Healthy soils create a variety of sounds that are hardly audible to humans, reminiscent of an underground rave concert filled with pops and clicks.
Recent recordings by ecologists from Flinders University in Australia indicate that this noisy blend of sounds can serve as an indicator of the variety of small living creatures in the soil, which generate noises as they move and engage with their surroundings.
With 75% of global soils experiencing degradation, the future of countless underground species is grim without restoration efforts, warns Dr. Jake Robinson, a microbial ecologist at the Frontiers of Restoration Ecology Lab in the College of Science and Engineering at Flinders University.
This emerging area of research seeks to explore the extensive hidden ecosystems that are home to nearly 60% of Earth’s species, according to Dr. Robinson.
“It has never been more crucial to restore and monitor soil biodiversity,” he states.
“Though it is still a nascent field, ‘eco-acoustics’ is becoming an effective means to detect and assess soil biodiversity, and it has already been applied in Australian bushland as well as various ecosystems in the UK.”
“Acoustic complexity and diversity are noticeably greater in restored and remnant areas compared to cleared regions, both in situ and within sound attenuation chambers.”
“Additionally, the diversity and complexity of sounds are strongly linked to the abundance and variety of soil invertebrates.”
The recent study, which included contributions from Flinders University’s Associate Professor Martin Breed and Professor Xin Sun from the Chinese Academy of Sciences, contrasted acoustic monitoring results from intact vegetation with those from degraded plots and land that had been restored 15 years earlier.
The research utilized passive acoustic monitoring tools and indices to evaluate soil biodiversity over five days in the Mount Bold area of the Adelaide Hills in South Australia. A specialized device for below-ground sampling and a sound attenuation chamber were employed to capture the soil invertebrate communities, which were also counted manually.
“It’s evident that the acoustic complexity and diversity of our samples correlate with the abundance of soil invertebrates — ranging from earthworms and beetles to ants and spiders — suggesting a clear link to soil health,” remarks Dr. Robinson.
“All living beings produce sounds, and our initial findings imply that distinct soil organisms emit unique sound profiles based on their activity, morphology, appendages, and size.”
“This technology presents a promising avenue for developing more effective methods for monitoring soil biodiversity, addressing the urgent need to protect our planet’s most diverse ecosystems.”
