HANDBOOK TO MITIGATE THE IMPACTS OF ROADS AND RAILWAYS ON ASIAN ELEPHANTS

The handbook details structural and non-structural mitigation strategies to protect Asian elephants from linear transport infrastructure (LTI). It emphasizes the use of the mitigation hierarchy, prioritizing avoidance and minimization. Key recommendations include specific dimensions for underpasses, overpasses, viaducts, and flyovers, as well as the use of data-driven site selection via GPS telemetry, camera trapping, and sign surveys. The document also discusses the role of specialized fencing, such as rail track fences and the Malaysian ELEfence, and non-structural measures like traffic calming and AI-based early warning systems for railways.

• Linear transport infrastructure (LTI) causes both direct impacts, such as wildlife-vehicle collisions and mortality, and indirect impacts, including habitat fragmentation, increased poaching, and pollution.
• Train collisions are a major cause of Asian elephant mortality, particularly in India and Sri Lanka; in India, 355 elephants died in such collisions between 1987 and April 2023, with two-thirds occurring in Assam and West Bengal.
• The handbook establishes a sliding scale for minor bridge underpasses (width < 30 m): for LTI length 10 m, minimum dimensions are 6.0 m height and 12.0 m width; for length 11-20 m, 6.5 m height and 15.0 m width; and for length >20 m, 7.0 m height and 20.0 m width.
• For engineered overpasses, the recommended minimum width depends on the total length including approach slopes: 60 m length requires 50 m width, 61-80 m requires 60 m width, and >80 m requires 70 m width.
• Viaducts and flyovers are described as highly effective due to their size and openness; the AsETWG recommends a minimum clearance height of 10 m to ensure effectiveness.
• Natural overpasses, created by tunneling through mountainsides, are effective in China because they maintain natural ecological corridors and vegetation without disruption.
• Effective site selection for crossing structures should be data-driven, utilizing methodologies such as GPS telemetry (the "gold standard"), camera trapping, and seasonal sign surveys to identify established movement corridors.
• Fencing is critical for funneling elephants to crossing structures; the handbook identifies rail track fences (using retired railway tracks) and the Malaysian ELEfence (prefabricated concrete columns with prestressed cables) as durable options.
• Non-structural mitigations for low-traffic roads include motorist alert signage and traffic calming measures like rumble strips, which can reduce mammal mortality by 59% based on a study in Australia.
• Railway mitigation is evolving through AI and sensor technology, such as the Northeast Frontier Railway's use of AI-integrated optical fibre cables and the use of thermal imaging (FLIR) cameras to detect elephants up to 800 m in advance.

APA

Dodd, N., Butynski, M., Ament, R., Chen, S., Jayasinghe, N., Lim, J. C., Saaban, S., Tiwari, S. K., van der Ree, R., Wang, Y., & Wong, E. P. (n.d.). HANDBOOK TO MITIGATE THE IMPACTS OF ROADS AND RAILWAYS ON ASIAN ELEPHANTS. WWF International. https://www.worldwildlife.org/documents/478/6p6mle7lmj_Asian_Elephant_Handbook_AsETWG_2024.pdf

Chicago

Dodd, Norris, Melissa Butynski, Rob Ament, Shu Chen, Nilanga Jayasinghe, Jia Cherng Lim, Salman Saaban, et al. HANDBOOK TO MITIGATE THE IMPACTS OF ROADS AND RAILWAYS ON ASIAN ELEPHANTS. WWF International, n.d. https://www.worldwildlife.org/documents/478/6p6mle7lmj_Asian_Elephant_Handbook_AsETWG_2024.pdf.

Wikipedia

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BibTeX

@techreport{doddndhandbook, author = {Dodd, Norris and Butynski, Melissa and Ament, Rob and Chen, Shu and Jayasinghe, Nilanga and Lim, Jia Cherng and Saaban, Salman and Tiwari, Sandeep Kumar and van der Ree, Rodney and Wang, Yun and Wong, Ee Phin}, title = {{HANDBOOK TO MITIGATE THE IMPACTS OF ROADS AND RAILWAYS ON ASIAN ELEPHANTS}}, institution = {WWF International}, url = {https://www.worldwildlife.org/documents/478/6p6mle7lmj_Asian_Elephant_Handbook_AsETWG_2024.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }