Fewer than 800 Tapanuli orangutans are left in the Batang Toru ecosystem in Indonesia.

Andrew Walmsley/MINDEN PICTURES

A dam threatens the world’s rarest ape. Why are some conservationists suddenly on board?

A Swiss conservation group named PanEco did a remarkable about-face last month. For years, it had fiercely opposed Indonesia’s plan to build a new hydropower dam on northern Sumatra, a project it said was an existential threat to the fewer than 800 remaining Tapanuli orangutans (Pongo tapanuliensis), a newly recognized species that PanEco is dedicated to saving. But on 23 August, the group, based in Berg am Irchel, announced a partnership to mitigate the dam’s impacts with the company building it and the Indonesian government.

Biologist Regina Frey, PanEco’s founder and president, says she is just making the best of a bad situation. “The project is high up on the government agenda … and will be implemented in any case. It makes great sense to change our strategy,” Frey tells Science. The orangutans now have the government and the company “on their side,” board member Carel van Schaik, a primatologist at the University of Zurich in Switzerland, wrote in a statement.

But some scientists and conservationists feel betrayed. An international group called the Alliance of Leading Environmental Researchers and Thinkers (ALERT) called the new partnership “a classic case of aggressive greenwashing,” and said PanEco had been pressured into the agreement by the company, Jakarta-based PT North Sumatera Hydro Energy (PT NSHE), and the Indonesian government, under threat of losing its permit to operate in the country. “It’s a disgrace that PanEco capitulated to bullying and intimidation by the dam company,” Mighty Earth, a conservation group in Washington, D.C., wrote. Similar pressure also led PanEco to fire two of its foreign researchers earlier this year, ALERT members say. But both PanEco and PT NSHE deny there was any sinister influence.

Construction on the 510-megawatt,$1.6 billion dam, part of China’s Belt and Road Initiative, began in 2017. But its location in the Batang Toru ecosystem threatens the small habitat of the Tapanuli orangutan population, discovered in 1997 by Dutch conservationist Erik Meijaard. In a 2017 paper, researchers showed the apes were different enough morphologically and genetically from the two known orangutan species, the Sumatran and the Bornean, to be called a new species. The Trans-Sumatran Highway and the Batang Toru River divide the species, the rarest of the great apes, into three subpopulations of 581, 162, and 24 individuals, says primatologist Serge Wich of Liverpool John Moores University in the United Kingdom.

Indonesian researchers collaborating with PT NSHE say the dam poses little threat. A recent survey by scientists at the Faculty of Forestry at IPB University in Bogor concludes that it will flood less than 0.1% of the ape’s 1051-square-kilometer habitat—and “will only create a small disturbance,” says IPB senior lecturer Haryanto Putro. A 2018 survey led by Yanto Santosa, also of IPB University, showed that more than 50% of orangutan nests in PT NSHE’s concession had been abandoned and that only 17 apes roamed the area. “This shows that the dam construction site is not the primary habitat of the Tapanuli orangutan,” Santosa wrote.

The company will also build orangutan-friendly bridges to connect the subpopulations, says Agus Djoko Ismanto, PT NSHE’s senior environmental adviser, and will take other measures, such as planting fruit trees to provide food. “So we are helping orangutan conservation actually,” says Ismanto, who says the university team is fully independent: “I never influence their work.”

But ALERT founder William Laurance of James Cook University in Cairns, Australia, says inundation is only one problem. Roads needed for construction and maintenance “are a particularly insidious threat because they open the ape’s habitat to poachers, illegal loggers, miners, and land encroachers,” Laurance says. The number of old nests is meaningless, Wich adds. Orangutans move around a lot, so finding half of the nests abandoned is nothing unusual, he says. Experience farther north in Sumatra’s Leuser ecosystem suggests bridge corridors work well for macaques but not for orangutans, he adds: “They don’t like novel things.” The ALERT scientists say plans for the dam should be abandoned entirely.

May brought the departure of two PanEco scientists, both outspoken critics of the dam: Gabriella Fredriksson and Graham Usher, who established PanEco’s orangutan research station in Batang Toru in 2006. Frey says the decision was made “by mutual consent” because the two “find it too difficult to embark on the new strategy with full conviction.” But Fredriksson, in a text message to Science, wrote, “We have been fired and kept in the dark.”

Several scientists suspect a link between their departure and a visit to Frey by politician and former environmental activist Emmy Hafild—who supports the dam—and former environment minister Sonny Keraf. “It is our understanding that Hafild threatened PanEco on behalf of PT NSHE that if they did not fire Gabriella and Graham, it would be made very difficult for them to continue to operate in Indonesia,” says Amanda Hurowitz, great ape program director at Mighty Earth. “That should not happen in a democracy,” Wich says. “It is a really black day for Indonesian conservation.”

Hafild denies that version of events. “I was just reminding them of the consequences if they keep opposing the dam,” she says. PanEco is allowed to do research and conservation in Indonesia, Hafild says, but not advocacy. “If my staff was conducting a campaign that violates my agreement with the Indonesian government,” she adds, “of course I would fire them.” Frey says the meeting with Hafild, who she says is an old friend, was “very friendly.”

Scientists claim there have been other forms of pressure as well. Meijaard suspects PT NSHE was behind a press release headlined “Electricity for Civilization,” from the Simanboru, an Indigenous community, that accused him and others of running a “black campaign” to influence the debate with false arguments. He also believes the company instigated recent protests in Jakarta to demand the deportation of Fredriksson and Ian Singleton, another PanEco scientist.

Ismanto says those claims are baseless. “They accuse me of doing so many bad things,” he says. “They are just making things up.” He questions foreign scientists’ role in the debate, however: “Indonesia has been independent for decades and the orangutan is part of our natural riches,” he says. “We don’t need bule [white people] to protect them.”