Conservation experts say fires driven by an intense El Niño have damaged forest habitat covering more than half of Borneo's wild orangutan population, and rescuers are evacuating animals from burned areas.
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| Mama Abu, an adult female orangutan, receives treatment from Yiari rescuers after she and her baby were trapped by smoke from forest fires in West Kalimantan, Indonesia. Photo: Muffidz Ma'sum/Yiari-Ministry of Forestry |
Wildfires burning across Indonesia's forests and peatlands are putting thousands of orangutans at risk of death, injury or displacement, according to primate specialists at the International Union for Conservation of Nature (IUCN). The group has appealed for urgent international help to bring the fires under control.
The IUCN specialists said the fires now affect habitat that supports 52% of the total Bornean orangutan population. Blazes have also reached the ranges of five gibbon species, all listed as endangered on the IUCN Red List.
Why the fires are so hard to stop
Wildfires occur in Indonesia every year, partly because fire is commonly used to clear land for palm oil and pulp plantations. This year, an unusually strong El Niño has made conditions much drier, and fires have spread quickly across parts of Sumatra, Kalimantan (the Indonesian portion of Borneo) and Papua.
Peatland has made matters worse. In its natural state, peat is waterlogged. Industrial agriculture has drained large areas over the past several decades, leaving the ground highly flammable. Peat fires can smolder underground, which makes them extremely difficult to put out.
Indonesia's forestry minister, Raja Juli Antoni, told reporters the fires could last until early November because the rainy season is expected to arrive late. The environmental group YKAN estimated that about 600,000 hectares, or roughly 1.4 million acres, burned in August alone.
Other wildlife is also affected. The environmental group Geopix warned earlier this month that 4,500 fires had been detected across 21 Sumatran elephant habitats in recent months. Local media have reported dead proboscis monkeys, Sunda pangolins and snakes, including a python and a king cobra.
Rescues in West Kalimantan
Yiari, a nonprofit focused on primate and habitat conservation, has evacuated more than 20 orangutans, along with other animals such as pangolins. The group works with West Kalimantan's Natural Resources Conservation Agency, searching burned forest and responding to tips from the public. One rescued orangutan died, probably from smoke inhalation. Others had burns on their hands from walking on scorched ground, or were hungry and dehydrated.
Dr. Karmele Llano Sanchez, a veterinarian who co-founded Yiari and serves as its CEO, said the number of wild animals killed is likely very high. She described conditions on the ground: "It hasn't rained in 80 days here." She said there are no leaves or fruit left for animals to eat.
The evacuations are physically demanding. Rescuers fire a sedative dart into the trees, from as high as 30 meters (about 100 feet). A team of about 10 people holds a net to catch the animal as it falls, and an adult male orangutan can weigh around 70 kilograms (about 154 pounds). When a mother is carrying a young baby, the two usually fall together. Sanchez said evacuation is a last resort, used only when the forest has been destroyed, because otherwise the animals "will for sure die."
One rescued pair, a mother named Mama Abu and her eight-month-old baby, Abu (Indonesian for "ash"), were found in an oil palm subsidiary estate. The mother's hands were peeling from walking on burned ground, and the baby was thin and dehydrated. They are now in a Yiari quarantine center. Rescuers plan to release them once it is safe, in a new location with enough food and no other orangutan populations competing for territory. Sanchez said finding such a place is not easy.
Lasting effects on surviving animals
Researchers say the danger does not end when flames die down. Forests recover slowly, food becomes scarce, and displaced animals can come into conflict when forced to live closer together.
Dr. Susan Cheyne, co-director of Borneo Nature Foundation International, said researchers have seen unusually heavy litterfall, meaning leaves and small branches dropping from trees, after large fires. She said this is probably because smog blocks sunlight and disrupts photosynthesis. The leaf drop tends to occur just as the dry season returns, when orangutans need more food and depend on flowers and leaves rather than the fruit and pulp that are plentiful in the rainy season.
Erin Vogel, a professor at Rutgers University in New Jersey, said forests can take years to recover, and trees often produce less fruit afterward, possibly because of fewer pollinators. Research has also found that tree diversity in burned peat forests can stay suppressed 12 years later, and repeated fires risk leaving a forest permanently degraded.
The health effects of long exposure to smoke are not fully understood. Orangutans show signs of ketosis, a marker of increased fat breakdown, during smoky periods. Researchers believe the smoke raises energy demands, probably because the immune system has to work harder. Studies after the 2015 fires found that orangutans called less and with reduced vocal quality in heavy smoke, and most of those changes lasted about two months after the air cleared. Gibbons, which use song to attract mates and defend territory, also sing less in heavy smoke. Vogel noted that smog is known to cause breathing problems, infections and other long-term health problems in people, and said there is no reason to expect animals would be affected differently.
Research stations under threat
The fires have also come close to scientific research sites. The Tuanan orangutan research station in Central Kalimantan and the Rangkong research station in West Kalimantan have both been threatened in recent weeks. Staff and local residents have set up improvised sprinklers and cleared ground cover to slow the flames. Localized rain has brought some relief at Rangkong, though staff fear it may be temporary. At Tuanan, where rain has not arrived, crews are fighting fires day and night.
Vogel, who co-directs the Tuanan research program, said decades of work are at stake. Researchers there have followed the same 2,500 trees and the same individual orangutans for 23 years.
What the IUCN is calling for
The IUCN said "urgent technical and financial support" is needed to control the fires. It also said the emergency response should be followed by greater investment in re-wetting peatland, addressing deforestation and restoring burned forests rather than converting them into plantations. For now, rescue teams continue to search burned areas for animals in need.
**IMAGE INFORMATION** Image 1 Alt Text: Rescuers tending to an orangutan after its evacuation from wildfires in West Kalimantan, Indonesia Caption: Rescuers treat an orangutan evacuated from wildfire-hit forest in West Kalimantan, Indonesia, where fires have damaged orangutan habitat.