A few years ago, the community of Periquito, one of a few within the Riozinho da Liberdade sustainable-use reserve near the town of Cruzeiro do Sul, Acre, reached an impasse. Realizing that they were having to travel farther and farther to find a paca, deer, or peccary to eat, the community established a rule: on one side of the river, hunting with dogs was allowed; on the other side, it was not. Canine assistance was making the hunt more efficient, perhaps even too efficient, exhausting their food supply.
Ricardo Sampaio, a biologist and environmental analyst from the Chico Mendes Institute for Biodiversity Conservation (ICMBIO), arrived in Periquito in 2018 amid discussions about the effectiveness of the self-imposed restriction. His objective was to investigate the impact of hunting on bird and mammal populations in sustainable-use reserves (SURs) — conservation areas that are also intended to preserve the livelihoods and cultures of traditional populations through the sustainable exploitation of natural resources. In addition to the eight communities of the Riozinho da Liberdade SUR, Sampaio and his colleagues collected data from another 91 communities located in eight other SURs in the central and southwestern Amazon. The results, published in the journal Biological Conservation in August, suggest that subsistence hunting, permitted exclusively to feed people living in the protected areas, only has a significant impact on wild species within a small radius of less than 5 kilometers (km) from the human communities. At greater distances, the impact decreases.
“In other tropical forests, hunting has a wider impact, at distances of 7 km to 10 km,” says Sampaio. According to the biologist, the absence of a legal meat market in Brazil helps to reduce the impact. “In Peru and countries in Asia and Africa where hunting is permitted, wild species are affected over a larger area,” Sampaio points out.
“In highly fragmented ecosystems like those found further south in Brazil, 5 km may seem like a lot. But in the Amazon, it is a very small area,” says Australian ecologist William Ernest Magnusson of the Brazilian National Institute of Amazonian Research (INPA), who did not participate in the study.
Between 2013 and 2019, Sampaio and his colleagues visited 100 communities close to or inside nine SURs to install camera traps, which they used to record the presence of 29 bird and mammal species. The cameras were positioned in lines, at distances from the center of each community ranging from 75 meters to 15 km, and remained active for an average of 42 days. “It took almost 30 days to install the cameras in each SUR and another 30 to remove them,” recalls Sampaio.
Ricardo Sampaio / CENAP / ICMBioAmazonian brown brocket (Mazama nemorivaga) and a group of white-lipped peccaries (Tayassu pecari) photographed by one of the camera traps used in the studyRicardo Sampaio / CENAP / ICMBio
Together with Ronaldo Morato of ICMBIO, and Adriano Chiarello of the Ribeirão Preto School of Philosophy, Sciences, Languages, and Literature at the University of São Paulo (FFCLRP- USP), he used the photographs to calculate species diversity and the number of individuals at varying distances from the human communities. In addition to the proximity to villages, the researchers considered the influence of six other variables on wild animal diversity and populations: the number of inhabitants and population density in the human communities, the distance from the nearest urban center and how many people live there, the availability of fish in the local area, and whether the area was inside or outside the SUR.
The factor that negatively affected species diversity and population size the most — by far — was the proximity to rural communities. Within 5 km of a village, the population size of the 29 wild species was smaller than it was 15 km away. Thirteen of the species had more than 50% fewer individuals within this distance. The tapir, curassow, peccary, brocket, and acouchi populations suffered some degree of decline even at greater distances, while red deer, paca, and agouti, which are better adapted to altered environments, were found in greater abundance even within 5 km of human communities.
The researchers suggest that the latter three species could theoretically be candidates for population management through controlled hunting by these communities, with the possibility of selling surplus meat, which is permitted by the legislation governing SURs issued by the Brazilian Institute for the Environment and Renewable Natural Resources (IBAMA) in 2002. At the same time, moratoriums could protect the more sensitive species.
Brazil’s 1967 Fauna Protection Law banned hunting and helped control the market for wild animal meat and skin, but created problems for people living in areas where this is one of the few available food sources. Although IBAMA regulations allow the use of fauna in sustainable-use reservations and the 1998 Environmental Crimes Law states that hunting “as a necessity to satisfy hunger” is not a crime, there is no standard definition of what constitutes a necessity. It is therefore left up to judges to decide whether hunting in a given situation occurred illegally or whether it was for subsistence.
“Hunting has been banned for so long in the country that we no longer have a hunting culture and we do not know, for example, how many peccaries or deer could be exploited per square kilometer without affecting conservation of the species,” says Chiarello from USP, one of the authors of the study. “Maybe that could change.”
Sampaio’s research helped the Periquito community make a decision. The data showed that species abundance and diversity were greatest on the side of the river where dogs were not used in hunting. “A year later, I received the minutes of a meeting at which they reinforced the agreement not to use dogs. They also began to limit dog breeding,” says the researcher.
Project
Conflicts between humans and wildlife in Amazonian sustainable-use reserves: Spatial ecological footprint and impact of subsistence hunting on forest-dwelling vertebrates (nº 17/08461-8); Grant Mechanism Regular Research Grant; Principal Investigator Ronaldo Gonçalves Morato (ICMBIO); Investment R$126,157.51.
Scientific article
SAMPAIO, R. et al. Vertebrate population changes induced by hunting in Amazonian sustainable-use protected areas. Biological Conservation. aug. 2023.
