Characterizing anthropogenic noise to improve understanding and management of impacts to wildlife

Abstract

Diverse biological consequences of noise exposure are documented by an extensive literature. Unfortunately, the aggregate value of this literature is compromised by inconsistencies in noise measurements and incomplete descriptions of metrics. These studies commonly report the noise level (in decibels, dB) at which a response was measured. There are many methods to characterize noise levels in dB, which can result in different values depending on the processing steps used. It is crucial that methods used for noise level measurement be reported in sufficient detail to permit replication and maximize interpretation of results, enable comparisons across studies, and provide rigorous foundations for noise management in environmental conservation. Understanding the differences in the acoustic measurements is vital when making decisions about acceptable levels or thresholds for conservation strategies, particularly for endangered species where mistakes can have irreversible consequences. Here we provide a discussion on how different acoustic metrics are derived and recommendations on how to report sound level measurements. Examples of additional measures of noise besides level (e.g. spectral composition, duration) are discussed in the context of providing further insight on the consequences of noise and will potentially help develop effective mitigation. It will never be possible to study all combinations of sources and species. Standardized methods of noise measurement and reporting are necessary to advance syntheses and general models that predict the ecological consequences of noise.