What do most people think of when it comes to worms? Typically, there’s nothing but good things to say about worms. The main thing is that they’re great for fertilizing the soil to produce better crops. Other than that, they’re basically harmless. At least that’s what I thought at first. Upon further research, I’ve learned that worms are not as harmless as they are said to be.
The problem with worms is that they are an invasive species. There are no native species of worms in the Great Lakes Region. According to the NRRI (National Resources Research Institute) they were all wiped out by glaciers 11,000 years ago in the last ice age. The worms you see now in this region were mainly brought in by European settlers through activities like fishing and gardening. Once the worms weren’t being used for those activities, they were left to do their own little colonization. These invasive organisms were entering ecosystems that were worm-free since the last ice age, which turned things around for these forests.
The issue with bringing the worms into the forests is that forests have already been functioning well for many years without worms. So that means that there were other forms of forest decomposition, and the rate of decomposition compared to plant growth was low. This resulted in a very rich forest floor. The ground level had a considerable amount of plant life that covered the whole forest floor, which provided food and habitats for many of the organisms in the ecosystem. But with the introduction of worms, they do more damage than good.
Worms are incredible decomposers, but their decomposition is not needed in these forests. With the addition of worms to this once worm-free ecosystem, the decomposition rate is faster than the rate at which plants are produced. That means that the forest floor loses that rich, vegetated duff layer that was once very beneficial for the wildlife. Now the forest floor environment is degraded because there is not enough food or shelter provided for the organisms that depended on it.
It was really surprising to see how something as simple as a worm can have a negative impact on an ecosystem. But then again, it’s something I never really thought about, and as I think about it now, this type of situation is not new. I’ve heard many examples of seemingly harmless organisms having a damaging effect on an ecosystem rather than a neutral or positive one. This shows how ecosystems have fully set up their way of life. So just one “small” change (an addition, subtraction, or something moved out of place) can have a huge impact on any ecosystem.