Brazilian tapir density in the Pantanal: A comparison of systematic camera-trapping and line-transect surveys
The density of Brazilian tapirs (Tapirus terrestris) was studied in the northeastern part of the Pantanal wetlands of Brazil using two simultaneous and independent methods: (1) systematic camera trapping combined with capture-recapture analysis, with camera traps spaced I km apart and distributed over 54 km(2); and (2) line-transect sampling using an array of 12 linear transects, from 3.8 to 7.2 km long, covering the principal open and forest habitat types across the entire 1063 km(2) SESC Pantanal Reserve. The two methods yielded conservative density estimates of 0.58 +/- 0.11 tapirs/km(2) (camera trapping) and 0.55 (95% CI 0.30-1.01) tapirs/km(2) (line transects). The study suggests that certain Pantanal habitats and sites can sustain relatively high population densities of tapirs when these animals are protected from hunting. Further testing of the camera-trapping methodology as applied to tapirs is required, particularly focusing on extending the survey period. As it represents a relatively rapid method for estimating population density, in comparison to line-transect surveys, and as it generates information simultaneously on multiple species that are conservation priorities, we recommend that camera-trapping surveys be applied more widely across a variety of Pantanal habitats and land-use categories in order to confirm the value of the vast 140,000 km(2) wilderness region for this vulnerable species.