Deforestation and dams threaten Sumatran orangutan

The Leuser rainforest on the giant Indonesian island of Sumatra is home to the endangered Sumatran tiger, Javan rhinoceros, Sumatran elephant and Sumatran orangutan but deforestation is destroying their remaining habitats.

In the last two decades, more than 110,000 hectares – around 4.2 million tennis courts – of the Leuser rainforest has purportedly been destroyed for palm oil plantations and timber extraction.

The Foundation for Sustainable Ecosystem said orangutans in Tapanuli, northern Sumatra, were under threat due to the construction of a dam for the Batang Toru hydropower plant (PLTA) project managed by PT North Sumatera Hydro Energi in South Tapanuli.

Foundation manager Burhanuddin said the ecosystem in Batang Toru, a biodiversity hub, was imperilled by the 510-megawatt plant, which could break the crossing routes for rare species in the forest.

The breeding grounds for 800 orangutans could be affected, it warned.

The dam could also threaten the rare rafflesia arnoldi flower, the Sumatran tiger, tapir, hornbill and other species, the foundation said.

“The PLTA dam is built near tectonic fault area and, if an earthquake occurs, it is might result in floods that fatally damage the lives of humans and wild species in the region,” Burhanuddin warned.

The project’s environmental adviser Dr Agus Djoko Ismanto said the warnings were an exaggeration.

“The strategic national project of PLTA Batang Toru that aims to support new renewable energy to reduce carbon emission has undergone intensive, scientific and professional study,” Agus said.

Orangutans are also under threat from being shot or sold as pets, especially as deforestation forces them closer to human settlements.

One male orangutan was shot 62 times with an air rifle, including in both eyes, the BBC reported.

“So he’s completely blind. And we’ll never be able to release him to the wild again. He’ll never be free,” said Dr Ian Singleton from the Sumatran Orangutan Conservation Programme.

“The plantations will say ‘orangutans come out of the forest to eat our palm oil seedlings’ but they’ll eat palm oil seedlings in the same way that a shipwrecked mariner will eat his shoes or his belt.

“It’s not food, it’s just the only thing there that they can try and survive with.”

The charity aimed to slow down the decline of the Sumatran orangutan population so, when Indonesia eventually tried to protect its remaining forest, there would be some orangutans and other endangered species left, Singleton said.

It estimated the 2016 Sumatran orangutan population at 14,000.

A Sumatran orangutan. Picture credit: Wikimedia