Asean’s orangutans are confined to Sumatra and Borneo.
In the widest study since 1999, the Max Planck Institute found the most dramatic declines where forests were cut down for timber or palm-oil plantations. Other major factors were “conflict killing, poaching and the collection of baby orangutans for the pet trade”, the study said.
“The one thing they cannot cope with, however, is the high killing rates seen currently,” said Professor Serge Wich of the study. “Orangutans are a very slow breeding species. If only one in 100 adults orangutan is removed from a population per year, this population has a high likeliness to go extinct.
“We didn’t expect the losses to be so large in standing forest, so these [findings] confirm that hunting is a major issue,” he told the BBC.
“When these animals come into conflict with people on the edge of a plantation, they are always on the losing end. People will kill them.
“Just last week, we had a report of an orangutan that had 130 pellets in its body, after being shot at in Borneo.
“It’s shocking and it’s unnecessary. Orangutans might eat farmers’ fruit, but they are not dangerous.”
The researchers estimate Borneo’s current orangutan population is between 75,000 and 100,000, a fall of more than 50 per cent since the start of the research period. It means the orangutan is listed as critically endangered by the International Union for Conservation of Nature (IUCN).
The IUCN’s orangutan estimate could fall to 47,000 by 2025 from their population estimate of 105,000 in 2016. The WWF estimates that there are 104,700 Bornean orangutans globally.
There was a glimmer of hope amid the gloom.
The Max Planck study said the primates may survive better than expected in smaller, fragmented forests because they walked on the ground more often than researchers expected, allowing them to survive on plants which are not part of their traditional diet.
Chester Zoo in England has been using artificial “forest canopy bridges” made from cargo-strapping to make swings and bridges in orangutan enclosures.
Catherine Barton of the zoo said, in cooperation with the charity Hutan in Malaysia, that the zoo tried to reconnect habitats fragmented by oil-palm plantations, roads and drainage channels.
“To see the animals start to use these bridges and to reconnect across this fragmented habitat is a really positive sign,” said Barton. “But it’s a short-term solution.”
Picture credit: Flickr