While deaths of large mammals such as elephants, leopards and tigers due to vehicular traffic are widely documented, a recent study has sought to bring attention to the rare species of amphibians, reptiles, birds and mammals in the Nilgiris that are also being lost to speeding traffic.
In their paper, ‘Road Kill of Animals by Highway Traffic from Udhagamandalam to Mettupalayam’, published recently in the International Journal of Pure and Applied Zoology, authors R. Deepan, B. Vickram, A. Samson, S. Dilip Clinton and J. Leona Princy, recorded the number of animals killed by vehicles between Coonoor and Mettupalayam, a 55 km stretch, during a one-year period between August 2017 and August 2018.
The route, popularly known as the Kotagiri Road, cuts through 32 kilometers of reserve forest, known to host a large variety of native and endemic flora and fauna. Motorists love smooth roads that are relatively free of traffic and have few speed breakers. Many use such roads to exceed speed limits.
The assessment was performed thrice a month for a year. At the end of the year, the authors noted that they had recorded 383 road kills, on 36 sampling days, including seven species of mammals, 17 species of birds, 12 species of reptiles and four species of amphibians. Worryingly, the researchers noted that among the wildlife, the most affected along the stretch were those classified as being ‘endangered’ or ‘vulnerable’ by the International Union for the Conservation of Nature (IUCN).
These include the Gray slender loris ( Loris Iydekkerianus) , as well as endemic frogs and toads such as Raorchestes signatus (Nilgiri bush frog) ,Duttaphrynus microtympanum (Southern hill toad) and Uperodon triangularis (Narrow-mouthed frog). Of the 383 road kills recorded by the team, 155 of them, or 40% were amphibians, with endemic frog species being greatly impacted.
Reptiles such as chameleons, spectacled cobras, Indian sand boas, Russell’s vipers and Bengal monitors were also among species of wildlife killed along the stretch. There was also a correlation between an increase in the number of road kills of a certain species, and taxa, with the time of day and season in which they were recorded. These correlations are behavior-specific, the authors note.
Speaking to The Hindu , Samson Arockianathan, one of the authors of the paper, said the point of the study was to assess the impact that roads have on wildlife. “We wanted to look at the impact of major, high-traffic roads not only on the movement of large mammals, but to also ascertain the number of smaller, less well-known species that are killed along the stretch,” he said.
The paper also noted the number of vehicles passing through the 55-km stretch during each assessment. On an average, 652 vehicles passed through the stretch. The number shot up to 1,044 during the peak summer season in April.
“As the Nilgiris-Kotagiri ghat is an extremely important bio-diverse region, it is important that we reduce the number of road kills. While it is impractical to advocate building speed breakers regularly along the entire stretch, it would be a huge benefit for the safety of wildlife if speed breakers are to be built along sections where cars build up speed, such as relatively long, unbroken straight roads and flat sections of the ghat,” said Mr. Arockianathan.
