Comparison of the Javan Gibbon (Hylobates Moloch) Population at Gunung Halimun - Salak and Ujung Kulon National Park, Indonesia

The Javan gibbon (Hylobates moloch) is a critically endangered species with remaining populations restricted to a few protected areas in West and Central Java. The goal of our ongoing project is to generate critical baseline data on the status of this threatened species. Here we report on the results of our populations surveys conducted at two different national parks (NP) in Java: Ujung Kulon NP in Banten and Gunung Halimun-Salak NP in West Java. Surveys were conducted in two locations in Ujung Kulon NP (Cibiuk region of Mount Honje) during November-December 2000 and at four locations in Gunung Halimun NP (Citarik, Cibeureum, Cisalimar, and Cikaniki) from December 2004-September 2005. All surveys involved the use of the line-transect sampling method along transects of 2.5 - 3.5m in length. The average group density of the Javan gibbons at Ujung Kulon NP was 2.8 grps/km2; slightly lower than found at Gunung Halimun NP with 3.4 grps/km2. Group size and population density estimates, however, were found to be greater in Ujung Kulon NP (3.3 indiv/grp; 9.2 indiv/km2) compared to Gunung Halimun NP (2.5 indiv/grp; 8.2 indiv/km2). During the surveys, three other primate species were observed at both NPs: silvered leaf monkey (Trachypitecus auratus), grizzled leaf monkey (Presbytis comata), and longtailed macaque (Macaca fascicularis). As habitat loss continues in Java, protected areas such as Ujung Kulon and Gunung Halimun NPs are of great importance to the long-term conservation of the Javan gibbon. Support by: Rufford Small Grant for Nature Conservation, IPS, ASP, and NIH Grant RR-00166. The attendance to the conference is being supported by the Rufford Small Grants Foundation.