05/18/2023
Since the fishing opener is upon us, we have earthworms on our minds! Some of you may have seen this information before, but lots of folks are surprised to learn that earthworms are an invasive species here in Minnesota and surrounding states.
As gardeners, we often hear about how great worms are for the soil, increasing air circulation, water infiltration, and adding fertilizer. While the benefits of worms in an agricultural setting have been well documented, worms in North America have a downside.
Unless you live in the southeast or parts of the Pacific Northwest, your region has no native worms. Vast regions of the continent have evolved without worms present, which has left a considerable legacy on the soils as well as the plant species that rely on them.
That's right, worms are bad for our native plants! Their burrowing activity mixes organic and mineral soil layers and allows for greater infiltration of water. This leaches valuable nutrients from the soil that plants, especially forest herbs, desperately require. It also increases runoff and erosion. Worm f***s, or casts, speed up microbial activity as well, which eats up vital stores of nitrogen in the organic soil layers. The loss of carbon from areas where worms have invaded has been likened to a complete functional loss of the forest floor. Worms have also been shown to eat vast quantities of small seeds, especially those of our dwindling orchid species.
The US has no restrictions on the import of worms, and new invasions are happening every year. Research has shown that epicenters of worm invasions are significantly correlated with roads and fishable streams. The Minnesota DNR advises that the best way to slow the spread of worms into new areas is to not release them. Worms are very slow to expand their populations, often moving less than 5 meters a year. Since humans are the most considerable vectors for worm movement, if we use the proper methods to discard worms used for bait, or composting, we can slow their spread across this continent.
*Please visit this link to read more articles about invasive earthworms.
linktr.ee/prairiemoonnursery
