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

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