Hollongapar Gibbon Sanctuary lies nestled amidst tea gardens in Jorhat district of Assam. Small villages also dot its fringes making them frequent jaunts of elephants and leopards that live in the forest. However, its most famous resident – the Western Hoolock Gibbons – the only ape species in India residing in the dense forests of the Northeast, rarely move out of their forest home, as by nature, they are shy and stay away from humans.
The Hollongapar Sanctuary gets its name from its dominant tree species Hollong or Dipterocarpus macrocarpus. However, the resident Hoolock Gibbons do not live in these trees, preferring instead fruit bearing trees like the fig tree as their home. Because of the numerous tea estates and villages dotting its landscape, the sanctuary is fragmented, and largely divided into two parts that are separated by a railway line. And this railway line is a big concern for the forest department as the gibbons often cross the tracks on foot to visit their troop members on the other side.
Hence, after discussions with the Railways and the Wildlife Institute of India (WII), the sanctuary is all set to build seven rope bridges over the railway track for the Hoolock Gibbons to swing over.
Speaking to Indian Masterminds, DFO of Jorhat district, 2017 batch IFS officer Nandha Kumar, gave some interesting information about the Hollongapar Sanctuary, its famous residents Hoolock Gibbon and the planned rope overbridges for them.
ENDANGERED WESTERN HOOLOCK GIBBON
The world celebrated International Gibbon Day on 24 October, a day in honour of the most intriguing primates in tropical forests. On this day, India celebrated her endangered Western Hoolock Gibbon, the only ape species in the country which are found in the dense forests of the Northeastern states.
One of their habitats is the Hollongapar Gibbon Sanctuary in Assam. Here, their current population stands at around 75 only which can be broken up into 15-18 families.
“They are monogamous and have nuclear families. Each family unit will have around 5 members consisting of the parents and their children. Once the children grow up, they then move out and form their own families,” said DFO Kumar.
THE RAILWAY LINE
These few gibbon families live in the fruit bearing trees of the sanctuary. Easily discerned by their long arms or front legs, the Hoolock Gibbons prefer to stay up on the trees and, when they move, they swing from one tree to another. However, a deviant behaviour came to the notice of the forest officials. “They are tree dwelling species. They spend their entire lives on canopies of fruit bearing trees. They don’t come down at all. But, we noticed that they come down from the trees to cross railway tracks on foot, which is unnatural,” Mr. Kumar said.
The tracks in question is a railway line that cuts through the sanctuary bifurcating it into two parts. “3-4 families live in one part and around 10 in the other, and they cross the railway tracks on foot to visit their troop members on either side,” Mr. Kumar said.
SEVEN ROPE BRIDGES
Realising the risk involved in this action as trains can hit them anytime, the forest department decided on building bridges over the railway tracks. These bridges will be a rope structure in canopy style to make it resemble the natural tree canopies.
DFO Kumar approached the Wildlife Institute of India which readily came forward to help. Their research team went to the sanctuary and identified, measured and marked strong, mature and undamaged trees for the bridges’ installation at 7 sites. These will be double-rope bridges at minimum 11.5 m height by tying mountaineering-grade rappelling ropes.
The design is ready and it is now with the Railways for safety clearance. Meanwhile, the Jorhat forest department is waiting for the formal approval to start the construction work. They plan on taking help from a mountaineering institute in Uttarakhand in its construction, and once started, work is likely to be completed in 3 months.
CONSERVATION CONCERN
As for the conservation of the endangered Western Hollock Gibbons, Mr. Kumar said that there is no immediate concern as their population has been stable for long in the Hollongapar Gibbon Sanctuary. “The only cause for worry is the railway line, and once the rope bridges are in place and the gibbons start using these, that risk factor will get mitigated,” he said.
Wildlife Institute of India, however, pointed out that at best, this can be a short term fix only. For a long term solution, the railway line needs to be rerouted to outside available non-forest areas, after discussion with the railway department.
