Published December 20, 2023
8 min read
Da Nang, VietnamIn this central Vietnamese city of 1.2 million people, almost every inch of land has been gobbled up by developers. Towering hotels line a miles-long white sand beach. But one prime piece of real estate remains mostly untouched: the mountainous and forested tip of the city’s peninsula. It is a 6,400-acre nature reserve called Son Tra, or, as it’s also known, “Monkey Mountain.”
The reserve, which is also home to a military base, is a last refuge for the red-shanked douc, a critically endangered langur that numbers only about 2,000 animals in Son Tra. On a recent visit, conservationist Hoang Van Chuong quickly spotted several brightly colored, long-tailed monkeys high in the treetops. “It’s hard to hide with those features,” chuckled Chuong, development director for the local nonprofit GreenViet.
Preoccupied with some late afternoon leaf snacking, the animals didn’t seem too bothered by our presence. But the doucs have good reason to fear humans. Long hunted both for meat and medicine, they have lost much of their native forest habitat, which once extended across the region. Driven into tiny jungle enclaves, they’re today found only in a few pockets of Laos and in two isolated populations in Vietnam, the largest of which clings on here in Son Tra.
The doucs are among the many species that have suffered huge declines because of habitat fragmentation, which studies show is the biggest driver of biodiversity loss globally, and especially in Southeast Asia. Urban growth is a major contributor to the problem. City populations worldwide are poised to increase by 2.5 billion over the coming 30 years, tripling the global footprint of cities. Experts warn that animals unable to adapt to urban settings may be pushed into ever-smaller, isolated spots. (Read about a new monkey species hiding in plain sight in Southeast Asia.)
“Species that require relatively large, intact areas of wildland,” like the red-shanked doucs, “will be lost, [while] native and introduced species that thrive in cities may take their place,” says Rohan Simkin, an ecologist at Yale University, who studies impacts of urban expansion on wildlife.
He and other researchers say there are likely many more urban “avoiders”—species unable to adapt to urban environments—than urban “adapters,” though no major studies have been conducted to confirm this.
Our peninsula, our monkeys
Douc is an old Vietnamese name thought to mean monkey. In addition to the red-shanked douc, there are two other douc species in Southeast Asia, also critically endangered: the black-shanked and gray-shanked douc. Some deforestation can be traced back to the Vietnam War, when forests were sprayed with the toxic defoliant known as Agent Orange. As the Vietnamese government’s focus remained squarely on growing its economy in the years following the war, wildlife protection received scant attention.
As recently as a decade ago,