Limestone mining in northern Vietnam pushes endangered langurs to extinction

A Delacour's langur in Vietnam. Photo: Olevy, CC BY-SA 4.0, via Wikimedia Commons

One of the last remaining populations of a rare primate, the Delacour’s langur, lives in forests south of Hanoi. But limestone mining and poaching are pushing the species to the brink of extinction, despite conservation efforts.


A critically endangered primate species endemic to northern Vietnam is facing threats from limestone mining and is approaching extinction, despite promising efforts at wildlife conservation elsewhere in Vietnam.

The Delacour’s langur, a small black and white monkey that lives in limestone karst forests, is one of many primates in Southeast Asia that has seen its habitat decimated in recent decades due to deforestation for agriculture and infrastructure. Three of the 25 most endangered monkeys in the world have been found only in Vietnam, according to a 2015 report. There are likely less than 300 Delacour’s langurs left in the world, all of them in Vietnam.

The second largest population of the rare monkey lives in Kim Bang forest in northern Ha Nam province, just south of Hanoi, and is seeing their habitat destroyed due to limestone quarrying for cement production, according to a report from VnExpress.

“[Langurs] appear less and less often as this area is being exploited by stone mining. I don’t know where the langurs would go,” said Duong Van Son, a member of a local community conservation team.

A limestone quarry. Photo: Thomas Bjørkan, CC BY-SA 3.0, via Wikimedia Commons

In the past 15 years, 11 different mining sites have been built around Kim Bang forest. The quarrying process involves frequent explosions and the operations leave areas of the forest coated in dust. There are 24 quarrying companies active around the forest, in Lien Son and Thanh Son communes, according to the provincial government. 

“Quarrying pollutes the air, destroys the vegetation and the only primary forest of Ha Nam—home to the Delacour’s langurs,” said Le Dac Phuc, a project coordinator with Fauna and Flora International. “If this activity continues, in the future, this primate would disappear.”

The threats to the langurs come amid a growing global drive to protect biodiversity, as what was previously treated as a fringe conservation concern is now seen as central to saving our climate, food supply and way of life.

As the International Union for Conservation of Nature (IUCN) wrote in a statement in December, “The world is increasingly recognizing the inextricable link between biodiversity conservation and human and economic wellbeing, a connection made all the more visible by the COVID-19 pandemic.”

Conservation efforts target langurs

In 2019, Vietnamese Prime Minister Nguyen Xuan Phuc singled out langurs and called for an investigation into the effects of stone mining on habitats.

Ngo Manh Ngoc, deputy director of Ha Nam’s Department of Agriculture and Rural Development, has proposed to turn the Kim Bang habitat into a conservation area but so far hasn’t succeeded. Fauna and Flora International is also reportedly working with the government and other local advocates to stop the mining that threatens the langur’s limestone home. Kim Bang forest is home to 105 monkeys; the only known larger population is a group in nearby Van Long Nature Reserve, in Ninh Binh province.

The Delacour’s langur is also threatened by poaching for traditional medicine and bushmeat. The wildlife trade has seen major attention and some attempts at reform due to the zoonotic SARS-CoV-2 virus, but it’s not clear yet that these efforts have had an impact.

Four years ago, Fauna and Flora International worked with local partners, including a former poacher, to establish a community conservation team for Kim Bang. Le Van Hien, a 60-year-old former hunter, once made his living trafficking wildlife from the area. But in the early 1990s, he began working with naturalist Le Van Dung. 

Today, the team tracks the langurs using GPS, documents the animals’ activities and removes animal traps, in partnership with government rangers. But the community conservation team has reportedly received death threats from poachers.

A red-shanked Douc langur. Photo: Art G., CC BY 2.0, via Wikimedia Commons

Langur populations dwindle towards extinction

Langurs more broadly are among the most endangered primates in the world. The golden-headed langur, found only on Vietnam’s Cat Ba island, may have just 30-35 mature individuals left alive. According to the group Global Wildlife Conservation, the listing of the golden-headed langur as critically endangered by the IUCN helped spark ongoing conservation efforts.

The Douc langur, found only in Vietnam, Cambodia and Laos, is also listed as critically endangered” by the IUCN. In fall 2020, Vietnam established a new nature reserve that protects one of the Douc langur’s few habitats. The 22,132-hectare Dong Chau-Khe Nuoc Trong Nature Reserve, in Quang Binh province, is also thought to be home to the extremely rare, antelope-like saola, sometimes called the “Asian unicorn.”

In 2020, researchers in Myanmar discovered a previously unknown species of langur, the Popa langur, on the flanks of Mount Popa in Mandalay region. With only around 200 or so individuals documented, the Popa langur was also immediately listed as critically endangered by the IUCN.

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