The tree bridges that help gibbons ‘cross’ highways, Pg11

Key Highlights:

• Hoolock gibbons, India's only ape species, face a 90% population decline in Northeast India due to habitat fragmentation.
• Linear infrastructure like roads and railways isolate gibbon populations, leading to genetic isolation and inbreeding.
• Conservation efforts include establishing canopy bridges, gantry bridges, and braided rope bridges to connect fragmented habitats.
• The Hoollongapar Gibbon Sanctuary in Assam, home to western hoolock gibbons, has seen successful canopy bridge development over a railway line.
• India is also implementing large-scale wildlife crossings, including overpasses and underpasses, on major expressways to mitigate fragmentation.

Hoolock Gibbon.jpg

Detailed Insights:

• Hoolock gibbons are highly arboreal, making them vulnerable to habitat breaks as they struggle to move on land.
• The fragmentation of their habitat began as early as 1887 with the expansion of railway networks in Eastern Assam.
• The Western Hoolock Gibbon is classified as Endangered, while the Eastern Hoolock Gibbon is Vulnerable by the IUCN, and both are protected under Schedule I of the Wildlife (Protection) Act of India, 1972.
• Local organizations like Aranyak have been instrumental in conservation, including training forest staff and establishing a Gibbon Conservation Centre.
• Other arboreal species like the Lion-tailed Macaque (Endangered) and Giant Indian Squirrel (Least Concern) also suffer from habitat fragmentation.
• The Delhi-Mumbai Expressway features India's longest animal overpass system, and the Delhi-Dehradun Expressway includes a significant elevated wildlife corridor.
• These wildlife crossings are designed to allow safe passage for animals, reduce roadkill, and maintain ecological connectivity.

Key Concepts Involved:

• Habitat Fragmentation: The process where large, continuous habitats are divided into smaller, isolated patches, often by human activities.
• Arboreal Lifestyle: Animals that primarily live in trees, relying on continuous canopy cover for movement and survival.
• Genetic Isolation: The lack of gene flow between populations, leading to reduced genetic diversity and increased susceptibility to diseases.
• Wildlife Crossings (Eco-ducts): Structures like overpasses, underpasses, and canopy bridges designed to help animals safely cross human-made barriers.