Earthworms, Soils, and Boreal Forests- NY Times

Photo of earthworm researcher from University of Minnesota.

I thought that this story was very interesting and well written. It also talks about the views of Canadians, who just like us and the Mexicans, inhabit this wonderful (in the original sense) continent. There are many different scientists quoted from a variety of perspectives. Well worth reading in its entirety IMHO. One thing that seems to be missing is that the “systems” are so complex that we really have no idea what’s going to happen, even if we spend millions on complicated models and a variety of assumptions. Take home message: new creatures get introduced. The biota changes. Some of the changes may be bad. Some of the changes may be bad, and there’s not much we can do about them at this point.

But what struck me most about it was how the situation illustrates that it is impossible to disentangle the effects of climate change and other activities by Native and Later Americans (I doubt whether North Americans have ever been all Euro).  Especially the very mixing that is leading to unprecedented levels of worldwide biotic homogenization.  It seems to me like a great policy intervention would be to stop international travel and trade. But our friends in the invasive species world don’t try to do that.. they try to change practices to be more protective. It’s definitely a policy choice to decide to stop things (selling trees on National Forests, producing oil and gas, international travel and trade).  The latter would conceivably count double for decreasing carbon emissions as well as reducing threats of invasives.  An alternative is to dig down and investigate the practices at the ground level so that they are more environmentally sensitive.  We might ask “who in the marketplace of ideas chooses to stop rather than improve practices” and of course, in each unique instance, why did they make that choice? Do certain kinds of people prefer stopping to fixing (disciplines, politics, class)? Why are there groups we all know who are for “keeping oil and gas in the ground”, or “no commercial timber sales on national forests” but none for “no international trade nor travel (I suppose including immigration from other hemispheres?)”. If we think “the cat’s out of the bag” on that, why not on climate change? I’m just exploring some different ways of thinking about how different threats are treated. Anyway, I digress.

Native earthworms disappeared from most of northern North America 10,000 years ago, during the ice age. Now invasive earthworm species from southern Europe — survivors of that frozen epoch, and introduced to this continent by European settlers centuries ago — are making their way through northern forests, their spread hastened by roads, timber and petroleum activity, tire treads, boats, anglers and even gardeners.

In northern Minnesota, the boreal forest has slowly been invaded by earthworms. They have altered not just the depth of the leaf litter but also the types of plants the forest supports, said Adrian Wackett, who studied earthworms in the North American and European boreal forest for his master’s degree at the University of Minnesota in St. Paul.

Endemic species such as the pink and white lady’s slipper — Minnesota’s state flower — as well as ferns, orchids and the saplings of coniferous trees rely on the spongy layer of leaf litter.

As earthworms feast on that layer, they allow nonnative plants such as European buckthorn and grasses to thrive, which in turn push out endemic plants. This process, combined with the effects of warming over time, may slowly transform Minnesota’s boreal forest into prairie, Mr. Wackett said.

If you’re interested in the Minnesota angle, here’s a link about their collaboration with the Fennoscandians.

Their research shows that some of the same earthworm species transforming North American forests have also invaded far northern arctic regions of Norway, Sweden, and Finland (Fennoscandia). They identified numerous locations with active, ongoing earthworm invasions.

These areas were also glaciated, but settlers from southern and central Europe came to farm and brought non-native earthworms with them. Modern gardens, composts, and fishing sites have also helped spread the “unseen invaders.”

“We can identify invasion points pretty easily,” says Wackett. “We target old farm sites or modern cabin lawns, and in many cases observe a radius where the worms have spread out into surrounding birch forests.”

9 thoughts on “Earthworms, Soils, and Boreal Forests- NY Times”

  1. Most of the people I know who study global wildlife trade — a major source of non-native animals, along with general endangerment and misery — would be thrilled to end all international trade in live animals, but the zoo / aquarium / pet store industry will not let that happen.

    Personally I’m 100% for ending imports of cheap wood from places with even less environmental protection than we have. I suspect most environmental groups would be on board with this too. But getting Americans to give up cheap wood products is unlikely, I think, and I’d expect the manufacturers associations to push back hard.

    If somehow this did happen, I’m worried there would be tremendous pressure to reduce costs. Then we’d have a continent of pesticide-saturated, short-rotation monoculture plantations with minimal attention to human or environmental health.

  2. Your comments on the complexity of ecosystems with enormous numbers of species, about the inadequacy of modeling that must be based on limited information and assumptions, and the apparent impossibility for low-risk predictions is an argument for preserving many large control areas for comparison against the rest of the world. At least, it would give us a chance to see what we have done, even if we don’t understand the mechanisms.

  3. QUOTE: “Their research shows that some of the same earthworm species transforming North American forests have also invaded far northern arctic regions of Norway, Sweden, and Finland (Fennoscandia). They identified numerous locations with active, ongoing earthworm invasions.”

    This is amazing. I’ve dealt with this subject before with biased agenda driven researchers who have written many of these papers demonizing everything about earthworms, blaming them from deforestation to global warming, etc. Tunnel Vision.

    Over here in Sweden, yes, these things are everywhere, but they never ever strip the Boreal Forests here of their forest floor cover. I also see Maple & Birch seedlings germinating on bare open ground, so what’s the deal over there ?? Is there maybe something else going on ??? Did anyone bother to check or care to check ??? The idea that the earthworms are invasive in their own land is asinine. Are native shrubs and trees here in Scandinavia also evil when environmental changes allow them to move further north ??? This is as bad as Kieran Sucklings demonizing take on the cloud forest on Ascension Island.

    When I was a kid in northern Iowa near the Minnesota border in the 1960s, all farms and forests had numerous Night Crawlers & other earthworms which we use to hunt for fishing, but never did they ever strip forest floors of vegetation. Over here in Sweden, the Magpies, a native black bird , etc spread out over all landscapes searching for these things and gorge themselves every single morning and evening with Earthworms. When I’ve asked some of those Minnesota researchers what if any predators of Earthworms they observed and/or were missing, all I’ve ever gotten is crickets. It seems the narrative to demonize earthworms was/is more important, then checking to see what sudden imbalance now has taken place that was not there before and restoring those checks and balances back to what they once were. Robins, Magpies, Black Birds, Moles (the critter people love to hate and kill), etc. But you won’t really find research out there on these missing earthworm predators. Why ??? I’m beginning to believe this has zero to do with real science as much as pushing some sort of political agenda which in the end is going to destroy Nature anyway.


  4. Well, I could’nt read the New York Times article because as usual they demand I subscribe. So I found the one from the University of Minnesota with Adrian Wackett. In his research post and the comparison photos used, one with bare forest floor (not really bare, just very little ferns, etc). Then the other photo showing forest floor understory plants. Message behind the photos is earthworms are evil, just look what they did here and other photo with understory with plants the message is this is what you get where very few to no earthworms exist. What I have asked repeatedly (and this isn’t the first time they have used comparison photos) and never receive a viable answer is where is the research where they investigated what predators may have existed in the fern covered floor vs the leaf litter floor ??? Again, this not the first time they’ve pulled this photo stunt to push forward their hatred of earthworms. Seriously, what other variables did they look at or consider ? Or was this just a quick surface read with a no so well thought out judgement because it was a better fit for their narrative and making assumptions and assertions as to why the difference ??? Again I questioned all this back in 2012 and got crickets.

  5. I think these might be the main points you were getting to: “Why are there groups we all know who are for “keeping oil and gas in the ground”, or “no commercial timber sales on national forests” but none for “no international trade nor travel (I suppose including immigration from other hemispheres?)”. If we think “the cat’s out of the bag” on that, why not on climate change?”

    Some SPECULATIVE answers. We own the federal lands so we can say yes or no, and the difference between yes and no has obvious consequences. And we have laws that apply to answering these kinds of questions. Neither is true for international trade or travel. It’s a much more diffuse problem.

    People are not being confronted with the reality of invasive species the way they are with climate change. While invasives may cause obvious problems in some cases (e.g. freshwater mussels), most are much more subtle (e.g. earthworms) and just don’t make most people fear for their health, safety or property like a climate boogeyperson.

    Therefore the benefit of avoiding these effects of invasives would not obviously outweigh the direct costs of trade or travel restrictions the way the cost of carbon restrictions compare to effects of climate change. (Partly because the alternatives to carbon are more clear than the alternatives to international trade/travel.)

  6. Jon, I’m not sure I agree. First “keeping it in the ground folks” are for doing that on private lands as well as public lands. Second, it’s not that easy to transform a fossil fuel based economy to a carbon free economy. If it were, enthusiastic countries would have done it already- e.g., Germany but promising is easier than accomplishing. We also have the puzzling phenomenon that the easiest and proven way to go low carbon (nuclear) is a controversial path.

    Transforming an economy away from carbon may be equally difficult to getting rid of trade and travel, since no one has successfully done either. I thought that this piece by Michael Shellenberger in Forbes was interesting.

  7. I am surprised by this: “Native earthworms disappeared from most of northern North America 10,000 years ago, during the ice age”

    Maybe I am missing something, but wouldn’t it be more likely that earthworms would disappear closer to the peak of the last ice age, not its end.

    •’s interesting to think how a person might study that question. But I’m with you, I’d think they’d be gone sometime before or slightly after the ice sheets were on top of the soil.

  8. 2ndLaw: “I am surprised by this: “Native earthworms disappeared from most of northern North America 10,000 years ago, during the ice age”

    I’m not surprised, frankly when I have read so many similar papers done on this subject of Minnesota earthworms over the last few years, every single paper had a different date (give or take a couple 1000 years plus or minus) and no explanation as to how they arrived at that date conclusion. I seems merely making the claim makes it so. If someone questions it, simply don’t answer. If pressed, find some like minded people and develop and consensus herd mentality to take on the heretic. Just doesn’t get anymre religious than that.

    2ndLaw: “Maybe I am missing something, but wouldn’t it be more likely that earthworms would disappear closer to the peak of the last ice age, not its end.”

    I went the other day over to the University of Michigan site and asked the Admin to clarify many of the assertions and assumptions made in the Paper and all they could send me is more research articles with similar fluff even from a couple of years ago. When I said I had already read those papers years before, all I got was crickets.

    Did not the same Ice Age occur in Europe & Asia ??? Why did earthworms not go extinct those places ??? Clearly they would not have gone extinct everywhere in North America, so why would they not move back north like all the other organisms after the ice age ended ???

    All I know is that Nightcrawlers (The paper’s main most hated Earthworm) were in Southern Minnesota & Northern Iowa when I lived back there in the summers of late 60s & early 70s and they were not destroying forests back then. And there were tonnes of them because we’d collect them at night to go fishing the very next day. So what changed between 1970 to now and don’t say climate change ??? Scandinavia have had them since I’ve been here (2006) and they have all the same predators here as they do in North America. But thepredators do their job here and none of these earthworms destroy forest floors. So am I to conclude climate change isn’t happening here ??? And so what, worms are supposedly moving further north here. So how do they know that ??? Maybe they were always in Northern Sweden, just very few or in a dormant condition. And what about the Shrubs and Trees moving north into Arctic. Is that a bad thing too ??? Should we now consider trees and shrubs evil if they move into Arctic Tundra ??? Frankly I’d like to see the earth once again forested and vegetated from pole to pole. At one time the earth was like that.

    Of course the reality here is that humans accelerate things and the disruption is more dramatic and noticeable as a result. All organisms (plants, animals, amphibians, reptiles, birds, fish, etc.) on earth have always had the potential to move either rapidly or more slowly anywhere eventually around the globe. I mean it’s not like living things here are like some sci-fi flick with some alien organism traveling thru space and infecting the planet to it’s detriment. Yes, things get out of balance and sometimes take over an area, but often times this has been accelerated by the ignorance of human land managers, or just your average landscape enthusiat. But there is no way to control that. I Like some of the thinking and ideas of Matt Chew of ASU. I don’t subscribe to all his ideas of course, but he provides some pause and thought before going forward with long held cherished assumptions and ways of viewing things in a negative light. One of the things we may disagree on is his views about Tamarisk.

    Over here in Europe, Lupines get demonized by many nature lovers, for example Iceland. Iceland has no forests to speak of anymore, but Lupines could be a way of preparing soil in some areas for planing trees. The homogeneous and eco-purists among nature lovers there have demonized the Lupine plant in Iceland because they have taken over in mass and crowded out some native ferns, mosses or lichens. This same Native Plant Nazi attitude was display in the comments section below in a Fred Pearce article about the Cloud Forest on Ascension Island in the South Atlantic where over 100+ years ago a British Botanist on a barren volcano & sailors planted numerous plants in gardens which escaped onto this desert island (true desert island where it really never rained previously and where nothing but mosses, lichens & perennial plants grew) and today boasts a beautiful subtropical cloud forest and other types of vegetative habitiats further down on the lower foothills below. But Kieran Suckling bashed Fred Pearce’s article and Matt Chew defended it. It was a beautiful comments section before it was closed. Suckling’s rant about ferns, lichens and mosses going extinct never materialized. I’ve kept up with happenings there and in direct contact with the conservation ranger named Stedson Stroud who has shown me photos where these same ferns, lichens and mosses are living off the branches of the non-native trees and are much healthier and bigger in appearance where they have been epigenetically transformed. They never went extinct. The cloud forest itself captures moisture off ocean marine layers and storms are now more often a regular occurence now. Sometimes this strict unflinching climate change dogmatism hinders understanding of how ecosystems really work, as opposed to embracing newer findings discovered thru observation which provides a pattern for using these as a means to not only re-establish, but also establish vegetative ecosystems on the planet where they may not exist today.


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