| Citation |
Brockelman, W & Geissmann, T. 2019. Hoolock leuconedys . The IUCN Red List of Threatened Species 2019: e.T118355453A17968300. https://dx.doi.org/10.2305/IUCN.UK.2019-1.RLTS.T118355453A17968300.en. Downloaded on 05 February 2020. |
Description |
JUSTIFICATION
This species is listed as Vulnerable because it is suspected that the population will decline by more than 30% over the next three generations (approximately 45 years), based on continued habitat loss and hunting throughout its range (Fan et al. 2011a, 2011b; Kumar et al. 2013). The total population of Hoolock leuconedys in Myanmar was estimated at over 10,000 individuals, and perhaps up to 50,000 or so in 2013 (Geissmann et al. 2013); however, much more survey work is needed as habitat loss and hunting are rife and will have negatively impacted the population. Eastern hoolocks are threatened by habitat loss and hunting, both for meat as well as for use in traditional “medicine” (Fan et al. 2011a, Geissmann et al. 2013). In Myanmar, commercial logging may eliminate most forest habitats outside of protected areas, but in and around Mahamyiang Sanctuary, selectively logged forests (with dipterocarps removed) still contain many gibbons (Geissmann et al. 2013). The more than 50,000 people settled in the Hukaung Valley Tiger Reserve constitute a threat to all wildlife in the area, and the future of the reserve will depend on the ability of the government as well as international conservation groups to curtail hunting. Gold mining has become a threat to conservation in Kachin State (W. Brockelman pers. comm).
RANGE DESCRIPTION
This species is found in between the Chindwin River and the Irrawaddy River Myanmar. A population in western Yunnan, China is now considered to represent a new species, the Skywalker Hoolock Gibbon, Hoolock tianxing (Fan et al. 2017). Das et al. (2006) reported the discovery of a population of Hoolock leuconedys in eastern Arunachal Pradesh, north-east India, which has traditionally been considered to be part of the distribution area of H. hoolock. This record has yet to be proven (T. Geissmann pers. comm).
The boundary between the two species of hoolock gibbon, H. hoolock and H. leuconedys, is uncertain (Das et al. 2006, Fan et al. 2011a, Zhang et al. 2014) in the Chindwin headwaters in the north, and possibly includes a zone of intermediates or variable population (T. Geissmann pers. comm). More fieldwork is needed to investigate populations on both sides of the river and in the headwaters of the Chindwin, where there is likely to be one or more hybrid zones or clines (W. Brockelman pers. comm).
DESCRIPTION
In India, a population of about 170 gibbons, which have been tentatively identified as Hoolock leuconedys, occurs in the Mehao region, in eastern Arunachal Pradesh state (Das et al. 2006), but further surveys are needed (J. Das pers. comm). The total population of H. leuconedys in Myanmar was estimated at over 10,000 individuals, and perhaps up to 50,000 or so in 2013 (Geissmann et al. 2013); however, much more survey work is needed as habitat loss and hunting are rife and will have negatively impacted the population. There have been some Wildlife Conservation Society surveys in Hukaung Valley Wildlife Sanctuary, which have approximately two groups/km² (Htun pers. comm. 2006). There are approximately two groups/km² in Mahamyaing Wildlife Sanctuary based on vocal surveys, with a total population of 4,000–8,100 individual gibbons (about half of which would be adult animals) (Warren Brockelman 2006, unpub. draft).
HABITAT AND ECOLOGY
This gibbon is a forest-dweller that inhabits primary evergreen, scrub and semi-deciduous hill forest, as well as mountainous broadleaf and pine-dominated forest. It ranges up to 2,700 m in elevation, (Kumar et al. 2013, Zhang et al. 2014) in mixed pine/broadleaf forest in northeastern Myanmar (Geissmann et al. 2013, Ujhelyi et al. 2000).
It is a frugivorous species, with ripe fruits composing a majority of its diet. Individuals also eat a large proportion of figs and some amount of leaves, shoots, and petioles. This diet contributes to a relatively large home range of some populations (Fan et al. 2011a, Kumar et al. 2013, Zhang et al. 2014).
THREATS
Eastern Hoolocks Gibbon are threatened by habitat loss and hunting, both for meat as well as for use in traditional “medicine” (Fan et al. 2011a, Geissmann et al. 2013). In Myanmar, commercial logging may eliminate most forest habitats outside of protected areas, but in and around Mahamyiang Sanctuary, selectively logged forests (with dipterocarps removed) still contain many gibbons (Geissmann et al. 2013). The more than 50,000 people settled in the Hukaung Valley Tiger Reserve constitute a threat to all wildlife in the area, and the future of the reserve will depend on the ability of the government as well as international conservation groups to curtail hunting. Gold mining has become a threat to conservation in Kachin State (W. Brockelman pers. comm).
USE AND TRADE
This species is hunted for meat and for use in traditional “medicine” (Fan et al. 2011a, Geissmann et al. 2013).
CONSERVATION ACTIONS
This species is listed on CITES Appendix I. In China there are two nature reserves with hoolocks (Gaoligongshan and Tongbiguan National Nature Reserves), but these are now considered to harbour the newly-named species H. tianxing (P.-F. Fan et al., 2017). In Myanmar, the Mahamyaing Sanctuary was created in part as a gibbon refuge, and the species occurs as well in the Bumhpabum, Hponkan Razi and Htamanthi Wildlife Sanctuaries, and in the Hukaung Valley Tiger Reserve (W. Brockelman unpub.). A project has been implemented by Wildlife Conservation Society to help educate local residents – especially school children – around Mahamyiang Sanctuary, and to urge them not to hunt wildlife. The project also provides some support to the wildlife sanctuary for increased patrols. Such projects need to be implemented in the Hukaung Tiger Reserve as well, in order to reduce hunting pressures. At present tourism is not promoted in the Hukaung Valley because it is a politically sensitive area, but there is great potential for tourism to have a positive impact on local development in the future. In the meantime, alternative sources of income are needed to compensate for the bans on direct resource exploitation (W. Brockelman pers. comm). |
