Scientists throw lifeline to world's rarest primate

PARIS, October 18 ------ Hainan gibbons — the rarest primates on Earth — were already teetering on the edge of extinction in 2014 when the most powerful storm to lash China's coast in half a century ravaged their island oasis. Decades of economic development, along with logging and deforestation, had reduced their habitat by more than half.

What primary forest remained was also fragmented, further hemming in the tailless apes, which travel exclusively above ground. But the massive mudslides unleashed by super typhoon Rammasun made things worse, gouging 15-meter wide gullies into the mountainous forest and effectively cutting off their treetop highways. "Canopy connectivity is critical for gibbons as they are strictly arboreal," lead author Bosco Pui Lok Chan, head of the Kadoorie Farm and Botanic Garden in Hong Kong's New Territories, told AFP.

"Forest fragmentation thus presents a major conservation challenge for gibbons." It not only limits their ability to forage for food, it can interfere with the search for a mate and make them more vulnerable to predators.

Light-bulb moment

After the typhoon, Chan and his colleagues noticed while monitoring the gibbons — only a few dozen of which remain in the wilds of China's Hainan Island — that they had trouble crossing these new gaps in the forest. And when they did, "they took very risky routes involving a lot of long jumps and high falls among the few surviving trees," he said.

Then Chan had a light-bulb moment. "We constructed a two-pronged canopy rope bridge across the damaged arboreal highway," he said. The "bridge" consisted of two parallel ropes tied at either end to trees. The conservationists also set up motion cameras to record any movement on or across the ropes. The group of nine gibbons most affected by this particular gash in the forest didn't avail themselves of the lifeline right away. Indeed, only 176 days later did the cameras capture the first image of a gibbon on the ropes. After that first crossing, however, others quickly followed suit.

Source: philstar.com