Acknowledgements 
The authors thank the National Mission on Himalayan Studies (Wildlife Institute of India, Dehardun and G. B. Pant Institute of Himalayan Environment, Almora, Ministry of Environment, Forest and Climate Change for providing the funds to AS to carry out this study. We thank the Director, Dean and Dr. S. Sathyakumar for facilitating the NMHS fellowship programme at the Wildlife Institute of India. We thank Dr. B. S. Adhikari for facilitating logistics for the Amrut Ganga field surveys and Hima Nair, Meghna Bandopadhyay, Jaswant Singh, Kuwar Singh, Manish Bisht, and others who helped in the field. We thank Dr. Fredric Windsor for providing valuable inputs during multiple stages of the study. Local residents of Bhagirathi and Tirthan valley and Mandal village are thanked for their support during field surveys.