Assessing the contribution of local experts in monitoring Neotropical vertebrates with camera traps, linear transects and track and sign surveys in the Amazon

Given the need for consistent databases for conservation planning and management in protected areas, a challenge is to develop more accessible approaches, while ensuring that the data are robust and fit for purpose. We compared the assemblage of medium and large vertebrates using three techniques, camera trap, diurnal line-transect census (sightings/vocalisations) and track and sign surveys, the latter two being carried out with the participation of local experts (local hunters). We observed that the methods employed were selective in detecting groups of species and, therefore, their use in combination is recommended for a more comprehensive assessment of wildlife biodiversity, as well as for detecting population trends. When evaluating the sightings/vocalisations and tracks and signs data together (given they can be applied concomitantly) in comparison to the camera traps, we verified that broadly the same numbers of species were detected, recording 29 and 28 species, respectively. The sightings/vocalizations were more efficient for detecting primates; track and signs allowed detection of most nocturnal and cryptic or evasive species (e.g., Artiodactyla and Cingulata); camera traps are most effective for rare carnivores and rodents. Thus, in an ideal scenario, the three methods should be used to monitor these species, however, the use of more accessible surveys to be practiced by local experts are efficient for most large and medium-sized vertebrate species. Considering developing countries such as Brazil, involving local experts and their knowledge in a monitoring program becomes essential for the continuity of monitoring in the long term.