Costa Rica’s regenerated forests are showing new signs of life, and researchers say the evidence can be heard. A new study led by researchers from ETH Zurich found that forests restored under Costa Rica’s Payment for Ecosystem Services program now sound far more like protected forests than cattle pastures.
The team placed acoustic recorders at 119 sites across the Nicoya Peninsula, collecting 16,658 hours of audio from degraded pastures, naturally regenerating forests, timber plantations and protected reference forests. That equals nearly one million minutes of recordings.
The recordings captured the daily rhythm of recovering habitats: insects, birds, rain, wind and other wildlife activity. Researchers then compared the acoustic profile of restored forests with older protected forests and open pasturelands. Their central finding was clear: naturally regenerating forests enrolled in the PES program were, on average, 1.4 times more acoustically similar to mature reference forests than to pastures. At dusk, their acoustic profiles were almost indistinguishable from those of national parks.
The study, published in Global Change Biology, adds weight to a question that has followed Costa Rica’s conservation model for years: has the country restored functioning ecosystems, or mainly recovered tree cover? The new research suggests that in many places, wildlife activity is returning along with the forest. ETH Zurich described the findings as evidence that Costa Rica’s PES program is restoring forest cover while also bringing back biodiversity.
Costa Rica’s forest recovery has become one of our country’s most important environmental stories. In the second half of the 20th century, cattle ranching and agricultural expansion stripped large areas of forest. Since then, national parks, land-use rules, ecotourism and payments to private landowners have helped reverse the trend. The World Bank has described Costa Rica as the first tropical country to reverse deforestation, with tropical rainforests now covering close to 60% of the country after shrinking to about 40% in 1987.
The Payment for Environmental Services program, known in Spanish as Pago de Servicios Ambientales, pays landowners for environmental services provided by forests. FONAFIFO says those services include carbon storage, biodiversity protection, water protection and scenic value. The program is framed as a financial recognition by the state for landowners and forest holders whose properties help protect and improve the environment.
One of the study’s most useful findings is that not all green cover delivers the same ecological result. Natural regeneration performed better than monoculture timber plantations, mostly teak. The plantations showed some recovery compared with pastures, but their recordings were quieter and less complex than those from naturally regenerated forests.
That matters in regions such as Guanacaste and the Nicoya Peninsula, where land has shifted for decades between cattle ranching, agriculture, timber, tourism and conservation. A property can look green from above but still lack the insects, birds, amphibians and mammals that make a forest function.
Acoustic monitoring gives scientists another way to measure recovery across large areas. It does not identify every species or prove that every animal group has fully returned, but it does show whether habitats are becoming more active and complex.
The findings also point to a practical challenge: restored forests depend on the people who own and manage the land. Costa Rica’s model relies heavily on rural landowners choosing conservation over cattle, crops or development. FONAFIFO says the PSA program has contributed to forest recovery, rural development and biodiversity goals, but also notes that available resources have not been enough to meet growing demand.
That warning is important as land values rise in parts of coastal Costa Rica and rural families face pressure to make properties produce more income. If conservation payments fall behind the real cost of keeping land in forest, some owners may be less willing to continue protecting it.
The study offers a rare piece of good environmental news backed by field data. The sounds returning to Costa Rica’s restored forests are part of the country’s natural identity, but they also support tourism, water protection, carbon storage and rural economies.
Costa Rica’s forests are not fully repaired, and the study does not erase the pressures facing protected areas and private land. But it shows that when degraded land is allowed to regenerate, and when landowners receive support to protect it, nature can return in ways people can hear.
