Focusing on the tiger and its prey species, this study was carried out in the Chilla Range (ca. 150 km2) of Rajaji National Park and adjoining Shyampur Range (ca. 90 km2) of Haridwar Forest Division, Uttaranchal, from November 2004 to April 2005. Both these forest ranges are having functional connectivity with Corbett Tiger Reserve through the Lansdowne Forest Division. The study analyses the effect of a resident community (Gujjars) on the tiger, its prey species and their habitat. The unsustainable resource use patterns of Gujjars had led to an overall decline in tiger, elephant and ungulate use of Chilla Range. A relocation programme carried out in 2003 in the Chilla Range by the Uttaranchal Forest Department has given an alternative livelihood to these people, while making the area free of human infringement. Following this, signs of recovery had been evident necessitating a quantitative study to assert the importance of the area for conservation.

This study focused on how the tiger and its prey species are responding to this newly available habitat. We compared this recovering habitat in relation to the adjacent Shyampur Range where Gujjars still continue to lop and utilize the forest. To assess the habitat condition and prey occurrence, we laid circular plots along radiating transects from gujjar settlements and employed streambed (rau) walks to determine tiger occurrence patterns in human evacuated and occupied areas. Results show that lopping is higher in human occupied Shyampur Range, and the area also has higher densities of annual weeds. Densities of many fruiting trees are higher in the evacuated area of Chilla Range and also have higher overall shrub density of many palatable species. It was also found that prey species occurrence is negatively influenced by mere human presence. The streambed (rau) walks show a considerably higher rate of pugmark encounter rate of tigers in all sampled areas of the evacuated Chilla Range (1.09 ± 0.25, ER ± SE) as compared to human occupied Shyampur Range (0.10 ± 0.09), and is strongly influenced by human disturbance.

For the establishment of baseline information on tiger densities in the evacuated Chilla Range camera trapping within a capture recapture framework was employed. Prey species densities were estimated using line transects coupled with distance sampling and food habits of tiger assessed by analyzing the scats collected from the study area. Camera trapping for a total of 895 trap nights yielded 25 captures of four individual tigers within an effective sampling area of 132 km2. The estimated density of tiger was 3.01 (±0.71) per 100 km2. With the line transect effort amounting to a total of 94.80 km of walk the total wild ungulate density (Chital, Sambar, Nilgai and Wild Pig) was estimated at 90.8 (±4.57) per km2. From a total of 44 scats analysed, it was estimated that among the prey species (sambar, cattle, chital, wild pig and buffalo), sambar was preyed upon significantly higher than its availability. However, the estimated off take of standing wild prey biomass was only 2.78% suggesting that higher densities of predators (tigers) could be attained in Chilla Range.

Our findings point out that human disturbanc  e is the key factor that is driving both predator and prey from using a given habitat. As a result of now available habitat and high resurgence in good water sources both tiger and its prey species utilize the evacuated area substantially. The ungulate density in the evacuated area has been found to be sizeable enough to support up to 11 tigers per 100 km2. Support to this emerges from photographic evidence of two breeding tigresses. As against this, the human occupied area, although having ample water sources is not used significantly by tigers and its prey species.
 

M. Sc. Dissertations:

1.  Response of tiger (Panthera tigris), prey species and their habitat in relation to human disturbance in and around Chilla Range, Rajaji National Park, Uttaranchal – Amit John Kurien

2. Population, Food Habits and Prey Densities of Tiger in Chilla Range, Rajaji National Park, Uttaranchal, India – Abishek Harihar

Grant-in-aid

November 2004 to June 2005