Project Anhangá: Bioacoustic recorders for detecting poaching and its impact on ungulates

Understanding the spatial and temporal distribution of hunting is essential for the management of protected areas, as well as for assessing its impacts on wildlife. This knowledge also allows patrols to be directed toward areas under greater hunting pressure. A promising approach to estimating hunting pressure is through the use of autonomous bioacoustic recorders combined with artificial intelligence tools. However, it is necessary to develop a process capable of accurately describing the spatial and temporal distribution of hunting and, in parallel with wildlife monitoring, understanding its ecological impacts. Therefore, our goal is to estimate hunting pressure across space and time and to assess its effects on forest ungulate species. We intend to evaluate the impact of hunting by testing its influence on the density, occupancy, and activity patterns of ungulates. To achieve this, we established a 1,500-ha sampling grid in Iguaçu National Park, where each of the 24 plots is equipped with one bioacoustic recorder and three camera traps, which will operate for two years. So far, we have completed four months of sampling. We also conducted a preliminary experiment to record gunshots from different types of firearms and ammunition at various distances from the recorders, aiming to model sound intensity as a function of distance. As a preliminary result, we found that gunshots from 12-gauge firearms can be detected with an intensity of 20 dB at distances of up to 900 meters, indicating this as an optimal spacing between recorders for triangulation of detected gunshots. uring the setup of the sampling grid, we already found seven clear pieces of evidence of poaching activity in different locations within the study area, including platforms used for poaching (2), campsites (2), artificial salt licks (1), and cartridges (2), and we recorded a poacher with a camera trap. In the coming months, hunting activity will be modeled spatially and temporally. The resulting database of bioacoustic recordings and camera-trap images will be made available to the scientific community to foster future collaborations and improve conservation strategies. Funded by FAPESP #2024/18433-5