Costa Rica's forest payment program is bringing wildlife back

A scientist in Switzerland wanted to know if Costa Rica's oldest conservation program actually worked. So Giacomo Delgado did what most ecologists wouldn't: he listened.

Delgado, a Ph.D. student at ETH Zürich, deployed 142 weatherproofed microphones across Costa Rica's Nicoya Peninsula and let them run for three months. The result: nearly a million minutes of audio recordings that tell a story the numbers alone couldn't.

The program he was studying started in 1996 as the world's first nationwide effort to pay landowners for protecting or restoring forest. It's funded by a tax on fossil fuels, and it's worked well enough that Costa Rica now grows more forest than it loses. But nobody had proven that the wildlife actually came back.

What the Soundscape Revealed

Using computer analysis to create acoustic "fingerprints" of different landscapes, Delgado's team found something encouraging: the forests regrowing on former pastureland—places where people were paid to simply stop farming and let nature return—sounded remarkably like intact native forest. The recovered forests were 1.4 times more acoustically similar to old-growth forest than to active pasture. Even replanted forests, where a single tree species was introduced, came in at 1.24 times more similar to natural forest.

The difference is audible. Natural forests are loud and chaotic, especially at dawn and dusk when birds and insects erupt in activity. Pastures are quieter, dominated by human sounds and lacking that sunrise-sunset burst of life. The regrowing forests captured that pattern—the animals were coming back, and the microphones picked it up.

There's still work to do. The dawn chorus in recovering forests remains muted compared to old growth, likely because biodiversity hasn't fully rebounded or because nearby human activity still dampens the soundscape. But the trajectory is clear.

What makes this study matter beyond the science is what it says about conservation economics. Costa Rica's program proves you don't need to lock away land in protected reserves to restore it. You can pay the people who live there—many of them poor—to protect and restore it themselves. The forests come back. The wildlife follows. The communities benefit.

Delgado put it plainly: "Empowering local people and sharing nature's bounty among all, instead of locking it away for the privileged few, is a radically effective ecological solution."

The next step is scaling this approach. If a tax on fossil fuels can fund forest recovery at this scale in one Central American country, the model is worth studying elsewhere.