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In Borneo, dwindling forests face further fragmentation as roads spread

  • A study by Indonesian and Australian researchers warns of a drastic reduction in forest habitat accessible to wildlife in Indonesian Borneo if a spate of road projects is completed as planned.
  • Wildlife would be able to access just 55 percent of the remaining forests in the region under this scenario, from 89 percent today, the researchers write.
  • The road-building spree is part of an economic development program that proponents say is desperately needed to improve livelihoods and welfare across Indonesian Borneo.
  • While conservationists agree that infrastructure access is essential, they have called for greater oversight to mitigate or minimize impacts to forests and wildlife corridors.

JAKARTA — Road projects throughout Indonesian Borneo threaten to fragment a third of the forest habitat currently accessible to the island’s wildlife, according to a new study.

Completion of ongoing and planned road construction would reduce accessible wildlife habitat to 55 percent of the remaining forests in Kalimantan, as the Indonesian portion of the island of Borneo is known, from the current 89 percent. The findings were published Jan. 15 in the journal Scientific Reports by a team of researchers from Indonesia and Australia.

“That’s an alarming figure,” said lead author Mohammed Alamgir, an environmental scientist at James Cook University in Australia. “And it’s just the tip of the iceberg, because the new roads and rail projects will open up the forest like a flayed fish, allowing illegal colonists, poachers and miners to invade the forest and cause even more forest disruption.”

Road development projects planned across Kalimantan by the Indonesian government could sharply reduce the area of forest habitats accessible to wildlife. Image courtesy of James Cook University.

Using spatial analysis and satellite monitoring, the researchers evaluated large-scale road-building projects in Kalimantan under the Indonesian government’s 2011-2025 development master plan. These include an upgrade of 3,316 kilometers (2,060 miles) of the Trans-Kalimantan Highway in southern Kalimantan; 1,920 kilometers (1,190 miles) of new roads in northern Kalimantan, skirting the border with Malaysian Borneo; and additional highways and expressways throughout the provinces of Central, South, East and North Kalimantan.

The report noted that the primary goal of this new infrastructure was to increase commercial connectivity and primary industries, particularly coal mining, palm oil production, and industrial logging.

“However, little is known of the potential impacts of this new infrastructure on Bornean forests or biodiversity,” Alamgir said.

The study shows that the ongoing and planned road developments would alter the current spatial pattern of forests in Kalimantan, creating more fragmented patches of forest and a greater span of forest habitat edged by roads, and threatening forest corridors used by wildlife. Such a transformation, the authors say, is “worrisome” because the region hosts one of the world’s largest tracts of native tropical forest, currently spanning 370,000 square kilometers (143,000 square miles) — an area a fourth the size of Alaska.

The roads, the study says, would cut through 25 protected areas that are currently free of any roads, including Kayan Mentarang National Park, one of the largest remaining protected areas in Kalimantan. Seventeen other protected areas, mostly in southern Borneo, will be impacted by the planned upgrades of existing roads, the study says.

It adds that most of the road projects, both planned and underway, fall inside or along the borders of primary or selectively logged forests, suggesting that “much road expansion will be at the expense of native forest.”

The researchers classified 634 kilometers (394 miles) of this infrastructure as “very high impact,” as it will cut through protected areas; 1,472 kilometers (915 miles) as “high impact” for going through primary or peat forest; and 1,242 kilometers (772 miles) as “moderate impact” for going through selectively logged or regrowth forests.

“The currently planned and ongoing expansion of roads and rail lines in Indonesian Borneo will have severe deleterious impacts on native forests in the region,” Alamgir said.

“These projects will promote and shape future investments, particularly for logging, mining, and oil palm developments, but will have major impacts on existing forests and wildlife, and will carry serious and poorly recognized economic, financial, social, and political risks,” he added.

Planned road projects by the Indonesian government in Kalimantan are expected to have different degrees of impact on the forests in the region. Image courtesy of James Cook University.

The researchers have called on the Indonesian government to halt the projects deemed “very high impact,” and to impose stringent environmental mitigation efforts and law enforcement those classified as “high impact” and “moderate impact,” should they proceed.

“Borneo’s forests and rare wildlife have already been hit hard, but planned roads and railways will shred much of what remains, slicing across the largest remaining forest blocks,” said co-author Jatna Supriatna, a conservation biologist at the University of Indonesia.

“These projects will be like daggers in the heart of the Borneo rainforest,” Alamgir said. “We implore the Indonesian government to reconsider them, because they’ll open a Pandora’s box of crises for the world’s biologically richest forests.”

Kalimantan is the third most populated region in Indonesia, after the islands of Java and Sumatra (both of which are notably smaller in size), and the government estimates the current population of about 16 million will increase by nearly a third to more than 20 million by 2035. The region is home to indigenous communities whose lives revolve around intact forests, as well as to critically endangered species such as Bornean orangutans.

But industrial-scale forest clearing in recent decades — for mining, logging, and oil palm cultivation — has threatened the well-being and lives of both human and animal inhabitants of Kalimantan. The extensive draining of the island’s peat forests to make way for agriculture has also rendered the organic-rich soil highly susceptible to fires. In 2015 alone, nearly half of the deforestation recorded in Indonesia, or nearly 8,000 square kilometers (3,100 square miles) of forest loss, occurred in Kalimantan.

Yet there persists a legitimate need for roads and railways that would serve as an economic catalyst for the region, even as they carve up the shrinking forests, said Kiki Utomo, an environmental engineering lecturer at Tanjungpura University in West Kalimantan, who was not involved in Alamgir’s research. The state of infrastructure across Kalimantan is dire, he said, lagging even less-developed provinces in Indonesia’s east.

“If there’s a small pothole in a road in Java, people will make a big deal out of it. But in Kalimantan, the road itself could be in a hole and people will just accept it as is,” Kiki told Mongabay by phone.

He said the island’s low population density meant there was historically little incentive for the government to build an extensive road network across the region. “If there’s any infrastructure development, it’s usually in [more populated] coastal areas like in the southeast or south of Kalimantan, or in East Kalimantan province, where there are oil reserves,” he said. “But the rest of Kalimantan has been underdeveloped for years. What we have now isn’t interconnected, and its condition isn’t the best.

“We’re in dire need of infrastructure development, especially roads,” Kiki added.

He said the concerns raised by the new study were fair and reflected the views of many conservationists across Kalimantan. He agreed that the impacts of state-backed road-building projects on forests and biodiversity needed to be considered in the environmental impact assessments carried out by the government.

But Kiki said shutting down any of the projects would be unwise, given the inadequacy of alternative transportation options: carrying freight by rivers is impossible during the dry season, and building new airports would require the government to subsidize ticket prices due to the projected low demand.

“It’s impossible to not build [road] infrastructure as this is something that the people here have wanted for so long,” Kiki said.

With legislative and presidential elections slated for April this year, voters in Kalimantan will go for candidates who support road projects in their respective constituencies, Kiki said. But voters are also sensitive to the negative impacts of road development, such as forest encroachment, illegal logging and wildlife poaching, Kiki said.

He said the government should revise the planning of road projects that cut through conservation areas, such as national parks and nature reserves, as these zones are supposed to be protected by law. He also called on the government to beef up law enforcement against illegal activities inside forests.

The image shows the expected ecological impacts from large-scale road developments by the Indonesian government if completed as planned. Image courtesy of James Cook University.

The government appears to have adopted mitigation efforts in planning the road works in Kalimantan, said Irwan Gunawan, director of the Kalimantan program at WWF-Indonesia, who was not involved in the recent study. He said the government had involved civil society groups to draw up guidelines for sustainable and environmentally friendly road construction.

These technical guidelines include exempting core zones of protected areas from any development; requiring developers to put grassroots conservation strategies into place; limiting the gap between a road and the edge of the adjacent forest to 25 meters (82 feet) to minimize tree clearing; and banning any type of exploitation activities (logging, poaching) along the roads. The developers are also required to remove any construction waste from forests and dispose of it properly, as well as involve residents in monitoring the work.

Irwan said some of the newly built roads were already benefiting local communities, cutting the cost of transporting their produce from farms to towns and cities.

“We appreciate the fact that the government is trying to adopt sustainable infrastructure concepts, albeit in a basic way,” he said. “However, we haven’t received any feedback on whether all of this has been completely adopted in the implementation.”

Irwan called for greater transparency from the government to ensure that both development plans and conservation efforts continued to be aligned.

“The call from conservationists is very simple: nobody is against development, but it mustn’t compromise the biodiversity value,” he said.

Vehicles ply a road in East Kalimantan province. Image by Tessa Toumbourou for Mongabay.


Mohammed Alamgir, Mason Campbell, Sean Sloan, Ali Suhardiman, Jatna Supriatna, and William F. Laurance. “High-risk infrastructure projects pose imminent threats to forests in Indonesian Borneo.” Scientific Reports, vol. 9, no. 140 (2019).

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