Tigers are globally endangered and continue to decline due to poaching, prey
depletion and habitat loss. In Nepal, tiger populations are fragmented and found
mainly in four protected areas (PAs). To establish the use of standard methods, to
assess the importance of prey availability and human disturbance on tiger presence
and to assess tiger occupancy both inside and outside PAs, we conducted a
tiger occupancy survey throughout the Terai Arc Landscape of Nepal. Our modelaverage
estimate of the probability of tiger site occupancy was 0.366 [standard
error (se) = 0.02, a 7% increase from the naive estimate] and the probability of
detection estimate was 0.65 (se = 0.08) per 1 km searched. Modeled tiger site
occupancy ranged from 0.04 (se = 0.05) in areas with a relatively lower prey base
and higher human disturbance to 1 (se = 0 and 0.14) in areas with a higher prey
base and lower human disturbance. We estimated tigers occupied just 5049 (se = 3)
km2 (36%) of 13 915 km2 potential tiger habitat (forests and grasslands), and we
detected sign in four of five key corridors linking PAs across Nepal and India,
respectively indicating significant unoccupied areas likely suitable for tigers and
substantial potential for tiger dispersal. To increase tiger populations and to
promote long-term persistence in Nepal, otherwise suitable areas should be
managed to increase prey and minimize human disturbance especially in critical
corridors linking core tiger populations