Artificial Canopy Bridges for Wildlife Conservation
Introduction
The first global instance of a Western hoolock gibbon using an artificial canopy bridge was recorded in Assam's Hollongapar Gibbon Sanctuary. This offers cautious optimism for the survival of India's only ape species.
Background
- Hollongapar Gibbon Sanctuary houses an estimated 120-130 gibbons.
- The Lumding–Dibrugarh railway line, recently electrified, cuts through the sanctuary, posing a risk to wildlife due to habitat fragmentation.
Development of Canopy Bridges
- An initial rigid iron canopy bridge (installed in 2015) was ineffective for gibbon movement due to its design.
- Natural canopy continuity was temporarily restored through plantation efforts, but was disrupted by storm damage.
- In 2022, five double-rope canopy bridges made of low-stretch nylon with safety nets were installed after consultation with the Wildlife Institute of India.
- A male gibbon was recorded using one of these crossings within two months.
Role of Artificial Canopy Bridges
- Help mitigate the impact of habitat fragmentation by providing connectivity.
- Materials vary based on local climatic conditions, e.g., steel cables, nylon ropes, bamboo, etc.
- Used globally in regions like Costa Rica, South Africa, Madagascar, and Australia for different species.
Challenges and Criticisms
- Make wildlife movement predictable, increasing vulnerability to predation.
- May concentrate animals, increasing pathogen and parasite spread.
- Risk of normalizing infrastructure projects in forests, potentially justifying further expansions.
- May not achieve a viable breeding population without meaningful habitat restoration.
Conservationists' Perspective
Artificial crossings are considered temporary solutions. Long-term conservation requires:
- Careful infrastructure planning and eco-conscious siting.
- Creating reforested corridors to connect isolated populations.
Conclusion
The Wildlife Institute of India highlights the need for a balanced approach, emphasizing long-term solutions for the survival of arboreal species like gibbons.
