The Silvery gibbon, Hylobates moloch, also known as the Javan gibbon, is endemic to Central and Western Java in Indonesia. Listed Endangered on the 2004 IUCN Red List of Threatened Species, there is a 50% chance of the Silvery gibbon becoming extinct within the next decade.
Inhabiting approximately eight sites, there are currently less than 2000 Silvery gibbons in the wild considered genetically viable. In addition, a dozen small non-viable populations exist which, if successfully translocated, may be saved from extinction. Aside from these wild populations many Silvery gibbons are held as pets throughout Indonesia. Welfare of the individual animal aside, the genetic material these isolated and captive animals possess is fundamental to the survival of the species and too important to be lost.
Gunung Halimun National Park, West Java, is able to sustain a population of 1000 gibbons. Other habitats throughout the region however are only able to sustain populations numbering in the mid-hundreds. In some instances Silvery gibbon habitat is protected, but in many it is not. Java is a small area of land attempting to both sustain wildlife and support an ever increasing human population. It is inevitable that the Silvery gibbon, with its specific territorial needs, is in perpetual conflict with man.
Few gibbons remain in the lowlands, forced by human encroachment to higher elevations. Isolated populations are concentrated at 800-1500 metres, the limit of their natural tolerance. Migration to ever higher ground is not a feasible option and the Silvery gibbons are losing the battle to remain at lower elevations.
Indonesia is a biodiversity hotspot. Threats to wildlife and their delicate habitat continue as the human population encroaches on the remaining rainforest, itself prone to intensive, often illegal logging. Species continue to decline with no reprieve in sight. Silvery gibbon populations that occupy habitats in close proximity to high-density areas and large cities, for example Jakarta, experience immense pressure. The illegal wildlive trade exacerbates the problem, in particular the demand for juvenile gibbons as pets.
The Silvery Gibbon Project appreciates that solutions to these issues must be sensitively addressed within the context of local situations and societal customs. Sustainable options providing alternative financial income, backed up by a community wide, comprehensive education program, must be offered to enable positive long-term solutions to habitat destruction and bring a halt to the illegal wildlife trade.