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The Toad

By
November 15, 2010

Will protecting an endangered toad trump Tanzania’s need for energy and development?

Kim Howell is a white-haired giant who wears Kissinger glasses that magnify his eyes. He was born in Pittsfield, Massachusetts, and paid for a degree in vertebrate zoology at Cornell University by working at the school’s Library of Natural Sound. Howell preserved archival recordings of birdcalls collected in Africa in the nineteen forties and after four years he was convinced he should go to Africa. He taught science at an elementary school in the Zambian bush before going north to Tanzania, where he taught at a school for apartheid refugees. That was in 1970. Howell has lived in Tanzania ever since, raising a family and teaching zoology at the University of Dar es Salaam.

During his career, Howell has discovered tapeworms, spiders, and other species previously unknown to science. Former students and colleagues have named a bird, a shrew and a lizard after him. Discovering a new species can define a zoologist’s career and Howell’s big find came in 1996 when he reached into some vegetation at the base of a waterfall and pulled out a little toad, believed to inhabit the smallest native habitat of any vertebrate on Earth. Following his discovery, the Kihansi spray toad became the focus of one of the most controversial conservation efforts in recent decades, a crucible for the clash between biodiversity conservation and Tanzania’s need for economic development.

“I’ve often said I wish I had never discovered the toad,” reflected Howell.

In 1993, Howell saw an ad in a local newspaper, placed by Norconsult, a Norwegian engineering firm. “There was this hydropower project that was going to be done and they were looking for someone to look at birds,” Howell said. He responded but didn’t hear anything until a man walked into his office nearly two years later and offered him the job. Howell accepted. “How often do you get to go someplace no one’s ever been to before and get paid for it?”

The journey from Dar es Salaam took a full day on a dirt road through the lush floodplains of the Kilombero Valley. To the west, the road hugs the lower curves of the crescent-shaped Eastern Arc Mountains.

With rainforests estimated to be thirty million years old, the range forms one of the world’s two-dozen biodiversity “hotspots.” Biologists have likened them to the Galapagos Islands. Like the Galapagos, they contain an extraordinarily high concentration of endemic species, at least ninety-six vertebrates and over eight hundred endemic plants. The archipelago analogy is also apt because, like a chain of islands, the Arcs are thirteen mountain “blocks” beginning in Kenya and cambering down through Tanzania, each with their own unique variations of species and habitat but formed by the same geological event and shaped by the conditions of the Indian Ocean.

Norwegians oversaw the man-made, underground powerhouse. Mauritians ran the canteens.

In the nineteen eighties, the Tanzanian government started eyeing a remote area of the Eastern Arcs, known as the Udzungwas, for a hydropower project. In the crevice between two mountains was a narrow gorge where a series of steep waterfalls, fed by the Kihansi river from above, created the perfect conditions for generating electricity. Over roughly two miles, the falls plunge nearly three thousand feet. Plus, unlike most rivers in Tanzania, Kihansi flowed throughout the five-month dry season. The cascades glinted in the sun from miles away.

From the moment they arrived in the Udzungwas to do the environmental impact assessment (EIA) for the hydropower project, Howell and the other biologists knew something wasn’t right. “We were conducting our studies literally one step ahead of the bulldozers,” recalled John Gerstle, a water resources engineer who headed the EIA. Normally construction for such a large project wouldn’t begin until after the study. In fact, the World Bank, the main financier, had commissioned a study years earlier. “They had done what they called an EIA,” said Gerstle, who lives in Colorado, “but it was not taken seriously by any knowledgeable person who saw the study.”

In 1993, following the flawed report, the World Bank’s Board of Directors approved a two-hundred-million-dollar loan to Tanzania’s government for the project, which would increase the country’s electricity capacity by nearly 40 percent. But a group of European donors balked at the slim fifty-page assessment and demanded a new report. “It was a bit late,” Gerstle said, “because the decision had already been made… They were just desperate to get new capacity.”

Like much of Africa, Tanzania was, and remains, mostly in the dark. Electricity shuts off without notice almost daily and stoppages can last hours. For three months this year, the semi-autonomous archipelago of Zanzibar went without electricity after a cable to the mainland failed. Villagers in Zanzibar recall their childhoods as a time when they had more consistent and cheaper access to electricity—and hence better running water and refrigeration—than they do today.

Only 10 percent of Tanzanians have any access to the power grid. Not coincidentally, 96 percent of the population survives on less than two dollars per day.

With Tanzania desperate for electricity, the biologists rushed through their assessment, sleeping in tents in the mountain rainforest around the gorge. Thousands of workers arrived: The labor camps were like small cities with dispensaries and pubs full of Italians, Portuguese, South Americans, Spaniards, and Swedes. Chinese built the access road from the bottom of the mountain to the dam site. Norwegians oversaw the man-made, underground powerhouse. Mauritians ran the canteens. Black South Africans worked on top of the mountain digging the one-thousand-three-hundred-foot vertical shaft, chipping away at the rock with hand tools and sending the debris up in buckets.

The biologists found no new or endemic species in the forests around the gorge but they couldn’t get to the spray zone of the waterfalls themselves because of the steep terrain. They knew any assessment would be incomplete. “You can see from a distance that from an ecological point of view, the base of the waterfall has to be the most significant part of the entire gorge,” said Peter Hawkes, a South African insect expert who worked on the EIA.

In December 1995, Gerstle’s team issued their assessment. “We didn’t feel too bad about the dam,” is how Howell summarized their three volume report. “But our caveat was that we could not get into the spray zone.” The team continued to monitor Kihansi and in December 1996, they assembled for a workshop. As Howell recalled, Gerstle suggested they see how far they could get up the waterfall and they were astonished to discover a new path, most likely made by Tanesco, Tanzania’s parastatal power company. “Why didn’t they tell us?” said Howell. “It was just by sheer chance that we went there that day.”

The spray zone was unlike anything they expected. “The spray was so much that it basically drowns any tree within one hundred yards,” Hawkes said. “You have this sloping grassland meadow, sunshine, it’s out in the open.” Within minutes of arriving, Howell stuck his hand into some wet vegetation and pulled out a frog. “I said, ‘Yes, it’s a yellow frog. It has to be new.’ I felt it had to be a species new to science because I knew all the other ones in Tanzania,” he said. The consequences of the hydropower project on the frog were immediately clear, said Howell. “We knew right away. The consequences were it would become extinct.”

Nectophrynoides asperginis is not a visually arresting frog; it has matte, mustard colored skin and a body about the size of a nickel. The most fascinating thing about the spray toads was their habitat: five acres of wetlands where the spray and wind generated by falls produced a unique microclimate. Rather than depositing eggs that then go through the tadpole stage in water, spray toad mothers give birth to fully formed babies that stay wet in the spray, a rare though not unheard of anomaly among amphibians. Spray toadlets are so small they can fit on the tip of a pen.

“Most toads are tough,” said Howell. “That’s the classic amphibian. Amphi, two. Bios, life. Two ways of living: outside the water and inside the water. But Kihansi spray toads aren’t like that.”

It was difficult to study the new species. “It was scary,” said Charles Msuya, Tanzania’s foremost herpetologist. The falls were deafening and navigating the wet rocks was treacherous. The earth was soft and spongy, almost gelatinous; stomping on it caused the ground to vibrate a yard away. Furthermore, it was freezing. “We tried everything, wetsuits, semi-wetsuits, six layers of jerseys, waterproofs on top of wetsuits, anything you could imagine,” said Hawkes. “Outside it would be ninety-five degrees.”

Rare toad or not, construction of the hydropower project continued. Norway’s development agency, Norplan, began citing the presence of the new species as early as 1997 but Tanesco ignored the information. When Howell told the World Bank about the toads in 1996, he said they considered him an alarmist, insisting that the species must exist elsewhere. The Bank’s attitude changed in November 1999 when a letter from the environmental group Friends of the Earth arrived for then-President James Wolfensohn. Someone had leaked the group information and it pointed out that the World Bank was in danger of violating its own environmental policies. For the World Bank and the Tanzanian Government, it was the beginning of a potential public relations nightmare.

“We were conducting our studies literally one step ahead of the bulldozers.”

It was into this fray that Bill Newmark, a prominent American biologist, arrived in 2000 as a World Bank consultant. Newmark is an expert on wildlife corridors, ways of connecting protected areas like national parks in order to facilitate movement between conservation “islands.” He first gained attention as a graduate student in the nineteen eighties, studying in the western United States, where he found that wildlife reserves were not protecting biodiversity but losing species. His findings appeared in Nature in 1987 and Newmark became one of his generation’s most influential conservationists.

The World Bank hired Newmark, who had also spent time in Africa, to help save the spray toads. “In many ways you could not have designed a more ecologically friendly dam,” said Newmark, who curates Utah’s Museum of Natural History. “All the water is returned to the river, it’s only diverted out of a five-kilometer section of the river. But it turns out, that five-kilometer stretch was where the spray toad was located.”

Within six weeks of all three turbines turning on, in 2000, Newmark found that the spray zone shrank 98 percent. In the gorge, he saw toads huddled in clumps near the bases of the falls. Within weeks the estimated toad population dropped from twenty thousand to twelve thousand. Newmark, whose findings were reported directly to the office of the World Bank president, recommended installing an artificial sprinkler system and creating a captive breeding population immediately.

Work began on the sprinklers—an ingenious gravity fed irrigation system of rubber hoses and dozens of sprinkler heads—but the Tanzanian Government refused to issue the export permit needed to begin a captive breeding program. The fear, according to Anna Maembe, an environmental official in the government, was that Tanzania would lose control of a potentially valuable natural resource if the frogs became the basis of a vaccine or drug. “We were of the opinion, by we I mean Tanzania, that we would rather have it here and do our studies here, rather than someone keep it for us,” Maembe said.

In the United States, the Bronx Zoo (owned by the Wildlife Conservation Society) and the Toledo Zoo offered to maintain toad populations. But Tanzania held firm until, according to one insider, oblique threats were made that if Tanzania did not cooperate, future World Bank funding for development projects could be at risk. It was an election year and Tanzania’s then-President Benjamin Mkapa received a call, according to the insider, from a Bank official saying, “I would hate for the President of the World Bank to call you and instead of congratulating you on winning the election, ask you about these toads.”

The government granted an export permit and Mkapa won reelection. Afterwards, Jason Searle, a Bronx Zoo biologist arrived in Tanzania to airlift the toads. “A lot of Tanzanian politicians wanted to know: ‘What’s the big deal? You are weighing these tiny little toads against power to our people,’” he said. “I don’t think anyone is going to argue that these toads are more important than providing electricity. I’m certainly not going to argue that.” At Kihansi, Searle collected five hundred toads and brought them back to the United States in boxes lined with tinfoil and wet paper towels. Only one toad died along the way.

They were kept in bio-secure rooms away from other species. Zookeepers entered only after sanitizing themselves and putting on special lab coats.

The Tanzanian public did not welcome the start of the captive breeding program, funded by a loan through the World Bank. A newspaper article asked: “…is it worth paying all that money for some tiny reptiles called spray toads when thousands of Tanzanian under-five kids, pregnant mothers and retired senior citizens are dying of want?” Even some conservationists grumbled: “I think many groups would have liked to see this toad go extinct, because they finally had a real issue for legal action against the World Bank,” said one scientist.

Captive breeding is nothing new; zoos and aquariums have served as custodians for endangered species for decades. The California condor, whooping crane, black-footed ferret, and Chinese crocodile have all benefited from rescues from disappearing or degraded habitats. After the 1973 Endangered Species Act, “a lot of people became very interested in doing more than just managing collections as zoo curators,” said Chris Wemmer, a scientist emeritus at the National Zoological Society. “There was a groundswell of enthusiasm for the idea that we could save wildlife.” But for as long as biologists have used “arks” they have been controversial. Advocates for captive breeding became zealous, Wemmer said, and “there wasn’t careful assessing of the needs of these different species, the goal was just captive breeding… It really pissed off people who were concerned with natural habitats and the animals in the wild.”

The spray toad captive breeding program began as an insurance population in case of a disaster in the gorge. Initially, the toads in the wild rebounded after the artificial spray system was installed, though it required daily maintenance by a team of at least half a dozen monitors. There were so many toads, Newmark recalled, that surveyors had trouble not stepping on them. Nonetheless, the American zookeepers were under pressure to maintain the captive population, as the zoo toads began to die.

“Amphibian medicine is so far behind bird and mammal medicine,” said Jenny Pramuk, who runs the Reptile House at the Bronx Zoo. The toads sickened easily and zookeepers realized that the normally-fecund toads weren’t procreating. They were kept in bio-secure rooms away from other species. Zookeepers entered only after sanitizing themselves and putting on special lab coats. They spent months troubleshooting, changing water filtration systems, food, and finally the light bulbs. Ultra-violet bulbs boosted the toads’ vitamin levels and they started reproducing. But the overall captive population had plummeted to as low as seventy specimens, shrinking the species’ gene pool.

Meanwhile, the worst case scenario unfolded at Kihansi. “We always wondered what would happen if the spray irrigation failed?” said Newmark. What was the minimum amount of water needed to maintain the spray zone? Diverting water from the dam for tests reduced its electricity output but Tanesco agreed to do them. In June 2003 two large-flow tests were conducted. A week later the spray toads’ numbers began to decline. By July, their number had dropped to about one hundred and fifty. In August, only two could be found.

The extinction of the spray toads in the wild remains a mystery. One hypothesis is that flushing the dam released sediment contaminated with pesticides from upstream farms. But most biologists agree that the cause was something none of them had predicted—an outbreak of a mysterious disease called Batrachochytrium dendrobatidis, otherwise known as chytrid fungus or “Bd.” About one thousand variations of the fungus exist in moist soil and leaf litter, but only one effects amphibians and it’s not always deadly. It attacks amphibian skin, causing it to harden and thicken. Amphibians transmit oxygen, sodium, and potassium ions through their porous skin and when their skin clogs, their hearts stop.

The Global Amphibian Assessment lists over four hundred species as critically endangered and one hundred and twenty-two as possibly extinct, almost all because of the fungus. The only countries where Bd has been tested for and not been found are New Guinea, Madagascar, and Borneo. On epidemiological maps of Central America, the spread of Bd looks like a tsunami: creeping north and annihilating species in weeks. Some scientists have linked global warming to the sudden deadliness of chytrid but no one is sure why it has become a problem now.

In recent years dozens of amphibian species have been placed into bio-secure arks to protect them from Bd. In 2007, a herpetologist named Kevin Zippel responded to the epidemic by launching The Amphibian Ark. Zippel wants to quarantine five hundred endangered frog species until a solution to chytrid is found. He is attempting to raise fifty million dollars—an incredible sum for amphibian conservation, since the public prefers large mammals. “We’re talking about whole members of an assemblage vanishing,” said Brian Gratwicke, a biologist at the National Zoo in Washington D.C. “We’re in the same place as everyone else: elephants, pandas, the fluffy stuff. Some people want to put all frogs in the same basket but there are six thousand species of frogs. If you want to compare apples to apples, you can put a Panamanian golden frog in the same basket as a panda.”

Zippel’s quarantine strategy has radically changed the conversation around captive breeding. “We’ll never know with any degree of certainty whether these animals can be reintroduced or not,” said Mark Michael, a professor of environmental ethics at Austin Peay State University in Tennessee. “There are a lot of environmentalists who say, ‘If you take a species out of the wild and there is very little possibility of reintroducing them, then you shouldn’t do it.’” But proponents of captive breeding believe it’s better to have the species in the world than to let them disappear, even if the animals that remain in zoos are essentially, as Michael said, “museum pieces.”

The debate goes beyond science and into philosophical territory: What are the implications of human intervention in the “narrative” of a species? For Zippel and many others, there isn’t enough time to answer these questions. “We’re the first ones to admit this is the last ditch solution,” Zippel said.

The fate of the Kihansi spray toad is far from determined. In addition to the Bronx and Toledo toads—at least four thousand total—there are one hundred toads at the University of Dar es Salaam. But both the government and conservationists want the toads back in the gorge.

This spring, seven biologists decontaminated their hiking boots in shallow buckets of bleach and started hiking into the Udzungwas rainforest. Porcupine quills and crab shells discarded by otters littered the narrow trail up the steep mountainside, over fallen tree trunks and around moss-covered boulders. After three hours, they arrived at the Kihansi research station, a spacious cabin where a group of Tanzanians live and collect data from the nearby gorge. They also maintain the artificial spray system, which has run twenty-four hours a day for nine years.

Newmark said the gorge is “probably the most highly engineered recovery plan for any species in the world.” The successful reintroduction of the toads would be unprecedented for an amphibian species, but the costs run into tens of millions of dollars. The captive frogs could carry an unknown pathogen into the gorge, or they might die off outside controlled conditions. A decade of captivity has undoubtedly led to unintended natural selection for characteristics beneficial to surviving in the arks. “I think our toads even look different from theirs,” Pramuk said comparing the Bronx and Toledo colonies.

Meanwhile, Tanzania’s electricity needs remain enormous and the conflict between protecting biodiversity and eradicating poverty is uncomfortably direct. “The international community has to understand that these countries need electricity,” argued John McIntire, country director at the World Bank for Tanzania. “It’s not just for the rich countries to say, ‘Well, we’ve got plenty of electricity but you can’t because of the environmental externalities in your countries.’”

The situation isn’t likely to change. Howell, who discovered the toad, said, “I’ve been here forty years, I know…there are many, many more Kihansis coming.”

The next morning in the Udzungwas, everyone put on raincoats and rubber boots and began to climb to the gorge. Even with the waterfalls reduced to a fraction of their original strength, they still roared. Eventually, the tree cover opened up and the towering rock faces of the gorge appeared, rising into the low-hanging cloud cover. As they stood in the artificial sprinklers, the biologists’ feet sank into the soft ground and they were drenched by the delicate, relentless spray. It was difficult not to look in the vegetation without a tingle of hope: maybe, just maybe, the mustard-colored creatures had saved themselves.

Newmark seemed pleased—some of the plant and shrub species that had invaded the wetlands when they dried out were less pervasive. The Bronx Zoo’s Jenny Pramuk appeared melancholy. She stared from beneath the hood of her blue raincoat at an enormous boulder where thousands of toads once fed and procreated. “What about the temperature?” she said. Without the floods of cold water coming over the falls, the gorge itself had warmed. Could the toads adjust? Was the environment itself extinct? “If the reintroduction doesn’t work, at what point are we just going to say goodbye?” she wondered.

G

Maura R. O’Connor is a freelance foreign correspondent. Her work has appeared in the Columbia Journalism Review, Slate, NPR, Global Post, and TIME.com. This year O’Connor was awarded a Robert Novak Journalism Fellowship and will be researching and reporting on American foreign aid from Haiti, Afghanistan, and Africa. She is a graduate of Columbia University’s Journalism School.

Writer’s recommendations:

The Ghost with Trembling Wings: Science, Wishful Thinking and the Search for Lost Species by Scott Weidensaul.

A little known but beautifully-written work that illuminates the mysteries of nature and extinction. Highly recommended.

Last Chance to See by Douglas Adams and Mark Carwardine.

Both hilarious and heartbreaking, a travel-narrative from the beloved author of A Hitchhiker’s Guide to the Galaxy about vanishing species written in the nineteen nineties.

Editors Recommend:

Dam Dilemma: Opportunistic speculators are eying Nepal’s burgeoning hydropower potential. Does wealth or woe lie ahead for the poverty-stricken nation?

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