Saving India’s only ape, the hoolock gibbon

Subject :Environment

Section: Species in news

In the news:

The Hollongapar Gibbon Sanctuary (HGS), a habitat of the endangered Western hoolock gibbon in Assam, is fragmented by a railway track that goes through the sanctuary.
At HGS, the gibbon population comprising 125 individuals (in 26 groups) inhabits an area that is fragmented by the Mariani-Dibrugarh railway line that is currently unelectrified.
Mariani-Dibrugarh railway line is a part of the Lumding-Dibrugarh broad gauge railway section.

About Hoolock Gibbon (Hoolock hoolock):

Gibbons, the smallest and fastest of all apes, live in tropical and subtropical forests.
The tailless Hoolock Gibbon is the only ape found in India.
The primate is native to eastern Bangladesh, Northeast India and Southwest China.
They are primarily arboreal, which means they live in trees.
The estimated population of hoolock gibbons is 12,000.
Like all apes, they are extremely intelligent, with distinct personalities and strong family bonds.
Key threats: Habitat loss and fragmentation, and hunting.
The Hoolock Gibbon is categorized into two types:
Western hoolock gibbon:
- It inhabits all the states of the northeast, restricted between the south of the Brahmaputra River and east of the Dibang River. Outside India, it is found in eastern Bangladesh and north-west Myanmar.
- It is listed as Endangered under the International Union for Conservation of Nature (IUCN) Red List.
Eastern hoolock gibbon:
- It inhabits specific pockets of Arunachal Pradesh and Assam in India and in southern China and northeast Myanmar outside India.
- It is listed as Vulnerable under the IUCN Redlist.
- In India, both species are listed on Schedule 1 of the Indian (Wildlife) Protection Act 1972.

Hollangapar Gibbon Sanctuary:

Formerly known as the Gibbon Wildlife Sanctuary or Hollongapar Reserved Forest.
It is an isolated protected area of evergreen forest located in Assam, India.
Initially in 1881, its forests used to extend to the foothills of the Patkai mountain range.
Since then, the forest has been fragmented and surrounded by tea gardens and small villages. In the early 1900s,artificial regeneration was used to develop a well-stocked forest, resulting in the site’s rich biodiversity.
It contains India’s only gibbons – the hoolock gibbons, and Northeastern India’s only nocturnal primate – the Bengal slow loris.
In addition to the gibbon, the HGS is home to six other primate species, making it an area with the highest biodiversity of primate species of any Protected Area in the country.
Western hoolock gibbon is the flagship species of the HGS.
The upper canopy of the forest is dominated by the hollong tree (Dipterocarpus macrocarpus), while the nahar (Mesua ferrea) dominates the middle canopy. The lower canopy consists of evergreen shrubs and herbs.
The habitat is threatened by illegal logging, encroachment of human settlements, and habitat fragmentation.