A bridge too far? India’s only ape species gets helping hand, but needs bigger steps, Pg1

Key Highlights:

• A western hoolock gibbon was recently recorded using an artificial canopy bridge over a railway line in Assam’s Hollongapar Gibbon Sanctuary.
• The sanctuary is home to an estimated 120-130 western hoolock gibbons, India’s only ape species, within its 21-sq km area.
• The first artificial canopy bridge was installed in 2015, with improved designs implemented in 2022 following consultations with the Wildlife Institute of India (WII).
• Five double-rope canopy bridges made of low-stretch nylon with safety nets were installed, and a male gibbon was recorded using one within two months.

Detailed Insights:

• Habitat fragmentation due to linear infrastructure like railways isolates wildlife populations, reducing movement, increasing competition, and limiting access to mates.
• Artificial canopy bridges aim to restore connectivity between fragmented forest patches, using materials ranging from steel cables to natural ropes, depending on local conditions.
• Similar structures have been deployed globally for species like sloths, monkeys, lemurs, orangutans and gliders, but are not a substitute for intact forests.
• Concerns exist that artificial crossings may increase predation risk, disrupt social hierarchies, and facilitate the spread of pathogens among wildlife.
• Conservationists emphasize that artificial crossings should not normalize infrastructure projects through forests and that habitat restoration and eco-conscious planning are crucial for long-term species survival.

Key Concepts Involved:

• Habitat Fragmentation: The division of a continuous habitat into smaller, isolated patches.
• Arboreal: Refers to animals that live primarily in trees.
• Brachiation: A form of locomotion in which an animal swings hand-over-hand through tree branches.