Bernie Krause: The voice of the natural world

Summary

Bernie Krause describes how wild habitats produce distinctive soundscapes that can reveal information about ecosystem health. He divides soundscapes into three components:

• Geophony: Nonliving natural sounds, such as wind, streams, waves, and movement of the Earth.
• Biophony: Sounds made by organisms in a habitat at a particular time and place.
• Anthrophony: Human-generated sounds, including music and often-disruptive noise.

Krause argues that listening can provide a broader way to assess habitat health than visual surveys alone. Rather than isolating individual species, soundscape ecology considers the combined activity, density, and diversity of organisms. Spectrograms can display these sounds over time and across frequencies.

Examples from the talk

• Lincoln Meadow: Krause recorded dawn choruses before and after selective logging using consistent methods. The recordings showed a major decline in the meadow’s biophony, despite little visible change in the landscape. After 15 visits over 25 years, he said the soundscape had not returned to its earlier density and diversity.
• Sea anemones: A hydrophone recording captured low, static-like sounds and a louder sound when an anemone did not find food. This suggests that even organisms not usually thought of as vocal may produce sound.
• Great Basin spadefoot toads: Their synchronized choruses help them compete for mates and may make it harder for predators to target an individual. Near Mono Lake, low-flying military jets masked the chorus and disrupted its synchrony. Krause reported that it took about 45 minutes for the frogs to regain it. The population later returned close to normal with habitat restoration and fewer flights.
• Beavers: A colleague recorded a surviving male beaver calling after game wardens destroyed its dam, killing its mate and young. Krause presents the recording as evidence that animal emotion may be expressed in sound.

Environmental change—including resource extraction, habitat destruction, global warming, and human noise—has made recording intact soundscapes increasingly difficult. Krause estimates that capturing the amount of usable material that once took about 10 hours can now take 1,000 hours or more. He also says that roughly half his archive comes from habitats that have been radically altered or have fallen silent.

Krause concludes that soundscapes provide an immersive, wide-ranging perspective on the natural world, offering both ecological data and a sense of place.

Researchers and sources featured

• Bernie Krause: Natural sound recordist and speaker.
• An unnamed colleague: Recorded the beaver’s calls.
• Recorded examples and locations: The Amazon rainforest; Lincoln Meadow in California’s Sierra Nevada; an Alaska tide pool; Great Basin spadefoot toads near Mono Lake; and a beaver pond in the American Midwest.