Passive acoustic monitoring of biological soundscapes in a changing climate

Abstract

Passive acoustic monitoring of biological soundscapes offers a long-term view into ecosystem state. This is particularly well studied for coral reefs and tropical littoral systems with evidence for similar capability in temperate and deep ocean biologically rich ecosystems. Monitoring ecosystem state under both climate change impacts and changing human usage is a critical piece of understanding how climate change and human use impact ecosystems. Passive acoustics allow for wide area coverage of an ecosystem heartbeat, and changes in key bioacoustic metrics in coral reefs indicate shifts from healthy coral dominated systems to more degraded systems with increased macroalgal cover. These shifts are typically associated with increased ocean temperatures and/or increased human use. The primary controls on coral reef soundscapes are time of day and year. Here, broad comparisons between warmer and cooler years at long term coral reef monitoring sites in Hawaii will be discussed, as well as summer versus winter biological soundscapes at temperate sites in New England. Reef soundscapes encompass contributions from a wide variety of marine flora and fauna, some of which can be identified to species level through characteristic calls and tracked with a high degree of fidelity through passive acoustics alone.