Rio de Janeiro’s Tijuca National Park is full of large, healthy trees… but no animals. ‘Project Refauna’ is working to change this by reintroducing essential species back into the Brazilian forest.
Image: Vitor Marigo / Project Refauna
A ‘Forest On Its Deathbed’ Is Full Of Trees, But No Animals
Brazil’s Tijuca National Park — located in the larger and severely fragmented Atlantic Forest — is the largest urban forest on the planet. From an aerial view, the forest looks lush, healthy and green. There’s just one problem: there are very few animals that call this place home.
“This is a conservation problem that tends to be underestimated, but it’s gigantic,” says Fernando Fernandez, a professor of ecology at the Federal University of Rio de Janeiro (UFRJ). A large part of the tropical forest is empty.
The broader Atlantic Forest is home to 1,160 plant species and 425 animal species categorised as threatened on the ICMBIO Red List. Around 48% of the threatened species in the Atlantic Forest are found nowhere else on Earth.
Image: Julia Lima / Project Refauna
‘Project Refauna’ Is Bringing Life Back To Tijuca National Park!
Now, Tijuca has become a laboratory, of sorts! It’s home to one of the first ‘refaunation’ experiments in the world, called ‘Project Refauna’. This initiative is working to reintroduce essential animal species, back into Tijuca to revitalise the forest ecosystem.
The team at Project Refauna recognise that Tijuca National Park has already lost two-thirds of its large and medium-sized vertebrates. Of the 33 species that should be there, only 11 really do occur.
Animals like “Jaguars, tapirs, peccaries, ocelots, oncillas, margays, ferrets, woolly spider monkeys, and otters can no longer be found there. This is why Project Refauna is working to reintroduce these lost species.
Image: Vitor Marigo / Project Refauna
The Story Of The Agouti & The Agouti Tree
In the early 2000’s, researchers began to notice the decline of fauna in Tijuca National Park due to the surplus of rotting fruit found on the forest floor.
“Each day, ICMBio environmental analyst Ivandy Nascimento de Castro-Astor passed a row of agouti trees on her way to work, and she always saw the fruits on the ground,” said Alexandra Pires, scientific director of Project Refauna. “She began to wonder why she never saw an agouti, if there were so many agouti trees”.
The relationship between agouti (a rodent the size of a domestic cat) and the agouti tree (a tall, nut bearing tree) is symbolic of the relationship between plants and animals. Without agouti consuming and spreading the seeds of the agouti tree, there are no new trees to replace the old ones. This realisation sparked the idea behind Project Refauna!
Image: Vitor Marigo / Project Refauna
Project Refauna Is Reviving The Forest’s Ecological Processes
It’s estimated that between 70% and 90% of a forest’s plant life may depend on animals at some point in the life cycle, mainly for reproductive purposes. This is why in 2010, the team behind Project Refauna reintroduced eight agoutis into Tijuca. The number of agoutis has expanded to 31, and they’ve been interacting with more than 40 different plant species!
"The world has plenty of empty forests in biodiversity-rich places where ecological interactions are waiting to be restored,” wrote Brazilian researchers, Fernando Fernandez and Luiz Gustavo Oliveira-Santos.
After the agouti, Project Refauna successfully reintroduced howler monkeys in 2015. Then, the yellow-footed tortoise — a seed-diserping species that went locally-extinct 300 years ago.
Image: Vitor Marigo / Project Refauna
What’s Next For Project Refauna?
After managing to reintroduce two seed-dispersing species and one resilient primate species, what’s next on the agenda for Project Refauna? According to Fernandez, “later on, we can try to place medium-size predators”.
Right now, Tijuca is home to just 3 carnivore species. So, Project Refauna is looking into reintroducing the ocelot; a 15kg cat species that preys on the agouti and other rodents. More predatory species are needed in the forest, though — like hawks and snakes, according to Project Refauna. Then, Project Refauna is working to reintroduce the blue-and-yellow macaw; a large, seed-dispersing bird (popular with the locals!)
Longer-term, Project Refauna is seeking to reintroduce the largest predator in the Atlantic Forest — jaguars, and their prey — peccaries and tapirs!
The concept of refaunation is a bit like a puzzle — working out which species go where, and for what purpose. The ultimate goal is to restore the forest’s natural ecological processes to support all flora and fauna.
We love what the team at Project Refauna are doing in Rio de Janeiro! Thanks to them, Tijuca National Park is likely to be filled with plenty of noise and activity for generations to come.
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