Responses of tiger (Panthera tigris) and their prey to removal of anthropogenic influences in Rajaji National Park, India

Presence of human settlements in most protected areas has forced tigers (Panthera tigris) to share space with humans. Creation of inviolate space for tigers in areas with high human densities is often daunting and requires hard political sacrifices. We conducted this study from 2004 to 2007 in the Chilla range of Rajaji National Park, along the northwestern portion of the Terai-Arc Landscape in the Indian subcontinent. Our objective was to document the recovery of prey and tiger populations following the resettlement of 193 gujjar (pastoralists with large buffalo holdings) families. We used distance sampling to estimate density of wild ungulate prey and camera traps to estimate tiger density. The study area supported similar to 66 ungulates/km(2), with chital (Axis axis) and sambar (Cervus unicolor) contributing >91%. While prey densities did not vary across 3 years, an increase in proportion of chital fawns was observed following the near complete removal of livestock. We also documented an increase in the density ((D) over cap) of tigers (from three to five tigers per 100 km(2)), probably due to immigrating tigers from nearby Corbett Tiger Reserve. A high turnover of individual tigers was observed during the study. With photographic evidence of breeding tigers in Chilla range, we believe that this area could serve as a source population from where tigers can colonize adjoining forests across River Ganga. It is therefore concluded that securing the connectivity between forests on the east and west bank of Ganga through the tenuous Chilla-Motichur corridor assumes significance for long-term persistence of tigers within this landscape.