ecoacoustics, soundscape, ecoacoustic metrics, acoustic complexity index, ecoacoustic events, acoustic monitoring 

Ecoacoustics is a recent ecological discipline focusing on the ecological role of sounds.
Sounds from the geophysical, biological, and anthropic environment represent important cues used
by animals to navigate, communicate, and transform unknown environments in well-known habitats.
Sounds are utilized to evaluate relevant ecological parameters adopted as proxies for biodiversity,
environmental health, and human wellbeing assessment due to the availability of autonomous audio
recorders and of quantitative metrics. Ecoacoustics is an important ecological tool to establish an
innovative biosemiotic narrative to ensure a strategic connection between nature and humanity,
to help in-situ field and remote-sensing surveys, and to develop long-term monitoring programs.
Acoustic entropy, acoustic richness, acoustic dissimilarity index, acoustic complexity indices (ACItf
and ACIft and their evenness), normalized difference soundscape index, ecoacoustic event detection
and identification routine, and their fractal structure are some of the most popular indices successfully
applied in ecoacoustics. Ecoacoustics offers great opportunities to investigate ecological complexity
across a full range of operational scales (from individual species to landscapes), but requires an
implementation of its foundations and of quantitative metrics to ameliorate its competency on
physical, biological, and anthropic sonic contexts. 

https://www.mdpi.com/2227-7390/7/1/21/pdf