“While satellite data have shown an increase in forest cover, it’s been more challenging to assess whether the recovered forests have life thriving within them. More often than not, forest cover regeneration is considered the key metric of success in PES programs. Biodiversity assessments, however, are more difficult and expensive to implement over large areas…

Enter bioacoustics. For years, scientists have used this noninvasive technology — essentially placing microphones throughout the forest to record animal sounds — to conduct large-scale biodiversity assessments over wide swaths of forests. It’s also used to understand the behavior and communication patterns of animals…

Delgado and his team captured close to 16,658 hours of audio data from 119 sites across the Nicoya Peninsula in northwestern Costa Rica. They placed their audio recorders in protected areas, forests recovering under the PES program, monoculture plantations, and pastures, and retrieved them a week later. The sites that were sampled include 50 forests that were allowed to regrow naturally without any human intervention. These forests have been recovering after being abandoned for cattle ranching and farming for anywhere between 25 and 42 years.

After analyzing the data, they found that the sound profile of naturally regenerated forests under the PES program was very similar to that of protected forests. These patches were found to be ‘1.4 times more acoustically similar’ to protected forests than they were to pastures. ‘Healthy forests have strong peaks of acoustic activity right when the sun is coming up and going down,’ Delgado said. ‘Whereas in pastures, these are much less pronounced and the biggest peak is in the middle of the day when humans are active there.’

Biodiversity in monoculture timber plantations was also found to be recovering, but not as strongly as in naturally regenerated forests.”

From Mongabay.