The newest family of the critically endangered Hainan Gibbons has just welcomed their first child, increasing the population of the world’s rarest primate from 13 (two family groups) in 2003 to 33 (five family groups) now. Although we do not know what the future holds, the Hainan Gibbon is out of imminent danger thanks to the concerted, long-term efforts by the Forestry Department of Hainan Province, Hainan Bawangling National Nature Reserve (Bawangling), NGOs and the local community.

Since 2003, KFBG has been collaborating with Bawangling to save the Hainan Gibbon from the grips of extinction. Today we would like to share with you one of the most interesting and meaningful stories during our 17-year-long conservation project.

How it all began

The story took place on the fringes of the Bawangling National Nature Reserve, deep within the territory of one of the families of Hainan Gibbon.

Back in June 2011, three juveniles left their respective families – the two only groups of Hainan Gibbons then –, started a new family – known to conservationists as group C – and established themselves near villages in Qingsong Township of Baisha County on the outskirts of Bawangling.

Benefiting from KFBG’s awareness-raising campaigns and sustainable agroforestry projects started in 2009 and a community monitoring team hired and trained by KFBG to keep constant watch on the rare primate since 2010, group C flourished into what is now the species’ largest family.

Having successfully earned the trust of group C through patience and dedication, we could research on their ecology and biology in detail, and in turn group C became the most well-studied members of the species.

The community monitoring team (from left: Li Quanjin, Lin Qing, Zhang Zhicheng and Li Wenyong) are old friends of the Hainan Gibbon.

Every morning, the Hainan Gibbons welcome a new day with their elaborate, melodious song and swing their way through the treetops to feast on fruits, returning to their roost before sunset.

But in 2014, Super Typhoon Rammasun, the strongest typhoon to hit China in decades, shook up their peaceful life. The typhoon wreaked havoc in Bawangling. After rough weather subsided, we found at least 11 landslides in the territory of group C and one of which destroyed the family’s major thoroughfare.

One of the landslides that ripped through the habitat of Hainan Gibbons

After the storm, group C could only use the few large standing trees to “fly” across the landslide area, increasing the risk of falling and injury

Help is here

After we deliberated with Bawangling, it is decided in 2015 to restore the typhoon-ravaged forests by planting trees and setting up a canopy bridge.

First, we worked with the nature reserve, local government and local community to plant about 1,200 tree saplings at various landslide areas.

Prof. Long Yongcheng, chairman of the China Primate Specialist Group, came to show his support at the tree planting event.

Then, we invited three professional tree climbers from Hong Kong to Bawangling to use mountaineering-grade ropes to set up China’s first canopy bridge to connect damaged gibbon habitat.

The weather unfortunately did not cooperate, making the task at hand more challenging.

The team camped out for three days and two nights to get everything up and running.

KFBG and the tree climbing team from Hong Kong

Although group C soon found out about the canopy bridge, they were in two minds about testing it out. After scrutinising this unfamiliar artificial crossing, they always opted for their vertigo-inducing stunts of flying across the canopy.

It took them 176 days to take the first step. On May 2, 2016, the infra-red camera traps, installed at either end of the tailor-made overpass, were triggered, snapping photos of the Hainan Gibbon’s first traverse of the canopy bridge.

A young Hainan Gibbon clings to its mother as they crossed our specially designed canopy bridge

What the gibbons make of the canopy bridge

After operating for 470 days, the camera traps recorded the Hainan Gibbons using the canopy bridge for 52 times. It is interesting that adult females and juveniles are the top users, while adult males are more daring and insisted on performing their “flying” manoeuvres, never once taking the canopy bridge, due to their difference in strength and skill.

We also found that the primates got more and more used to the canopy bridge over time. From January to February 2019, they used the canopy bridge 21 times in 50 days. This is comparable to the frequency of gibbon observed crossing this area before the typhoon tore through the island.

Adult females and juveniles are the top users of the canopy bridge

Adult males are more “adventure seeking” and always choose to “fly” across the forest gap

Members of group C get to grips with the canopy bridge. Each one has its unique way of using the crossing.

Now, the tree saplings planted in 2015 have grown up. As the young trees gradually connect forests divided by Super Typhoon Rammasun, the canopy bridge might become less and less trodden. Although the “headstrong” adult males stick to their aerial acrobatics when passing through landslide areas, the new trees will act as a safety net and reduce the risk of falling and thus injury. And as the mountaineering ropes reach the end of their lifespan, we will bring in a team to take down or replace the canopy bridge soon.

This photo was taken in 2019. When this Autumn Maple tree (Bischofia javanica) was planted, it was only slightly taller than the pictured member of our community monitoring team.

Around the world, more and more conservationists are erecting canopy bridges to connect fragmented wildlife habitats, but this is the first time it is used to help gibbons in China, and few papers review the effectiveness of canopy bridges tailored for gibbons.

For details about our canopy bridge, you can refer to our recently published study in Nature journal’s Scientific Reports: https://www.nature.com/articles/s41598-020-72641-z

What we learnt

Whether we succeed or fail, we gain from the experience. Here are three lessons learnt:

1. Monitoring target species daily is pivotal to its conservation because only with the long-term efforts by the community monitoring team of Hainan Gibbons can we develop well-grounded, timely solutions to cope with problems including typhoon-caused habitat destruction.
2. The canopy bridge is only a temporary solution. Restoring the forests should be the goal in resolving habitat fragmentation issues.
3.  Before taking action, look for references locally and abroad. During the project, record and analyse the findings vigorously, and publish the results so others can benefit from your work.

Chinese Text: Li Fei
English Translation: Joyee Chan