Ecological factors at fine spatial scale associated with habitat use by tigers in western Terai Arc landscape, Nepal

Conservation of designated source sites is a fundamental strategy for
global tiger recovery. Reliable estimates of tiger Panthera tigris habitat
use within these source sites are crucial for informing effective
management strategies. In this study, we assessed tiger habitat use within
Bardia-Banke Complex, one of the 42 global source sites, situated in the
western Terai Arc Landscape (TAL) of Nepal. We conducted a grid-based
detection and non-detection camera trap survey across 719 grid cells, each
measuring 2×2 km². To assess tiger habitat use while accounting for
imperfect detectability, we applied a single-season occupancy model. We
analyzed nine covariates that have potential to influence tiger habitat
use in the Complex, including terrain, co-predators, prey, water
availability and disturbance. We found that fine scale (2x2 km2) tiger
habitat use in the Complex was 0.43 (SE ± 0.0085, 95% CI: 0.414 - 0.448).
Our analysis demonstrated that tigers used habitats unevenly across the
Bardia-Banke Complex. Our results showed that terrain ruggedness index,
prey index, and proximity to waterholes were key determinants of tiger
habitat use. Tiger habitat use was positively associated with prey
abundance and negatively associated with terrain ruggedness, and distance
to waterholes. We emphasize the importance of influencing habitat
covariates that determine the probability of habitat use for taking
appropriate habitat-management decisions for tiger conservation in the
TAL. We highlight the importance of periodic assessment of tiger habitat
use in this globally significant source site to monitor changes in spatial
habitat use patterns, serving as a measure of the effectiveness of
wildlife management interventions.