Counting the Tigers in Bhutan: Report on the National Tiger Survey of Bhutan 2014 - 2015

Abstract

<p>Tigers have formed integral part of religion, culture, and livelihood in Bhutan. The Royal Government of Bhutan formally began scientific conservation of tigers with the establishment of the Department of Forests in 1952 and enactment of the Bhutan Forest Act in 1969. Since then, numerous tiger surveys and conservation efforts were initiated to ensure maximum protection of this endangered species in the country. </p> <p>In recognition of the sheer ecological and cultural significance of tigers in Bhutan, the Government has conducted the National Tiger Survey from 2014 to 2015 to reliably estimate tiger abundance and density in the country. The survey was fully conducted by a team of Bhutanese professionals from the Department of Forests and Park Services, signifying enhanced national capacity to undertake such a mammoth scientific exploration. </p> <p>Latest survey methods and equipment, such as Spatial Capture-Recapture (SCR) estimation methods and advanced models of camera traps, were used to estimate tiger populations in the country. The Bayesian based SCR estimation method was used to analyze data. The country was divided into two major survey blocks, the Northern Block and the Southern Block, considering the inherent limitations posed by numerous factors. A total of 1,129 survey grids were sampled from March 2014 to March 2015. </p> <p>A total of 1,784 tiger images and 138 videos were obtained from only 157 grids, and from these 68 adult tigers and 8 cubs were identified. In total, 103 tigers (between 89 to 124 individuals for the 95 percent credible interval) were estimated to occur at a density of 0.46 (between 0.40 to 0.55 for 95% credible interval) tigers per 100 Km² for the whole survey area of 28,225 km². The density estimate for overall survey area is low, but areas like Royal Manas National Park, Jigme Singye Wangchuck National Park, and Zhemgang Division has high tiger densities between 2 to 3 tigers per 100 Km². </p> <p>Tigers were mostly distributed within the north-western, central, and south-central part of the country between the altitudinal range of 150 to 4,000 meters. Four tigers were recorded from eastern Bhutan. The current camera trap survey confirmed the presence of tigers for the first time in Sakteng Wildlife Sanctuary (WS), Jhomotshangkha WS, Phibsoo WS, Wangchuck Centennial National Park, Tsirang Division, Gedu Division, Bumthang Division, and Samdrupjongkhar Division. Indeed, the highest numbers of tigers were recorded inside Zhemgang Division with 17 adults and three cubs.</p> <p>The current study further ascertains Bhutan as an important tiger conservation area in the region. It is evident that Bhutan is a source population for tigers in the region as supported by multiple female tigers with cubs at different locations. Thus, Bhutan forms the critical tiger conservation area within the global priority Tiger Conservation Landscape 37 for the long-term persistence of this endangered cat species in the eastern Himalayan region. </p> <p>It is strongly recommended that anti-poaching and surveillance programs be strengthened in addition to reassessing the alignment of corridors to ensure safe protection of the tigers in the country. </p>