Sensation Matters: Applying Masking Potential to Assess Noise Effects on Global Bat Species

Abstract

Aim: Anthropogenic noise is a global pollutant that threatens biodiversity. However, we currently lack effective methods to assess and compare the impacts of anthropogenic noise on extended terrestrial species. This can be critical for the majority of species that lack conservation attention and empirical measurements. Location: Global. Time Period: 1963–2023. Major Taxa Studied: Bats. Methods: We leverage the conserved mechanisms of how the vertebrate brain processes sound in noise to propose a simple sensation metric, the masking potential. To illustrate its usage, we assessed the effects of highway traffic noise on bats, which are a species-rich, important, yet under-represented mammalian lineage vulnerable to human disturbances. We first applied masking potential to a global dataset of bats to test whether auditory masking is an important explanation for bats' vulnerability to highway traffic noise. We calculated the impact ranges of highway traffic noise on bat species with audiograms. Then, we compared the predicted impact ranges with empirical measurements reported in the literature. Results: We show that auditory masking of both target echoes and social communication calls represents an important explanation for bats' sensitivity to highway traffic noise. The masking potential predicted maximum impact ranges (i.e., the distance beyond which animals are not impacted) of a median of 40 m for 71 species of bats, 614 m for the common marmoset, 1118 m for the great tit, and 1430 m for the budgerigar. The maximum impact ranges predicted by masking potential were supported by empirical measurements which yet remain scarce, stressing the value of masking potential for applied wildlife conservation. Main Conclusions: We propose that masking potential is a simple sensation metric that can help assess noise effects on diverse terrestrial species. This metric bears implications for real-world conservation practice and can be particularly useful to most wildlife species that lack conservation attention.