When Animals Disappear, Forests Lose Their Power to Capture Carbon

Redacción HC
04/10/2025

Tropical forests are often described as the "lungs of the planet," playing a vital role in absorbing carbon dioxide and mitigating climate change. But new research warns that their ability to recover from disturbance is being critically undermined by a factor often overlooked: the loss of animals that disperse seeds.

A recent study published in Proceedings of the National Academy of Sciences (PNAS) by Evan C. Fricke and colleagues reveals that the disappearance of seed-dispersing animals drastically reduces the capacity of tropical forests to regrow and store carbon. The findings highlight an urgent reality: conserving trees alone is not enough — forests also depend on the silent work of the animals that carry seeds and enable regeneration.

Animals: The Invisible Gardeners of the Forest

Seed dispersal by animals is a cornerstone of tropical forest ecology. Birds, primates, bats, and other frugivores transport seeds far from parent trees, creating opportunities for seedlings to thrive in new areas. Without these "ecological gardeners," regeneration slows, and carbon storage potential drops sharply.

Fricke et al. estimate that 81% of tropical tree species depend on animals to disperse their seeds. This interdependence means that the loss of dispersers directly translates into diminished forest resilience.

Measuring the Impact of Seed Dispersal Disruption

To assess how much seed dispersal disruption limits regrowth, the researchers developed a Seed Dispersal Disruption Index. This innovative tool combines data from:

• More than 3,000 tropical forest regeneration plots, tracking carbon accumulation over time
• 406 plant–animal interaction networks, mapping how tree species depend on dispersers
• Nearly 500,000 GPS locations of ~80 animal species, modeling their movement and dispersal capacity

The study found that regeneration plots with intact disperser communities accumulated carbon four times faster than sites with high disruption. On average, disruption reduced carbon accumulation potential by 57%, equating to a loss of 1.8 tons of carbon per hectare per year in degraded areas.

Implications for Climate and Restoration Policy

The results carry profound implications for climate policy and global reforestation initiatives. Many large-scale projects assume that tropical forests can rebound naturally and deliver major carbon sequestration benefits. But the study warns that such expectations are overly optimistic when fauna is missing.

“Ignoring the disruption of seed dispersal risks overestimating the carbon potential of tropical forest restoration,” the authors caution (Fricke et al., 2025).

For policymakers, this means reforestation strategies must not only protect tree cover but also safeguard — and in some cases reintroduce — key animal dispersers. In areas with high disruption, active tree planting may be required to complement natural regeneration.

Why Latin America Matters

The Amazon, the Atlantic Forest, and the Andes harbor some of the world’s most important seed dispersers: toucans, howler monkeys, tapirs, and fruit bats. Their decline due to hunting, deforestation, and fragmentation jeopardizes not just biodiversity but the climate regulation services of entire ecosystems.

Latin American nations, which have pledged ambitious restoration and climate targets, face a challenge: meeting commitments will require integrating wildlife health into forest recovery metrics. Protecting fauna is not a secondary conservation goal — it is essential for forests to deliver on their carbon promises.

The Bigger Picture: Biodiversity as Climate Infrastructure

The study contributes to a growing body of evidence showing that biodiversity is not just about species richness — it underpins key ecosystem services. As Bello et al. noted in Science Advances (2015), defaunation reduces tropical forests’ carbon storage potential by altering species composition. The new findings extend this insight globally, quantifying the massive impact of disrupted dispersal on carbon capture in regrowing forests.

Forests cannot fight climate change effectively without animals. In other words, biodiversity is climate infrastructure.

Conclusion: Conserving Fauna to Conserve Climate

Fricke and colleagues make clear that tropical forest restoration cannot succeed without the animals that move seeds. Protecting and restoring disperser populations should be a central component of climate strategies. The study serves as a powerful reminder that the health of forests and the fate of the climate are inseparably linked to wildlife conservation.

Governments, NGOs, and local communities must align reforestation with wildlife protection to ensure resilient forests capable of sustaining both biodiversity and global climate stability.

Topics of interest

Climate