- The IUCN has cited “ongoing and new threats” to the Tapanuli orangutan, found in a single forest ecosystem in northern Sumatra, to call for a suspension and reassessment of projects being undertaken within the ape’s habitat.
- With a population of no more than 800 individuals, the Tapanuli orangutan is the world’s rarest and most threatened great ape species.
- Roads through the Batang Toru ecosystem where it lives have fragmented the orangutan’s population.
- The most high-profile threat is a planned hydropower plant and dam in the ape’s habitat, which scientists and conservationists have increasingly called to be halted.
JAKARTA — The International Union for Conservation of Nature (IUCN) has called for a halt to all projects that threaten the world’s rarest great ape species, the Tapanuli orangutan.
“IUCN is deeply concerned about ongoing and new threats to the Critically Endangered Tapanuli orangutan in Sumatra, Indonesia,” the organization said on its website.
The call adds to a growing chorus of concerns from the science and conservation communities about the future of the ape, which was only described in 2017 but is already teetering on the brink of extinction.
Infrastructure projects such as roads have already fragmented its habitat in the Batang Toru ecosystem, causing the population of Tapanuli orangutans (Pongo tapanuliensis) to plummet by 83 percent over the course of three generations.
Fewer than 800 individuals are believed to survive in a tiny tract of forest less than one-fifth the size of the metropolitan area that comprises Indonesia’s capital, Jakarta.
The most high-profile threat to the species’ survival is a $1.6 billion hydroelectric plant and dam being built in the Batang Toru ecosystem. The 510-megawatt plant was announced in 2012 and would be the largest on Sumatra if completed as planned by 2022. The Indonesian government considers it a priority project under President Joko Widodo’s wider infrastructure-building push.
Conservationists are worried the dam would devastate the most critical areas of the ecosystem and thwart the last chance to build forest corridors connecting the already fragmented habitats, which might lead to inbreeding among the isolated groups of orangutans and the eventual extinction of the species.
That fragmentation has already cut off a group of around 17 orangutans in a small patch of forest south of the larger eastern and western blocks of the Batang Toru carved up by roads.
While the IUCN didn’t specifically mention the hydropower project in its statement, the organization said any projects affecting the apes should be halted to allow time to formulate a plan to save the Tapanuli orangutan. Any such plan, the IUCN added, should be based on an independent, objective population and habitat viability assessment.
It also emphasized the need to establish corridors to connect the three forest blocks to which the species is confined, by converting the status of 81 square kilometers (31 square miles) of land into a protected zone.
“Until then, further development of projects with an impact on the habitat and viability of the Tapanuli orangutan should be put under a moratorium,” the IUCN said.
As the apes were just recently described, little is known about them, including their life cycle and how resilient they are to disturbances, according to the IUCN.
Therefore, it said, “it’s imperative that any activity that could potentially lead to the degradation of its habitat and direct threats to the population is carefully assessed and all measures taken to avoid any impact.”
Pre-construction activity for the dam and power plant has already driven some of the orangutans out of the project area and into nearby plantations.
Banner image: A male orangutan in the Batang Toru ecosystem. Image by Tim Laman via Wikimedia Commons (CC BY 4.0).