Critically Endangered Hainan Gibbon Uses Man-Made Rope Bridge for the First Time

The most critically endangered primate is the Hainan gibbon, found in a single forest on Hainan Island, China. To help with the survival of the 30 primates left, a man-made rope bridge may help the species thrive. A study in the journal Scientific Reports describes the first time an artificial canopy bridge has been used by the Hainan gibbon.

The rare mammal species, also known as the Hainan black-crested gibbon, used to have a population of 2,000 primates during the 1950s until they were affected by severe habitat loss and hunting.

By the 1970s, there were only 10 gibbons left. Today's remaining population lives on the island's Bawangling National Nature Reserve.

All 17 gibbon species around the world are at high risk of extinction, wrote the authors in the study. The canopy bridge is for the small apes to be able to travel between fragmented parts of the forest.

Hunting and Habitat Loss

Habitat fragmentation is the result of human activity as well as landslides caused by tropical disasters. It is estimated that the species has lost 95% of its original habitat.

For years, they were hunted so that their body parts could be sold for Chinese traditional medicine. Dutch writer Robert van Gulik wrote that gibbon skin was used to treat hemorrhoids as a cover. The primate's fat would be made into an ointment to treat itching sores.

For years, the Hainan gibbon thrived on the island's indigenous forests. Efforts of planting pine forests and expansion of the rubber industry and plantations have not helped the species. They also play an essential role in the local ecosystem by dispersing seeds of the various fruits they eat.

Bosco Pui Lok Chan of the Kadoorie Farm & Botanic Garden said that the gibbons first used the bridge after 176 days. Instead of swinging along the ropes, they hold on to tree branches as handrails and walk along the rope as they balance.

The females and young apes were observed to willingly use the bridge. Meanwhile, the adult males seemed strong enough to leap over the gap.

Long-Term Solutions for Conservation

Conservation biologist Tremaine Gregory said that "There are many different designs of canopy bridges used all over the world, but this one is particularly cool because it is simple, low cost, and well adapted to this species."

The Hainan Gibbon Conservation Project continues to monitor the region and protect the Hainan gibbons. Previous efforts of breeding the species in captivity have failed.

"As we chop up the world into smaller and smaller pieces with roads and other infrastructure, it's important to think about solutions for maintaining connectivity between fragments of habitat," said Gregory. The bridge may inspire other conservationists to protect other endangered arboreal species.

However, the authors noted that the bridge is only a short-term solution. Chan said that the priority should be to restore the natural forest with native trees beneath the artificial canopy bridge. A reforestation project "is the most sustainable and long-term solution for conservation."

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