News this Week

Science  17 Sep 1999:
Vol. 285, Issue 5435, pp. 1089

    FDA Weighs Using Tumor Cell Lines for Vaccine Development

    1. Gretchen Vogel

    A technique for making vaccines that has been off limits in the United States for 40 years is now getting a second look from the U.S. Food and Drug Administration (FDA). Experts in cell biology, retrovirology, cancer, and vaccinology gathered in Rockville, Maryland, on 7 to 10 September to advise the FDA and other health agencies on the risks of using “immortal” and tumor-derived cells to generate viral particles for vaccines.

    Since 1954, the U.S. government has ruled out the use of immortal cell lines in live vaccine production for fear that cancer genes or other hazardous factors might be transferred to people receiving vaccines. This risk has never been substantiated or quantified; some say it is entirely hypothetical. But many vaccine researchers now believe that the benefits of using immortal cell lines outweigh the risks. For example, one meeting participant said future AIDS vaccines may not be commercially viable unless manufacturers are allowed to use efficient tumor cell lines to generate reagents. According to William Egan of FDA's Center for Biologics Evaluation and Research, several groups have already applied to FDA to make products relying on immortal cell lines.

    But FDA officials are not ready to give the green light—at least, not without more scientific support. It was clear at last week's meeting that FDA is particularly concerned about how consumers would view such a change. Already, public trust in vaccines is a bit shaky. For example, according to press reports last week, some parents in Wales are holding “measles parties” to infect their children with the disease rather than vaccinate them. To get concerns about a shift to immortal cell lines “out on the table,” Egan says, FDA, the U.S. Centers for Disease Control and Prevention, the World Health Organization, the U.S. National Institutes of Health, and the International Association of Biologicals invited scientists to come to last week's 4-day brainstorming session.

    Manufacturers have good reasons for wanting to use immortal cell lines. Viruses can't grow on their own, so companies that produce viral vaccines grow the target virus in living cells, for example, in chick embryos or monkey kidney cells. However, most normal cells have a limited lifetime in culture. It can be more efficient to use cells that have been modified to survive indefinitely. And some scientists argue that it is safer to rely on such well-characterized laboratory strains. But to become immortal, a cell must override the normal braking mechanism that controls growth. That change can arise in several ways, including by spontaneous mutations or infection with a cancer-causing virus. Regulators have feared that continuous cell lines might transmit their cancer-causing genes to vaccine recipients. They also worry that, because such cell lines are genetically unstable, they might cause disease directly by encouraging the growth of previously latent viruses or create a new infectious agent by recombining their DNA with the target virus.

    These theoretical concerns are not new. In 1954, fearing that adenovirus vaccine made in tumor cells might cause cancer in recipients, the U.S. Armed Forces Epidemiology Board recommended that manufacturers use only normal cells to make the virus. But even normal cells carried risks. Most famously, some monkey kidney cells used to make polio vaccine carried SV40, a monkey virus that can cause tumors in hamsters and has been found in a few rare human cancers (Science, 7 February 1997, p. 748).

    Even though continuous cell lines could be more thoroughly screened for hidden viruses, they still might pose unknown risks. The production of live vaccines requires a relatively gentle purification process, which might leave pieces of DNA from the host cell intact, posing a risk to vaccine recipients. Although the potential risk from a vaccine contaminated with a live cell or DNA fragments is probably slight, it is simply unknown, says molecular virologist John Coffin of Tufts University: “It's still a hypothetical risk, largely because there hasn't been any experimentation done.”

    There is a precedent for using continuous cell lines for live vaccines. Several European governments have approved the use of vero cells, an immortalized cell line developed from normal monkey kidneys, for the production of live attenuated polio vaccine. Although it is not approved for use in the United States, tens of millions of children around the world have received the vaccine since 1988, with no obvious ill effects. However, “very little postmarketing follow-up has been done,” Coffin notes. And subtle effects might have so far gone undetected.

    Quantifying such unknown risks is nearly impossible without more data, says Stephen Hughes of the National Cancer Institute. Hughes told the meeting attendees, “I am not concerned” about the safety of continuous cell lines. “But the data we have are not sufficient to satisfy me as a scientist.” To learn more, says Egan, the FDA plans to join European regulatory agencies in supporting experiments, such as testing the cancer-causing potential of DNA fragments, that will help quantify the risks. It is all right to “make mistakes in calculations,” the FDA's Andrew Lewis said at the meeting. “But if we make mistakes in terms of delivering products that are unsafe, the costs will be incalculable.”


    New Center Gives Japan an Arctic Toehold

    1. Bernice Wuethrich
    1. Bernice Wuethrich is an exhibit writer at the Smithsonian's National Museum of Natural History.

    FAIRBANKS, ALASKA—Japan and the United States have launched a $32 million research center to plumb the consequences of climate change in the Far North. Late last month, researchers from the two countries gathered here on the campus of the University of Alaska, Fairbanks, to dedicate the International Arctic Research Center. Guided by representatives from several Japanese and U.S. organizations, the center plans to do “big picture, big science.”

    By compiling satellite data on everything from sea ice to vegetation patterns in the Arctic, where the effects of global warming are being felt first, IARC hopes to do some informed crystal-ball gazing. Most of the center's funding is expected to come from Japanese and U.S. agencies and universities. Besides supporting outside scientists, the center hopes to expand its 50-person research staff to 150 by 2005. The upshot, says Syun-Ichi Akasofu, IARC's U.S. director, will be clearer forecasts of global climate and of the ways perturbations in the Arctic might influence northern countries. “The ultimate purpose of IARC is to make it possible to predict global change,” adds Taro Matsuno, director-general of Japan's Frontier Research Program, a key player at IARC.

    Climate models suggest that the Arctic is a good place for predicting climate changes, because global warming, stoked by rising levels of carbon dioxide and other greenhouse gases, should be amplified there. Higher temperatures melt permafrost—possibly liberating trapped CO2 and methane, two greenhouse gases—and drive the boundary of permanent snow cover northward, eating away at a layer of white that reflects sunshine back into space. Both effects could feed back to spur global warming. Indeed, temperatures in many parts of the Arctic are already climbing faster than in regions to the south. Average annual temperatures in Alaska have increased 1 degree Celsius in each of the last 2 decades, whereas Earth's average annual temperature has increased less than 1 degree over the last century.

    “People are seeing earlier breakup and later freeze-up of sea ice and warming of permafrost, and native people are talking about changes in wildlife,” says John Calder, director of Arctic research at the National Oceanic and Atmospheric Administration, an IARC funder.

    Changes in the Arctic may also be having effects at lower latitudes, a link that IARC researchers will probe. For instance, 6 years ago a quarter of Japan's summer crop of rice was wiped out during a frigid year that resulted from shifts in the Arctic atmosphere. Japanese researchers also worry that changes in Arctic Ocean circulation will further affect fisheries in the North Pacific and the Bering Sea, where disturbing shifts are already taking place.

    Although both U.S. and Japanese officials say their governments are committed to the Arctic endeavor, which is an outgrowth of the “U.S.-Japan Common Agenda” signed by President Bill Clinton and former Japanese Prime Minister Ryutoro Hashimoto in May 1997, neither side has fully clarified how that commitment translates into cold cash. But the center's backers don't expect to have a tough time attracting funding or researchers: After all, IARC is a sleek new facility where the climate action is. “If you build it,” Calder says, “they will come.”


    Rhetoric Meets Reality on the House Floor

    1. Jeffrey Mervis,
    2. David Malakoff

    A full-court press by Administration officials and scientific groups to fend off attacks on science funding was no match for congressional budget realities last week. The House of Representatives passed a spending bill that imposes deep cuts in NASA's budget and erases a proposed increase for the National Science Foundation (NSF). The Senate has yet to act on the bill—a $92 billion measure that funds housing, veterans' care, and dozens of independent agencies—and its fate is uncertain as Congress and the White House remain deadlocked over whether to lift tight caps on domestic spending or break their pledge not to spend the surplus from Social Security. But a series of floor votes last week suggests that researchers face an uphill battle in the stiff competition for federal funds.

    The scientific community has organized an effort to offset the July actions of the appropriations committee, which took a $1 billion bite out of NASA's overall budget and stripped all but $8 million from a proposed $235 million increase for NSF research (Science, 6 August, p. 813). On 1 September White House Chief of Staff John Podesta gave a speech extolling the value of research, warning that this and other spending bills are “playing politics with science and technology funding.” Last week NSF director Rita Colwell called the budget process “disturbing,” saying that it “turns our backs on the country's capability” to do great things in science.

    But even as she spoke to a roomful of reporters at NSF headquarters in Arlington, Virginia, House members were voting 212 to 207 to shrink NSF's $2.7 billion research account by an additional $10 million, putting the money into a $225 million program to house indigent people with AIDS. “This is a Sophie's Choice, [putting us between] a rock and a hard place,” lamented Representative Sheila Jackson-Lee (D-TX), an advocate for research on the Science Committee who the next day unsuccessfully proposed adding $924 million to NASA's budget. “I have always supported NSF, but today I am making a choice.”

    Representative Jerrold Nadler (D-NY), the author of the amendment that put Jackson-Lee and others in a tight spot, explained that the funds were needed to restore an earlier cut in the AIDS program. He said he singled out NSF's $245 million polar research program to absorb the blow because “there are 12 other agencies that support Antarctic research, so we would not be greatly hindering this research … while significantly improving the lives of individuals who need our help now.” Social science lobbyist Howard Silver, chair of the Coalition for NSF Funding, confessed that his group did not try to defeat the amendment: “It's hard to ask members to vote against homeless AIDS patients.”

    To keep within the spending caps, members were prohibited from proposing any funding increase without an offsetting cut. That rule left research advocates with little room to maneuver. Representative Vernon Ehlers (R-MI) proposed—and then quickly withdrew—an amendment to boost NSF research by $230 million by cutting every other discretionary program in the bill by 0.35%. The pattern was repeated twice for portions of NASA's budget in hopes of recovering some of the $566 million sliced from the agency's $3.7 billion space and earth science accounts. The ploy was intended to put pressure on House legislative leaders to fight for these programs when they meet with their Senate counterparts later this fall to negotiate the final version of the bill. Science supporters were leery of putting the amendments to a vote, however, because “it is more difficult to bring something up in conference if you've already lost on the House floor,” notes the American Astronomical Society's Kevin Marvel, who called the final House vote “disappointing for the space sciences community.”

    NASA and NSF supporters remain hopeful that the appropriations process will ultimately go their way, however. They note that Science Committee chair Representative James Sensenbrenner (R-WI) voted against the bill and pledged to fight for a bigger budget for both agencies. The Senate was expected to begin work on its version of the bill this week, with spending panel chair Senator Christopher Bond (R-MO) and ranking member Barbara Mikulski (D-MD) hinting that they may be more generous to the two agencies. How generous, however, will depend on whether the spending caps remain in place.


    Tough Questions Greet New Research Chief

    1. Robert Koenig

    The European Parliament was set to vote this week on the entire slate of new commissioners—the European Union's (EU's) equivalent of a cabinet—put forward by incoming European Commission President Romano Prodi. If, as widely expected, the Parliament approves Prodi's team, Belgian Socialist Philippe Busquin will move into his new Brussels office as the head of the EU's $4-billion-a-year research program.

    Busquin is something of an unknown quantity, but he outlined his plans earlier this month at a hearing during which he was grilled by conservative members of the European Parliament (MEPs). He said he wants to make greater use of the EU's Joint Research Centre (JRC), review the extent of Europe's participation in the planned International Thermonuclear Experimental Reactor (ITER) fusion project, and pursue a proposal to develop a patent that would be valid across the EU.

    As the head of the EU's research directorate, Busquin, 58, will administer the 4-year, $17 billion Fifth Framework research program and plan its successor. Although he has focused on politics for the past 2 decades, he started his career in science. He received a physics degree from the Free University of Brussels in 1962 and was an assistant physics lecturer on the university's medical faculty from 1962 to 1977. In 1976, he studied ecology and environmental issues at the Free University, and from 1978 to 1980 he chaired the board of directors of Belgium's Institute of Radioelements. He later rose to political prominence as the leader of the Socialist Party in Belgium's French-speaking region. Along with his new colleagues, Busquin will be taking office 4 months early, because the former commission resigned en masse last spring in response to allegations of cronyism and mismanagement (Science, 19 March, p. 1827).

    In written and oral answers to the MEPs' questions, Busquin expressed support for the JRC but made it clear that he wants to make some changes. The JRC was set up as a nuclear research center 40 years ago but has since grown to include institutes covering fields from space applications to consumer protection. Europe's current concern over food safety shows that a body like the JRC is needed, he said, but the JRC “should play a more structured role” in supporting EU policy-making. The JRC's director-general, Herbert Allgeier, told Science that he was impressed with Busquin's knowledge and interests: “He has studied physics, he is a good listener, and he has an energetic approach.”

    As for intellectual property issues, Busquin noted that “the patent system in Europe is cumbersome and complex. The cost of a patent is on average four times higher in Europe than in the U.S., and the current European patent does not automatically guarantee protection in all member states.” He said he favors the introduction of a “Community patent” to grant protection across the EU.

    Italian MEP Guido Bodrato also quizzed Busquin about the EU's involvement in ITER. The United States pulled out last year, but the EU remains a partner in the project, along with Russia and Japan. A decision on the EU's participation “can only be taken in the context of the next nuclear research program,” Busquin said, indicating some qualms about a recent proposal to scale ITER down to a smaller machine. “The laws of physics require the construction of relatively large facilities in order to study conditions in a future fusion reactor.” Busquin called for further debate on the future of EU fusion research.

    The harshest questioning during his appearance before the Parliament's research committee concerned his qualifications for the post and his ability to administer public funds. Critics asked whether—in the wake of the cronyism and mismanagement allegations that plagued his predecessor, Edith Cresson—Busquin's authority would be compromised by past financial scandals involving Belgium's Socialist Party. Busquin denied any involvement in those scandals and offered to resign if Prodi asked him to do so. In the end, the parliamentary panel neither endorsed nor opposed his nomination.

    The chair of the research committee, Spanish Socialist Carlos Westendorp, reported after the hearing that some members “doubted both Mr. Busquin's future capability to perform as research commissioner, and his leadership capacity to restructure and reform” the research directorate. However, Westendorp added that “many others found him to be adequate, conscientious, and familiar with the research world.”


    Wellcome Seeks New Home for Business Park

    1. Helen Gavaghan*
    1. Helen Gavaghan writes from Hebden Bridge, U.K.

    “WANTED: Huge biomedical research charity seeks 40,000 square meters of empty space for biotech business park. Proximity to world-class genome research center would be an advantage. $160 million available to spend on development. Offers from anywhere in the world will be considered.”

    After being refused planning permission by the local council to build facilities in which biotech companies would rub shoulders with researchers at its Genome Campus, Britain's Wellcome Trust is looking for an alternative venue. And, to the consternation of the U.K. biotech industry, the trust will consider sites overseas, which trust director Mike Dexter says is not an empty threat. That possibility has touched off a furor. John Sime, director of the BioIndustry Association, a trade body representing small and medium-sized bioscience companies, says, “If Wellcome decided to go overseas, it would be a tragedy. Towns like Munich, Rotterdam, and Lyons [all vigorously wooing biotech companies] must be laughing themselves silly.”

    The site search follows a decision last month by John Prescott, minister for the environment, transport, and the regions, to uphold the decision of the South Cambridgeshire District Council to deny the trust, after a 2-year battle, the permission it needs to develop land next to its Genome Campus at Hinxton near Cambridge. The council argues that the local infrastructure could not support the 1000 new jobs created by the 40,000-square-meter facility, which would house start-up companies and R&D offshoots of larger pharmaceutical firms. It suggested that the trust could use one of several existing science parks elsewhere in Cambridgeshire or, if that were unacceptable, build a smaller, 24,000-square-meter facility that would house only new spin-off companies.

    Both suggestions miss the point, says Dexter. The trust wants to tap into the intellectual powerhouse of the Genome Campus, comprising Wellcome's sequencing facility, the Sanger Centre, as well as the European Bioinformatics Institute and the government's Human Genome Mapping Project Resource Centre. “It is important,” says Dexter, “to have daily, face-to-face interactions and for spin-off companies to learn from established, successful firms.”

    The trust also hoped that the site might benefit from the SNP Consortium of major pharmaceutical companies which, with backing from Wellcome, is trying to identify genetic markers (single nucleotide polymorphisms, or SNPs) that will give medical researchers an idea of how effective a medicine will be for each individual. This “not-for-profit” $45 million effort is taking place at the Sanger Centre and three other major research centers in the United States. For these reasons, a site elsewhere in Cambridge or a smaller site that excluded established firms would not be commercially viable, says Dexter. So last week, the trust decided that if it could not establish a biotech melting pot to exploit its own genome center, it would consider a site near a different research powerhouse.

    Ironically, Wellcome's tribulations at Hinxton come at a time when the U.K. government is promoting the biosciences as critical for the country's economic well-being and employment prospects. The Department of Trade and Industry, for example, is encouraging companies to gather together into biotech “clusters” similar to those in Maryland, North Carolina, and around the Massachusetts Institute of Technology. Urban geographer Alan Wilson of the University of Leeds says updating Britain's dusty planning regulations is crucial for biotech's development. Wilson is part of a team working with Science Minister David Sainsbury to identify ways in which government can help the biotech sector. “It is a shame that these issues are polarized as single planning questions, such as can the village stand an extra thousand houses,” he says.

    Dexter says he is still trying to arrange a meeting with the council. In the meantime, several cities—both in the United Kingdom and overseas—are eager to attract the prestige and money of the Wellcome Trust and have submitted proposals that the trust is evaluating. “Think about the major genome sequencing centers around the world,” says Dexter. “There are some attractive overseas options.”


    Firming Up the Case for a Flat Cosmos

    1. Mark Sincell*
    1. Mark Sincell is a science writer in Houston.

    Doing research in modern cosmology is a bit like watching the game show Wheel of Fortune. At the beginning, the hidden phrase is impossible to guess, but as Vanna White turns over each letter the answer suddenly becomes blindingly obvious. A long-sought hump in measurements of the universe's faint background radiation, for example, was no more than a hint in earlier observations, but now a telescope high in the Chilean Andes has opened a clear view of it. The discovery, which will be reported in the 10 October Astrophysical Journal Letters, confirms a long-standing prediction about the universe's total mass and energy density and hints that a major part of the total may be a mysterious form of energy in empty space.

    The “hump” actually measures the coarseness of the ripples imprinted on the cosmic microwave background (CMB) shortly after the big bang. In its first 100,000 years or so, the baby universe was so dense and hot that matter and light behaved like a single fluid, so that fluctuations in the density of the ionized gas created corresponding hot and cold spots in the radiation. But as the universe expanded and the gas cooled, light broke free, or decoupled, from matter. A fossil record of the fluctuations at the time of the decoupling can be seen even today, imprinted on the CMB.

    Because cosmologists can calculate the actual size of the most common ripples, their apparent size in the sky reflects the overall shape of space, just as the apparent size of objects seen through a lens depends on the shape of the glass. By measuring the angle at which the fluctuations are most common—the “hump”—cosmologists can trace the geometry of the universe, which is determined by the total amount of energy and matter it contains. Theorists' favorite picture of the big bang implies that the universe contains just enough matter and energy to retain a flat geometry, in which parallel lines always remain parallel, rather than diverging or converging, as they would in “open” or “closed” universes. In a flat universe the hump would fall at an angular size of about 1 degree.

    Finding the hump has proved difficult, however, because it requires extremely precise comparisons of the CMB's temperature at different points in the sky. A first glimpse came from two experiments done last year at the South Pole, Viper and Python. Viper showed that the abundance of ripples seemed to increase from 1/6 of a degree up to 1 degree; Python showed it falling on scales larger than 1 degree (Science, 1 January, p. 21). But no single experiment covered the entire hump, and cosmologists were concerned that they might be forcing mismatched pieces of the puzzle together. “There are always calibration issues” when the results of different experiments are combined, says Princeton University astrophysicist Amber Miller.

    The new measurements by the Microwave Anisotropy Telescope (MAT) team, a collaboration led by Lyman Page of Princeton and Michael Devlin of the University of Pennsylvania, seem to have put that concern to rest. Observing from a dedicated 85-centimeter telescope perched high on the southern slopes of Cerro Toco in northern Chile, the MAT team compared the CMB at different spots in the sky for almost 1200 hours. They found that the abundance of ripples clearly “rises and then falls” near 1 degree, says Miller.

    “All by itself it shows the existence” of the 1-degree hump, says University of Chicago cosmologist Michael Turner. He says it will take the Microwave Anisotropy Probe satellite, to be launched in fall 2000, to reveal the precise shape and position of the hump. But already, Turner says, “we can claim to have a complete accounting of the matter and energy in the universe.”

    If so, the universe that astronomers can see is seriously underweight. Simply counting up all of its stars, gas, and hidden “dark matter,” astronomers have found only 30% of the critical density needed to flatten it. Theorists speculate that the rest takes the form of a cosmological constant first proposed by Einstein, an energy in empty space that pushes on the fabric of space-time. Its effects may already have been spotted in observations of distant exploding stars, or supernovae, which appear to show that the expansion of the universe is accelerating (Science, 18 December 1998, p. 2156), says Saul Perlmutter of Lawrence Berkeley National Laboratory in California.

    Happily, the supernova observations point to a cosmological constant that accounts for nearly 70% of the critical density, just enough to make up the deficit. The consistency of the two results is “nudging us from having to believe [in the cosmological constant] to being able to measure it,” says Harvard University astrophysicist Robert Kirshner.


    A Less Powerful NIF Will Still Cost More

    1. David Malakoff,
    2. Andrew Lawler

    The managers of a giant laser project have proposed drastically shrinking the National Ignition Facility (NIF) to curb rising costs, a step that could reduce its chances of achieving an important scientific goal in fusion research. But the downsizing will not eliminate cost overruns at the facility, and scientists in laser fusion and other fields are also worried that the Department of Energy (DOE) might tax their programs to complete the world's largest laser project.

    Earlier this month DOE officials revealed that the $1.2 billion NIF, slated for completion in 2003 at Lawrence Livermore National Laboratory in California, was a year behind schedule and at least $200 million over budget. Now DOE managers say that, because of problems building and housing the lasers, the full 192-laser configuration would cost about $350 million more than planned and would not be finished until 2005. To rein in the project, Livermore officials propose cutting the number of lasers in half and finishing initial construction in 2004, a plan that would limit the cost overrun to about $100 million. Additional lasers, they say, could be added by 2008 if funding became available.

    Researchers have been counting on NIF to blast a tiny capsule of deuterium-tritium fuel with high-powered lasers, triggering a tiny burst of fusion that could simulate nuclear weapons explosions without underground tests and test the feasibility of generating fusion energy. DOE officials say the weapon simulations, intended to help make stored bombs safer, would be relatively unaffected by the proposed redesign, one of several cost-saving options developed by Livermore researchers. But fusion researchers say that having fewer lasers could complicate efforts to ignite a self-sustaining fusion burn in the target, a controversial civilian goal that helped DOE convince Congress to fund the dual-use megaproject.

    Some critics have argued that ignition, an essential step toward realizing inertial confinement fusion, would have been unlikely even with NIF's original design (Science, 18 July 1997, p. 304). Now, even some of NIF's supporters concede that having only 96 beams could make the job that much harder. “Getting ignition with half the beams is iffy,” says one DOE manager. “The bigger the hammer, the better the chance of success,” adds physicist Richard Petrasso of the Massachusetts Institute of Technology in Cambridge.

    Still, Petrasso and others say that other technical improvements, such as target designs that absorb more of the available laser energy, could make up for much of the shortfall. Indeed, a Livermore official predicted last week that the smaller system could produce almost as much energy as the original arrangement. A pared-down NIF would also be able to contribute to a next-generation laser fusion effort. “A 96-beam version would still give us most of what we need,” says Robert Goldston, chief of DOE's Princeton Plasma Physics Laboratory in New Jersey. DOE officials, however, say they won't decide how to cope with NIF's troubles until they hear from an independent scientific panel they are still assembling (Science, 10 September, p. 1647).

    An even greater worry for many scientists is that DOE may rob other defense science programs to pay for the NIF overruns. “I'm concerned about where they are going to find the money” to complete NIF, says Anne Davies, chief of DOE's fusion program, which includes defense and civilian elements. Energy Secretary Bill Richardson has already said he will not ask Congress for more money, meaning that DOE and Livermore will have to work within existing budgets. And Livermore officials have already informed several researchers that planned funds for detectors and other equipment won't be available anytime soon, indefinitely delaying some science projects. “This is beginning to look like the space station,” says one DOE scientist, alluding to NASA's delay-plagued project.

    The House Science Committee this week asked the General Accounting Office to investigate the causes of the overruns and delays. Ironically, the revelations came as more than 150 researchers were preparing for a 3-day conference to draw up a research portfolio for NIF.* Although anxiety may be high at the summit, organizer Petrasso is upbeat. “We're concerned, but this is just the beginning of the beginning,” he says. “There will be lots of science to do.”

    • *Frontier Science at the National Ignition Facility: Episode I, Pleasanton, California, 4 to 6 October.


    Iranian Delegation Makes Rare U.S. Visit

    1. Jeffrey Mervis

    In what could be a prelude to warmer scientific relations between the United States and Iran, a delegation of five high-ranking Iranian scientists spent 5 days in Washington last week meeting with several nongovernmental scientific organizations. It was the first such visit since the 1979 Islamic revolution that toppled the shah. The U.S. National Academies of Sciences and Engineering and the Institute of Medicine, which co-hosted the visit, are hoping to send a delegation to Iran next spring to flesh out some of the ideas raised during a daylong session at the academy.

    The trip was arranged by Jeremy Stone, president of the Federation of American Scientists, who led a three-person FAS delegation to Iran last December. He says it took 8 months of “tortuous negotiations” with the Iranian bureaucracy to arrange a visit for his hosts, who were eager to discuss possible collaboration with their U.S. counterparts in fields such as renewable energy, environmental cleanup, earthquake hazard mitigation, agriculture, education, and health. Abolhassan Vafai, president of Iran's civil engineering society and founding editor of the fledgling journal Scientia Iranica, says, “There have been no ties for a long time. So any contact would be welcome.” The delegation's liaison, Ali Mansoori, a chemical engineering professor at the University of Illinois, Chicago, and a foreign member of the Iranian Academy of Sciences, adds, “We are interested in exchanges by students and faculty members and in joint research.”

    The meetings were mostly show-and-tell exercises for groups such as the American Physical Society (APS), the American Chemical Society, and the American Association for the Advancement of Science (publisher of Science), combined with window-shopping by the Iranians. According to Mehdi Bahadori, a mechanical engineer and academy vice president, Iran is particularly interested in beefing up its educational system in an effort to train a larger proportion of a growing population: “We are also increasing our graduate programs, so that more [Iranian scientists] can be trained in Iran.” Still, the lure of the United States remains strong. After meeting with the delegates, APS's Irving Lerch notes that “they suggested that a majority of students would prefer to study in the U.S. After all, four of the five visitors were trained here.”

    A major obstacle to closer links, however, is restrictions on travel. Because there is no U.S. consulate in Iran, Iranians must go to a third country to submit a visa application and then make a second trip, often several months later, to pick up the visa if it has been approved. This month's visit was made possible by what Stone calls “the full cooperation of the State Department,” which arranged for one-stop shopping in Bern, Switzerland. Full diplomatic relations would be a boon to increased cooperation, says Lerch, who noted that both Iranian President Khatami and President Clinton have expressed a desire for closer cultural ties between the two countries.


    Biological Invaders Sweep In

    1. Martin Enserink

    As a tidal wave of exotic species transforms environments worldwide, ecologists are scrambling to predict where and when new invaders may strike

    One spring morning in 1995, ecologist Jayne Belnap walked into a dry grassland in Canyonlands National Park, Utah, an area that she had been studying for more than 15 years. “I literally stopped and went, ‘Oh my God!’” she recalls. The natural grassland—with needle grass, Indian rice grass, saltbush, and the occasional pinyon-juniper tree—that Belnap had seen the year before no longer existed; it had become overgrown with 2-foot-high Eurasian cheatgrass. “I was stunned. It was like the aliens had landed,” says Belnap, a researcher with the U.S. Geological Survey (USGS) in Moab. “Now, we've lost this ecosystem forever.”

    A few years earlier and a continent away, as Yugoslavia fell apart in a series of wars, Serbian scientists discovered a new enemy in a field near Belgrade airport: the western corn rootworm, apparently flown in from the United States. Vigorous international action might have curbed this pest's first known venture outside North America, says entomologist József Kiss of the University of Agricultural Sciences in Gödöllô, Hungary, but the turmoil of war prevented such a collaboration. Now it's too late. By 1995, the rootworm—which is actually a beetle, Diabrotica vigifera, whose wormlike larvae feed on corn roots—had spread into Croatia and Hungary. It has now been spotted in Romania, Bosnia-Herzegovina, Bulgaria, and Italy. There's little doubt that Diabrotica will eventually gnaw its way into every corn-producing country in Europe and perhaps beyond, reducing crops and forcing farmers to use chemicals, says Kiss: “There are no limits. It's a big disaster.”

    Meanwhile, in South Africa, ecologists are bracing for the rise of Varroa, a mite that parasitizes honeybees. After sweeping through Europe and North America for decades, Varroa was found near the Cape Town harbor in 1997; now it's all over South Africa, and the first colonies have died, says Mike Allsopp, who heads the honeybee section of the Plant Protection Research Institute in Stellenbosch. What worries Allsopp most is the fact that between 50% and 80% of South Africa's native flower species are pollinated by bees—a much higher percentage than in Europe or the United States. “Commercial keepers can keep their colonies alive with chemical treatments,” says Allsopp. “But if Varroa wipes out 99% of the natural colonies, as it has done elsewhere, what effect is that going to have on the indigenous flora? No one really knows.”

    These are just three examples on a list that could be extended almost endlessly. As the world shrinks and travel and trade boom, plant and animal species have become globetrotters too, sometimes because humans decide to take them along, sometimes by accident. And whereas globalization may be the mantra of the new economy, for the environment it may spell disaster. The innocent-looking zebra mussel, a Eurasian invader that entered U.S. waters in the late 1980s and clings by the thousands to every hard surface it finds, does tens of millions of dollars worth of damage each year by clogging U.S. water pipes. Even worse, exotic species can devour or outcompete species that have called an ecosystem home for tens of thousands of years. Biological invasions are the second biggest cause of biodiversity loss in the United States, after habitat destruction, according to a 1998 study; they could soon become the first.

    Ecologists are paying more and more attention, if only because they increasingly find themselves studying not primordial ecosystems but collections of microbes, plants, and animals from around the world, flung together in an ecological melting pot. “It's the fate of all ecology,” says marine ecologist Jeb Byers of the University of California, Santa Barbara. Some ecologists have suggested, only half-jokingly, that the field should start calling itself “mixoecology” or “recombination ecology.” Many fear that another century or so of frenetic international traffic will lead to an “ecological homogenization” of the world, with a small number of immensely successful species, like the zebra mussel, cheatgrass, the European house sparrow, and the Argentine ant dominating nature everywhere—a global McEcosystem.

    Hopes of arresting this process are spurring new studies. Policy-makers trying to restrict traffic in exotic species and prevent invaders from running rampant (see p. 1836) are hampered by not knowing exactly where the danger will spring up next. If ecologists could identify likely invaders, governments could simply restrict imports of those treacherous species, and managers could mercilessly weed them out or trap them. But making such predictions has been devilishly difficult; the few predictive models are still hotly debated, and they apply to only a narrow range of organisms at best. Some past invasions seem to fit no pattern at all. A true theory of prediction—what several researchers call the “Holy Grail of invasion biology”—still proves elusive. “It will always be very difficult to predict,” says ecologist Ted Case of the University of California, San Diego (UCSD).

    Portrait of an invader

    For most of human history, shipping animals and plants around has been considered a good thing. New World colonists brought in seeds, plants, and livestock and took other species back to Europe; 19th century “acclimatization societies” strived to populate America and Australia with European plants, birds, and mammals, including every bird mentioned in Shakespeare's work. Most such imports quickly die, but others—perhaps one in 10—settle into their new home. Of those, perhaps another 10% spread unchecked. As early as the late 19th century, when imported rabbits started ravaging Australian vegetation (see p. 1842), it became clear that newcomers could be dangerous. Now, the U.S. Department of Agriculture (USDA) intercepts about 3000 potential pests at the border every year, but many others make it through, and thousands of exotics are firmly established. In a lush state like Florida, one in every three or four plant species is non-native; in parts of San Francisco Bay, a staggering 99% of all biomass is thought to belong to non-native species.

    After a slow start, the field of invasion biology is at last taking off. The journal Biological Invasions was launched just last month, and invasion biologists suddenly find themselves attracting more and more grants, students, and postdocs. Hundreds of scientists are staging plant takeovers in the lab or fencing off patches of sea floor to watch competition between marine critters in action. “People who worked on invasions used to feel like bastard children,” says ecologist Sarah Reichard of the University of Washington, Seattle. “Like we had said something dirty. Now, all of a sudden everybody is interested. It's great!”

    For scientists seeking the ecological principles behind invasions, one place to start is with common traits of invaders. Many researchers have noted, for example, that invaders often grow fast and have short reproductive cycles; plants typically have small seeds that spread easily, and most invaders are generalists that aren't too picky about their environment. Some researchers are now trying to use these commonalities to understand why certain alien species overrun natives while others don't.

    Take one of South Africa's biggest pests, pine trees from Europe and the Americas. Introduced for forestry as early as 1680, pines have spread out of plantations and into the Cape's fynbos biome, a richly diverse belt of shrublands north and east of Cape Town, says David Richardson of the University of Cape Town. To understand why only a handful of the 100 or so introduced pine species have encroached on native territory, Richardson, together with Marcel Rejmánek of the University of California, Davis, compared the life histories of invasive and noninvasive pine species. They found that “invasiveness” depends largely on three characteristics that help a species reproduce fast and spread widely: a short interval between successive large seed crops, small seed size, and a short juvenile period. Richardson used these factors to create a “discriminant function” that is “pretty accurate in distinguishing invasive from noninvasive species,” he says. And although built on pine studies, it works for other plants as well—the model gave the right answer for 38 of 40 known invasive woody plants.

    But such tidy results are rare in other systems. In a recent review in Ecography, Mark Williamson of the University of York pointed out serious disagreements among three studies since 1995 that sought common traits among Britain's invasive plants. One found that large seeds favored invasions, another found that it was small seeds, while a third said size didn't matter. Back in the 1980s, the Scientific Committee on Problems of the Environment had raised similar doubts after trying to tease out the factors that make for successful invaders or vulnerable habitats, says Williamson. “We just didn't find anything,” he says. “I don't think there is an answer to come up with.”

    Vulnerable territory

    Even if the stereotypical invader's signature is still uncertain, is there a typical ecosystem that easily gets invaded? Many researchers have found that exotic species move in more easily amid other types of ecological disruption. That was the common denominator Case identified in a set of invasions by ants, birds, and geckoes. Argentine ants are abundant in Californian towns and suburbs, says Case, and although they sometimes spread into the surrounding coastal sage scrub, they are never farther than 50 or 100 meters from the humanmade landscape.

    Case also studied why native, asexually reproducing geckoes were driven out of Pacific islands by a sexual species from Southeast Asia. Turning Hawaiian aircraft hangars into makeshift laboratories, he watched how well the two species do under different circumstances and found that the newcomers are good at snapping insects on smooth surfaces with abundant light—in other words, on the walls of buildings. The invaders don't do nearly as well in forests, and without urbanization, Case says, they wouldn't have made it.

    Another long-standing theory is that ecosystems rich in species, with their dense, interconnected webs of ecological relationships, can resist invasions, while those with fewer species succumb. For example, islands—which usually have fewer species than comparable areas of mainland—are often also the most heavily invaded. Models and lab experiments seem to support the idea; in an as-yet-unpublished study, for instance, a team led by John Stachowicz of the University of Connecticut, Groton, created artificial marine ecosystems with anywhere from zero to three North Atlantic species and then seeded each with a known invader, a Pacific tunicate called Botrylloides diegensis. The more species there were, the smaller the tunicate's chance of survival.

    But a growing number of researchers think it's exactly the other way around. “To those small-scale experimenters and modelers I say: Go take a hike,” says ecologist Tom Stohlgren of Colorado State University in Fort Collins—and he means it literally. His team recently sampled 100 plots in nine natural grasslands, national parks, and wildlands throughout the central United States. The number of exotic species in each, he reported at an ecological meeting last month, was positively correlated with the number of native species. The very circumstances that favor a wealth of native species, says Stohlgren, such as light, water, and nitrogen, also make a place attractive to newcomers. And experiments with just a few species don't remotely resemble real life, he adds.

    There's yet another shadow on the prospects of prediction. Scientists have repeatedly witnessed exotic species living inconspicuously in their new habitat for decades—until the population suddenly explodes like Teletubbies in a toy store. In some cases, the reasons were obvious: Three species of exotic fig trees grown in Florida gardens for a century started spreading only 20 years or so ago—after the arrival of the fig wasp species that pollinate them. But often, such lag times are “quite mysterious,” says ecologist Daniel Simberloff of the University of Tennessee, Knoxville. Take Brazilian pepper, “an incredibly awful” invader in south Florida, Simberloff says. “It sat around in people's yards as a harmless ornamental for many years, doing nothing. And suddenly in the late '40s, early '50s, it exploded”—and nobody knows why.

    The zebra mussel is another case in point. Scientists have predicted its arrival into the Great Lakes from Europe via ballast water since the 1920s, says aquatic invasion expert James Carlton of Williams College-Mystic Seaport in Mystic, Connecticut. Yet the invasion just didn't happen. “By 1988, it would have been a worthwhile academic exercise to figure out why zebra mussels could not successfully establish themselves in America,” says Carlton. It's still not clear why the animal finally invaded when it did. One possibility is that some change in the environment makes it more suitable to a particular exotic species, says Simberloff, although it's often unclear what that is. (In the case of the zebra mussel, ironically, improving water quality in the Great Lakes has been blamed.)

    Another likely boost to an invader's chances is simply repeated and widespread introduction. Robert Pemberton, a weed scientist with the USDA Agricultural Research Service in Fort Lauderdale, Florida, recently leafed through old catalogs from the Royal Palm Nurseries, a famous, trend-setting company that bred and sold plants in Manatee County, Florida, from 1881 to 1937. He found that plants sold for just 1 year had only a 1.9% chance of establishing in the wild, while favorites that were in the catalog for over 3 decades had a 68.8% chance of taking hold.

    And some species may simply need a stroke of good luck to get started. One reason that cheatgrass exploded in Canyonlands in 1995 and not before, says the USGS's Belnap, is unusually frequent rainfall in late 1994, which spurred germination of hundreds of thousands of dormant seeds. In other parts of the West, fires sometimes wipe out the existing perennials and give annuals like cheatgrass, yellow star thistle, and medusahead rye their lucky break.

    Given all this uncertainty, many ecologists are quite modest about their power to predict. For now, just forecasting the advance of a limited group of species in a number of habitats is difficult enough. Belnap, for instance, discovered that at least in Utah soils, cheatgrass often strikes where the potassiummagnesium ratio in the soil is high, suggesting that potassium uptake may be limiting for this species. She's now looking to see if the same holds true for other annual weeds and for other soils. Such studies are arduous, but they may be the only way to go. Says Case of UCSD: “The best approach is case by case.” It's scant comfort that there will be many more cases to study.


    Stemming the Tide of Invading Species

    1. Jocelyn Kaiser

    Researchers agree that prevention is the best medicine, but they are also battling established exotic species with everything from chemicals to traps

    Last Easter weekend, four divers from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) research agency splashed into a marina in Darwin on the north coast in a routine inspection. They got an unpleasant surprise: Hundreds of millions of fingernail-sized mussels were clumped in balls stuck to boats, lines, and piers—where no mussels had been 6 months before. Taxonomists identified the critter as a Central American cousin of the zebra mussel, notorious for clogging up North America's Great Lakes. Within 5 days, Australia's Northern Territory government had braved objections from boat owners and quarantined all boats in the marina, closing off the entire 1.5-kilometer-area, and two other marinas where the black-striped mussel had been spotted. Then they poisoned the marinas with chlorine and copper, killing every living thing in the water.

    It sounds like drastic medicine, but no black-striped mussels have been seen since, the natural biota is bouncing back, and CSIRO is counting the $1.5 million strike as perhaps one of the most dramatic defeats ever of a marine invader. “Nobody's questioning it at all,” says Ron Thresher, head of the CSIRO Centre for Research on Introduced Marine Pests in Hobart, Tasmania. “If it shows up again, we'll do it again.”

    Australia's quick victory over the mussel, which probably arrived stuck to a yacht's hull, shows that it is possible to battle exotic species and win. The world's ecosystems will never revert to the pristine state they enjoyed before humans began to routinely crisscross the globe, and the pet and nursery industries still import many alien species. But people are fighting back against invasive species as never before, with weapons ranging from ballast-water exchanges that keep species out of harbors, to parasites that attack exotic plants and insects (see p. 1841). On heavily invaded territory, such as parts of Hawaii, fenced “exclosures” claim at least some patches of territory for the natives (see sidebar on p. 1837). “There's more interest in invasives now than there has been in the last 25 years,” says Jim Carlton, a marine biologist at Williams College-Mystic Seaport in Mystic, Connecticut.

    Researchers agree that preventing an invasive species from getting in is far and away the best and cheapest approach. But they are having increased success at managing exotics that have already landed. Although conventional wisdom once held that removing an already established exotic is all but impossible, some scientists are becoming more optimistic that local invasions can sometimes be stopped—if they're caught in time. Invaders such as parasitic worms in California abalone and a South American rodent ravaging British estates (see sidebar on p. 1838) have succumbed to aggressive counterattacks. “The practical approach is to have a diverse portfolio: Prevent as many things as you can and control the things you can control,” says Liz Chornesky, a senior scientist with The Nature Conservancy.

    Still, stopping ongoing invasions is a daunting task, and even preventing them is not easy. Because of the scope of the problem, and because exotic plants and animals are transported as part of international trade, control measures “potentially step on a lot of toes,” says Daniel Simberloff, an ecologist at the University of Tennessee, Knoxville. Tackling invasives requires not only beefing up the budget—more than $500 million in the United States, with the bulk of the money going for customs inspections—but also politically sensitive steps such as cracking down on what timber companies can import and plant nurseries can sell. “It's very easy to get people aware of the problem. … But there are some parts of this that are really intractable,” says Alan Holt, a senior scientist with The Nature Conservancy.

    Closing the borders

    One strategy is simply to ban traffic in exotic species known to pose a threat. Today, in addition to a hodgepodge of federal and state laws restricting transport of various plants, animals, and insects, the United States bans imports of more than 100 troublemaker taxa on “blacklists” established by various agencies. But blacklists will always be incomplete, leaving the door open for many other noxious organisms.

    One solution comes from Australia. In mid-1997, in a policy also followed by New Zealand, it adopted a “white list” model for plants: All plant species are barred unless they have been determined to be safe. For new plants, officials developed a 49-question form handed out at airports and seaports that asks, for example, whether a species has been invasive elsewhere or reproduces by windblown seeds. The weed questionnaire has slowed influx of new species “by about 30%,” says CSIRO ecologist Mark Lonsdale.

    As U.S. exotics from the zebra mussel to a Western weed called leafy spurge make a huge dent in the nation's bottom line, researchers argue that the time is right for such strict measures. “I don't see why we couldn't do something as stringent as [what] Australia [has done], personally,” says Bill Brown, science adviser to Interior Secretary Bruce Babbitt. Many scientists also favor this approach. “The burden of proof would be on the person bringing it in. That changes things quite a bit,” says San Francisco Estuary Institute marine biologist Andrew Cohen.

    Back in the 1970s, however, the U.S. Fish and Wildlife Service proposed such a white list policy—and got nowhere. “They had their heads handed back to them” after the pet and nursery industries—and even some scientific groups—skewered the idea, says Don Schmitz, a biologist with the Florida Department of Environmental Protection.

    The prospect of tighter regulations on exotic species still riles powerful industries, including nurseries and pet stores. Marshall Meyers, general counsel for the Pet Industry Joint Advisory Council, fears that officials may regulate “easy targets” like animals sold in pet stores, even if accidental introductions or biocontrol agents gone awry are a greater threat.

    And the booming gardening industry is probably an even bigger importer of pests, researchers say. Richard Mack, an ecologist at Washington State University in Pullman, says that he “keeps a collection of seed packets that I bought in U.S. garden stores and nurseries that shouldn't be sold anywhere in the country,” like the Brazilian pepper and even seemingly innocent European baby's breath. Both species are already problem weeds in some states, yet are sold legally.

    Nurseries are still opposed to legal restrictions, but they are beginning to take voluntary measures. For example, the Florida Nurserymen & Growers Association recently identified 24 marketed species on a blacklist drawn up by Florida's Exotic Pest Plant Council—and decided to discourage trade in 11 of them. True, those were the least promising sellers, says exotic plant expert Ken Langeland, a researcher at the University of Florida, Gainesville, but stopping such sales can help slow invasions: “It's a major step. Before, they were just pushing the issue aside and ignoring it.”

    Of course, even if intentional traffic in exotic species is slowed, there remains the tougher problem of those organisms that sneak in with the inadvertent help of humans, such as the Asian clams that hitchhiked into San Francisco Bay in ballast water, or voracious brown tree snakes that arrived in Texas hidden in a cargo shipment. “Accidental introductions will be much more difficult to address,” says ecologist Jennifer Ruesink of the University of Washington, Seattle. Global traffic is so heavy that “there's excellent evidence now that whatever can get in, will get in.”

    Still, there are ways to help prevent such stealth invasions, too. The United States is focusing on one vulnerable spot—ballast water, often a veritable aquarium of exotic species, which ships generally discharge in port. As of July, a Coast Guard regulation requests that the 30,000 to 60,000 ships that steam into U.S. waters each year voluntarily exchange ballast water at sea; that way only marine species will be brought into brackish water harbors. Each ship must report whether it has done so, and after 2 years the Coast Guard will decide whether to make exchanges mandatory. But exchanging ballast risks unbalancing the ship in rough seas, and spot checks in the United States and Australia suggest that many captains lie about the exchange. A better long-term fix may be to sterilize the water with ultraviolet light or biocides, says Smithsonian Institution marine biologist Greg Ruiz.

    Other pathways require even more creative solutions. The Asian longhorn beetle, for example, a pest whose larvae are now devouring hardwoods in New York City and Chicago, likely hitchhiked in on wooden packing crates and pallets from China around 1996. Experts are still struggling with their options, Brown says: Short of banning wood packing materials altogether, the government might require that the wood be fumigated or heat-treated at its port of origin, or even allow only plastic pallets. Other pest conduits, such as personal mail, can't be addressed without trampling on people's civil rights. “If you want to send me a brown tree snake, just put it in first-class mail,” says Holt.

    Contain and control measures

    For those invaders that inevitably get across borders, the other half of the challenge is to craft better management strategies, including a monitoring network for spotting invaders early, researchers say. Australia's victory over the mussels, for example, was triggered by a new monitoring effort that sent divers down to inspect boats and piers. But most existing monitoring programs don't track species in sufficient taxonomic detail.

    Once the alarm is raised, wiping out recently established invaders can be done if there's enough political will to do it, insists Simberloff. He notes that the medfly has twice been eradicated from Florida, and over the past decade North Carolina has almost conquered witchweed—a parasitic plant from Africa that strangles corn and sorghum crops—with a combination of hand pulling, chemicals, and quarantines. California scientists last month declared victory over a South African parasitic worm that infects a wild abalone species, after having plucked from shorelines 1.5 million black turban snails, one of the worm's main hosts. “By far and away, the most effective and cheapest way is to destroy it soon after you've discovered it,” says Mack.

    For those invaders already too entrenched to remove, coordinated effort can keep them in check—but such coordination is often lacking. Indeed, sometimes federal or state agencies actually help spread exotic species. For example, the Natural Resources Conservation Service, a U.S. Department of Agriculture agency that has focused on tasks such as helping farmers reduce soil erosion, has a history of planting non-native, weedy species to reduce the threat of forest fires or stabilize road embankments. Or one agency will spray weeds with pesticides, thwarting another agency's biocontrol insects released on the weeds in an adjacent field.

    To eliminate such problems, President Bill Clinton in February signed an executive order calling on federal agencies to stop activities that spread invasive species; the order also created a high-level federal council charged with devising a “management plan” for invasive species by August 2000. With this new high-level directive, “I'm hopeful that cross-purposes will disappear,” says Mack. For even more coordination, Simberloff, Schmitz, and some others are lobbying for a government-sponsored North American Center for Biological Invasions to keep a directory of experts and maintain a sort of 911 emergency number that anyone could call to report an invasion.

    Ultimately, it will take action on the part of millions of individuals to stop the tide of invaders. Perhaps one model is Australia, where “the average taxi driver” is well aware of the devastation wrought by invading species, says CSIRO's Thresher, an American expatriate. Such a culture supports strong measures, such as insecticide spraying on arriving overseas flights, and airport “amnesty boxes” where passengers can hand over fruits or wood.

    Right now such tactics are hard to envision elsewhere, but even so, some scientists are increasingly optimistic. “I'm amazed at the attention that's coalescing around this, the disparate factions,” says Nature Conservancy senior scientist Bruce Stein. Adds Simberloff: “This has taken so long to get under way. I'm hoping for the moon.”


    Keeping Paradise Safe for the Natives

    1. Richard Stone

    KULANI, HAWAII—When the Kulani Correctional Facility took in 400 fresh inmates in May, the hope was that the new prisoners, and their descendants, would be locked away for the rest of their lives. Not that these wards of the state were guilty of any crime: They were sent to Kulani because the 3000-hectare prison grounds and adjacent state and private reserves are part of an innovative program to protect native species from the ravages of invaders. The young inmates—seedlings marked by pink flags amid the surrounding grass—are endangered Mauna Loa silversword, a majestic plant with silvery, sharp leaves and a massive flowering stalk that blooms once and then dies. Sheltered inside a pig-proof fence, other native species are mounting comebacks too: Tree ferns, their starchy cores now off limits to pigs, are thriving. Native songbirds, driven from the lowlands by a triple whammy—habitat loss and avian malaria, plus invasive species that prey on their eggs—flit from branch to branch in the gnarled ohia forest.

    The silverswords and songbirds are refugees from a war that has taken a heavy toll on Hawaii's native life-forms. Islands are particularly vulnerable to biological invaders, and Hawaii has suffered wave upon wave since the arrival of the first Polynesian settlers some 2000 years ago. Although it's hard to assign full blame to an invader for any particular extinction, statistics tell a sad tale: Of 140 known native bird species, 70 have gone extinct since human arrival, and 30 are on the endangered list. “Alien species are the biggest problem we're dealing with now,” says Jim Jacobi, a botanist with the U.S. Geological Survey's Pacific Island Ecosystems Research Center in Hawaii. And as one of the hardest hit places on Earth, Hawaii has come up with an innovative way of protecting natives from invaders. Instead of trying to eliminate established exotic species—a nearly impossible task—Hawaii is creating well-defended reserves where native species can find refuge.

    Hawaii's menagerie of imports includes plenty of unpleasant customers. Take the rosy wolf snail, Euglandina rosea. It was imported in 1958 to knock off another alien predator, the giant African snail, and is an ideal killing machine, tracking its victims by their slime trails. However, Euglandina swiftly developed a taste for the native snails too and went on a binge. “It's very difficult to prove that Euglandina is responsible for the extinction of native snails, but the weight of the evidence virtually forces this conclusion,” says Robert Cowie, a biologist at the Bishop Museum in Honolulu.

    Wiping out Euglandina is almost impossible—“everything you think of that can kill Euglandina would kill the native snails as well,” says Stephen Miller, a population ecologist with the U.S. Fish and Wildlife Service in Honolulu. So scientists have for now forsaken the sword for the shield: snail “exclosures” designed to protect the natives from the exotic predators. A team led by zoologist Michael Hadfield of the University of Hawaii, Manoa, has built the largest of them, a 430-square-meter corrugated aluminum fortress, in the northern Waianae mountains on Oahu. Erected around a population of endangered Achatinella mustelina snails, the barrier is ringed by a salt trough, a substance as painful to snails as battery acid to people. “The minute Euglandina touch the salt, they just drop back,” says Hadfield. The fence also has two electrified wires to deter rats, another snail predator, and rat motels inside the exclosure.

    Across the state, land managers are protecting other natives by throwing up fences and hunting down the exotics that remain inside. “Fencing of native preserves is considered state of the art,” says Dave Bender, a restoration ecologist with the National Tropical Botanical Garden on Kauai. At Volcanoes National Park and on adjacent public and private lands on the northern slope of Hawaii's Mauna Loa volcano, managers have fenced off thousands of hectares of forest. Staff hunters have killed nearly all the feral pigs in the protected area. And from a population of 20,000 feral goats several years ago, the park is down to about a dozen “Judas” goats, allowed to stick around to attract any goats that sneak through the fence. Scientists keep tabs on the Judas goats, fitted with radio collars, and shoot any new faces. Next on the hit list, says Jacobi, are bird-eating feral cats—a controversial move among cat lovers—and nasty invasive plants like the yellow Himalayan raspberry, whose heart-shaped leaves belie its aggressive advance across the islands.

    Of course, biologists would rather not have to build such reserves, so they are trying to prevent new threats from spinning out of control. After seeing the devastation that a Central American tree called Miconia calvescens has visited on Tahiti—where it covers 75% of the island and has earned the nickname “the green cancer”—Hawaiian biologists Betsy Gagne and Steve Montgomery mounted a 15-year-long campaign to get the tree on Hawaii's Noxious Weed list, which would prohibit its import. They finally succeeded in 1992. Since then, Maui and Hawaii have launched 10-year programs to eradicate Miconia, a laborious job that involves applying a thin line of herbicide at the base of each tree. It's working: So far, mature Miconia plants have been eliminated from 70% of Hawaii island, although all these areas must be treated again as the seed bank sends up shoots.

    Hawaiian scientists have also lobbied to close the border to potential invasive species, but they have been opposed by horticultural interests. “I know the nursery industry would kill me if they heard me say this, but we need a broader list of plants that are prohibited,” says Charles Lamoureux, director of the Lyon Arboretum in Honolulu. Others suggest a “white list” of permitted plants, such as exists in Hawaii for animals. “If we don't act now,” says Jacobi, “we're going to have a much harder time dealing with the problem as time goes on.”


    Vanquishing Nutria: Where There's a Will, There's a Way

    1. Erik Stokstad

    CAMBRIDGE, UNITED KINGDOM—In the 1920s, enterprising English farmers imported a large South American rodent whose glossy brown pelt was a hit with fur-loving flappers. But the farmers soon realized that the fur was the only appealing trait of the animal they called the coypu, which escaped their farms and ran rampant through the low-lying fields and wetlands of eastern England. The 7-kilogram rodents devoured crops and native reeds, and burrowed into river dikes. Early eradication efforts failed. But persistent British biologists zeroed in on the animal's weaknesses, and a campaign that killed nearly 35,000 animals in 6 years finally ended the invasion in 1989. Coypu, also called nutria, have never troubled the British Isles again.

    Today, however, the rodents are wreaking havoc across the Atlantic. Worried biologists are watching them eat their way through sensitive coastal wetlands, where their digging allows salt water to invade and poison vegetation. Drawn by the unusual success of the British effort—the only eradication of widely dispersed vertebrates in recent decades—American researchers have adopted its strategies for their own efforts. “It could be a model of how to deal with invasive mammals,” says Robert Colona, a biologist for the Maryland Department of Natural Resources (DNR).

    Conventional wisdom has it that once an alien species is well established in new territory, the prospect of eradicating it is rather dim (see main text). Most attempts—from whacking away Japanese seaweed clogging English harbors to poisoning fire ants in the southern United States—have failed, except on small islands. “When something builds up a strong population, getting rid of it is almost impossible,” says Roger Mitchell, head of biodiversity for English Nature, a government advisory group.

    But Britain's battle of the nutria belies that wisdom and suggests that, as in any territorial conflict, unanimous political support and overwhelming force can win the day. It was not a skirmish: By the 1950s, long after the market in pelts had faded, some 200,000 nutria had made their home in more than 12,500 square kilometers of English soil. In 1962 the Ministry of Agriculture, Fisheries and Food (MAFF) established the Coypu Research Laboratory (CRL) in Norwich, with a half-dozen scientists and 14 trappers. After 3 years—combined with a winter of record-breaking cold—researchers estimated that 90% of the nutria were dead.

    But a spell of mild winters followed, and the population began to explode, says Morris Gosling, a zoologist at the University of Newcastle in the U.K., who headed the CRL. To create a more realistic battle plan, CRL scientists decided they needed to know more about the enemy. By catching and dissecting more than 30,000 nutria they learned, for example, that females abort litters in severe cold—implying that trappers would have their hands full after warm winters. To better estimate population size and therefore the number of trappers needed, the scientists tallied trapped animals' sexes and ages.

    These data allowed researchers to predict the workforce needed, a firm price tag, and a completion date—all of which proved vital to winning the government's commitment to a second, $4 million assault, says Gosling. That second attack worked. From 1981 to 1986 trapping records and modeling indicated that the population had dropped to 40. No nutria were caught after 1987, although trappers searched for two more years. “The popular view was that it couldn't be done,” says Gosling.

    Can this success be repeated elsewhere? Officials in Maryland hope so. “It's like a cancer that's eating the marsh from the inside,” says Colona. In the Blackwater National Wildlife Refuge alone, nutria ranks have swelled from 150 in 1968 to up to 50,000 today. With 21 partners, the DNR last year put the finishing touches on plans for a $3.8 million pilot project modeled heavily on the MAFF campaign. The plan—which is not yet fully funded—calls for research into how nutria behave and reproduce in Maryland, plus a trial eradication on a test site.

    Officials warn that eradication may be harder in the United States, where nutria seem to be much more prolific breeders. With the rodents gnawing on nearly half a million hectares of land in National Wildlife Refuges alone, the stakes are high. “Nothing like this has ever been tried in North America before,” says Colona. “The other 15 states with nutria problems are waiting for us to give them the answer.”


    Fighting Fire With Fire

    1. David Malakoff

    Demand is up for natural enemies, from insects to viruses, to keep invaders in check. But ecologists warn that this tactic may backfire

    WEST BOULDER RIVER, MONTANA—On a hot afternoon, rancher Matt Pierson drags a heavy hose down a steep hillside, straining to spray weed killer on a patch of showy, yellow-leaved plants. “If we don't get 'em now, they'll spread and it will take even more spraying next year,” says the fifth-generation rancher. His target: leafy spurge, a Eurasian perennial that invaded Montana at the turn of the century and now threatens to crowd out native grasses favored by cattle and wildlife. Someday, however, Pierson would like to hand off the backbreaking weed work to some unusual hired hands: swarms of flies and beetles, imported from the spurge's Asian homeland due to their taste for the plant.

    The hungry swarms, he hopes, can repeat the success of another insect, a seed-eating weevil that Pierson and other ranchers used to subdue Russian thistles, a.k.a. tumbleweed. The weevil “knocked back the thistles in a year. It was great,” Pierson says.

    That's the promise of what researchers call classical biological control—fighting fire with fire by importing natural enemies of exotic weeds and pests. As the menace posed by biological invaders grows, many scientists are turning to biocontrol as the most sophisticated solution, safer and cheaper than chemicals or mechanical killing methods, and perhaps the only practical way to suppress exotics in remote areas. Governments bent on reducing chemical use are pushing the search for natural henchmen, and biocontrol—once chiefly restricted to agricultural pests—is becoming a high-profile tool for fighting invaders of all kinds, with dozens of agents released worldwide each year.

    But biocontrol has its own dangers, some environmentalists and ecologists warn: The “good” exotics may become problems themselves, attacking nontarget native species or reshuffling ecosystems in unwanted ways. The weevil that Pierson admires, for instance, has also attacked some rare native thistles, sparking debate over prerelease testing and postrelease monitoring. Controversy also swirls around a host of other biocontrol agents, including a mosquito-eating fish that munches on threatened amphibians, and a virus that attacks Australia's rabbits (see sidebar). And even biocontrol researchers admit that the long-term fate of introduced agents is often unknown. Because of these risks, biocontrol “should be a method of last resort,” argues ecologist Daniel Simberloff of the University of Tennessee, Knoxville, a longtime critic.

    Thus, just as demand for biocontrol is rising, environmentalists and ecologists are scrutinizing it as never before. “The goalposts have moved—we're being challenged to meet tougher standards” for both safety and effectiveness, says weed biocontrol researcher Anthony Willis of Australia's Commonwealth Scientific and Industrial Research Organisation in Canberra.

    Centuries of success

    It's a new challenge for a strategy that goes back at least 2 centuries. In one of the earliest documented biocontrol efforts, British officials in 1836 released a Brazilian scale insect in southern India, where it successfully controlled prickly-pear cactus, a South American import. Since then, published surveys suggest that weed managers worldwide have introduced nearly 300 kinds of insects and pathogens in bids to control more than 50 plants, while pest scientists have loosed nearly 1000 predators, parasites, and pathogens against nearly 500 unwanted insect species.

    Biocontrol has remained a hit-or-miss effort, however. Although statistics are scarce, researchers estimate that less than a third of the insects introduced to control other insects have taken hold, and just half of those imported to attack weeds have become established. Even fewer make a dent in target populations. The success rate may be lower still for many microbial, viral, and fungal biocontrols, which often can't stand the stress—differences in climate and sunlight, for example—of new settings. “There are a lot of things you let loose and never see again,” says weed biocontrol specialist Ed Coombs of the Oregon Department of Agriculture in Salem.

    As a result, some observers dismiss biocontrol as a long shot, especially compared to the seemingly sure bet of killer chemicals. But others argue that the statistics aren't really so gloomy. At a recent conference,* Australian weed scientist Rosalyn McFayden of the Queensland Department of Natural Resources in Sherwood argued that researchers have successfully tackled about 40 of the 50 weeds they have tried to hold in check worldwide, an 80% success rate—even though in many cases they had to try a number of insects or pathogens to find one that worked. “The number of unsuccessful releases is irrelevant,” she argues, because it's unrealistic to expect that it will take just one try or one agent to control weeds. Researchers typically try four or more insects per weed, for instance, and U.S. Department of Agriculture (USDA) officials—who help research and must approve U.S. biocontrol agents—have already authorized the release of 13 insects against leafy spurge, with uneven results.

    Although even some biocontrol advocates don't buy McFayden's rosy numbers, they agree there are spectacular success stories. Long-snouted weevils and other insects, for instance, have swept exotics such as water hyacinth and Eurasian milfoil from lakes and rivers around the world. The crawlers deliver a one-two punch: Some weaken the plant by gnawing on leaves, stems, or roots, while others devour seeds, eating into the next generation. From New Guinea to Florida, such teamwork has cleared massive mats of vegetation from major rivers once virtually closed to boats and fishing. “Water weeds are the big success of this decade,” says McFayden.

    Insect biocontrol experts have also claimed numerous victories, usually against agricultural pests. In the United States, for instance, introduced parasites have controlled the alfalfa weevil, once the nation's major alfalfa pest, saving an estimated $90 million annually. “The rate of return on biocontrol is something like $30 [in saved crops] for every $1 invested in research,” estimates Keith Hopper, a population ecologist at the USDA's Beneficial Insects Introduction Research Station in Newark, Delaware. For some low-value crops such as dryland wheat, where the cost of pesticides would eat up any profits, biocontrol is the “best option,” he says.

    Minnows run amok

    Along with the success stories, however, are an increasing number of cautionary tales of biocontrol agents gone awry. For instance, for decades Los Angeles County mosquito-control officials have handed out free bucketloads of a small insect-eating fish from the southeastern United States that researchers say also has a devastating appetite for tadpoles. Despite warnings that it should be stocked only into ponds, not free-running streams, in the last decade the Gambusia minnow—“Damnboosia” to its detractors—somehow made its way into once fishless streams in the Santa Monica mountains, ecologists Lee Kats and Jeff Goodsell of Pepperdine University in Los Angeles reported last month in Conservation Biology. Now, the fish appears to be eating its way through populations of increasingly rare Pacific tree frogs and two other amphibians, just as it has displaced native fish and amphibians in New Zealand and elsewhere. The government “should not be handing out the fish to anyone who asks,” says Kats.

    An even higher profile controversy involves the thistle-slaying Eurasian weevil Rhinocyllus conicus. Two years ago, ecologist Svata Louda of the University of Nebraska, Lincoln, and three other researchers, including Simberloff, published a paper in Science (22 August 1997, p. 1088) showing that the weevil's seed-eating larvae are attacking not only Russian thistle but several native North American thistles as well, including at least one rare species. The paper was accompanied by an essay (p. 1058) by ecologist and biocontrol researcher Donald Strong of the Bodega Marine Laboratory in Davis, California, who suggested that the weevil's release in the late 1960s was just one example of a continuing practice—“willy-nilly biological control without regard for environmental costs.” The resulting ecological damage could reduce public support for biocontrol, Strong wrote.

    Many in the U.S. weed biocontrol community were outraged by Strong's criticisms. Agents are hardly released “willy-nilly,” says Ernest Delfosse, the USDA's point man on biocontrol in Washington, D.C. He says that in most industrialized nations, weed and insect biocontrol agents undergo lengthy “host-specificity” testing, designed to ensure that, even if it's starving, the insect will not attack valuable crops and insects. More and more, such tests—run in the United States by USDA's Animal and Plant Health Inspection Service and reviewed by a panel of government scientists—also include endangered species related to the target.

    Even at the time of the weevil's release, Delfosse adds, the tests were good enough to show that the insect would feed on the native thistles. The decision to approve the release anyway says more about risk-benefit calculations 30 years ago than about the testing regimen, Delfosse insists. “You can't judge what was done 30 years ago by today's standards,” he says, speculating that officials might make a different choice today. Louda and Simberloff aren't so sure: Both note that just 2 years ago, USDA approved the release of another thistle-eating weevil with worryingly broad tastes.

    Others note that prerelease testing hasn't prevented some “near-misses,” such as allowing imposter insects—which look like the control agent but may have very different behavior—to slip out. USDA researchers in California, for instance, discovered in 1996 that the “wrong” fly had become widely established on a weedy thistle. Luckily, the insect so far hasn't taken a liking to valuable sunflowers, which some tests suggested it might.

    To try to eliminate such sloppy practices, researcher Joe Balciunas of USDA's invasive weeds research lab in Albany, California, is promoting a voluntary “code of conduct” for researchers, hoping to “cut out the cowboys” in biocontrol. At the moment, he says, “I'm ending up defending some practices that I'm not comfortable with anymore.” His code encourages researchers to target only weeds that pose “serious” problems, and to release as few insects as possible. “Releasing more species is not necessarily better,” he says. He's also pushing for expanded follow-up studies so researchers can better evaluate the results—good and bad—of their efforts.

    Currently, such follow-up studies are difficult and therefore rare, say researchers. For example, insect “populations [naturally] fluctuate by orders of magnitude,” so it can be hard to measure an agent's impact on either target or nontarget insects, says Hopper. And Louda notes that it took nearly 30 years for her weevil to spread into the range of rare thistles, implying long-lasting uncertainty over ill effects.

    As a result, scientists don't really know how an insect interacts with other species a year or two—or 20—after its introduction. In particular, agents that get established but don't damage their target are often completely ignored, notes Delfosse. USDA's $40 million biocontrol program, he adds, will now fund only projects that have “detailed postrelease monitoring.”

    Delfosse and other biocontrol advocates hope such steps will boost public trust in biocontrol by promoting realistic assessments of both its risks and benefits. “Biocontrol is not risk free—and neither is any control strategy,” says Delfosse. When it comes to fighting invasive species, he says, “there is no silver bullet.”

    • *10th International Symposium on Biological Control of Weeds, Bozeman, Montana, 4 to 14 July.


    Australian Biocontrol Beats Rabbits, But Not Rules

    1. Elizabeth Finkel*
    1. Elizabeth Finkel writes from Melbourne, Australia.

    MELBOURNE—In 1859, Thomas Austin, one of Victoria's landed gentry, introduced a few European rabbits onto his estate for sport—and Australians have been cursing him ever since. To stop millions of foliage-eating rabbits from turning huge tracts into desert, Australia has become the only nation to successfully use a biocontrol agent on a vertebrate. Officials released the myxomatosis virus in the 1950s, and then, as that virus's potency waned, followed it with the European rabbit calicivirus disease (RCD) in 1995. The new virus appears to be a stunning success: Rabbit numbers are way down and once barren deserts are blooming (Science, 10 January 1997, p. 154). Yet for biocontrol officials, the calicivirus experience has been a major embarrassment, a sobering lesson in the unpredictability of biocontrol agents.

    The problem is that RCD escaped into the wild while it was still being tested on an island off the Australian coast. The Commonwealth Scientific and Industrial Research Organisation (CSIRO) had already determined that the virus would not harm humans or Australia's unique native mammals. But before the CSIRO could complete field tests on how well the virus spread, flying insects are thought to have picked it up from two infected rabbits and carried it to the mainland. The escape left the CSIRO legally vulnerable and has eroded public trust in biocontrol. “We have a track record of an escape,” says Bob Seamark, director of another biocontrol institute, the Pest Animal Control Cooperative Research Center in Canberra. “This is a problem for us,” one that may come back to haunt Seamark's agency in a few years when it attempts to release a next-generation biocontrol agent, a myxoma virus that carries an antifertility gene.

    Officials had planned to seek public approval for the release—after they finished field trials—as part of an act protecting CSIRO legally should anything go wrong. But because the escape happened before the public consultation was finished, CSIRO now faces a lawsuit from those in the wild rabbit trade, including the makers of Australia's famous icon, the rabbit-pelt Akubra hat.

    The lesson, biocontrol researchers say, is that biocontrol agents are so likely to escape that agencies should seek public approval before starting field trials. “The question is at what point should the public be responsible for [permitting] the release,” says Niall Byrne, a former PR officer for the Australian Animal Health Laboratories in Geelong, which did the testing. If CSIRO had gotten approval before the field trial, then RCD might be considered a complete success.

    Indeed, Australia's farmers already count it as such. In the arid zones that make up two-thirds of the country, where rabbits have been most voracious, farmers are reporting near-total eradication and saving an estimated $3 million to $4 million per year in rabbit control. CSIRO ecologist Brian Cooke's studies show that the virus is retaining its punch, unlike the myxomatosis virus, whose effectiveness dropped from 99% to 70% after 4 years. “This is no flash in the pan,” he says. And for the first time since the 1800s, there are signs of regeneration in Australia's fragile ecosystems. The vast Nullarbor plain that stretches across the southern coast is coming alive with knee-high acacia seedlings next to big old trees that predate the rabbits; similar scenes of young and old cypress pines can be seen in northern Victoria.

    Next time, biocontrol officials say, they'll be as smart about politics as they were about the science. “We got a lot of understanding from the process going wrong,” says CSIRO scientist Lyn Hinds. “It wasn't the steps we took but the order we took them in.”

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