Shut away from most but a small group of armed guerrillas for more than 40 years, 200 square miles of some of the richest tropical rainforest on Earth was recently opened to a handful of lucky visitors to take stock of the biodiversity there.

View Images A UN helicopter lifts off from a camp that was previously used by FARC rebels, some of whom are now taking scientists into the jungle. Photograph by Federico Rios, National Geographic

The expedition was in the rural municipality of Anori, roughly 80 miles northeast of Colombia’s second-largest city, Medellin. It joined together a team of demobilized guerrillas from the Revolutionary Armed Forces of Colombia (FARC), university researchers, UN peacekeepers, and local community members.

The plan: to survey a tropical rainforest—until 2017 it was, and in many respects still is, largely inaccessible to the outside world—for plants, birds, mammals, insects, reptiles, and amphibian species.

Colombia boasts the second-highest rate of biodiversity of any country in the world; only Brazil has more. And Anori municipality falls between two biodiversity hotspots.

“In terms of biodiversity, we’re in a spectacular place. When we look at a biodiversity map of Colombia we see there are two places that stand out: the Andes and Pacific Choco,” said biology professor Juan Fernando Diaz. “Anori sits right where the two meet,” he said, which boded well for finding many species, some of which may be new.

View Images Two biologists from the team cross a river using zip lines that farmers use every day. Photograph by Federico Rios, National Geographic

The conservation of that “biodiversity miracle” was an unintended consequence of armed conflict with Latin America’s oldest and largest guerrilla group, said Carlos Ivan Lopera, regional United Nations Development Program (UNDP) coordinator.

Since the 1970s the conflict between leftist rebels, right-wing paramilitaries, and state authorities has killed more than 260,000 people, with nearly 83,000 still missing and 7.4 million forced to flee their homes. The situation made it impossible for biologists to visit the area and survey the species there. But a historic 2016 peace deal allowed demobilized FARC members to take select groups into the remote forest, Lopera said. (Learn more abut healing after decades of war.)

FARC’s presence in Anori has prevented large-scale development, but also widespread environmental destruction.

“This is about discovering the natural wealth of biodiversity treasure that was unexplored by institutional actors and scientists as a consequence of the armed conflict in Colombia,” said Lopera. “Without the peace deal and collaboration with the ex-combatants, frankly this mission would not be possible.”

This expedition is one of 20 sponsored by the Colombian government through the Colombia Bio program, whose goal is to spread awareness and understanding of the country’s biodiversity and natural resources. Another goal is sustainable use of those resources through science, technology, and innovation, especially in areas—like Anori—that were off-limits during Colombia’s conflict.

View Images A rural bus called a "Chiva" carries the researchers and former rebels from FARC from Anorí to La Tirana, where the journey started. Photograph by Federico Rios, National Geographic

Into the Forest

The research team set off from a UN-monitored camp called La Plancha in a brightly colored Chiva bus that passed wooden shacks spray-painted with messages that signaled a rebel group remained active in the area: “ELN 52 years of struggle... welcome.” The National Liberation Army (ELN), Colombia’s last-standing guerrilla group, has been in peace talks with the government for the last 18 months in Havana, Cuba. (See why this woman can't return home after years of violence.)

After four hours over a narrow, unpaved road, the first stop was the village of La Tirana. Communal Council President Ricardo Suárez (name changed to protect identity) explained that the local economy is based on cattle ranching and gold mining—much of it illegal. Both industries put intense pressure on the forest ecosystem.

View Images A mule guide arrives in the camp with equipment for the expedition. Photograph by Federico Rios, National Geographic

“Nobody appreciates you taking their spoon out of their mouth,” said Suárez. “It would be pretty easy to imagine oneself ending up threatened, wounded, or displaced if you were to speak out against the destruction.”

According to a report by non-profit organization Global Witness, Colombia is the third-most dangerous country in the world for environmental activists, with at least 30 murders in 2017 alone.

A few days later, the team finally got permission to enter the forest they wanted to survey, and set off with fully loaded pack mules.

Rock-covered roads wound through steep river valleys and up nearly vertical paths sunken in thick mud. Five hours of hiking brought the team to camp, which had been prepared by resident Obed Quiroz.

View Images Jorge Blanco Escobar prepares his equipment inside his barrack at the expedition camp. Blanco Escobar is a farmer from Solano and is part of a team of local guides helping the expedition through the unexplored jungle. Photograph by Federico Rios, National Geographic

“Look what we brought back yesterday,” said Quiroz, pointing toward a silvery palm leaf with long, blade-shaped leaves radiating in a circle from a central point.

Dino Tuberquia, a biology professor at CES University in Medellin, explained that the plant was likely the first evidence of the noli palm (Chelyocarpus dianeurus) in the area, and could even be a new species. The palm can grow 18 feet (6 meters) tall with massive, circular leaves that reach up to 6 feet (2 meters) in diameter. It was previously only known to grow in a small part of Colombia’s Pacific coast.

View Images Obed Quiroz (left) and Lina Bolivar (right), part of the botany team, said these leaves resemble Chelyocarpus dianeurus but have significant morphological differences, suggesting it could come from a new species. The team thinks they found at least five new species of plants on the expedition, but more research is needed to confirm this. Photograph by Federico Rios, National Geographic

Quiroz, who grew up nearby with his grandparents, said he had always maintained a special relationship with palms.

“Our survival was based on the palms,” said Quiroz. “The brooms we made all directly from the palm trees and with that, we were able to buy food and clothes.”

Quiroz has since moved into gold mining, but wants to return to the forest. “When my grandpa died, my work with the palms ended,” he said. “I would like to go back to working with palms, but this time to protect and conserve them for future generations.”

View Images This striking flower belongs to a plant-climbing vine called Thoracocarpus bissectus. Photograph by Federico Rios, National Geographic

The botany team identified a critically endangered wax palm (Ceroxylon sasaimae) in the research area. The iconic wax palm had only been rediscovered in the wild in 2011, and there are thought to be no more than 200 individuals left on the planet.

During the trip the research team also identified a tree-dwelling mouse, two types of flowering palm, and an orchid species. Some of the findings may be new to science.

View Images A team scientist looks for wildlife in the canopy. Photograph by Federico Rios, National Geographic

Looking to the Future

Ex-combatant FARC Olga Torres, nom de guerre Monica, said she hoped the scientific discoveries would lead to long-term benefits for the forests, ex-combatants, and the community. Torres imagined that someday the locals could set up scientific tourism projects, a botanical gardens, or a plant nursery for rare local species that could be sold to collectors.

“The state will have to play a role in the conservation of this forest, but not through repressive measures such as forcibly taking down illegal miners,” said Torres.

“The only way we’re going to achieve this is by working together to establish a new political structure and economy that allows us to put food on the table without cutting down the forest.” (Read about the former Colombian president's plans to protect the environment.)