Earthworms are good, right? They aerate the soil with their burrows, and their poop – wormcasts, to be precise – is fine, rich, sought-after fertilizer.
That’s true for most worms, especially the European Nightcrawler, even though it’s an invasive (most worms in Canada were destroyed by the glaciation).
But the Asian Jumping Worm, Amynthas Agretis, is not a nice worm. It lives in leaf litter rather than soil, breaks it down quickly, making forest soils more susceptible to erosion. But it is what it breaks it down into that is the real concern. According to researcher Janelle Wempner:
The way these worms change the soil is something new. They leave little balls of soil. Imagine a soil surface covered in coffee grounds. These soil aggregates lock up nutrients and chemically alter the soil composition.
Potassium and calcium are held up in these little pellets, and as a result plants and fungi have a harder time growing. (I’m no chemist, but I would imagine that immobilizing calcium would also lower soil pH, never a good thing in forest soils.)
Yup, all that from poop: what a good worm produces can be undone by its evil twin. Plus, the jumping worm is downright creepy; see the video below.