Asia's Longest Wildlife Viaduct Shows Early Success in Animal Movement

Asia's Longest Elevated Wildlife Corridor Demonstrates Early Success in Animal Movement

In a significant development for wildlife conservation, one of Asia's longest elevated wildlife corridors—a 12-kilometer stretch of the Delhi-Dehradun Expressway arching over the Mohand area—is showing promising early signs of successful animal movement. A joint study conducted by the Wildlife Institute of India (WII) and the National Highways Authority of India (NHAI) has documented a diverse range of species utilizing the underpasses beneath this innovative infrastructure.

Expressway Inauguration and Study Findings

The 213-kilometer expressway, which connects Akshardham in Delhi to Dehradun, is scheduled to be inaugurated by Prime Minister Narendra Modi on April 14. According to the study titled 'Landscape Reconnected: First Evidence of Wildlife Movement across the World's Largest Animal Viaduct on NH-72 (Asharodi–Ganeshpur)', at least 18 different species have been recorded using the underpasses along an 18-kilometer stretch between Ganeshpur in Uttar Pradesh and Asharodi on the outskirts of Dehradun.

The documented species include:

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• Carnivores such as leopards and golden jackals
• Herbivores including elephants, spotted deer, sambar, and nilgai
• Ungulates like wild boar
• Pheasants such as peacocks
• Primates and smaller mammals including the Indian hare

This diverse usage indicates active and varied animal movement through the specially designed passages.

Monitoring Methodology and Key Observations

The findings are based on a comprehensive 40-day monitoring exercise that analyzed over 110,000 images captured through systematically deployed camera traps and 29 AudioMoth acoustic recorders positioned along the corridor. Officials designed this monitoring setup to detect a broad spectrum of terrestrial fauna, ranging from small to large-bodied species.

Key observations from the study include:

1. Golden jackals were the most frequently recorded species
2. Nilgai, sambar, and spotted deer followed in frequency
3. Elephants were recorded using the corridor on at least 60 occasions, demonstrating that even large mammals are navigating the infrastructure while maintaining natural movement patterns
4. Smaller mammals like the Indian hare showed consistent movement through the structures

Infrastructure Design and Conservation Context

The 20-kilometer stretch between Ganeshpur and Asharodi features nearly 11 kilometers of dedicated animal underpasses designed to facilitate unobstructed movement. The elevated corridor, with an average height of six to seven meters, ranks among the largest of its kind in Asia and is specifically built to accommodate even large mammals such as elephants.

"This is the world's largest viaduct of 12 kilometers. It will help in the unobstructed movement of wildlife from Uttarakhand to Himachal Pradesh and Haryana," said Bilal Habib, scientist at WII and lead author of the study.

The landscape falls within the Terai Arc, one of India's most critical conservation zones that forms the westernmost distribution range for species including tigers, elephants, greater hornbills, and king cobras. The expressway passes through the Shivalik Elephant Corridor, spanning the Shivalik forest division, the westernmost edge of Rajaji Tiger Reserve, and the Dehradun forest division.

Soundscape Management and Expert Perspectives

The study identified soundscape management as a crucial factor influencing wildlife movement. While generalist species such as jackals and wild boar appeared tolerant of traffic noise, more sensitive species like elephants and deer preferred quieter underpass segments. Researchers suggested implementing targeted noise barriers in high-use areas to improve the corridor's effectiveness.

Offering a more cautious perspective, former dean of WII, YV Jhala, noted that while such corridors represent a positive step, movement alone does not guarantee settlement. "If there is a source population of tigers in western Rajaji, they may move toward the Shivalik forests. But the Shivalik forests in UP have a poor prey base, which limits further movement toward areas like Kalesar in Haryana or Himachal. Wildlife needs not just passage, but viable habitat," he explained, adding that until prey populations recover, large carnivores are unlikely to establish themselves beyond certain zones.

Historical Context and Future Considerations

Earlier reports from 2021 indicated that nearly 55% of the last 20-kilometer stretch of the expressway falls within critical wildlife crossing zones, based on a WII study examining mitigation measures in the Shivalik hills.

Local environmentalists have urged caution in interpreting these early findings. "The study was conducted before the expressway became operational. It is yet to witness full traffic volumes, especially during peak tourism seasons. A more accurate assessment will only be possible once the road is fully in use," said Dehradun-based environmentalist Reenu Paul.

This pioneering infrastructure represents a significant step in balancing development with conservation, though continued monitoring will be essential to assess its long-term effectiveness in preserving wildlife connectivity across this ecologically sensitive region.