Blackbuck occupancy in Moyar Valley, Tamil Nadu
Student name: Ms Devika Rathore
Guide: Dr Sudipta Chatterjee
Year of completion: 2017
Host Organisation: Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore
Supervisor (Host Organisation): Dr Jagdish Krishnaswamy
Abstract: Endemic to the Indian sub-continent, the population of the Blackbuck (Antilope cervicapra) was
estimated at 43,500 in India in 1989. Today, due to large-scale land use and land-cover change,
poaching, and loss of habitat due to invasive species, their habitat has mostly been restricted to a
few isolated patches of open grassland and agricultural fields. Living in close proximity to human
settlements, these ungulates are worshipped in some places and have actually thrived in some
protected areas. The alien invasive, Prosopis juliflora, which was introduced and now is wide-
spread in semi-arid areas, has been known to drive substantial losses of native vegetation in
savannas and grasslands, thereby resulting in the possible shrinking of blackbuck habitat.
Confoundingly, blackbuck are also known to eat Prosopis juliflora seeds, and inadvertently aid in
its dispersion through their dung piles in high density lekking aggregations.
This study seeks to explain the land-cover and land-use factors that influence the blackbuck
occupancy in the Moyar valley in Tamil Nadu (with a special focus on the invasive Prosopis
juliflora). This was done by combining detection probability data that accounts for imperfect
detection of blackbuck occurrence with covariates hypothesized to influence site occupancy of
blackbuck in the Moyar Valley. The Moyar Valley encompasses portions of the Sathyamangalam
Tiger Reserve, Nilgiri North and Coimbatore forest divisions in the Western Ghats. This valley
holds a large contiguous population estimated in the past to be 800-1000 individuals, although this
estimate needs to be verified using rigorous line transect data that accounts for detection
probability. Little is also known about factors influencing habitat for blackbuck in this landscape.
This study generates baseline data and identifies factors affecting blackbuck distribution in the
Moyar Valley.
Key words: Blackbuck, Habitat, Occupancy, Spatial replication, Prosopis
juliflora
