By Luciana Crema, 6th June 2019
Since pre-colonial times the Amazonian manatee has been the most hunted aquatic mammal in Brazil, yet its ecology has been little studied. To improve our knowledge of the feeding habits of this Vulnerable species we worked with Ribeirinhos (Riverine People) to study the diet of the manatee in the vicinity of Anavilhanas National Park, Tapajós–Arapiuns Extractive Reserve and Tapajós National Forest in the Brazilian Amazon. Aided by the traditional knowledge of the Ribeirinhos we identified 31 plant species, predominantly vines, consumed by the manatee in Anavilhanas, and 37 food plants, primarily submerged species with floating leaves, in the Tapajós region.
Using the traditional knowledge of the Ribeirinhos we found that the diet of the manatee differs between different water types. The local communities who live in these areas have in-depth knowledge of manatee biology and the plant species it consumes. Two-thirds of the plant species we identified with the help of the Ribeirinhos had not previously been reported as components of the manatee’s diet.
Although pressure on the Amazonian manatee has declined, hunting still occurs in Anavilhanas, probably because of its proximity to the city of Manaus in Amazonas State. In the Tapajós region, however, manatee hunting appears to be infrequent and has little impact on the species. Because of their knowledge and their historical interaction with the species, the involvement of Ribeirinhos in manatee conservation is the key to reducing threats to the species and increasing the effectiveness of biodiversity management in these wetlands.
The importance of our study went beyond the novelty of our findings: we were empowered by the connection and motivation that we felt in working closely with these communities. We held several initial meetings with the relevant community leaders, to discuss the relevance of our work, and as a result the Ribeirinhos trusted the team and collaborated with us.
We observed the significant level of involvement that these riverine communities have with their environment, and the depth of their knowledge of ecosystem functions and the relationship between biotic and abiotic factors. Such relevant knowledge is often ignored by researchers.
We were able to bond and share personal stories with the Ribeirinhos, and we also carried out environmental education campaigns during our time with them. We held film sessions—with popcorn and juice—and distributed books and threatened species activity notebooks to children, and held discussions about the importance of conservation and the sustainable use of environmental resources. There was extensive interest in these activities.
Our findings have been presented to the managers and advisory council of the protected areas, and we are hopeful that the information will inform decision making to improve the management and conservation of the fauna and flora—and especially of the manatee– of these Amazonian protected areas.