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Hylobates albibarbis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA MAMMALIA PRIMATES HYLOBATIDAE

Scientific Name: Hylobates albibarbis
Species Authority: Lyon, 1911
Common Name(s):
English Bornean White-bearded Gibbon, Bornean Agile Gibbon
Synonym(s):
Hylobates agilis (Lyon, 1911) subspecies albibarbis
Taxonomic Notes: This taxon has traditionally been considered a subspecies of H. agilis, but is considered a distinct species by Groves (2001). It hybridizes with H. muelleri in a wide area of central Borneo (Marshall and Sugardjito 1986, Mather 1992).

Assessment Information [top]

Red List Category & Criteria: Endangered A4cd ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Nijman, V., Richardson, M. & Geissmann, T.
Reviewer(s): Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)
Justification:
This species is considered Endangered based on an estimated population reduction of over 50% when considering the past 30 years and projected future habitat change due to draining of peat swamps, logging and burning into the next 15 years (totalling 45 years which is approximately 3 generations). Where the species persists there is hunting and collection for the wildlife trade and for human consumption. A large part of the species range is in peat swamp - an extremely threatened ecosystem. This species may qualify for Critically Endangered in the future if rates of habitat change increase, and thus should be carefully monitored. In addition, the effectiveness of the protected areas should be considered, as these areas seem to be strongholds for the species.

Geographic Range [top]

Range Description: This species is found in Kalimantan, Indonesia south of the Kapuas River and west of the Barito River (Marshall and Sugardjito 1986).
Countries:
Native:
Indonesia (Kalimantan)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is generally common in suitable habitat (J. Hon pers. comm.). A tentative estimate suggests a population size of 19,000 individuals within the mixed-swamp forest habitat subtype in Sabangau, representing one of the largest remaining continuous populations of this species (Buckley 2004; Buckley et al. 2006). Density estimates range from 7.4 individuals/km2 (2.16 groups/km2) in the logged peat swamp forest of the Sabangau catchment area of central Kalimantan (Buckley 2004; Buckley et al. 2006), and 8.7 individuals/km2 in primarily heath forest of Tanjung Puting National Park (Mather 1992), to 14.9 individuals/km2 in a dominantly mountain forest area of the Gunung Palung Reserve (Mitani 1990).
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: The species is found in primary, secondary and selectively logged tropical evergreen forests, as well as peat swamp forest types (Buckley 2004; Buckley et al. 2006). These arboreal and diurnal primates are dominantly frugivorous, preferring fruits high in sugar, but will also eat immature leaves and insects. They are recorded from forests up to 1,200 m asl (V. Nijman pers. comm.) with densities decreasing at higher elevations. Average home range sizes of 28 ha and 45 ha were determined at Gunung Palung and the Sabangau catchment area, respectively (Buckley et al. 2006; Mitani 1990).
Systems: Terrestrial

Threats [top]

Major Threat(s): This species was certainly affected by fires of 1990s and continuing deforestation (legal and illegal logging, draining of peat swamps, expanding oil palm plantations, etc), but no recent surveys are available on population trends. A large part of the species range is in peat swamp - an extremely threatened ecosystem. From 2003-2004, Nijman (2005) observed 79 individuals in markets in Kalimantan. It is also hunted for human consumption.

Conservation Actions [top]

Conservation Actions: Bornean white-bearded gibbons are protected throughout their range by Indonesian law and are listed on CITES, Appendix I. They are found in a number of protected areas, including Bukit Baka - Bukit Raya National Park, Ganung Palung National Park, and Tanjung Puting National Park.

Citation: Nijman, V., Richardson, M. & Geissmann, T. 2008. Hylobates albibarbis. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 26 November 2014.
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