Proximate Determinants of Ungulate Distribution and Abundance in Pilibhit Forest Division, Utter Pradesh, India

Abstract

This study was conducted in Pilibhit Forest Division, Uttar Pradesh from December 2010-April 2011 to quantify the current status of ungulates, as a measure of tiger conservation efforts. The study focused on understanding the distribution and population size of ungulates in PiIibhit, and assessed the contribution of these species in tiger's diet. The study also looked into species-habitat association, at the level of proportion of habitat availability and grassland over space. Sampling framework followed Stratified Random Design, with spatially balanced approach. Estimates of distribution and population density were obtained following Single Season Occupancy Model and Distance sampling method. A total of 41 grids (5.20 sq km each) were sampled following the above framework. These grids were sampled based on 41 line transects ranging from 1 to 3 km long, which accounted for 288 km sampling efforts, including 3-5 temporal replicates for each transects. This study was carried out in four ranges (Mahof, Mala, Barahi & Haripur) of Pilibhit Forest Division with spatial coverage of ca. 420 sq km. Occupancy pattern of ungulates were in the order of chital (100%), hogdeer (17%), wild pig (93%), nilgai (81 %), swamp deer (11 %) and sambar (3%). Global density estimate of ungulates for Pilibhit Forest Division was 40.5 animals/sq km. The most abundant ungulate was chital (22.4/sq km), followed by nilgai (12/sq km) and hog deer (7.2/sq km). It was found that there were higher densities in edge habitats and that there was a particular association for grassland, signifying the importance grassland patches in the ungulate densities in terai habitats. Scat analysis (n= 24) revealed that hogdeer and wildpig, though occur in low densities, appeared to be the preferred prey, while chital contributed in tigers diet substantially in proportion to availability in the area. With given prey availability, forests of Pilibhit has the potential to support tiger population of 8.1 animal 100 sq km. The study highlights the significance of managed forests in terms of supporting considerable population of ungulates relevant for tiger conservation efforts. The study also supports the previous claim that grasslands support higher abundance of ungulate prey, and that in the absence of large sized prey, tiger switches to medium sized prey. The available information generated for the first time in Pilibhit Forest Division at large spatial scale provides a useful baseline for managers.