Indonesia is home to nine species of small apes, all of which are categorized as Endangered on the IUCN Red List but conservation efforts for them have been limited. To address this, Perhimpunan Ahli dan Pemerhati Primata Indonesia (an Indonesian primatology association) held a webinar series during November–December 2020 to update information on the ranges of these species on Java, Sumatra (including Mentawai) and Borneo.
For the silvery gibbon Hylobates moloch there has been long-term behavioural research in Gunung Halimun Salak National Park, West Java, and a community livelihood-based conservation programme has been initiated outside the protected areas of Central Java. Nevertheless, the species' range is fragmented, and habitat corridors thus need to be developed, and law enforcement and a behavioural change strategy are required to counter illegal trade of this species.
The major threats to gibbons on Sumatra and Mentawai are habitat fragmentation and disease. The siamang Symphalangus syndactylus, agile gibbon Hylobates agilis, and lar gibbon Hylobates lar are known to occur in fragmented forests, but the degree of population persistence remains unknown, and there has been an outbreak of scabies in a siamang population. Corridors need to be included in land-use planning for these species, and research on disease outbreak risks is needed. Information on the status of these species is outdated, although there has been a recent survey of Kloss's gibbon Hylobates klossii.
There are two main issues for the conservation of gibbons on Borneo. Firstly, although the Bornean Hylobates muelleri and Bornean white-bearded Hylobates albibarbis gibbons are on the Indonesian protected species list, the northern gray Hylobates funereus and Abbott's gray Hylobates abbotti gibbons are not listed. Secondly, these four species occur mostly outside protected areas, on private and community-owned lands, and thus there needs to be multi-stakeholder engagement for the development of a conservation strategy.
To improve the conservation of Indonesia's gibbons, Perhimpunan Ahli dan Pemerhati Primata Indonesia, with the support of the Indonesian government, plans to design a policy brief and conduct a conservation planning workshop.
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