Usually, when one thinks of worms, they may think of squirmy slimy invertebrates best kept away from them, and in the ground, where they are helpful and good. It’s easy to see where that last idea comes from. I mean, they help to cycle the nutrients though the soil; decompose organic matter, leaving incredibly nutrient-filled droppings; and make it easier for air and water to penetrate the soil. So of course worms are good, right?
Well, it’s not that simple. Yes, worms can be good on farmland, in your garden, or in a forest that has coexisted with them for millennia. In fact, they can often be essential in these situations. But in a forest that evolved without them, they can be devastating.
Michigan forests, for example, have no native worms. None! The last Ice Age killed any and all worms that were living in Michigan and a lot of the rest of North America. “But there are worms all over now”, I can hear you saying. That’s completely true. However, these worms did not evolve here. They came from Europe, Africa, Asia, and lower sections of North America, and in all cases were brought by people like us, whether on purpose or on accident.
“But what’s wrong with worms here?” It’s quite simple, actually. Worms are too powerful of a decomposer. Before worms, bacteria and mushrooms were the powerhouses of decomposition, and let me tell you, they aren’t that powerful. Because of this, dead leaves were piling up faster that they could be decomposed, creating what is known as a “duff layer.” There are many types of plants native the wormless forests use this duff layer as protection, as it’s much harder to find a seed when it’s buried under several inches of dead leaves, and massive variety of plants grow weak roots, perfect for gathering nutrients from a spongy duff layer.
Worms, however, decompose much faster than the bacteria and mushrooms put together, and if there are enough worms in an area they quickly demolish the duff layer, leaving the seeds dependent on it eaten and the plants dependent starving. A lush, diverse forest ecosystem can swiftly be reduced to a wasteland in comparison, with little variety and much more spread between plants.
“How can we stop it?” Now that’s the question we all want an answer for. Unfortunately, once worms have infested and area, there really isn’t any way of getting rid of them right now. However, you can slow the spread of worms, as they only spread themselves a whopping 5 meters a year, and that’s at maximum speed. The real way they spread is by being moved by us, whether through our old garden getting thrown out into the yard, our tire treads picking one up on the dirt road on the way to the forest, or out leftover bait getting thrown out onto the ground, or even into the river we were fishing in.
Worms haven’t infested all of our “virgin” forests (a forest without worms), and they won’t if we don’t help them. Help stop the spread of worms to where they will hurt more than help by taking precautions yourself, and helping others by spreading the dirt on worms.