Potencializando estudos na conservação de primatas: utilização de drones para localizar espécies ameaçadas, com destaque para os muriquis (Brachyteles Spix, 1823), na Serra da Mantiqueira

Abstract

In recent decades, Unmanned Aerial Vehicles (UAVs) have become significant allies in conservation studies, yielding superior results in the detection of endangered species compared to traditional survey techniques. In this context, the aim here, is to investigate which primate species, especially muriquis (Brachyteles hypoxanthus) and (Brachyteles arachnoides), can be better detected through the use of drones. Muriqui species are currently classified as "Critically Endangered" by the IUCN, primarily due to habitat loss, illegal hunting, and low reproductive rates. In this study, high-tech thermal cameras mounted on drones were employed to detect primates. In total, 83 drone flights were carried out in 9 different locations in Serra da Mantiqueira, covering 403 kilometers in 23 hours and 24 seconds. The average distance per flight was 4,855 kilometers (σ = 1,932 kilometers) and the average time per flight was 16 minutes and 26 seconds (σ = 3 minutes and 48 seconds). Through thermal and RGB images, individuals of the species Brachyteles arachnoides, Callicebus nigrifrons, Alouatta guariba, and Sapajus nigritus were successfully recorded. Drones with thermal cameras proved to be instrumental in locating two new populations of southern muriquis (Brachyteles arachnoides) on the eastern slope of the Serra da Mantiqueira, Gomeral neighborhood, municipality of Guaratinguetá and in the RPPN Gigantes de Itaguaré, municipality of Cruzeiro, state from Sao Paulo. These new discoveries reduce the area between populations of the genus to around 46 km, and the animals identified in Cruzeiro become the closest southern muriqui population ever recorded to the northern muriqui population, present in the Itatiaia National Park, in Rio de Janeiro. We also addressed the challenges in researching threatened primates surviving in low densities and inhabiting remote and relatively extensive areas. We validated the effectiveness of using drones equipped with thermal cameras as a new research tool for quickly locating primates, especially rare species, reducing time spent, and expanding efforts in large and difficult-to-access areas, such as the Serra da Mantiqueira. Furthermore, our results contribute to expanding knowledge about the current distribution of the Brachyteles genus, especially at the physical boundary of the species, providing guidance for future investigations based on the location of the Serra da Mantiqueira, allowing for a more precise delineation of this boundary in the region.