"Without wildlife, the forests are doomed," warns expert.

Beatriz Bevilaqua, 247 - Forest restoration cannot stop at planting trees. Without animals to disperse seeds, control populations, and maintain functioning ecological cycles, tropical forests become barren, silent, and doomed landscapes. This is the premise that guides the work of the NGO Refauna, led by biologist Marcelo Rheingantz, PhD in Ecology from UFRJ, who for over a decade has been leading pioneering actions to reintroduce native fauna to fragments of the Atlantic Forest.

In the program “Sustainable Brazil”, Marcelo spoke about the urgency of “re-faunating” degraded ecosystems, explained the behind-the-scenes aspects of species translocations, and argued that restoring wildlife is also a way to confront the climate crisis.

Inspired by the concept of trophic rewildingPopularized by European initiatives, the term "rewilding" was coined in Brazil to designate the reintroduction of recently extinct native species from certain areas, with the aim of restoring essential ecological functions. "We advocate for bringing back species that once existed in these territories and that disappeared, often due to direct human action, such as hunting or habitat fragmentation," explains Marcelo.

Unlike initiatives that use exotic species to try to rebalance ecosystems, such as cattle and horses in Europe, Refauna works with Brazilian species, respecting the complexity and endemism of biomes like the Atlantic Forest.

The strategies adopted by the NGO include two main types of translocation: reintroduction – when a species has completely disappeared from an area – and population reinforcement – ​​when it is still present, but in reduced numbers or with low genetic diversity. In both cases, animals are carefully moved from breeding grounds or natural areas to the target fragments, where they live under monitoring.

But the decision to reintroduce a species is not simple: “We need to be sure that the cause of the local extinction has been resolved. It’s almost detective work to understand why that animal disappeared from there and whether the environment is ready to receive it back,” he points out.

Atlantic Forest: an incomplete puzzle

The Atlantic Forest, which once covered more than 1,3 million km² of Brazilian territory, now survives in only 12 to 16% of its original extent, and most of the fragments are less than 100 hectares. “It’s like putting together a jigsaw puzzle with missing pieces. Without wildlife, this forest doesn’t regenerate,” says Marcelo. “Four out of five tropical trees depend on animals to disperse their seeds. If the animals disappear, the forest stops renewing itself.”

A study coordinated by his laboratory showed that medium and large mammals have lost, on average, 88% of their original distribution in the Atlantic Forest – a rate similar to that of forest loss. “The data confirms this: we are living through the sixth great mass extinction, the first caused by a single species, our own.”

One of Refauna's most emblematic projects takes place in Tijuca National Park, in the heart of Rio de Janeiro, where red agoutis have been reintroduced. These small frugivorous rodents are essential for the regeneration of some tree species. Before the reintroduction, fruits from the tree known as "cutieira" rotted on the ground, with no one to disperse them.

“This park is the most visited in the country, it houses the Christ the Redeemer statue and is an island of forest surrounded by urbanization. Even so, it was silent, without its animals. Today, we receive photos and videos from visitors delighted to rediscover the wildlife. This shows that restoring ecosystems also restores people's connection with nature,” says Marcelo.

The reintroduction of species is not just a conservation action. According to Marcelo, it also contributes to mitigating the climate crisis. Animals help maintain carbon flows in the forest, regulate the microclimate, retain water in the soil, and even influence rainfall patterns. "A functional forest is a living forest. And to be alive, it needs its animals," he emphasizes.

Education and mobilization as part of the solution.

In addition to scientific and ecological work, Marcelo argues that environmental education and social engagement are fundamental. “Children today are born with a greater environmental awareness than we do. The solution lies with them, but it also depends on our decisions now, such as voting for representatives committed to the environmental cause and combating greenwashing.”

The idea that a forest without wildlife is a doomed forest comes from the concept of "Empty Forest Syndrome," coined by ecologist Kent Redford. "It's not enough to have trees. If there's no animal life, that ecosystem is dead inside," summarizes Marcelo. This diagnosis guides Refauna's actions and inspires a new way of thinking about conservation in Brazil: more active, bolder, more connected to life.

Marcelo recommends the series “Our Planet, narrated by David Attenborough, and “The Most Fascinating National Parks in the World, narrated by Barack Obama. For those who wish to delve deeper, the books “"By Fire and Sword", by Warren Dean, and “A Gap in NatureTim Flannery's books are essential reading.

Watch the full interview here: