Hope for Java’s Silvery Gibbon After Lost Communities Found

Fidelis E Satriastanti Jakarta Globe 23 Jul 10;

Sanur, Bali. The survival prospects of the silvery gibbon, also known as the Javan gibbon, are looking a lot rosier now following revelations that there are more than 1,000 of the primates in previously overlooked forests in Central Java.

A previously unrecorded population of 896 gibbons was discovered near Mount Slamet in Central Java, while 176 were found at the nearby Dieng Plateau, Arif Setiawan, a wildlife researcher at Yogyakarta’s Gadjah Mada University, told the International Meeting of the Association for Tropical Biology and Conservation, currently under way in Sanur, Bali.

Additionally, the results — gathered between August 2009 and February 2010 — were from a study that was still ongoing, so the final figures could be even higher, Arif added.

The silvery gibbon, which is endemic to Java, is found mainly in the forests of the Ujung Kulon, Gunung Halimun Salak and Gunung Gede Pangrango national parks in Banten and West Java.

In 2005, the Indonesian Institute for Biodiversity Sciences recorded that Ujung Kulon had 560 gibbons, Gunung Gede Pangrango 447 and Gunung Halimun Salak 1,221.

Conservative estimates put the total wild population of silvery gibbons at about 5,000. However, conservationists believe only 2,000 are genetically viable to propagate the species.

“They’re mostly found in natural forests that fall outside established national parks, despite a study back in 1998 that recommended the government include these habitats in protected areas,” Arif said.

However, he argued that even this measure would not guarantee the survival of the species. “While it won’t vouchsafe for the future of the silvery gibbon, it will at least send out the strong message that the government is committed to protecting them,” he said.

The gibbon is threatened by poaching for the illegal pet trade and also by the continued destruction of its habitat.

Arif said it was a logistical challenge to conduct an accurate census of the gibbon population because it normally spent all of its life high up in the treetops.

“Unlike orangutans or other primates that travel along the ground, gibbons are always hanging around in trees and never come down,” he said.

The current study is being carried out with the help of satellite imagery to initially map out forest areas suitable for gibbon habitats, Arif said.

“We then figure out where they’re most likely to be before we go conduct the study,” he said. “During the study, we map out the boundaries of their territory.”

He said silvery gibbons often moved about in groups of four to seven individuals.