Watching a movie or going for a walk? Testing different Sun bear (Helarctos malayanus) occupancy monitoring schemes

Size and distribution of wild populations are key elements in determining their conservation status, especially for vulnerable and elusive species, therefore choosing the proper monitoring method is fundamental to estimate population indices and consequently address conservation actions. In this study we worked in Rakhine State (Myanmar) applying and comparing two occupancy-based sampling methods to evaluate Sun bear (Helarctos malayanus) presence: camera traps and sign survey (line transects). Moreover to apply occupancy models it is necessary to establish length (time or space) of sampling occasion, therefore we tested for both methodologies four different sampling intensities to explore if results are affected by different temporal or spatial replicates. Both occupancy and detectability values varied between the two methods: we found lower values from camera traps analysis with no differences between different sampling occasions/segment lengths. Sign survey showed higher values for both parameters but changes in spatial segment lengths (line transects) affects occupancy estimates. Overall camera traps represent a more appropriate tool to study Sun bears in tropical forests as in our study area. Our results provide useful information to plan an appropriate monitoring scheme for bears in tropical forests.