A Rainforest's Voice Is Being Recorded Before It Changes Forever
Somewhere in the forested hills of East Kalimantan, the call of a gibbon at dawn once told the Balik people what kind of day lay ahead. Today, that same dawn is more likely to carry the sound of a chainsaw. Indonesia's new administrative capital, Nusantara, is rising in these mountains, and the acoustic landscape of one of Borneo's most biodiverse regions is shifting in real time.
A new documentary, Sound Guardians, produced as a collaboration between Mongabay, Scientific American, and Project Multatuli, follows the effort to capture that shift before it becomes irreversible.
The Science of Listening to a Landscape Under Pressure
Wendy Erb, a bioacoustic scientist from the Cornell Lab of Ornithology who has worked in Kalimantan for a decade, is leading the recording effort. Her team has gathered audio from a wide range of environments across the region, from mountain ridges to mangroves and caves. Erb describes the resulting archive as a "time capsule," a baseline that will allow researchers to track environmental change as construction and economic growth accelerate.
The data has practical conservation value. Erb notes in the film that recordings could reveal where wildlife is being displaced, pointing to areas where conservation investment might be most urgently needed. "Maybe those are places where more investment could be made in conservation efforts," she says. Her broader question is whether people, scientists and residents alike, can train themselves to notice when a natural environment is beginning to deteriorate.
What the Balik Community Stands to Lose
For Abidin, a Balik community member from Pemaluan, a village now incorporated into the Nusantara territory, the stakes are cultural as much as ecological. He explains that his ancestors read gibbon calls as spiritual signals, but younger generations no longer recognize those sounds or the species that make them. The Great Argus, a large forest pheasant, is now rarely seen or identified by children in the community.
"Our people say that usually the chainsaw is the loudest," Abidin says, describing the replacement of natural sound with industrial noise.
What was once forest in the area now includes apartment buildings, a hotel, and a presidential palace. The project's future remains uncertain: Indonesia's current president cut the capital's budget in 2025, though construction has continued. The original push to relocate the capital came from former President Joko Widodo, who cited the severe subsidence threatening Jakarta. Experts estimate that a third of Jakarta could be submerged by 2050 due to sea-level rise combined with excessive groundwater extraction. Official plans describe Nusantara as a "smart forest city" with a projected completion date of 2045.
Abidin, Erb, and their partners are working to turn the recordings into something the Balik community can actually use. They are developing a book on Balik biocultural heritage and building a platform that gives community members direct access to the sound archive. Despite his fears about displacement, Abidin says he continues to teach his children the language of the forest. "Even though there are changes now, I still feel that this is my home," he says.
Why It Matters for Hosts
Independent operators running eco-lodges, nature retreats, or cultural tourism experiences in East Kalimantan are sitting at the intersection of two growing traveler interests: witnessing a landscape in transition and supporting indigenous-led conservation. Connecting guests with community-based projects like the Balik sound archive, or simply framing the region's ecological and cultural complexity honestly in your communications, can differentiate your offering in a destination that is about to receive significantly more international attention as Nusantara develops.
The details in this post were first reported by Mongabay on 3 August 2026. The documentary Sound Guardians was directed by Leah Varjacques, Rizky Rahad, and Sandy Watt.
First reported by news.mongabay.com.