The spatial distribution and population density of tigers in mountainous terrain of Bhutan

Habitat loss, prey depletion, and direct poaching for the illegal wildlife trade are endangering large carnivores across the globe. Tigers (Panthera tigris) have lost 93% of their historical range and are experiencing rapid population declines. A dominant paradigm of current tiger conservation focuses on conservation of 6% of the presently occupied tiger habitat deemed to be tiger source sites. In Bhutan, little was known about tiger distribution or abundance during the time of such classification, and no part of the country was included in the so-called 6% solution. Here we evaluate whether Bhutan is a potential tiger source site by rigorously estimating tiger density and spatial distribution across the country. We used large scale remote-camera trapping across n = 1129 sites in 2014-2015 to survey all potential tiger range in Bhutan. We estimated 90 individual tigers (60 females) and a mean density of 0.23 adult tigers per 100 km(2). Bhutan has significantly higher numbers of tigers than almost all identified source sites in the 6% solution. With low human density and large swaths of forest cover, the landscape of Bhutan and adjacent northeast India is a promising stronghold for tigers and should be prioritized in large-scale conservation efforts.