Assessment of impacts of National Highway 715 (Earlier NH 37) on Wildlife passing through Kaziranga Tiger Reserve, Assam

Abstract

As part of the project funded by the National Tiger Conservation Authority, New Delhi, three sites were chosen for study- the Central Indian tiger landscape including major roads cutting across the animal corridors in the landscape, the National Highway 37 (now 715) cutting through the Kaziranga-Karbi Anglong landscape in Assam, and the State Highway 33 passing through the Nagarhole Tiger Reserve, Karnataka. At Kaziranga National Park, we intended to quantify the characteristics of mortality of animals due to wildlife-vehicle collisions, and to assess the responses of wild ungulates to road-related disturbances in terms of changes in group size and composition, and habitat use patterns. Result shows that highways have adverse effects on the population of wildlife including endangered species of mammals and reptiles. Seasonal or monthly changes are the factors that influenced probability of roadkill numbers as it increased with the onset of summer and decreased towards winter. Annual monsoon floods in Kaziranga National Park from adjacent Brahmaputra River was found to be the main factor influencing large mammal mortality in wildlife-vehicle collisions. Apart from the direct impacts of roads on wildlife the indirect impacts like noise and disturbances associated with them impact significantly on the species that require an undisturbed or interior habitat. Similarly, present study exhibits variation in the group size composition of ungulates relative to distance from road. Group-size increased with respect to distance which indicates that anthropogenic effects of roads can lead to the habitat fragmentation of such species affecting population distribution. However, numbers and factors of wildlife-vehicle collisions may vary with site and condition