Vehicular traffic and the use of highway edges by large mammals – Urgent need for holistic EIA

Impact of vehicular traffic on the use of highway edges by large mammals in a South Indian wildlife reserve

Sanjay Gubbi, H. C. Poornesha andM. D. Madhusudan

CURRENT SCIENCE, VOL. 102, NO. 7, 10 APRIL 2012

Here is a paper that is of great relevance to wildlife managers.

Expansion and improvement of transport and other infrastructure networks is a natural accompaniment to the economic boom that India is experiencing. The authors of this paper say that even though there are legally mandated assessments of the potential ecological impacts of such infrastructure projects prior to implementation, rarely are there any post-implementation assessments of their real ecological impacts.

The researchers present results of a preliminary study examining the impact of vehicular traffic on the usage of road edges by large mammals along a highway passing through Nagarahole Tiger Reserve. Using triggered camera traps they estimated large mammal encounter rates on two consecutive sections of the same highway – one closed to vehicular traffic and the other open to vehicles only during daytime.

The researchers observed lower encounter rates of chital, gaur and elephants at camera traps in the highway segment with higher vehicular traffic density. They add that this is an indication of the fact that these species avoided busy highways. A more sustained monitoring over time is required for a better understanding of how these species respond to vehicular traffic along highways.

State Forest Departments do not take road kills seriously unless the animal killed is large. Hence systematic record-keeping of all mortalities due to road kills would provide the necessary data to assess and mitigate impacts of vehicular traffic on wildlife. There is an urgent need for scientifically designed wildlife crossing structures while planning highways through wildlife reserves.

 Based on their findings, the researchers emphasize the importance of continued ecological impact assessments of development projects to identify and mitigate unforeseen impacts. They make a fervent plea for an approach that integrates development planning with conservation concerns, especially where development projects coincide with ecologically critical areas.

The prevailing system of rapid EIAs by untrained people, often hired by project proponents themselves should be dispensed with. What is needed is rigorous and peer-scrutinized assessments carried out by trained wildlife biologists.  The country needs to invest in a more holistic process of development planning that includes – rather than ignores – the conservation of its priceless natural heritage.

I thank Annapoorna Daithota of ncf-india for sending me a copy of the paper