The odds are good, if you live in the contiguous United States, that you’ve never seen a native earthworm. It also turns out that the invasive European earthworms, that have been colonizing North America for centuries, are causing radical changes to the landscape. I periodically talk about the various environmental problems that would merit concern even in the absence of global warming, and this is one of those. Invasive species can do incredible amounts of damage, and often in ways that nobody sees coming. Apparently the ways in which they alter soil structure and soil chemistry decrease water availability for native plants, warm the soil, and they’re even contributing to the so-called “Insect Apocalypse”. For all I grew up thinking of worms as Good For Plants, it turns out the wrong kind of worms can cause as much damage to a forest understory as I’ve ever seen from things like garlic mustard or honeysuckle.
Tegan came across this breakdown of where the current front of the invasion is, and how it’s doing harm, so I thought I’d share it. There are also a couple links above with more information. The first link above indicates that they might help with natural carbon sequestration, but it’s unclear to me how certain that is, or how it would balance with the cascading harms done by their activity. To my knowledge, there’s not anything that folks like us can do about this at this stage, but I’ll keep an eye out for any direct action that could help. It seems like some forest makeups are hostile to European worms, so maybe there’s a way to do a little ecosystem engineering of our own, to fight back. Beyond that, this is one of the many ways in which human activity has had a huge and fascinating effect on this planet, from an ecological perspective.