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Study identifies climate-resilient trees to help orangutan conservation

Aerial views of Buluq Sen village, Kutai Kertanegara District. East Kalimantan on December 18, 2017. Photo by Nanang Sujana/CIFOR

  • Once written off as lost cause for conservation, Indonesia’s Kutai National Park supports one of the last intact forest canopies on Borneo’s eastern coast, a habitat for the critically endangered East Bornean orangutan (Pongo pygmaeus morio).
  • An IUCN study funded through the Indianapolis Zoological Society has identified tree species native to Kutai National Park that are resilient to climate change and support orangutan populations.
  • Climate change has become an emerging threat that is likely to intensify drought conditions and wildfires. Currently, land settlement and human-caused fires pose the greatest existential threat to the park’s ecosystem functions and biodiversity.
  • The study authors recommended that the fire-resistant native trees they identified in the study be planted in buffer zones around fire-prone areas. They hope the study will help spur research to enable forest restoration in other parts of the world.

The IUCN has identified tree species that are resilient to deepening drought and fires brought on by climate change in Indonesian Borneo. The species will be used for government-backed forest restoration efforts in a national park that has been severely degraded by human settlement and forest fires.

The ongoing destruction of Indonesia’s Kutai National Park forests threatens the survival of the critically endangered East Bornean orangutan (Pongo pygmaeus morio), representing the largest population of orangutans in Kalimantan, the Indonesian portion of Borneo. The park is also home to the rare Miller’s grizzled langur (Presbytis hosei canicrus) that was thought to be extinct less than 10 years ago.

“Increasing drought and fires caused by a warming climate are important emerging threats to species-rich areas such as Kutai National Park,” said Alan Lee, lead author of the study and member of the IUCN SSC Climate Change Specialist Group. “Selecting climate-resilient tree species can help protect the park and the orangutan populations it shelters from the impacts of climate change.”

Female and infant orangutan in Kutai National Park. The morio orangutans of east Borneo are usually much darker than their Sumatran cousins. Image by Orangutan Project Kutai.

The study, funded through the Indianapolis Zoological Society, aimed to single out native plants that could provide food and habitat for threatened orangutans. Jamie Carr, a conservation biologist at the University of Leeds and IUCN SSC Climate Change Specialist Group member, told Mongabay that until relatively recently the park was written off as a conservation disaster.

The park was already being decimated by human activity when fires “wiped everything out,” Carr said. “That was one of the reasons we wanted to do this study to wave a flag for the park. Although it’s just a fraction of its former size, [the park] is still very precious and worthy of attentions.”

The arrival of oil palm and coal mining caused human settlements to expand inside the park in the 1980s. In 1991, a road was opened to connect a coal mine near the town of Sangatta to a population center in Bontang. The road was settled and today several thousand people live inside the park.

Severe El Niño droughts in the early 1980s and again in the late 1990s were accompanied by massive human-caused fires. The fires in the 1990s destroyed 90 percent of the park’s forests. At the time, most researchers and conservationists considered the park’s orangutans almost extinct and believed the ecosystem was unrecoverable.

“We found out pretty fast when we started conducting this study that restoration efforts will only be relevant if you eliminate the more urgent threats caused by human encroachment,” Carr said.

“Threats brought by a changing climate must be addressed together with more urgent threats presented by slash and burn agriculture that is moving toward the heart of the park.”

Map showing the location of Kutai National Park. Kutai is situated on Borneo’s eastern edge, where the effects of the ENSO cycle are at their strongest. Image by Orangutan Kutai Project.

Despite the past and ongoing environmental damage, Carr said there was still hope for conservation efforts. Carr praised the on-the-ground restorations efforts being carried out primarily by national park staff and argued that increased tourism infrastructure may create a stronger economic incentive to preserve the park.

“The staff at the park is full of well-informed, hard-working people,” Carr said. “The park authorities are building new facilities for tourists that hopefully will bring in more money and hopefully push the people and the government to more clearly recognize the park’s value.”

Study co-author Douglas Sheil said that while reforestation efforts were important for species conservation, it would make more sense to prevent forest loss and degradation from happening in the first place. Rumors continue to swirl among locals that mining concessions and a new toll road are planned for within the park and that encroachment is still being funded by powerful people.

“Clearly these issues require scrutiny. There is no point in replanting the forest if there is little chance to protect it,” Sheil said. “At the same time the formal commitments by the central government, the park authorities and the many local companies that are helping to replant and protect the park suggests that there are powerful positive forces at work as well as negative ones.”

The study analyzed around 250 species of trees and other plants native to the rainforest of Kutai National Park. It identified species resilient to the fires and drought conditions that are expected to go up as the global temperature rises. These were defined as plants that were not sensitive to changes, had a high capacity to adapt, or were both. The authors also identified tree species that provide food and habitat for threatened East Bornean orangutans. Carr said the orangutan population was currently stable and that it had the potential to increase in the future.

For orangutans, food availability affects a wide range of factors, including population health, reproduction and behavior. There were seven species the study identified as the most important food plants for orangutans: Dracontomelon dao, Merremia mammosa, Kleinhovia hospita, Alangium hirsutum, Dillenia reticulata, Callicarpa pentandra and Ficus obpyramidata.

The researchers  also singled out two tree species that were resilient to fire: a native palm (Borassodendron borneense) and the hardwood tree (Eusideroxylon zwageri), known locally as bendang or ulin.

The participants in the study included Anne Russon of York University, the staff of Kutai National Park, the Indonesian Ministry of Environment and Forestry, the Yorkshire Wildlife Park, and other local and international conservationists and researchers. Three members of the IUCN SSC Climate Change Specialist Group played leadership roles.

The authors recommended that the fire-resistant native trees they identified in the study be planted in buffer zones around fire-prone areas. The restoration work will be carried out by the Kutai National Park staff as well as coal-mining companies that are required by law to provide reforestation services to the park.

Nur Patria Kurniawan, head of the Kutai National Park, said the results would guide ecosystem restoration activities and “will be implemented not only in Kutai National Park, but also in tropical forests outside the KNP.”

Carr, who originally conceived the study, said practical challenges arose when trying to meet their overall objective to meld climate and restoration science into a single concept. But he said he felt satisfied overall with the results.

“I would like to see people taking this concept to apply it elsewhere,” Carr said.

Banner image: Cauca River. Photo via Wikimedia Commons. 

About the reporter: Taran Volckhausen is Colorado-based freelance journalist who regularly reports from Colombia. You can find him on Twitter at @tvolckhausen

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