Landscape analysis of tiger distribution and habitat quality in Nepal

Despite move than two decades of conservation efforts only limited informat ion is available on the metapopulation structure of the tiger (Panthera tig ris). We report on the geographic distribution of tigers in Nepal in relati on to habitat quality and describe an inventory and monitoring system that can be applied across the entire range of the species Using information fro m previous studies, interviews with local people, and digital thematic mapp er satellite data, we identified four populations of tigers three occur pri marily within the borders of Nepal, and a fourth is across the border in In dia. We estimate that there are 153 breeding tigers in these four populatio ns. in the Chitwan population 77% of breeding tigers live in three protecte d areas; the rest occupy national forests. Tigers in all four populations s urvive in isolated forest remnants of what was once a continuous subtropica l forest zone lying south of the Himalayas. Within central Nepal the ratio of good- to poor-quality, tiger habitat ranged from 16% to 86% across seven forest districts. The four areas with the highest ratio of good-quality, h abitat (>54%) supported breeding populations, one area with a marginal rati o of good-quality habitat (46%) was used only occasionally, and the two are as with the lowest ratio of good-quality habitat (<26%) were not used by ti gers. We suggest that when the ratio of good to poor habitat drops below ap proximately 50%, tigers no longer breed when it drops below 30%, tigers no longer occur in an area. Estimates of potential tiger habitat and data on h abitat used by tigers demonstrate the need to expand current management bey ond parks to encompass the entire land base supporting these fragmented pop ulations so that small tiger-populations can be managed as ecosystem or tig er management units rather than as portions of population within protected areas.