Date of Degree Completion
Master of Science (MS)
Lori K. Sheeran
Second Committee Member
Third Committee Member
Fourth Committee Member
I assessed extirpation risks of the golden langur (Trachypithecus geei) in two landscapes (inside and outside the biological corridor). Working with a team of trained scientists, I collected data on group size, feeding range, sleeping sites, and predation on golden langurs from Langthel sub-districts, Trongsa district, central Bhutan. I used scan sampling to follow 24 groups of golden langurs (15 groups outside and 9 groups inside the biological corridor) to estimate average group sizes in the two landscapes. I confirmed their sleeping sites and recorded the physiognomies of sleep sites and dimensions of the trees used as sleeping sites. I used a GPS device to record each encounter point and from these aggregated points, I estimated winter feeding range for each group. Using a combination of remote camera trapping, sign survey method, and key informant interviews, I confirmed the presence of potential predators for golden langurs. I used qualitative risk analysis to analyze the probability and impact of six extirpation risks: 1) electrocution, 2) road kill, 3) retaliatory killing, 4) predation, 5) habitat destruction, and 6) population instability. I hypothesized that the golden langur’s average group size and feeding range would be bigger in the landscape outside the biological corridor, and that golden langur groups living outside the biological corridor would be more vulnerable to these six extirpation risks. My data and analysis showed that for groups living outside the biological corridor, average group size was larger, feeding range was larger, and groups were more vulnerable to extirpation risks. Focused efforts will be needed to conserve golden langurs living outside of protected areas.
Dorji, Kuenzang, "Extirpation Risk of the Endangered Golden Langur (Trachypithecus geei) Inside and Outside Biological Corridors, Langthel Sub-district, Trongsa, Central District Bhutan" (2021). All Master's Theses. 1485.
Available for download on Friday, March 17, 2023