- Four major conservation groups have joined forces to establish the Jaguar Rivers Initiative across South America’s Paraná River Basin.
- Its goal is to protect the big cat and other threatened species, rewild native wildlife, and protect land throughout the basin, a biodiversity hotspot shared by Argentina, Bolivia, Brazil and Paraguay.
- Many rivers form the borders between the four countries, and by collaborating on protections, the initiative seeks to reconnect fragmented habitat, using rivers and riparian forests to rebuild wildlife corridors.
- By 2030, the initiative plans to protect at least 1,200 square kilometers (460 square miles) of land in these countries, preserving approximately 34 million metric tons of carbon at risk of being released through deforestation, fire and land-use change.
Forced to quarantine at a ranger station during the COVID-19 pandemic, a group of researchers in northern Argentina passed the time by monitoring wildlife around a lagoon on the Bermejo River. One day, something unexpected appeared in the water: a giant river otter, thought to be extinct in the country for nearly 50 years.
The researchers paddled out in kayaks to photograph the animal, which soon began building a den beside their station, allowing them to monitor its behavior. They eventually launched a campaign for its protection.
“We couldn’t believe it. It was like it had come looking for us,” recalled Sofía Heinonen, executive director of the nonprofit Rewilding Argentina, the group working at the ranger station. “Everyone’s reaction was that it was as if everything seemed to be aligning too perfectly. The encounter was so powerful that we were practically stunned.”
Giant otters (Pteronura brasiliensis) are the largest otter species in the world, reaching nearly 2 meters (6 feet) in length and weighing up to 32 kilograms (70 pounds). They are highly social, typically living in family groups that communicate with a variety of calls.
Heinonen and her team said they believe this otter came downstream from neighboring Paraguay. The sighting, inside El Impenetrable National Park, is about 140 kilometers (87 miles) south of the Paraguayan border. They wondered how many other otters might still be out there, and how their habitat connected to allow one to reach Argentina.
Rewilding Argentina has been working in the country for more than 30 years, reintroducing native wildlife and purchasing and restoring private lands to help create state and national parks. However, its knowledge largely stops at the country’s borders. Heinonen said she realized that safeguarding some of the most threatened native species and their habitats would need a regional approach.
She also noted that conservation, as the giant river otter had shown, could be shaped around the rivers themselves. The Paraná River Basin — extending through Argentina, Paraguay, Brazil and Bolivia — is a single system. Protecting it will help protect jaguars (Panthera onca), red-and-green macaws (Ara chloropterus) and everything else living there.
“We have to look upstream if we want to understand how to restore all these ecosystems ecologically,” she told Mongabay.
In 2025, several organizations officially came together to form the Jaguar Rivers Initiative. The core of the group’s stated mission is to restore, reconnect and protect ecosystems, offering “a new vision for the future of conservation in South America: One where rivers are no longer barriers or boundaries, but living lifelines to a wilder, more resilient continent.”
Four groups have banded together: Rewilding Argentina, Brazil’s Onçafari, Bolivia’s Nativa, and the Moises Bertoni Foundation in Paraguay. Since many rivers here also form borders between countries, the organizations note that redrawing how people think of the continental map may be the only way to safeguard the interconnectedness of different biomes.
Power players come together
Before the initiative began, Rewilding Argentina was sharing best practices with Onçafari, a conservation group with jaguar-focused projects in the Pantanal, Amazon, Cerrado and Atlantic Forest.
Onçafari was founded by former race car driver Mario Haberfeld in 2011 with a simple desire: to see a jaguar in the wild. (The group’s name is a portmanteau of onça, Portuguese for “jaguar,” and “safari.”)
Onçafari habituates jaguars and maned wolfs (Chrysocyon brachyurus) in the Cerrado savanna and other biomes to get them used to humans, using a similar model as those used for big cats in many African habitats. In the Pantanal — a tropical wetland straddling Brazil, Bolivia and Paraguay, and threatened primarily by cattle ranching — livestock protection methods, education programs and other strategies have brought down retaliatory killings of jaguars. Their numbers are up, which has helped with ecotourism that supports local people. Sightings have risen from two per year to around 1,200, according to Onçafari.
While Onçafari and Rewilding Argentina weren’t working in the same biomes, they were often working on similar initiatives, such as fighting climate change-driven fire and drought; trying to build nature-based economies; and training local and Indigenous communities for conservation work and nature-based jobs. There were also hurdles for both organizations in navigating government bureaucracies involved in purchasing land for new protected areas.
“We felt that [wildlife] needed bigger spaces to live, bigger protected spaces,” Haberfeld said of Onçafari’s land purchases. “So we started buying land in strategic places.”
It made sense to work together. Brazilian and Argentinian biomes are connected by rivers that form the Paraná River Basin. The Paraguay River flows south from the Pantanal into the Gran Chaco, a tropical dry forest. There, it converges with rivers draining out of the Atlantic Forest, a tropical biome stretching across eastern Paraguay and along much of the Brazilian coast into Argentina.
But the organizations envisioned a broader collaboration. They started looking for conservation groups with strong grassroots connections to local communities and a history of buying and managing land. They were especially interested in groups with nonpartisan track records that had successfully worked with government agencies regardless of political affiliations.
One of those groups was Paraguay’s Moises Bertoni Foundation. Its director of programs and innovation, Alicia Rivarola, stressed the importance of collaboration with government. “The most important things that will help us survive through the years and all the different governments and the different things going on in the world is understanding that our role is to communicate with the government, with the private sector, with the international sector,” Rivarola said.
The foundation was established in 1988 at the tail end of Paraguay’s 35-year dictatorship, which had overseen an aggressive agricultural expansion into the country’s eastern region. This part of Paraguay was once covered in unbroken Atlantic Forest. Through a series of land purchases and agreements with the government and the U.N., the foundation now manages more than 700 square kilometers (270 square miles) of protected area. Most of it lies within the subtropical Mbaracayú Forest Nature Reserve, as well as land in Aguapey Nature Reserve in the Humid Chaco.
The foundation also runs a boarding school inside Mbaracayú Nature Reserve, where students can graduate with a technical high school diploma in environmental sciences, allowing many of them to work as park guards, guides and in other nature-based jobs.
In Bolivia, Nativa works in the Gran Chaco, Chiquitanía and Pantanal. Its regional, cross-border approach also aligned well with the Jaguar Rivers Initiative’s goals. Since its founding in 2003, the group has established numerous alliances in the tri-border area with Argentina and Paraguay, focused on stopping the advancing agricultural frontier.
Nativa also helps conserve 19 protected areas, covering more than 17,000 km² (about 6,600 mi²). In many of these areas, it helps local communities and governments develop ecotourism, sustainable agriculture projects and climate change adaption plans. That also includes strengthening carbon sinks, long-term food security and extreme weather resilience.
Despite its success, the organization’s conservation efforts are sometimes dwarfed by the scale of cattle ranching and agribusiness expansion that has been destroying the Gran Chaco and Chiquitanía dry forests.
“The scale of the challenges is so large that the only way to think about overcoming them is collectively,” Iván Arnold, executive director of Nativa, told Mongabay.
Initiative goals
The four organizations launched the Jaguar Rivers Initiative at Climate Week in New York in 2025 and held another launch event in London last month.
Together, the organizations bring a record of protecting approximately some 35,000 km² (13,500 mi²), an area roughly the size of Taiwan. They’ve also reintroduced 13 species and fostered the participation of more than 10,000 local people in nature-based economies.
In addition to jaguars, giant river otters and maned wolfs, reintroduced species include the South American tapir (Tapirus terrestris), lowland paca (Cuniculus paca), Pampas deer (Ozotoceros bezoarticus) and collared peccary (Pecari tajacu).
But the grander vision is to reconnect the basin’s fractured habitats by restoring rivers and riparian lands, allowing wildlife to move freely across borders and ensuring that landscapes can sustain both nature and people alike.
“Only through collective work, through an integrated understanding of ecosystems, can we take meaningful steps in this fight that we have against fires, against excessive deforestation, against agribusiness,” Arnold said.
A main pillar of the project involves “arks,” strictly protected core areas with full ecological function that, in some cases, will stretch across borders and ensure connectivity between biomes. The arks will be a generating source for wildlife populations, most notably for apex species like the jaguar.
Jaguars have been listed as near threatened globally since 2016, largely due to habitat loss and hunting. They’re an emblematic species and a focal point for conservation across their range, from Mexico to Argentina. Conservationists are trying to protect breeding populations and create wildlife corridors that allow the big cats to hunt, find water, and mate — and to escape from increasingly frequent extreme weather events.
The groups were already working in five areas that will become arks: the Chaco-Pantanal, the Alto Pantanal, Alto Bermejo, Iberá Park and El Impenetrable National Park.
Initially, groups will ensure they have territorial presence on both sides of all relevant rivers, while strengthening populations of threatened species and fighting poaching, deforestation and wildfire. They will need to consolidate existing management plans to improve coordination between the four organizations.
The arks will eventually be turned into binational areas, where protections are present and effective on both sides of the border.
The initiative will also create buffer zones around these arks and will establish “stepping stones” between them. These smaller patches of habitat will build corridors, allowing animal movement between the arks. They’ll be privately owned by companies, farmers, ranchers or others committed to an “economy of nature” model that may include wildlife tourism or agroforestry plantations.
By 2030, the initiative plans to add a minimum of 1,200 km² (460 mi²) of protected land across the four countries. Beyond the wildlife and ecosystem benefits, the initiative is expected to prevent approximately 34 million metric tons of carbon dioxide emissions from deforestation, wildfire and land-use changes.
In Argentina, there are plans to close protection gaps in Iberá Park and consolidate a continuous protected corridor along the Bermejo River in the Dry Chaco, South America’s second-largest forest. A cross-border project will restore connectivity between Argentina’s Baritú National Park and Bolivia’s Tariquía Flora and Fauna National Reserve. And in Brazil, the coalition plans to enlarge the Alagados do Taquarí wetlands.
Land purchases can take time and figuring out how to manage lands across international borders is complicated. But members of the initiative said they feel confident their collaboration will make the process easier in the coming years.
If the initiative is successful, Heinonen said, it should lead to the return of more giant river otters and other emblematic species to threatened habitats across the region.
“If we remove threats from the river, they will come,” she said. “They will recover their territory.”
Citation:
Ioris, A. A. (2024). Socio-economic geography and the land rights of indigenous peoples in Paraguay. Journal of Social and Economic Development. doi:10.1007/s40847-024-00347-3
Banner image: An aerial view of the Pantanal. Image courtesy of Arnaud Hiltzer.
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