Conservation threats to the endangered golden langur (Trachypithecus geei, Khajuria 1956) in Bhutan.

Threat assessment is critical to species conservation and management planning, because prior identification and assessment of key threats to conservation planning can assist in developing appropriate interventions or strategies. Comprehensive threat assessments are currently lacking for many threatened primates. In this paper, we classify and rank all direct threats to the endangered golden langur (Trachypithecus geei) in Bhutan in order to provide a practical guide to future conservation of the species. Information on threats was based on interviews with local people, discussion with field forestry staff, and social media interaction. We classified threats to golden langur habitats and populations, and ranked them using Miradi™, an analytical software for the adaptive management of conservation projects. We identified five habitat threats: (1) hydropower development, (2) road development, (3) housing development, (4) resource extraction, and (5) agricultural expansion. We also identified seven population threats: (1) electrocution, (2) road kill, (3) road injury, (4) dog kill, (5) retaliatory killing, (6) illegal pet keeping, and (7) hybridization with capped langurs. We rated the overall threat to golden langurs in Bhutan as 'medium'. Hydropower, road, and housing development constituted 'high' impact, while agricultural expansion, resource extraction, electrocution, and road kill had 'medium' impact; the remaining threats had 'low' impact. To immediately mitigate threats to golden langurs, we recommend: (a) installing speed limit signage and speed breakers with strict enforcement of speed limits; (b) installing insulated electric cables and fencing around power transformers; and (c) reducing and restraining domestic dog populations.

Population abundance and distribution of the endangered golden langur (Trachypithecus geei, Khajuria 1956) in Bhutan.

Reliable population estimates are lacking for many South Asian primate species, including the golden langur (Trachypithecus geei), which is endangered and restricted to Bhutan and northeast India. Although well studied in India, few studies exist on this species in Bhutan. In November 2017, we undertook a nationwide survey of golden langurs in Bhutan using double observers along trail-based transects in 17 blocks within its habitat, and modeled its distribution using MaxEnt. A total of 2439 golden langurs in 222 groups were collectively encountered by 17 teams of double observers, from which, an overall population of 2516 ± SE 363 individuals and 236 ± SE 9 groups were estimated. Group sizes varied from 2 to 35 individuals with a mean of 11 ± SD 0.38 individuals. A total of 468 adult males (19%), 924 adult females (38%), 649 juveniles (27%), and 398 infants (16%) were counted. Adult male-to-female sex ratio was 1:1.97 and adult female-to-infant ratio was 1:0.43. We determined 2848 km2 of suitable area for golden langurs in Bhutan and estimated a density of 0.88 individuals/km2. Our population estimate of golden langurs in Bhutan is much lower than the current IUCN estimate of 4000 individuals for Bhutan, necessitating a reassessment of its current conservation status due to threats from road kills, electrocution, and development activities like road construction, hydropower, and electrical transmission lines. We further recommend our refined double-observer survey method to reliably estimate primate populations in rugged terrain.

Understanding primate-human interaction: Socioeconomic correlates of local awareness and attitude toward the endangered golden langur Trachypithecus geei (Khajuria, 1956) in Bhutan.

Despite the golden langur's (Trachypithecus geei) endangered and totally protected status, local awareness and attitude toward this species is poorly understood. We investigated local awareness and attitude in Bhutan by interviewing 1,143 households in the districts of Dagana, Sarpang, Trongsa, Tsirang, and Zhemgang, and analyzing data through a conditional inference tree analysis. Most respondents were not aware of the golden langur's nationally protected (53%; n = 604) and globally endangered status (64%; n = 730), but their location of residence (inside/outside a protected area; p < .001) and education level (p < .001) significantly influenced awareness. The majority of respondents (87%; n = 999) liked the golden langur but the attitude was significantly influenced primarily by whether or not they experienced crop damage by golden langurs (p < .001), and subsequently by location of residence (p < .001), local belief (p < .01), gender (p < .05), and personal encounter with a golden langur (p < .001). Socioeconomic variables like age, education level, and annual income did not influence attitude. We recommend environmental education and awareness campaigns outside protected areas, and intensifying existing programs inside protected areas to forge harmonious human-golden langur coexistence.