# The native American earthworm. What's the real story? **URL:** \ **Category:** Factual Questions\ **Created:** [September 24, 2013, 10:26am UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570 "2013-09-24T10:26:48Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![davidmich](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@davidmich](https://boards.straightdope.com/u/davidmich)\ **Post date:** [September 24, 2013, 10:26am UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/1 "2013-09-24T10:26:48Z")
Hi, I have a question regarding the native American earthwormas opposed to the European introduced by the Columbian exchange. Compare a Straight dope link from 2001 to a recent Spiegel magazine review of “1493: Uncovering the New World Columbus Created,” by Charles Mann. Who is correct here? I look forward to your feedback. davidmich > **[What’s the story on North American earthworms?](https://www.straightdope.com/21343051/what-s-the-story-on-north-american-earthworms)** > > A STAFF REPORT FROM THE STRAIGHT DOPE SCIENCE ADVISORY BOARD First off, all of North America was not scraped down to bare rock during the ice ages, and that’s about what it would take to wipe out all the earthworms. It might be fair to say that much of Canada was stripped of its native earthworms last time around, but relatively little of the U.S., and none of Mexico, was affected. I haven’t read the book yet: > **[The 'Columbian Exchange': How Discovering the Americas Transformed the World](https://www.spiegel.de/international/world/a-923220.html)** > > Columbus' arrival in the Americas sparked the globalization of animals, plants and microbes. A recent book takes a closer look at how items from the New World, such as potatoes, guano and rubber, quickly and radically transformed the rest of the... “Extinct in large parts of North America since the Ice Age, earthworms began spreading there once again following Christopher Columbus’ voyage. Wherever this species appeared in American forests, it changed the landscape, aerating the soil, breaking down fallen foliage and accelerating erosion and nutrient exchange.” ---
**Author:** ![Chimera](https://avatars.discourse-cdn.com/v4/letter/c/8e8cbc/32.png) [@Chimera](https://boards.straightdope.com/u/Chimera)\ **Post date:** [September 24, 2013, 1:05pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/2 "2013-09-24T13:05:05Z")
They’re considered an [Invasive Species](http://www.sciencedaily.com/releases/2000/09/000904130558.htm) in our forests; “Ninety-nine percent of the populations of native plant species normally found in hardwood forests, including large-flowered trilliums, yellow violets, and Solomon’s seal, are destroyed in affected areas,” said Frelich, a research associate in forest resources. “In many areas, the remaining bare soil is simply eroding away.” Minnesota DNR has some good information [here](http://www.dnr.state.mn.us/invasives/terrestrialanimals/earthworms/index.html). ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [September 24, 2013, 2:19pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/3 "2013-09-24T14:19:50Z")
I’ve seen news reports claiming earthworms are invasive too. That just doesn’t make sense. Any gardener or farmer will tell you earthworms are essential for creating rich soil suitable for plant growth. They eat organic material and turn it into [humus](http://en.wikipedia.org/wiki/Humus). It’s a critical step in producing a [rich loamy soil](http://www.hort.purdue.edu/ext/loam.html). ---
**Author:** ![Labrador\_Deceiver](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@Labrador\_Deceiver](https://boards.straightdope.com/u/Labrador_Deceiver)\ **Post date:** [September 24, 2013, 2:40pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/4 "2013-09-24T14:40:18Z")
> [@aceplace57](#): > > I’ve seen news reports claiming earthworms are invasive too. > > That just doesn’t make sense. They make perfect sense if you bother to actually read them. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [September 24, 2013, 2:57pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/5 "2013-09-24T14:57:02Z")
I have read them and they make no sense. The reporters assertions are totally unsupported. Unless we’re supposed to believe the soil in North America was basically useless. How did Native Americans farm soil that didn’t have rich humus? Earthworms are essential for that. ---
**Author:** ![robert\_columbia](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)\ **Post date:** [September 24, 2013, 3:02pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/6 "2013-09-24T15:02:10Z")
> [@Chimera](#): > > They’re considered an [Invasive Species](http://www.sciencedaily.com/releases/2000/09/000904130558.htm) in our forests; > … Invasive species aren’t limited to animals. Northern Virginia has been waging a losing war against bamboo for years now. It spreads like crazy, grows very fast, is difficult to completely kill (it’ll be back), and no local animals eat it. ---
**Author:** ![Labrador\_Deceiver](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@Labrador\_Deceiver](https://boards.straightdope.com/u/Labrador_Deceiver)\ **Post date:** [September 24, 2013, 3:07pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/7 "2013-09-24T15:07:23Z")
> [@aceplace57](#): > > Earthworms are essential for that. No they aren’t. > [@](#): > > Minnesota’s hardwood forests developed in the absence of earthworms. Without worms, fallen leaves decompose slowly, creating a spongy layer of organic “duff.” This duff layer is the natural growing environment for native woodland wildflowers. It also provides habitat for ground-dwelling animals and helps prevent soil erosion. Like I said, it makes perfect sense if you bother to read about it. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [September 24, 2013, 3:39pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/8 "2013-09-24T15:39:43Z")
I first saw the earthworm invading America theory in reviews of \*1493: Uncovering the New World Columbus Created \* by Charles Mann. It’s on my list to read. > **[1493: Uncovering the New World Columbus Created: Mann, Charles C.:...](https://www.amazon.com/1493-Uncovering-World-Columbus-Created/dp/0307278247)** > > 1493: Uncovering the New World Columbus Created \[Mann, Charles C.\] on Amazon.com. \*FREE\* shipping on qualifying offers. 1493: Uncovering the New World Columbus Created > **[How the lowly earthworm changed the face of America forever after stow](https://www.dailymail.co.uk/news/article-2428511/How-lowly-earthworm-changed-face-America-forever-brought-early-European-colonists-chickens-malaria-common-cold.html)** > > We all know that Christopher Columbus and European pioneers brought back potatoes, tobacco and rubber from the New World in the wake of his voyage of 1492, but a new book examines the overlooked impact of the Old World on the newly discovered... ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [September 24, 2013, 5:24pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/9 "2013-09-24T17:24:49Z")
> [@robert\_columbia](#): > > Invasive species aren’t limited to animals. Northern Virginia has been waging a losing war against bamboo for years now. It spreads like crazy, grows very fast, is difficult to completely kill (it’ll be back), and no local animals eat it. Obviously we need to introduce Pandas to Northern Virginia. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [September 24, 2013, 7:16pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/10 "2013-09-24T19:16:06Z")
> [@Sailboat](#): > > Obviously we need to introduce Pandas to Northern Virginia. And then Tigers\* to combat the Panda infestation. :D:p - More leopards than tigers but the joke isn’t as good that way… ---
**Author:** ![aNewLeaf](https://avatars.discourse-cdn.com/v4/letter/a/ac91a4/32.png) [@aNewLeaf](https://boards.straightdope.com/u/aNewLeaf)\ **Post date:** [September 24, 2013, 7:35pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/11 "2013-09-24T19:35:37Z")
> [@Sailboat](#): > > Obviously we need to introduce Pandas to Northern Virginia. They probably would thrive there, you should round up a herd and see. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [September 24, 2013, 8:34pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/12 "2013-09-24T20:34:20Z")
> [@aceplace57](#): > > I have read them and they make no sense. The reporters assertions are totally unsupported. Unless we’re supposed to believe the soil in North America was basically useless. How did Native Americans farm soil that didn’t have rich humus? Earthworms are essential for that. What you’re saying makes as much sense to me as recommending that what Arizona really needs is some peat moss and water so that we can grow the best cactus possible. Or like saying that what Venus flytraps really need is some better drainage. In fact, I’m surprised that you’re not recommending Brawndo. When a species has adapted to a particular condition, pretty much any change to that condition is bad for that species. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [September 24, 2013, 9:17pm UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/13 "2013-09-24T21:17:38Z")
Maybe there is something odd about those Minn trees and they don’t do well in rich garden soil. The expert scientist should know. I concede that. I’ve gardened and worked flowerbeds since my early teens. Read lots of books on the subject. The earthworm doesn’t take nutrients from the soil. They accelerate the process of turning leaf litter into nutrients that go back into the soil. I gave cites earlier on humus and loamy soil. Loamy soil is something any gardener or organic farmer works very hard to achieve with various soil amendments, earthworms etc. But, that’s not the natural soil these old growth trees originally adapted too. ---
**Author:** ![davidmich](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@davidmich](https://boards.straightdope.com/u/davidmich)\ **Post date:** [September 25, 2013, 12:10am UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/14 "2013-09-25T00:10:42Z")
Very useful link. Here’s the horticultural/scientific perspective > **[The Trouble with Earthworms](https://www.npr.org/templates/story/story.php?storyId=9105956)** > > An invasion of worms is threatening forests in the Northeast and Midwest. Peter M. Groffman, senior scientist at the Institute of Ecosystem Studies in Millbrook, N.Y., explains why worms might not be your garden's best friend. davidmich ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 25, 2013, 1:27am UTC](https://boards.straightdope.com/t/the-native-american-earthworm-whats-the-real-story/669570/15 "2013-09-25T01:27:22Z")
> [@](#): > > Maybe there is something odd about those Minn trees and they don’t do well in rich garden soil. The most likely mechanism would be that the Minn trees don’t themselves actually have a problem with rich soil, but that when the soil is rich, they have to compete against other species that like it too, and lose. On the other hand, when the soil is poor enough that only they can tolerate it, they have no competition, and so thrive.