Tigers are one of the world’s most endangered large carnivores with an estimated global population of approximately 3200 individuals. They currently occur in 13 countries, representing 7% of their former range (Dinerstein et al. 2007). The survival of tigers in the wild depends largely upon the willingness of the tiger‐range countries to ensure adequate protection of sufficiently large areas from inappropriate development and activities such as roads and poaching. Tigers are threatened by roads and traffic. Research on Amur tigers in Russia suggests that direct mortality due to wildlife-vehicle collisions (WVC) can reduce survivorship and reproductive success of surviving animals (Kerley et al. 2002). Tigers have been affected in western Malaysia through construction of the North–South highway and another highway that bisected a bottleneck area in Taman Negara National Park (Kawanishi et al. 2010). The current rate of mortality of tigers due to WVC in India appears to be relatively low, with approximately 20 documented tiger deaths in various reserves over the past 15 years (Prakash 2012), although this number is likely an underestimate due to non‐detection or non‐reporting. Furthermore, as the size of the tiger population declines and the road network expands, the direct and indirect effects of mortality due to WVC and fragmentation of tiger habitats will become of greater concern. In addition to direct mortality, the death of individual tigers results in social instability. The death of a territorial male can lead to infighting of transient males trying to establish territories and infanticide by the new territorial male, and it also affects tigresses due to unstable male ranges, possibly leading to depressed birth rates. Axis deer, a principal prey species for tigers in India, are also commonly killed by WVC, resulting in reduced food for tigers. Furthermore, roads are used for illegal activities including hunting of tigers and their prey (see also Chapters 2, 36 and 56). In eastern Russia, at least six Amur tigers were poached over a 10‐year period along one road (Kerley et al. 2002). In 2010, poachers apprehended in southern India confessed to the illegal hunting of axis and other deer species in Bandipur, Bhadra and Biligirirangaswamy Tiger Reserves by driving on roads at night. 318 Handbook of road ecology In India, the National Wildlife Action Plan 2002–2016 (Government of India 2002) specifically prescribed regulation and mitigation measures for threats to wildlife posed by roads. However, there have been few serious attempts to implement the policy on the ground.
Sanjay Gubbi and H.C. Poornesha, Case study: Finding the middle road – grounded approaches to mitigate highway impacts in tiger reserves. Handbook of Road Ecology, First Edition. Edited by Rodney van der Ree, Daniel J. Smith and Clara Grilo. © 2015 John Wiley & Sons, Ltd. Published 2015 by John Wiley & Sons, Ltd.