In addition to habitat loss and illegal hunting, the jaguar (Panthera onca) faces another threat that increases its risk of extinction in the South American Atlantic Forest: food scarcity.
A study by Brazilian researchers found that the availability of jaguar prey is reduced, even in the protected areas of the biome, which covers approximately 15% of Brazil and extends across 17 states in the South, Southeast, and Northeast regions, as well as parts of Argentina and Paraguay.
Jaguar prey species, including peccaries (Tayassu pecari), agoutis (Dicotyles tajacu), and deer, are hunted by humans and have dwindled to numbers that likely cannot support viable jaguar populations in the Atlantic Forest. The researchers warn that if this situation worsens, the biome, which currently has fewer than 300 jaguars, could become the first in the world to lose a top predator.
The results of the study, which was supported by FAPESP (projects 14/09300–0 and 18/16662–6 ), were published in an article in the journal Global Ecology and Conservation. The study also involved researchers from the Cananeia Research Institute (IPeC), the Chico Mendes Institute for Biodiversity Conservation (ICMBio), as well as its National Center for the Research and Conservation of Carnivorous Mammals (CENAP/ICMBio), the State University of Mato Grosso (UNEMAT), and the Iguaçu Jaguar Project – Pro-Carnivores Institute.
"We found an alarming situation of low abundance of key prey species for the jaguar even in protected areas of the Atlantic Forest, where national and state parks are located and where one would expect the situation in terms of the animal's conservation to be better," Katia Ferraz , a professor at the Luiz de Queiroz School of Agriculture at the University of São Paulo (ESALQ-USP) and coordinator of the study, tells Agência FAPESP. "Most likely, the decline of these prey species is one of the main causes of the critical conservation situation facing the jaguar in this biome," she notes.
Field survey
The researchers combined information on the jaguar's diet and feeding habits with data obtained through an on-site survey of the feline's prey species. They did this using camera traps distributed across nine protected areas in the Atlantic Forest. Based on the data, they estimated the abundance and biomass of 14 prey species in these areas, which have varying levels of jaguar populations, and made comparisons between them.
The analyses revealed that the largest feline in the Americas primarily feeds on large prey, particularly wild pigs and deer. These prey were more abundant and had higher biomass in the Green Corridor than in the Coastal Atlantic Forest regions, such as the Serra do Mar, where jaguars are absent or occur at very low densities. The data reveal a striking difference in biomass between the Green Corridor (638 kg) and the coastal regions (8.2 kg).
"The results show a consistent pattern. Areas with greater prey availability, especially of medium- and large-sized prey such as wild pigs and deer, are also those where jaguars persist. Where the prey base is very limited, jaguar populations tend to be absent or extremely small," notes Ferraz.
Easier access
According to the researcher, the low abundance and reduced biomass of the analyzed species were due to human presence. Prey were more abundant in areas that were more difficult to access and less abundant where illegal hunting was easier, indicating that this activity remains a core problem, even within conservation areas.
"We've observed that the low availability of prey is linked to increased human access to protected areas. In areas that are more easily accessible due to factors such as terrain and proximity to villages and urban centers, prey availability is lower," says Ferraz. "This suggests a direct link to hunting pressure. In addition to the pressure on the jaguar itself, the predator, there's very strong pressure on prey populations, leading to the decline of the feline," she explains.
In the Green Corridor, protected areas are more connected and less accessible to human activity. Ongoing conservation initiatives, such as the Iguaçu Jaguar Project, and long-term efforts to combat illegal hunting also help explain why there is a prey base capable of sustaining viable jaguar populations.
In the coastal portion of the biome, such as the Serra do Mar, the low abundance of prey may reflect historical and still-persistent human pressure, despite the vast territorial extent and numerous ongoing conservation efforts, whether government-led or not. The authors of the study note that this reality is linked to the region's proximity to major urban centers, such as Curitiba and São Paulo, and to the greater ease of access to protected areas.
According to the authors, this scenario poses a core challenge to environmental management. While some regions function as refuges that maintain ecological balance, others require intensive actions to control hunting, recover wildlife, and manage human use to prevent the permanent disappearance of the Americas' largest predator in the Atlantic Forest.
Conservation oases
Of the areas evaluated in the study, Iguaçu National Park stood out as one of the last places in the Atlantic Forest with relatively high populations of predators and prey.
The successful conservation of jaguars in the park is due to a combination of human and ecological factors, including the work of the Iguaçu Jaguar Project and altitude. "Across all the areas analyzed, it was observed that the lower the altitude, as in the park, the greater the abundance of prey – a pattern also recorded in other areas of the Atlantic Forest," explains Ferraz.
The Iguaçu Jaguar Project is based on three pillars: research, coexistence, and engagement. In the research area, applied studies are conducted to inform effective strategies on topics such as food ecology, vegetation corridors, and monitoring.
The engagement pillar aims to transform fear into understanding and fascination with jaguars, strengthening the bond between local communities and conservation efforts. The coexistence pillar involves working with communities surrounding the park to offer guidance on best practices for livestock management, preventing predation, and reducing misinformation. When there are reports of sightings or tracks, immediate guidance on safety and appropriate behavior is provided.
"Jaguars here in the region were nearly extinct. In 2009, we had between nine and 11 animals, and over the past 15 years, the population has nearly doubled," says Yara Barros, the executive coordinator of the project. One of the actions that contributed to this result was precisely the increased effort to combat illegal hunting. "Hunting poses a major threat because people often enter the forest to hunt the animal's prey and end up killing it as well," she says.
The increase in agriculture and decrease in cattle ranching around the park may have also contributed to the recovery of the species, as the change in land use has reduced retaliatory killings. "We collaborate with communities in ten municipalities. A project technician visits rural properties not only when predation occurs," says Barros.
According to Barros, coexistence is key: "We're creating a tri-national network with partners from Paraguay and Argentina to share and replicate our experience," she says.
About São Paulo Research Foundation (FAPESP)
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