Costa Rica paid landowners to restore forests and biodiversity—bioacoustics indicate that it worked

June 4, 2026 report Costa Rica paid landowners to restore forests and biodiversity—bioacoustics indicate that it worked Krystal Kasal Author Gaby Clark Scientific Editor Robert Egan Associate Editor Forest restoration can help fight climate change and restore lost biodiversity, but the satellite-based techniques used to measure successful forest restoration have been less-than-helpful for measuring changes in biodiversity. Instead, a team of researchers listened to the sounds of life in the restored forests. Their new study, published in Global Change Biology, reveals that forest restoration efforts in Costa Rica seem to be working to both regrow forests and restore lost biodiversity. Costa Rica's Payment for Ecosystem Services program Much of Costa Rica's rich forest had been cut down for farming and cattle pasture from 1960 to 1980. In 1996, however, the country established the world's first Payment for Ecosystem Services (PES) program, which pays landowners to help restore forests, aiming to benefit both nature and local communities. Now, the program protects over 200,000 hectares of land and acts as a way to evaluate the environmental impacts of a redistribution of wealth benefiting local land stewards. "Today, the PES program is widely regarded as a model program and an integral part of Costa Rica's progress in protecting its natural heritage. Having recognized the link between ecological degradation and inequality, the program is built on the need to address the social challenges that underpin environmental destruction at scale," write the authors of the new study. Previous research has linked PES programs to reduced deforestation and improved human well-being. But while satellite data could easily show increased canopy cover of Costa Rica's restored forests, it was still unclear if the PES program had truly restored biodiversity. Comparing sounds from different ecosystems Giacomo Delgado from the Institute of Integrative Biology in Zurich and his team came up with a novel way to assess forest biodiversity. The team set up audio recorders at 119 sites across Costa Rica's Nicoya Peninsula, including PES regenerated forests (in the PES program for a minimum of 10 years), monoculture plantations, degraded pastures, and mature forests for reference, and then recorded 16,658 hours of audio. They used soundscape analysis to compare biodiversity across the different land-use types, focusing on biologically relevant times and frequencies associated with different animal groups or human-related noise. Particularly relevant times were the "dawn chorus" from 5:00 and 6:30 a.m. and at dusk. The results showed that the forests naturally regenerating under PES were much more acoustically similar to the mature reference forests than to degraded pastures, indicating strong biodiversity recovery. Natural regeneration sites were on average 1.4 times more similar to reference forests than pastures, and up to 4 times more similar at certain times and sites. Monoculture plantations, which were typically timber plantations with trees between 7 and 20 years old, were 1.24 times more similar. "Among the PES sites, natural regeneration sites shared considerable acoustic characteristics with reference forests. This was significantly larger than the similarities between either reference forests and pastures or reference forest and plantations. The similarities peaked during the early afternoon and particularly during the dusk chorus, where mean similarity values regularly exceeded 0.90, indicating almost complete acoustic overlap," the study authors explain. Similarities during the dawn chorus were less pronounced, however. During this time, both natural regeneration sites and plantations exhibited significantly larger similarities to pastures than reference forests. Still, the regenerated forests were closest to natural forests compared to other land-use types. The team notes that comparing soundscapes only during the dawn chorus might underestimate the level of ecological recovery. Helping forests by helping people Overall, the study provides robust evidence that large-scale, redistributive restoration can drive real ecological recovery and that sound can act as a measuring device for biological diversity. Furthermore, it shows that efforts to help people can also help the environment. PES programs paying local landowners for ecosystem services have restored biodiversity at scale, showing that additional policies combining social equity with environmental goals may also be successful. The study authors write, "Weaknesses in the PES program remain, and improvements are needed to achieve truly equitable wealth redistribution, but studies suggest that many program participants perceive strong socio-economic benefits. Costa Rica's attempt to distribute wealth directly to those living in association with nature—through taxes on environmentally destructive behavior and rewards for ecological stewardship—represents a model that could be replicated and expanded globally. Learning from attempts to improve Costa Rica's PES is especially relevant given both increasing environmental degradation and economic inequality in the 21st century." Written for you by our author Krystal Kasal, edited by Gaby Clark, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you. Publication details Z. Buřivalová et al, Bioacoustic Baselines for Intact Forests, Global Change Biology (2026). DOI: 10.1111/gcb.70917 Journal information: Global Change Biology © 2026 Science X Network