Dr Jacqueline Stroud‚ the worm whisperer

Years of farm-based field work led her to a specific interest in earthworm biology and ecology, and recently she has been exploring the potential of eco-acoustics.

What led you to get involved with eco-acoustics?

Traditionally we collected earthworm population data by digging holes to count them, but disturbing the soil in this way made it hard to get a true picture of what was going on, so I started exploring other options, including going out on rainy nights when worms were active on the surface. Two years ago, I was invited to take part in an experimental eco-acoustic project listening for noises worms make in the soil. There’s some precedent for this approach – for over 50 years scientists have recorded song data to help track bird populations, but it was always more difficult with soil organisms because they don’t make harmonic sounds. They tend to scrape or drum in their soil burrows, producing percussive vibrations that transmit through the ground. We just needed the right equipment to capture those sounds.

Dr Jacqueline Stroud

So what actually is eco-acoustics?

What do worms have to do with soil health?

We have three main types of worms in our soils, and they all play a part. Surface-dwelling epigeic worms are the small red ones you find in piles of leaf litter. Anecic worms excavate as deep as six feet down but come to the surface at night to eat leaves, which they draw down and use to plug the top of their vertical burrow. But the most common is the endogeic, which you find when digging. They burrow horizontally, eating large amounts of soil, backfilling with their casts creating nutrient rich veins that plant roots can use. Together, worms types have a beneficial effect on soil structure and can promote plant growth by making soil nutrients, including nitrogen, more readily available. So farmers and gardeners should have an interest in encouraging their own worm populations. 

Endogeic worm