Ecoacoustic Monitoring Terminology/Glossary

Note: If a term has a [**] next to it, we are giving a definition that is specific to the term’s use in Arbimon.

Amplitude: The relative strength of a sound wave, with higher amplitude sounds perceived as louder. Amplitude is determined by the amount of displacement of air particles in a sound wave.

Acoustic Indices: Mathematical calculations used to measure a soundscape holistically based on its acoustic properties (i.e., statistical measures of acoustic energy). Many (60+) have been developed, most of which calculate the power ratio between different frequency and/or time bins across a raw soundscape.

Figure: Example of an Acoustic Complexity Index (ACI) by time of day from a protected and unprotected lake in the Amazon Rainforest. Higher values mean time intervals with more diversity of sound intensities. For more information, see Do Nascimento et al 2020.

**Acoustic Space Use (ASU): An acoustic index that measures the amount of the frequency range and time being used in a soundscape. Some studies have shown this index to be positively related to species richness such that sites with higher ASU values have more species. By analyzing the frequencies most used in a sonogram, it is possible to identify which taxonomic groups are contributing to the ASU (e.g. birds, frogs, insects).