USING PASSIVE ACOUSTIC MONITORING TO ASSESS BIODIVERSITY PATTERNS IN A ROMANIAN BIOCULTURAL LANDSCAPE

Passive acoustic monitoring (PAM) is a relatively modern approach with numerous applications in detecting biodiversity patterns and ecological research, in general. This study explored the diversity in a protected area from southeastern Romania, which shelters a unique blend of natural and cultural heritage. We conducted PAM over a one-month period and analyzed the acoustic data to assess the reliability of five most common acoustic indices used to characterize and monitor natural soundscapes. For this purpose, we also manually quantified the number of biophonies and vocalizing species, and the presence of noise (i.e., non-biological origin) in each recording. We found that only three of the acoustic indices were significantly correlated to the number of biophonies and vocalizing species. These indices reflect the level of disturbance (NDSI), diversity (AEI), and structure (H) in natural soundscapes. Noise, especially wind, affected the first 1 kHz frequency band, masking biophonies emitted within this range. Noise significantly influenced the acoustic indices, but the acoustic activity was also significantly lower during periods with strong wind, thunderstorms, or rain. We present the main challenges and solutions to overcome the limitations of PAM and provide a baseline description of the studied soundscape. We recommend integrating PAM in monitoring and management strategies of protected areas in Romania.