Acoustic masking of soniferous species of the St-Lawrence lowlands

Abstract

How much of the acoustic resource shared by vocalizing animal species is masked by human-induced noise has become a central question in the emerging field of soundscape ecology. The goal of our study was to evaluate the joint probability that masking could occur for anuran, bird, or stridulating orthopteran species along the spectral, spatial and temporal dimensions of the acoustic space. We evaluated acoustic overlap in the dominant frequencies, absolute amplitudes (emitter-receiver distances), and time-series (temporal match-mismatch) of human- and animal-induced sounds in three landscape settings: urban, peri-urban and rural. Acoustic overlap was evaluated at the day scale during the active vocalizing period of each taxon. Our results suggest that acoustic masking is unlikely for a vast majority of species in the three taxonomic groups; ranging from 5–7% for anurans to 3–4% for birds and less than 1% for orthopterans. However, in urban contexts, acoustic masking could be a selective force when coupled to other factors that covary with the amount of noise produced by human activities, such as habitat loss and degradation.