New research has found that animals play a key role in restoring forests

As countries meet in Montreal this week to tackle unprecedented biodiversity loss – more than 1 million species threatened with extinction – a new study published in the Royal Society journal, Transactions with the Royal Society Philosophy Transactions B, points to a unique and important role
that animals play in reforestation.

Aerial view
of secondary tropical forest regeneration at the Baro Colorado Natural Monument, Panama.
Source: Christian Ziegler
, Max Planck Institute for Animal Behavior.

Efforts to restore forests tend to focus on trees, but the study found that animals play a key role in tree species recovery, bringing a wide variety of seeds to areas
that were previously cut down.

The study was conducted by an international team led by Sergio Estrada-Villegas, a postdoc at Yale University's School of Environment, who collaborated
with Liza Comita, a professor of tropical forest ecology.
The project studied the regeneration of a series of forests in central Panama over a period of 20 to 100 years after abandonment, completed by Estrada-Villegas as a Cullman Fellow in a joint YSE and New York Botanical Garden
.
The study, published in a special issue of the journal as part of the UN Decade on Ecosystem Restoration, focuses on forest landscape restoration
.

"When we talk about forest restoration, people usually think of going out and digging holes, planting seedlings
," Comita said.
"It's not actually a very cost-effective or effective way
to restore natural forests.
If you have a well-preserved forest nearby, coupled with animal seed spreaders around you, you can get natural regeneration, which is a less costly and less labor-intensive method
.
”

The team analyzed a unique long-term dataset from Panama's Barro Colorado Natural Monument Forest, overseen by the Smithsonian Tropical Institute, to compare how many tree species in the forest were dispersed by animals or other methods, such as wind or gravity, and how that changed over time
.
The team focused on the proportion of plants scattered by four groups of animals: flightless mammals, large birds, small birds, and bats
.

Thanks to about a century of in-depth study of the region by Smithsonian biologists, the team was able to delve into data dating back decades, including aerial photographs
taken in the '40s and '50s of the 20th century.
The area also offers a unique forest landscape where there is little hunting or logging
.
According to the study, these results provide the most detailed data
on the dispersal of animal seeds within the framework of the maximum time frame of natural recovery.

Comita and Estrada-Villegas say the study's most important findings are the role that flightless animals play in seed dispersal across all forest ages, from 20 to old age, and the diversity of animal species involved, and point to the importance
of natural forest regeneration.
In tropical forests, more than 80% of tree species can be dispersed
by animals.

The findings could serve as a roadmap for the natural regeneration of forests, protect biodiversity, and capture and store carbon, the researchers said, and that the current UN Restoration Decade has highlighted the need for land conservation and that world leaders are working to slow climate change
caused by fossil fuel emissions.
Forests absorb carbon dioxide from the atmosphere and store it in
biomass and soil.
The researchers note that tropical forests play an important role
in regulating the global climate and supporting high levels of plant and animal diversity.

Estrada Villegas, an ecologist who studies bats and plants, said the study highlights the importance of
animals for healthy forests.

"In these tropical environments, animals are essential for the rapid recovery of forests," said Estrada-Villegas, who recently joined the faculty of
Rosario University in Bogotá, Colombia.