The sound of logging: Tropical forest soundscape before, during, and after selective timber extraction

Over half of the world's tropical forests are used for timber extraction by selective logging. Even though these forests are degraded to a variable degree, they are still important for tropical forest biodiversity. It is not yet known how biodiversity is impacted during and immediately after logging, and how fast it recovers. Here, we use ecoacoustics, and specifically the recording and analysis of soundscape dawn time series, to monitor the immediate impact and early recovery of biodiversity after selective logging. We describe the results of capturing a dawn time series of soundscapes in a Bornean tropical lowland forest before, during, and after selective logging. Soundscape saturation, which is correlated with the number of different calls that make up the soundscape, dropped significantly immediately after selective logging was carried out. The reduced saturation was mostly due to the loss of bird vocalizations, whereas insects did not seem to be impacted. In a space-for-time recording from the same area, soundscape saturation during the equivalent time of day recovered after one year, however began to drop again in years 2 and 3 after logging. Our results are suggestive of a strong effect of logging and seasonality on tropical forest soundscapes. Being able to track biodiversity changes and recovery over time in tropical forests managed for timber production can ultimately improve our odds of avoiding more species extinctions, by providing evidence-based recommendations on how much time forests need to recover biodiversity.