in conversation with Gianni Pavan
Gianni Pavan was a true pioneer in the field of bioacoustics, dedicating his life to the study of animal and ecosystem acoustics like no other. He held the Professorship of Bioacoustics and Ecology at the University of Pavia and led the "Centro Interdisciplinare di Bioacustica e Ricerche Ambientali" (CIBRA). Additionally, he was a member of the International BioAcoustic Council (IBAC), served on the Scientific Council of the International Ecoacoustics Society (ISE), and was an ordinary member of the Italian Association of Acoustics (AIA).
Gianni developed numerous digital and analog tools that significantly expanded the body of knowledge in acoustic ecology.
His unexpected passing in May 2023 marked the end of a remarkable career, and this interview serves as a tribute to his inspiring personality.
LM: Hi Gianni, it's a pleasure to meet you! As a biologist specializing in the study of sound, could you provide us with a definition of what sound represents?
GP: Certainly! It's important to note that sound, as a standalone phenomenon, doesn't inherently exist. Instead, I would describe it as a sensory perception that our brains generate when our ears detect rapid fluctuations in the surrounding air pressure. This mechanism is prevalent across most animal species and serves as a means to gather information from the environment. These vibrational cues are then processed by our brains to form the sensation we commonly refer to as "sound."
However, it's crucial to recognize that the sound experienced by humans isn't universally identical to the sound perceived by other animals. Different species possess their own unique auditory systems and interpretations of sound. For instance, creatures like bats and dolphins can both hear and emit ultrasonic frequencies that fall outside our audible range. Unlike humans, they employ sound not only for communication but also for spatial navigation through a process known as echolocation. So, for them, sound isn't just a form of communication; it's also a means of navigating their physical surroundings.
LM: How can the study of sound contribute to our understanding of ecological systems?
GP: To put it simply, sound opens a window to understanding ecological systems that would otherwise remain closed. Just as our eyes perceive only a fraction of the light spectrum, our ears are attuned to a specific range within the acoustic spectrum. To access the broader acoustic environment beyond our hearing, we rely on specialized instruments. This scientific approach hinges on precise and objective recordings of the acoustic signals in the environment.
These sounds can be categorized into distinct components. Firstly, there's "biophony," encompassing sounds produced by organisms. Then, there's "geophony," comprising natural sounds from the physical environment, like rain, sea waves, wind, and running water. Lastly, "anthropophony" encompasses human-produced sounds, with "technophony" referring to machine and transportation-generated noises found worldwide.
Only in recent decades have we realized that animal sounds serve functional roles in their lives, and that the entire tapestry of natural sounds represents life, ecosystems, and biodiversity. Sound not only helps us understand the behavior of individual species, a core aspect of bioacoustics, but also the broader "soundscape." This complex auditory landscape comprises sounds from the physical environment, animals, and humans, collectively conveying crucial information about a place.
For instance, in an agricultural area devoid of sounds like birdsong, frog calls, or insect chirping, a dearth of these natural sounds may raise concerns. This notion resonates with Rachel Carson's observations in her influential book "Silent Spring" nearly six decades ago. Carson noted how the shift from traditional to industrial agricultural practices dramatically altered the countryside soundscape by degrading natural habitats.
Noise pollution, both for humans and animals, poses a significant concern. It can lead to stress, health problems, and reduced hearing ability. The European Environmental Agency estimates that noise, primarily from transportation, contributes to over 10,000 annual deaths in Europe, causing a million health-related issues related to noise exposure. Addressing noise pollution is paramount, with the European community advocating for noise reduction from cars, ships, and airplanes.
We must also consider the impact of noise on animals' acoustic systems. Many species rely on sound for communication, courtship, feeding, predator avoidance, and resource location. Noise can disrupt this vital communication, known as "acoustic masking." When noise levels spike, animals can't hear each other or occupy specific areas due to excessive noise. While some animals can adapt to these conditions to some extent, many cannot. It's essential to remember that animals evolved their communication systems without human interference, particularly technophony, which is viewed as pollution with negative effects on humans, animals, and ecosystems.
Take humpback whales, for example. They produce intricate songs for courtship that can travel hundreds of kilometers. However, increased ocean noise from shipping, military exercises, oil exploration, and other activities confines their communication range to just a few kilometers. This disruption affects not only individual whales but entire populations by hindering reproduction. The harm extends to the population level, not solely the individual level.