem very well. He chose the Carpinteria Salt Marsh, a sliver of wetlands along the California coast near Santa Barbara. Over the years, he and his colleagues created a relatively complete list of parasites in the marsh, thanks not just to their hard work but to the simplicity of the wetland ecosystem. Most of the photosynthesis taking place in the marsh is carried out by algae, which are grazed by snails and other invertebrates. A few species of fish live in the flooded areas of the marsh, feeding on the invertebrates, and they in turn are eaten by water birds.

When Lafferty read Marcogliese and Cone’s paper, he realized that he was in the rare position of knowing an ecosystem well enough to construct a food web complete with parasites. But despite all their previous research, it still took years for Lafferty and his colleagues to complete the project. They had to scoop up thousands of snails and dissect them; they had to analyze sea water for free-living parasites; they had to figure out which birds ate which invertebrates.

These days, whenever Lafferty talks to an audience about his food web project, he first shows the Carpinteria food web without parasites—a typical maze of arrows between algae and grazer, between predator and prey. Then he switches to a slide with the parasites added in and the audience is shocked. “When you show the parasite links added in, they totally overwhelm the predator-prey links,” Lafferty says.

Among the parasites that dominate the Carpinteria food web are flukes, flatworm-like invertebrates related to tapeworms. Flukes start their lives in snails. In a diabolical twist, they castrate the snails, so that the resources the hosts might direct to reproduction can instead go to sustaining the parasite. Flukes can take up as much as one-third of the body mass of a snail, and 17 species of flukes in the salt marsh can live in a single species of snail.

After flukes develop, they escape into the water in a free-living stage as cercariae. Cercariae swim in search of their next host (in this case, fish). The marsh, Lafferty and his colleagues have shown, positively seethes with these free-swimming parasites. He estimates that the cercariae outweigh all the birds of the marsh. In other words, more of the sunlight that strikes the salt marsh ends up as parasite biomass than bird biomass. It also means that there’s an important food source for other animals in the marsh that Lafferty never appreciated before: free-swimming flukes.

Now Lafferty and other researchers are investigating other ecosystems to see whether their food webs resemble Carpinteria’s. The early results indicate they do. Lafferty and Kuris have collaborated with Norwegian scientists from the University of Tromsø to draw the food web for a lake in Norway near the Arctic Circle. They find once more that parasites dominate the links of the food web. It’s now clear, Lafferty argues, that if you ignore parasites in an ecosystem, you can’t understand the patterns in that system’s food webs.

The question researchers now want to answer is what effect the parasites have on food webs. Would ecosystems behave differently if there were no parasites? Some research suggests they would.

At the Carpinteria salt marsh, for example, parasites help the predators find food. Many flukes in the wetlands need to get from fish into birds in order to mate and produce eggs. The birds, which do not get sick from the parasites, shed the fluke eggs with their droppings. Lafferty has found that when one species of fluke, Euhaplorchis californiensis, infects a killifish, the fish begins to swim jerkily near the surface of the water, flashing its silver scales. This behavior makes it easier for birds to spot the fish and catch them. Lafferty estimates that an infected fish is 10 to 30 times more likely to be eaten than a noninfected one. Take away the parasites, and you might well make it much harder for birds to find food. There would be fewer birds in the salt marsh, and the change in their population would affect the population of other animals in the food web.

By killing or castrating other hosts, parasites may also help keep ecosystems from flying out of control. If the population of a species expands quickly, it may threaten to exhaust its food supplies. But its parasites will expand their numbers as well, driving down the population of their host. Yet parasites can rarely drive their hosts to extinction because, once their hosts become rare, they can no longer sustain their own population. “Parasites probably increase the stability of free-living species,” Lafferty says.

Lafferty doesn’t deny the risk that parasites can pose to wildlife, particularly when humans ship parasites to new habitats where hosts have not evolved defenses. In Africa, for example, Ebola viruses are pushing some gorilla populations to the brink of extinction. A fungus has been implicated in the disappearance of many frog species around the world.

Nevertheless, a healthy ecosystem is usually rife with parasites, and when the parasites begin to disappear, this may foreshadow serious problems. For example, Lafferty has found that the fish in pristine Pacific coral atolls carry many more kinds of parasites than fish living in nearby overharvested atolls. Marcogliese has found that when acid rain damages Canadian rivers, the parasites fall out of the river food webs even while their fish hosts seem in good shape. Pollution can kill delicate parasites outright, while overfishing may wipe out parasites by removing some of their hosts.

All of which could point to the need for an about-face within the scientific community. With so many ecosystems in turmoil, perhaps parasites’ absence—not their presence—is what should cause ecologists concern. “The time you really ought to be worried,” Lafferty says, “is when you go into a system and you don’t see any parasites at all.” ❧

Literature Cited:
1. Kuris, A.M. et al. 2008. Ecosystem energetic
implications of parasite and free-living biomass in three estuaries. Nature 454:515-518.
2. Marcogliese, D.J. and D.K. Cone. 1997. Food webs: A plea for parasites. Trends in Ecology & Evolution 12(8):320–325.

Carl Zimmer is author of Parasite Rex, a regular contributor to The New York Times, and a columnist and contributing editor at Discover magazine.

By Fred Pearce
October-December 2008 (Vol 9, No. 4)

Pity the banana. Despite its unmistakably phallic appearance, it hasn’t had sex for thousands of years. The world’s most erotic fruit is a sterile, seedless mutant—and therein lies a problem. The banana is genetically old and decrepit. It has been at an evolutionary standstill ever since humans first propagated it in the jungles of Southeast Asia at the end of the last ice age. And that is why some scientists believe that the banana could be doomed. It lacks the genes to fight off the pests and diseases that are invading the banana plantations of Central America and the small holdings of Africa and Asia.

The banana needs a pick-me-up fast. But science has so far let it down. For decades, plant breeders have all but ignored it, because developing new plant varie-   ties without the help of sexual reproduction is expensive and time-consuming. As a result, most people in the developed world eat just one variety, the Cavendish. And the world’s favorite fruit—the one I eat most regularly—could be on the cusp of extinction, says Emile Frison, an old banana hand and head of the International Plant Genetic Resources Institute in Rome.

In some ways, the banana today resembles the potato before blight brought famine to Ireland a century and a half ago. But it holds a lesson for other crops too, says Emile, about how the increasing standardization of food crops is threatening their ability to adapt and survive. Popular fruits are at risk more than most. Your favorite could be on the verge of extinction.

The early farmers cultivated these sterile freaks by replanting cuttings. And so began mankind’s love affair with the banana. The first banana boats took the giant herb to Africa several thousand years ago. Anthropologists believe it became the nutritional mainstay that allowed the Bantu people to colonize most of the continent. And when Europeans first went to the Americas, the banana was among the first old-world fruits that they planted in the new world.

But on this long journey the sterile, constantly cloned banana has barely changed. Today we eat the descendants of the original cuttings taken by the Stone Age cultivators, probably from somewhere in the Malaysian jungle. Normally, cultivated plants develop genetic variety through random mutations during sexual reproduction, just as humans do. This process means that different varieties develop resistance to various pests and diseases, and adaptability to stresses like droughts. Plant breeders tap into this genetic variety all the time. But without sexual reproduction to throw the genetic dice every generation, each variety of modern banana—yellow, red, and green, from big starchy ones to small sweet ones—has come down almost unchanged from a separate sterile forest mutant. Each is a virtual clone, almost devoid of genetic diversity. And that uniformity makes the banana ripe for disease like almost no other crop on Earth.

Until the 1950s, one variety, the Gros Michel, dominated the world’s commercial banana business. Found by French botanists in Asia in the 1820s, the Gros Michel was by all accounts a fine banana, richer and sweeter than today’s standard Cavendish, and without the latter’s bitter aftertaste when green. I don’t remember, but I must have eaten it when I was young. However, the Gros Michel was vulnerable to a soil fungus that produced a wilt known as Panama disease. “Once the fungus got into the soil, there was nothing farmers could do. Even chemical spraying wouldn’t get rid of it,” says Rodomiro Ortiz, top banana in charge of research at the International Institute for Tropical Agriculture in Ibadan, Nigeria. So plantation owners played a running game, abandoning infested fields and moving to “clean” land—until in the 1950s they ran out of clean land and had to abandon the ill-fated Gros Michel. The king of the plantations—a fruit that ruled nations and toppled governments, that brought us the phrase “banana republic”—is now just a laboratory curiosity.

Its successor, and the reigning commercial king, is the Cavendish. This is a variety from southern China “discovered” by British colonial botanists and brought home in 1828, when it was named after the English lord who provided house room for the first samples. Being less tasty than the Gros Michel, the Cavendish languished until the latter’s demise. But in the 1960s, tastiness mattered less than resistance to Panama disease. The Cavendish resisted the fungus and almost overnight replaced the Gros Michel in plantations and on supermarket shelves. If you buy a banana today, it is almost certainly a Cavendish.

But, less than half a century on, the day of reckoning may be coming for the Cavendish. The plan-B commercial banana is already being stalked by another fungal disease. Black Sigatoka has become a global epidemic since its first appearance in Fiji in 1963. Commercial growers keep it at bay by a constant chemical assault. Forty sprayings of fungicide a year is typical, making the Cavendish the most heavily sprayed food crop in the world. This is not good news for the employees of the big Latin American banana-plantation owners. In Costa Rica, the second-largest banana exporter after Ecuador and the place where my bananas usually come from, women in banana-packing plants suffer double the average rates of leukemia and birth defects. Meanwhile, a fifth of male banana workers are sterile, allegedly as a result of exposure to dibromochloropropane, which is now banned, and other fungicides that are not.

Organic farmers, who use natural pesticides, are much healthier, but they face the same problems of infestation. However the banana is farmed, black Sigatoka is getting more and more difficult to control. And now comes what could be the coup de grâce. Panama disease is making a comeback in a new form—known as tropical race 4—that attacks the Cavendish with particular virulence. So far, tropical race 4 has reached South Africa, Australia, and much of Asia. Millions of banana plants have died in southern China, the Cavendish’s original home. Chemical fungicides cannot control it. So, it is only a matter of time before what they are calling the banana cancer makes it to the commercial plantations of Ecuador, Costa Rica, Honduras, and Colombia.

One footprint could do it, says Richard Markham, director of the International Network for the Improvement of Banana and Plantain. “A dirty boot with a few grams of soil from an infested site in Asia planted inadvertently in a Latin American plantation is all it would take. It’s just a matter of time.” And when it arrives, it will do to Cavendish what its predecessor did to Gros Michel. Game over.

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Crop genetic diversity provides important resources for food security, environmental sustainability, and economic stability. Yet, according to the U.N. Food and Agriculture Organization, 75 percent of the genetic diversity of agricultural crops has been lost in the last century due to the abandonment of genetically diverse traditional crop landraces in favor of genetically uniform modern crop varieties. (Source: Food Stores: Using Protected Areas to Secure Crop Genetic Diversity. A research report by WWF, Equilibrium, and the University of Birmingham, U.K., 2006)

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With most crops, such a threat would unleash an army of breeders, scouring the world for resistant relatives whose traits they could breed into commercial varieties. Not so with the banana. Because all edible varieties of bananas are sterile, introducing new genetic traits to help cope with pests and diseases is nearly impossible. Nearly, but not totally. Very rarely, a sterile banana will itself experience a genetic accident that allows an almost normal seed to develop. This gives breeders a tiny window for improvement. Honduran breeders tried to exploit this to create a disease-resistant Cavendish variety.

Every day for a year, workers laboriously hand-pollinated thirty thousand banana plants with pollen from wild fertile Asian bananas. The resulting fruit, some 440 tons, had to be peeled and sieved in search of any seeds. “I’ll let you guess how many seeds they collected,” says Emile. “About fifteen. And of those, only four or five germinated.” Further backcrossing with wild bananas yielded a new seedless banana resistant to both black Sigatoka and Panama disease. Bingo! Well, no. Western consumers didn’t like the new hybrid. Some accused it of tasting more like an apple than a banana. The only buyers today are in Cuba, where black Sigatoka wiped out normal Cavendish plantations and there is nothing else on the shelves.

Not surprisingly, the majority of plant breeders have until now turned their backs on the banana and gotten to work on easier plants. Even the commercial banana companies stay away. “We supported a breeding program for forty years, but it wasn’t able to develop an alternative to Cavendish. It was very expensive and we got nothing back,” says Ronald Romero, head of research at Chiquita, which, along with Fyffes and the Dole Corporation, dominates the international banana trade.

Could genetic modification come to the banana’s rescue? Maybe. A global consortium of scientists is trying to produce a genetic map of wild banana varieties. If they can pinpoint the genes that help them resist diseases like black Sigatoka and tropical race 4, those genes could be spliced into edible varieties in the lab. Whether we will want to eat GM bananas is another matter, but Emile sees it as the only hope for the Cavendish. Without it, the most popular single product on the world’s supermarket shelves could be heading for a sterile grave.

All over the world there are fruits, nuts, and other foodstuffs vulnerable to genetic fortune. The story is usually the same. Commercial fruit growers have concentrated on a handful of varieties, discarding the others. They have bred the chosen few to maximize yield or for some specific trait that they value most. In the process, the plant’s natural ability to withstand pests and disease has been undermined. Meanwhile, the genetic stores of old varieties and wild relatives alike have often been lost. Most of the time, commercial planters spray their way out of trouble. But sometimes, as when Gros Michel stumbled, the sprays prove useless and the crop is doomed.

It could happen to some of your favorites. There are six major types of pineapple, for instance. But we eat only one, the Smooth Cayenne. By neglecting the others, and ignoring the fruit’s genetic base in the wild, we risk losing the genes they contain and undermining the future of the fruit. The mango is suffering similar genetic erosion. A thousand or more varieties of sweet potatoes in New Guinea are undocumented and uncollected. In the Himalayan foothills of northern India, cultivated varieties of garlic and its wild ancestors are dying out.

The farms and hedgerows of dozens of tiny Italian islands in the Mediterranean are the last refuges for many rare and ancient plants. Watermelons are holed up in Vulcano, tomatoes in Elba, and cabbages in Linosa. But as holiday villas and desertification encroach, how much longer will they survive?

Or take the case of the world’s most widely eaten nut. The peanut began in the jungles of South America. The Portuguese took it to Africa, from where it reached North America and first gained wide popularity. Today, it is not just the world’s favorite nibble, but also the most important source of vegetable protein for half a billion of the world’s poorest people, mostly in Africa. But cultivated peanuts have lost much of their natural resistance to disease. In an echo of the banana story, a fungus is chasing the nut across the world, and it has few genetic defenses. The peanut’s wild ancestors are believed to live only in a tiny area of remote rain forest in eastern Bolivia. Researchers believe that if they can find them, they can extract genes that can counteract the fungus. But the area has been declared out of bounds to scientists because of local unrest caused by opposition to an oil pipeline through the forest. Can the peanut survive? It would make a great movie.

A few botanical Indiana Joneses are out there trying to track down the wild ancestors of many modern crops. One of them is Emile’s colleague Stefano Padulosi, the world’s foremost authority on rare, unusual, and plain exotic fruits and vegetables. Without him, the chic salad vegetable called rocket would still be a forgotten weed in the ruins of his hometown, Pompeii. His main stomping ground is Central Asia, the genetic heartland of many of our most familiar crops, where he tracks down both wild ancestors and the collections of traditional varieties. Soviet scientists were masters at the business of collecting obscure varieties. But many of their collections have languished since the Russians went home after 1989. And, like your grandfather’s stamp collection, the fate of the plant collections is in doubt because nobody realizes their value. The loss of these plants could prove another casualty of the fall of the Berlin Wall.

The future of the apple, for instance, may now hang in the balance. Around the world, farmers have over the centuries bred about ten thousand distinct varieties. Though only around fifty are grown commercially today, many more are kept for breeding purposes. Britain has more than two thousand apple varieties, and the U.S. government and Cornell University keep more than three thousand in research orchards. But by far the world’s greatest genetic resource is in the Tien Shen mountains of Kazakhstan, where wild apple woods still grow. Ninety percent of the world’s apples are believed to come from parent trees taken long ago from these woods. Many apple trees with potentially invaluable genetic traits are still in these hills. Or were when Stefano last looked. They could have been chopped down for firewood by now.

Stefano is also concerned about what has happened to the watermelons and pistachios that once grew wild across Uzbekistan, and the native walnuts of Kyrgyzstan, not to mention the equally prized forerunners of modern apricots, peaches, and almonds in their homeland of Afghanistan—a country where protecting wild geneses does not have the highest priority right now.

Quixotically, perhaps, I am most interested in the fate of another native of Central Asia, the pomegranate—one of the world’s juiciest fruits and prized for its exceptional nutritional qualities. Some say it fights prostate cancer. I enjoy its taste but, to be truthful, what interests me most is the prospect of one day going to find its genetic homeland in one of the world’s oddest and most inaccessible countries.
Turkmenistan was, until his recent death, the fiefdom of Turkmenbashi, an eccentric leader of the former Soviet socialist republic. Once off the Moscow leash, he became an increasingly paranoid and megalomaniac leader of the independent state. Such was his omnipotence that he renamed the days of the week after members of his family and on a whim banned men from growing beards and anyone at all from sporting gold teeth. He prevented all access to the World Wide Web, shut down most of the country’s universities, uprooted the state botanical gardens, and cut off funding for the country’s other plant collections. Which left the pomegranate in the lurch.

People have been growing pomegranates in the remote valleys of the Kopet Dam mountains of southern Turkmenistan for six thousand years. While other countries grow pomegranates, the assemblage of ancient varieties is found only in Turkmenistan. In recent decades most of the old varieties have been lost from the country’s orchards. Only around fifty are still grown. But on the edge of the mountains, starting in the 1930s, Soviet scientists assembled a unique collection of more than one thousand varieties of pomegranate trees at the Garigala experimental station. It is the holy grail of pomegranate biodiveristy.

How is the collection doing? Few people really know. Most of the varieties have never even been catalogued, says Stefano. Garigala has been all but impossible to get to for some years. The last curator was Russian-born botanist Grigory Levin, who spent much of his life nurturing the collection but eventually fled to Israel. He keeps in touch with the demoralized and frequently unpaid staff. “Many of the trees are being plowed under to make way for vegetables,” he says.
The world’s pomegranate collection is expiring. But the fruit could still survive. For Grigory says that the Kopet Dam mountains have one last treasure. Somewhere up there is the world’s one and only wild pomegranate forest. Still flourishing, it is said. I want to walk through that forest, pick some fruit. Just for the hell of it. And now that Turkmenbashi is gone, I may get my chance. ❧

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BOX: Wild Crop Relatives Nearing Extinction

The negative impacts resulting from the loss of wild species are hard to measure, since in most cases lost species were not previously well studied. Nonetheless, like the growing tide of animal extinctions, the loss of wild crop relatives not only changes the ecosystems in which they once flourished but also limits human opportunities for the future.  Following are a few examples of wild crop relatives on the way to extinction:

Soybeans: Wild soybeans could once be found growing over almost all of China’s Yellow River Delta and Sanjiang Plain, but now they are scattered in just a few sites.

Tomatos: Across the South American center of diversity, populations of wild tomato are being severely reduced. Many are endangered by goat herding in the highlands and by habitat loss. One species in Chile is now restricted to about half a dozen populations, and open pit copper mines pose a potential threat to another desert species. Sprawling shantytowns around Lima, Peru, have eliminated others. The loss of just one extremely diverse population can have disproportionate effects.

Coffee: A wild species of coffee that once grew in Côte d’Ivoire in West Africa is known to be extinct. Ten others are either endangered or vulnerable in the wild.

Hard wheat: Triticum monococcum is a species that was once widely grown for bread in the ancient Roman Empire. Today it is almost lost, with relic populations existing only in Turkey and possibly in Yemen. Because of its high fiber content, T. monococcum is again in demand, and a special project has begun to bring back this crop.

Grapes: The world’s grape species are threatened in all areas of their range. In North America, the grape species Vitis rupestris has been grazed to the point of near extinction. It was once found in gravelly and sandy creek beds from Tennessee to Texas. Seven other North American grape species are also threatened. Scientists believe these may contain a range of valuable genes, including genes for drought tolerance and resistance to the root-knot nematode pest.
Excerpted from Crop Diversity at Risk: The Case for Sustaining Crop Collections, a 2002 report compiled by the Department of Agricultural Sciences, Imperial College Wye, U.K. The report is available at www.croptrust.org/main/publications.php.

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Fred Pearce, a frequent contributor to Conservation magazine, is the author of over 14 books and a regular columnist for New Scientist magazine in the U.K.

Reprinted from Confessions of an Eco-Sinner: Tracking Down the Sources of My Stuff by Fred Pearce. Copyright ©2008 by Fred Pearce. By permission of Beacon Press, www.beacon.org.

Munson, L. et al. 2008. Climate extremes promote fatal co-infections during canine distemper epidemics in African lions. PLoS ONE 3(6):e2545.

Studies of disease ecology have shown that shifts in climate can alter relationships between disease-causing organisms and their animal hosts, thus leading to unexpected epidemics. A new study of lions in Africa, appearing in PLoS ONE, shows how a complex set of factors triggered by extreme drought helped transform a normally benign parasite into a deadly killer.

Lion populations in the Serengeti experienced unprecedented mortality during canine distemper virus (CDV) epidemics in 1994 and 2001. But CDV is not normally fatal to lions, making the die-offs hard to explain. A team led by Linda Munson of the University of California, Davis, set out to unravel the mystery.

The researchers studied blood samples collected from Serengeti lions over a 20-year period, including the 1994 epidemic in which roughly a thousand lions died. The researchers also studied lions from a 10-week period in 2001, in which the Ngorongoro Crater lion population lost 24 of its 61 members.

In both cases lions showed depressed immune systems, consistent with CDV infection. But they were also lethargic and severely anemic and showed high levels of the protozoan parasite Babesia in their blood. Strangely, evidence suggested the parasitic infection was a major contributor to the lion die-offs, even though Babesia doesn’t normally affect the animals’ health.

Study coauthor Craig Packer of the University of Minnesota said the pattern suggested a rare and deadly interaction between two conditions that are normally benign. “CDV by itself apparently inflicts no mortality in the lions,” Packer said. “High levels of Babesia also apparently inflict no mortality. But the combination of the two caused about 40 percent mortality.”

In seeking to understand how the combination came together, the researchers focused on another factor that the 1994 and 2001 events had in common: both occurred near the end of periods of severe drought. Babesia is transmitted by ticks, and tick populations on the Serengeti soared during the long dry spells as herbivores became sick and malnourished. Packer says lions probably acquired huge parasite loads by feeding on tick-infested Cape buffalo, which had become easy prey due to the drought. “The tick exposure coincided with the CDV,” Packer said. “It was the alignment of events that proved devastating.”

The researchers note that, as climate change makes extreme weather events more frequent, such unusual problems might become regular events. “Animal die-offs often occur during droughts or floods, but it hasn’t always been clear why,” Packer said. “[If] weather extremes may synchronize outbreaks of different diseases, fatal co-infections may be more common.” ❧
—Scott Norris

By Douglas Fox
October-December 2008 (Vol. 9, No. 4)

One cool day in January 2006, eight students from Stanford University went on a shopping binge—and not for the latest iPods or Levi’s. They visited two dozen grocery stores, fish markets, and sushi restaurants and brought home 77 fillets of Pacific red snapper.

Back at the lab, the students snipped off bits of flesh, digested them with enzymes, and spun the DNA down in centrifuge tubes. They identified the species of fish by sequencing segments of DNA. Their results raised eyebrows all around.

Those generic strips of flesh might as well have been called marine mystery meat. Sixty percent of them came from species other than what was written on the label, including Pacific Ocean perch and tilapia.

It wasn’t the first time scientists had peeked under the cellophane. Other, seemingly isolated studies have found similar results. For example, in Florida a local newspaper discovered that 70 percent of fish labeled on restaurant menus as grouper were some other fish; in New York City’s Fulton Market, a New York Times survey revealed that six out of eight “wild” salmon fillets were actually farm-raised. In most studies, the sleuths usually end up exposing 25 to 75 percent of the fish as impostors. Yet despite the pattern, a certain denial somehow persists: the studies are local—a drop in the ocean of commercial seafood—surely, they’re not representative.

Stephen Palumbi, the fisheries biologist who led the study at Stanford’s Hopkins Marine Station in Monterey, California, didn’t expect to find so many species among the sample fillets. “We were very surprised by what we saw,” he says. “We didn’t expect species on the fisheries endangered list, and we certainly didn’t expect to see any tilapia.”

Shoppers might bristle at the thought of paying for Pacific red snapper at a sushi bar, only to eat tilapia—which should sell for half the price. But that is, in fact, what happened, according to the Stanford study. The implications, however, go way beyond that.

Pocket seafood guides telling us which fish to eat and which to avoid have become our trusted sidearms in the consumer-centered war on overfishing. But ichthyologic name-swapping undermines a key premise of these save-the-fish campaigns—that ordinary citizens can glean sufficient information from the marketplace to make sustainable choices.

The Stanford study, published in the June issue of Biological Conservation, suggests consumers often have no idea what they’re buying. (1) Labels be damned—and the public with ’em. “The ability of individuals to vote with their restaurant bill is pretty much short-circuited,” says Palumbi.

The handlers of seafood have long treated fish names with slippery finesse, replacing unappealing terms with more gastronomically mellifluous ones as the need arises.

Just as a Hollywood agent transformed Norma Jean Baker into Marilyn Monroe for smoother public consumption, so it went with the Patagonian toothfish. A businessman from Los Angeles discovered the five-foot behemoth one day in 1977, tossed aside as trash on a fishing boat in Chile. He brought her home, dressed her up as “Chilean sea bass,” and turned her into an icon of fine dining.

These makeovers sometimes even enjoy government support. The US National Marine Fisheries Service worked through the 1970s to rehabilitate the images of 18 “underutilized” fish species. Tensile strength, bulk modulus, and other measures of fish fillet texture were assayed at the US Army Natick Research Center in Massachusetts, using the kind of high-tech gadgets that would normally be deployed to test parachutes and body armor. Five-hundred thousand dollars later, the data were leveraged to rename fish according to their taste and feel.

Over the years, slimehead became orange roughy. Stumpknocker became spotted sunfish. And Pacific red snapper became a staple in grocery stores and restaurants across the western U.S. Except for one thing: there is no such thing as Pacific red snapper. This term—essentially a brand name—covers 13 different species of rockfish found up and down the West coast which the US Food and Drug Administration (FDA) allows retailers to sell under a single umbrella. But even that broad umbrella didn’t cover all of the fish that Palumbi’s students found hiding on store shelves.

Sixty percent of the fillets they tested fell outside the FDA’s 13 codified species. Among these were several nonsanctioned species of rockfish—aurora, blue, blackgill, and splitnose—and in sushi restaurants they found things as utterly unrelated as tilapia. All told, over half of the fillets that they tested belonged to species listed by government authorities as overfished (indicating a 75 percent decline from virgin biomass).

It turns any purchase of Pacific red snapper into a game of Russian roulette, says Cheryl Logan, lead author of the Stanford study. “There’s no way you can know whether you’re buying an over-fished species.”
No one knows exactly how often this shadowy practice of mislabeling occurs, but one thing is certain: the seafood trade is as messy as a fish-gutting factory.

Much of that mess arises from the global travels of a fish, beginning from the moment it’s dragged up on a hook. Salmon swimming in the waters off Alaska may be caught by U.S. or Norwegian fishing vessels, travel all the way to Vietnam for canning, then eventually find their way back to grocery stores in the U.S. or Europe.

A fish can change hands half a dozen times as it travels from hook to plate. Along the way it sheds its head, fins, scales, and other identifiable parts. “As distance from the hook increases and knowledge of fish decreases, the likelihood of mislabeling grows,” says Jennifer Jacquet, author of a recent paper examining the consequences of renaming seafood and a PhD student under well-known fisheries biologist Daniel Pauly at the University of British Columbia in Vancouver. (2) Pauly and Jacquet suspect that a lot of mislabeling happens at the hands of distributors and middlemen.

All told, the U.S. imports 80 percent of its seafood—and the FDA inspected only 0.59 percent of it in 2006. Fish imported into the U.S. usually carry species labels, but loopholes still allow fish to arrive under generic names such as “frozen fish fillet.” Contraband, such as illegally caught Patagonian toothfish, sometimes hides among the fish sticks. Even for legally imported fish, mandatory species labeling ends when customs is cleared. From then on, the fish fillet can indulge in that quintessential narrative of immigration: reinvention of the self and adoption of a new, sexier, more glamorous name.

Even when wrongdoers are caught, the fines pale next to the profits. Two fishermen caught poaching American sturgeon caviar in the 1990s paid US$17,375 in fines—compared to their estimated US$2 million in sales. “The picture is consistent,” says Pauly. “There’s lots of cheating going on in all Western countries.”

That deceit carries insidious consequences. “Why on earth should consumers think that any of these species are in trouble if they can always go to the grocery and find something called red snapper?” asks Peter Marko, a biologist at Clemson University in South Carolina, who has tested supermarket fish. “Mislabeling creates a warped perception in the public’s mind.”

Admittedly, mislabeling often shifts consumption from less-abundant fish species (such as grouper) to more-abundant fish (such as tilapia), a direction that should theoretically tilt consumers toward eating less-exploited fish—even if they don’t realize they’re doing it.

Unfortunately, that’s not how it works. Mislabeling and renaming drive a vicious cycle in which preferred species are depleted, only to be replaced by less-palatable fish which in turn are depleted and replaced by even less-palatable ones.

Consider our belated embrace of the slimehead and stumpknocker. “These fish were [originally] given such names,” says Jacquet, “because no one thought they’d ever end up on dinner plates in fine restaurants.” But as favorites such as Atlantic cod grew scarce, ugly-named stand-ins became our fish du jour. In the case of Patagonian toothfish and orange roughy, these stand-ins have themselves grown scarce.

The same goes for monkfish—a dumpster-mouthed angler which prowls the dark waters a kilometer below the surface. “In the 1950s or –60s you would have caught monkfish while fishing for cod, and you would have thrown monkfish away,” says Pauly. This ugly fish was never meant to see the light of day. But by 1997, culinary magazines hailed it as the poor man’s lobster. “They have to cut the head off,” says Pauly, “because it’s so ugly that it would be horrible to see.”

Restocking store shelves with successive waves of stand-ins also creates, and conceals, a geographic problem. Marko saw it in 2004 when he led a DNA study (similar to Palumbi’s) in which he and his students tested 22 red snapper fillets sold in the southeastern U.S.

The fish called “red snapper”—lest the reader misunderstand—bears no relation to those species of rockfish, found along the Pacific U.S. coast, which grocery stores sell as Pacific red snapper. Instead, red snapper represents a bona fide species, which inhabits coral reefs in the Gulf of Mexico, part of an entirely different family—the snapper family. Consumers consider red snapper top-dollar dining. But when Marko’s students tested fillets, they found 77 percent of them to be something else. Most of the counterfeits turned out to be other, less-expensive members of the snapper family; a few were lowly tilapia.

The tale of economic fraud naturally grabbed headlines when Marko published his results in Nature in 2004. (3) But something more subtle caught Marko’s eye. Nearly 40 percent of the fillets came from species found far from the Gulf of Mexico—such as crimson snapper, which ranges from India to Japan to Australia.
Foreign fish feeding the U.S. appetite for dwindling red snapper concerns Marko. “Many of the countries that we’re getting these fish from don’t have the same kinds of fishing regulations [that we have],” he says—meaning that exhaustion of U.S. fisheries, or even careful management to limit catches, could lead to overfishing elsewhere in the world.

The problems plaguing consumer choice look a lot like those facing carbon credits, fair labor certification, and other market-based interventions. The likely solutions include tracking fish reliably from hook to plate and providing more complete information on the shopping label, including the exact species name, the farming or fishing method, and the country of origin. To do this, says Jacquet, “we need to work higher in the demand chain than just consumers.” In other words, target the likes of the U.S. seafood restaurant chain Red Lobster, global seafood brands and distributors such as Birds Eye, and governments that import fish.

Whole Foods Market has begun certifying its suppliers of farmed seafood for sustainability and is developing similar standards for wild-caught fish. Certification involves site visits by third-party consultants to ensure that suppliers meet Whole Foods’ guidelines. Those guidelines include a tracking system allowing each crate of fish to be traced back to its original hatching source, farming cage, feeding method, processing plant, and so on.

Wal-Mart has also pledged to develop sustainable, traceable seafood suppliers. And the London-based Marine Stewardship Council (MSC) (formed by a partnership between WWF and Unilever, a major buyer of seafood) has embarked on a program to audit and certify fisheries as sustainable—again, with a chain-of-custody component built in. MSC has certified 32 fisheries to date, with more in the pipeline.
“They’re not doing it because nobody cares,” says Carl Safina, executive director of the Blue Ocean Institute. Industry eco-consciousness, he says, stems in part from the pressure applied by consumers who have become educated through these seafood guide campaigns.

Pauly, too, sees these efforts as laudable examples of what should be done. But he cautions that they’re not a complete solution. MSC-certified fisheries still account for far less than 10 percent of the worldwide fish haul. And while a few select stores can guarantee the identity of what they sell, much seafood consumption in the U.S. still occurs in restaurants.

“Chain of custody is a problem,” says Pauly. People in grocery stores can see certification labels on packages, but customers at restaurants have no such opportunities. Conversations with waiters and chefs often produce assurances that the fish on the plate is sustainable, that the swordfish is farmed (no such thing exists), or that fishermen make sure to release “pregnant” swordfish from the net (again, no such thing).

Pauly believes these basic problems will persist until government steps in with regulation, enforcement, and large penalties for mislabeling. He cites U.S. and European government agencies tasked with tracking down counterfeit Gucci bags and pharmaceuticals as examples of what could be done. Counterfeit Gucci bags can net millions in fines. Fake drugs can result in the shutdown of a business.

Government enforcement remains a lofty goal. Consider that the most visible mislabeling studies—Marko’s and Logan’s—were class projects. Another study, reported on August 21 in The New York Times, was done by high school students. (4) Others were commissioned by newspapers investigating local restaurants. These projects occupy the margins of fishery science, far from funding and grant priorities.

The problem of mislabeling arises not just from poor regulation, but also from consumers’

distorted expectations. There exists a fundamental mismatch between how consumers think of fish and how fish actually exist in the real world.

Western consumers, accustomed to a limited pantheon of domestic-raised meats and poultries, seem to expect that kind of uniformity in wild-caught fish. One might call it the comfort of having familiar choices—but only a few choices—on store shelves.

These expectations may encourage retailers or distributors to shoehorn a fish with the wrong-colored spots into a familiar bucket, such as red snapper, Pacific red snapper, or cod. “I don’t think there’s a grand conspiracy,” says Palumbi; “I think vendors have found it easier to call things by generic names that people kind of recognize.”

But what if every single species of rockfish, dogfish, snapper, and cod were labeled correctly? What if supermarket fish counters came to resemble the cheese aisle at Whole Foods Market, with dozens of varieties available? “I think some consumers would enjoy seeing that kind of diversity,” says Marko. But we’re a long way from that kind of awareness and that kind of transparency.

The diversity lurking beneath familiar labels in today’s supermarkets might even surprise scientists. When Marko’s students sequenced DNA from those 22 fillets sold as red snapper, six of them didn’t correspond to any known species. It raises the possibility that their expedition to the seafood aisle actually turned up something that biologists have yet to discover—a species unknown to science but well known to grocery stores. ❧

Literature Cited

1. Logan, C.A. et al. 2008. An impediment to consumer choice: Overfished species are sold as Pacific red snapper. Biological Conservation (141):1591-1599.
2. Jacquet, J.L. and D. Pauly. 2008. Trade secrets: renaming and mislabeling of seafood. Marine Policy 32(3):309-318.
3. Marko, P.B. et al. 2004. Fisheries: Mislabelling of a depleted reef fish. Nature (430):309-310.
4. Schwartz, J. Fish tale has DNA hook: Students find bad labels. The New York Times, August 21, 2008.