Are Worms Natural? The Global Worming Debate

Robin Eating Worm

Photo: Male American Robin (Turdus migratorius) eating an earthworm. Source: Wikipedia.

To be more specific, are earthworms natural?  For the chronically busy and distracted, the short answer to that question is – absolutely not!  Earthworms are not natural!  Not even a little bit!  At least they’re not natural if they’re non-native, introduced earthworms that are devouring the forest floor and radically changing the ecology of some hardwood forests in the northern United States.

Science Underfoot

Surely I must be kidding?  What could be more natural and beneficial than the common earthworm, slowly churning through our compost piles and garden soils, dutifully converting organic waste into productive elements of soil?  They’re everywhere.  You see them when you dig in the garden.  Many birds and other animals love to eat them. After heavy spring and summer rains, they cover our sidewalks and roads, and squish under the feet of the careless.

On the other hand, maybe this is just another Commie, liberal, university, leftist, socialist, hippie, environmentalist plot to alarm a gullible public and scare them into donating more money to “save the world.”  Unfortunately, the truth of the matter isn’t quite that simple.  Many introduced earthworms are not natural in their environmental effects and they are wreaking ecological havoc in some North American forests. Forget environmental opinion. Let’s talk science.  But first, a bit of history.

Cleopatra and Julius Caesar

Cleopatra and Julius Caesar. Painting by Jean-Léon Gérôme. Source: Wikipedia.

Cleopatra – Worm Worshipper

Cleopatra VII was the last pharaoh of ancient Egypt, one of the most famous female rulers in history, and apparently was somewhat of a worm worshipper based upon reports that she considered earthworms to be sacred:

“Did you know the ancient Egyptians were the first to recognize the beneficial status of the earthworm? Cleopatra (69 – 30 B.C.) recognized the earthworm’s contribution to Egyptian agriculture and declared them to be sacred. Removal of earthworms from Egypt was punishable by death. Egyptian farmers were not allowed to even touch an earthworm for fear of offending the god of fertility. A 1949 study by the USDA confirmed that the great fertility of the soil in the Nile valley was due in large part to the work of earthworms.”  Source: Did You Know……. Earthworms

However, Cleopatra is hardly alone in lauding the importance of earthworms to humans and the world.  Aristotle called earthworms “the intestines of the soil” while Charles Darwin studied worms for 39 years and concluded that: “It may be doubted whether there are many other animals which have played so important a part in the history of the world as these lowly organised creatures.”

It will be difficult to deny the probability that every particle of earth forming the bed from which . . . old pasture land springs has passed through the intestines of worms.”

Model of a merchantman ship.

Model of a merchantman ship. Source: Wikipedia.

But Blame the Pilgrims

No one knows for sure when non-native earthworms were introduced to North America, but for the sake of convenience, let’s blame the first pilgrims and colonists for starting the process of bringing in passenger and cargo ships containing rocks and soil for ballast. Introduced earthworms probably got their toehold on the continent when these materials were dumped ashore, and when plants with soil and other cargo accompanied passengers to North America.

Dang Pilgrims! There goes the neighborhood! And there goes some of Mother Nature’s magnificant hardwood forests as well.

It is just possible that John Rolfe was responsible for the worms—specifically the common night crawler and the red marsh worm, creatures that did not exist in the Americas before Columbus…

Most people know him today, if they know him at all, as the man who married Pocahontas. A few history buffs understand that Rolfe was one of the primary forces behind Jamestown’s eventual success. The worms hint at a third, still more important role: Rolfe inadvertently helped unleash a convulsive and permanent change in the American landscape….

As the colonists bitterly came to realize that Virginia had no gold and that the Indians weren’t going to selflessly provide them with all the food they needed, they began to mold the land to their needs. Unable to adapt to this foreign landscape, they transformed it into a place they could understand. In doing so, they unleashed what would become a multilevel ecological assault on North America. Their unlikely weapons in this initial phase of the campaign: tobacco, honeybees, and domestic animals.  National Geographic: America Lost and Found

There is little doubt that the earthworms that you find in your yard, garden, and crawling across sidewalks and streets after rains are all non-native, introduced earthworms.  In reality, they don’t belong here.

Our colleagues at the University of Idaho, Yaniria Sanchez-de Leon and Dr. Jodi Johnson-Maynard, have conducted one of the few detailed studies of earthworms in the Palouse region, and they found that three introduced species (Aporrectodea trapezoides, A. tuberculata, and Lumbricus terrestris – often called the common earthworm, or nightcrawler) dominated the earthworm community, whether samples were taken in planted grasslands in an agricultural setting or in native prairie remnants.

Earthworm Research at Washington State University

In an earlier study of earthworms, in 1999, WSU researchers Mary Fauci and Dr. David Bezdicek, of the Department of Crop and Soil Sciences, sampled earthworms at 46 sites in mostly farm fields and some grasslands in Palouse Prairie, but all of the worms they found were of introduced species. The highest earthworm diversity (8 species of non-native earthworms) occurred right here on the campus of Washington State University in the agronomy teaching gardens, perhaps illustrating the potential to bring in non-native earthworms in cultivated gardens when using plant materials originating from different sources.  

So where are all the native earthworms? And isn’t one worm as good or bad as another? First, we don’t have as many native worms as you might suspect.  And second, not all worms are created equal. While some introduced worms may have beneficial effects in the human-created habitats of compost piles, gardens, and agricultural systems, some of our native forest habitats evolved without any earthworms at all.  

Pleistocene ice map

Distribution of continental ice sheets (white area) during the last Pleistocene glaciation. Source: Wikipedia.

The last Pleistocene glaciation ended some 12,000 years ago (see map). Any native earthworms were destroyed by the permanent ice cover and bordering permafrost, causing distributions to be pushed to the south.  It is easy to see from the map of continental ice sheets that the northeastern and north central United States were devoid of earthworms when the ice finally started melting and forests began their march northward following the retreating glaciers.  

Forests in these regions have had thousands of years to evolve and develop communities of trees, shrubs, and understory plants all without any native earthworm community. And now the bad guys show up, and that would be us by the way, not the earthworms!

Worms As Ecological Engineers

Scientists have suspected for some time that introduced earthworms were having negative ecological impacts in these particular North American forests. As introduced earthworms invaded these forests, a series of largely negative ecological changes cascaded throughout the system, changing the structure, function, and even the overall appearance of the forest.

Not all worms are created equal because different species of worms occupy different habitats and eat different organic materials as food.  Some species of worms specialize by living in different layers or types of soil, or specialize in eating different foods such as animal manure vs. decaying logs, vs. leaf and organic matter on the soil surface.  

Hermit Thrush in Winter

Photo: Hermit Thrush in winter. Source: Wikipedia.

Forest Gingivitis

In the absence of native earthworms, sugar-maple and basswood forests in the northern United States develop relatively thick layers of calcium-rich duff composed of leaves and organic matter that decay slowly through the actions of fungi and bacteria.  This moist, thick, rich organic layer on the forest floor supports a diverse community of herbaceous plants, fungi, arthropods (i.e., insects, spiders, crustaceans), vertebrates such as small mammals, frogs, salamanders, and birds that specialize in nesting and living on the forest floor.  Many trees, shrubs, and herbaceous plants are adapted to germinate and survive under these conditions.

When non-native earthworms invaded these forests, they quickly devoured the organic layer on the forest floor and rapidly changed the ecology of these temperate hardwood forests.  Scientists began to notice that as the organic layer decreased, so too did many forest floor plants, insects, and salamanders.  Even the density and nest success of ground-nesting songbirds, such as Ovenbirds (Seiurus aurocapillus) and Hermit Thrushes (Catharaus guttatus), declined.  Instead of a layer of duff, the forest floor began to give way to grass cover and other non-native introduced plants, that are themselves invasive.  

Populations of white-tailed deer also have increased in our forests as well due to a variety of human-related factors (e.g., logging and fragmenting forests; elimination of top predators like cougars and wolves), and intensive browsing by deer further induced changes in plant communities, including threatening populations of rare and endangered plants.  All of these and other impacts, such as mixing and fundamentally changing soil structure, soil chemistry, and altering bacterial and fungi communities amount to pretty impressive ecological impacts from a lowly worm!

While cause and effect relationships are complicated in ecosystems with many interacting players, scientists increasingly suspect and see evidence that introduced earthworms are intimately linked to the changing structure of hardwood forests in the northern U.S.  In essence, as the forest floor disappears (is consumed by worms), the surface roots of trees and other plants are suddenly exposed to a more open, dryer, and harsher environment.  A somewhat appropriate analogy is that worms end up causing gingivitis in forest communities by exposing tree roots and the forest floor.

Hand with earthworm

Common earthworm. Photo by barockschloss. Some rights reserved.

Are Worms Natural or Not?

Natural is a relative word and the subject of debate in ecology.  For some people, humans are natural, therefore anything that humans do in the world is natural and we shouldn’t worry about it.  Therefore, New York City is natural.  Disneyland is natural.  Walmart parking lots are natural.

For others, humans long ago crossed the threshold of natural effects in the world when we began to control fire, make sophisticated tools for hunting, and then later domesticated crops and farm animals and began converting the world to agricultural production. For these people, who believe technology puts us in an entirely different category, natural means having as close to no human influence as possible.

I would answer the question about worms this way.  Worms, whether native or introduced are the products of natural evolution. In that sense, all organisms are natural.  However, whenever we introduce non-native species into new continents, islands, and ecosystems anywhere, then their ecological effects are not natural if and when they disrupt or change existing ecological processes and communities.  In that sense, introduced earthworms in hardwood forests in the United States are not natural.

What should we do about it then?  Should we attempt to kill and eliminate all introduced earthworms to save our northern hardwood forests? Hardly.

The answer to these questions is that we likely can do very little, if anything realistic, to stop the changes that are rapidly occurring in northern forests.  It is not feasible to try to eradicate large earthworm populations in the soil, because attempting to do so probably would not work very well and only disrupt other beneficial soil organisms.

New Zealand Flatworm

New Zealand Flatworm. Source: Wikipedia

It also is not wise to consider introducing predators on earthworms, such as the New Zealand flatworm, which has apparently been accidentally introduced into Europe and Great Britain. Flatworms don’t discriminate between introduced and native earthworms and may cause more unintended environmental damage than they might cure by preying on native earthworms. In Great Britain, where New Zealand and Australian flatworms have been introduced, native earthworm populations have been devastated in some areas. And trying to foresee the consequences of potentially introducing yet additional predators that prey on the flatworms themselves, such as the maggots of a Tasmanian gnat, only lead to more uncertainties and ecological risks.

So where does that leave us? Should we become a nation of worm stompers and worm haters?

Currently, there are no easy answers about what to do about introduced earthworms, except for efforts to educate the general public, and especially fishers who might be tempted to dump unused fishing bait in natural habitats (see: Great Lakes Worm Watch).  

Scientists will continue to study the effects of introduced earthworms, if nothing else, to better predict what changes may overcome our hardwood forests in the future.  At issue will be whether the native organisms that were adapted to conditions in historical hardwood forests (e.g., herbaceous plants, insects, salamanders, ground-nesting birds) will be able to persist in this new uncertain future, and how we might try to help them survive.

Where Are the Good Earthworms?

Typical of the differences we tend to see between native species and introduced species exhibiting highly invasive characteristics, there seems to be a difference between native and introduced earthworms. There are roughly 180+ species of native earthworms in North America, but probably because they have co-evolved for thousands of years with other organisms in their respective ecosystems, they do not seem to have the dramatic or obvious negative effects that we see for newly-introduced earthworms in northern hardwood forests.

Arctiostrotus vancouverensis

[Photo. The native earthworm, Arctiostrotus vancouverensis. Copyright 2005 William Leonard. Used with permission. Source: CalPhotos.

For example, on Vancouver Island and the Olympic Peninsula, Arctiostrotus vancouverensis is normally found in decaying conifer logs and other cool moist substrates and is an integrated part of the ecosystem.  Similarly, other native earthworms occupy a variety of habitats oftentimes south of the former permafrost line that occurred during the Pleistocene glaciation, and they have not invaded our northern hardwood forests.

The Mysterious Giant Worms

Of course our favorite native earthworm is our very own giant Palouse earthworm (Driloleirus americanus), which means “lily-like worm” because it purportedly smells like lilies.  The scent, if indeed it does occur, could potentially be a chemical defense which results from handling, but most of what is stated about the giant Palouse earth is nothing more than common lore that keeps getting repeated in the popular press.  

Very little is actually known about the giant Palouse earthworm, which was thought to be possibly extinct during the 1980s, until was rediscovered in 2005 by Yaniria Sanchez-de Leon from the University of Idaho while studying earthworms at the Washington State University, Hudson Biological Reserve at Smoot Hill.  This “giant” worm, which supposedly could reach about 3 feet in length (although recent collected specimens are much smaller – about 12 inches or less) has been the subject of controversy as conservation groups have unsuccessfully petitioned the U.S. Fish & Wildlife Service to have the worm listed as endangered.

Dr. Jodi Johnson-Maynard, soil scientist from the University of Idaho, says that perhaps instead of the giant Palouse earthworm, we should just call it the “larger-than-average Palouse earthworm.”  Either way, it’s a mysterious creature that deserves to be better known by science.

Another favorite native earthworm is the Oregon giant earthworm (Driloleirus macelfreshi).  Similar to the giant Palouse earthworm, this giant worm is known from primarily 15 sites in the Willamette Valley and may reach lengths over 4 feet. However, one of our very favorite worms in the world is the threatened Giant Gippsland earthworm (Megascolides australis).  These enormous earthworms apparently average about 3 feet in length, but purportedly may reach up to nearly 9 feet.

Do Worms Make Sounds?

If you’ve never heard an earthworm, you should.  Just travel to Australia and try to track down one of these creatures. Or, you may watch the video below.

Global Worming Skeptics

There are undoubtedly many people who will have difficulty believing that introduced earthworms are such powerful agents of ecological change and that they could be doing harm in our forest environments. These skeptics would do well to realize that the biomass (weight) of earthworms in a productive pasture is likely much greater than the weight of the farmer’s cattle standing on top of the ground. And what happens below the ground, largely determines what happens on top of the ground.

Charles Darwin once estimated that there were more than 13 earthworms in a square meter, but we now know that productive soil may have hundreds of earthworms in a square meter and well over a million worms in an acre. The potential work of that many miniature soil bulldozers, powered by their organic fuel of decaying leaves, should not be underestimated.  If you don’t believe it, start a compost pile or get a shovel and find out for yourself.

Pandora's Box

Engraving of Pandora trying to close the box she had been given by Zeus. Source: Wikipedia.

A Philosophy of Worms

I hold no animosity towards night crawlers and other introduced earthworms. They are simply natural organisms put in an unnatural place – the innocent pawns of environmental change placed there by human ignorance. It is not the worm’s fault. It is our fault. But in many cases, even we didn’t know any better when we opened Pandora’s Box and turned loose scores of unintended ecological forces now ravaging the natural world.

While I lament the loss of beauty, biological diversity, and the potential extinction of native species that may occur when ecosystems are changed by highly invasive plants and animals, it is now up to scientists and educators and the public to do better in the future.  Now that we do know better, we should not make the same mistakes as our ancestors.

So the next time that you see a night crawler crossing or being stranded on a drying sidewalk, don’t stomp on it as an unnatural invader.  It is simply a natural organism trying its best to survive like all other natural organisms on Earth. Like it or not, it is now part of a new natural order, created not by Mother Nature, but by humans.

While you needn’t worship the worm like Cleopatra, perhaps you pause just for an instant and appreciate the often hidden complexity and mystery of the natural world? And if you’re not afraid of such an immensely powerful creature, perhaps you even pick it up and rescue it by putting it back on some moist soil where it may resume its life. After all, a little bit of worm worship, or environmental philosophy, never hurt anyone.

R. Sayler

For the Curious:

Wikipedia: Earthworm

Wikipedia: Invasive Earthworms

MN Department of Natural Resources: Invasive Earthworms in Our Forests

Scientific American: Invasive Earthworms Denude Forests in U.S. Great Lakes Region

Great Lakes Worm Watch.


Online Classes, School of the Environment, Washington State University:

For those who are interested in taking online science classes and studying the types of ecology and environmental issues covered here in Nature @ WSU, you may contact the WSU Global Campus for information about:

Conservation Biology (Natrs 450 / 550) 3 cr. The science of conserving life on Earth. Dynamics of conserving biological diversity and threatened and endangered species. Junior-senior-graduate standing, next offering Spring Semester, 2015.

Restoration Ecology (Natrs 454) 3 cr., Ecological principles used to restore biological communities, ecological processes, and species on degraded landscapes. Interdisciplinary Capstone Science Course. Senior standing, next offering Fall Semester, 2015.

Environmental Assessment (Envr_Sci 444) 4 cr. Environmental impact statements and their national and state policy frameworks, methods of assessment, and team preparation of an impact statement.

The Science and Policy of Climate Change (Envr_Sci 285) 3 cr. The science of the climate system; the case for reducing greenhouse gas emissions, and the best policies to do so.

Earth’s History and Evolution (Geology 210) 4 cr. Introduction to Earth’s history and evolution through observations, data collection and analysis, readings, and writing exercises.

The Environment, Human Life, and Sustainabiltiy (Envr_Sci 101) 4 cr. Interactions between humans and their environment; multidisciplinary introduction to environmental concepts and concerns.

47 Responses to “Are Worms Natural? The Global Worming Debate”
  1. kyle schneiders says:

    This was a very intresting article i didint know non-native earthworms had such an impact on an ecosystem.

  2. Steven Woodley says:

    This article was very intriguing. I never considered worms as invasive or native before reading this article. Furthermore, I am surprised to learn how much non-native worms can alter ecosystems like the hardwood forests of the eastern United States.

  3. Jarrett Schuster says:

    I was not surpirsed by the facts in this article although I believe that they are eye opening to the antropogenic factors driving habitat loss and alteration. I remember learning the difference between non-natve and invasive species. Non-native meant not endemic to the area or region, while invasive meant not endemic and destructive. It seems that earthworms can fall into both of these categories given species and location, which make management of these species that much more difficult to grasp.

  4. Kyall Hagemeyer says:

    I did not know this issue with invasive earthworms but it did not surprise me. Rather it makes sense as as the movement of human cultures across the landscape always leaves environmental changes. Yeah education on this issue is the best and only action we can take. Like it or not invasive earthworms are here now, we may be able to slow their spread through educated practice, yet all we can do is restore what we have and plan on the future.

  5. Molly Alar says:

    I remember doing a research paper on the subject in conservation biology, and I did think the topic of unnatural worms was interesting, but not surprising. Like many species the worms have found their way to new areas and have become a part of most ecosystems, an invasive species. Worms may not seem like it but are a very influential part to an ecosystem but from the bottom up and can really do damage if they are not native. It would be very difficult to know the original state of an ecosystem worm free, since they have been so ingrained in the area for so long, so restoration efforts must take this into consideration,

  6. Erin Buch says:

    It’s incredulous to think that the arrival of Europeans in the New World has created biological legacies that are still being uncovered today. I agree that any attempt to undo the impacts might be futile or possibly even detrimental, and that the best thing might be to try ameliorating any further impacts, but also to accept the landscape will inevitably transform because of our actions. They are such simple creatures, yet their influence is profound, and this is both amazing and humbling.
    While I was reading this, I thought about recombinant DNA technology, the ultimate form of anthropogenic interference, and how genetic engineering techniques relate to earthworms. Do GMOs that are composted alter the soil at all? Do they affect the worms and other microbial activity in soil, and what will our future look like given these impacts? (Upon further investigation, I came across the link posted below.)
    Latin philosopher Augustine of Hippo once asked, “Do you desire to construct a vast and lofty fabric? Think first about the foundations of humility. The higher your structure is to be, the deeper must be its foundation.” I think this applies well to the topic of earthworms. Such seemingly trivial creatures with such pivotal powers, they are more important than we tend to think. To have “a vast and lofty fabric,” I think we should take care of the soils that we tread on, the foundations beneath our feet.

  7. Irena Neffeova says:

    I did not know that the common earthworms are not native in North America. You can see them everywhere back at home (in the Czech Republic), and I would never thought that the worms were brought to North America from Europe.
    I always thought that earthworms are good and “healthy” for soil and that they add “aeration” to the soil, which can be good for roots. They did I think improve soil, but the reality, as I read in the lecture, is different: they did not improve soil conditions; they also change the habitat composition such as forest understory composition. So what to do with the non-native worms in North America? Should we try to get rid of them? I think we should focus how to improve the ecosystems and habitats with the worms as a actual part of it.

  8. Andy Moore says:

    This short article about introduced worms in North America is interesting to me. I was surprised to read that first, many worms found in the United States are non-native, and second that they can be detrimental to certain habitats. The video about the giant earthworm in Australia was interesting as well.

  9. Nikkole Hughes says:

    This article does a lot to demonstrate the average person’s ignorance regarding natural versus introduced elements in our ecosystems–particularly in America. I had no idea that there were non-native earthworms in our soil; indeed, it has never before been discussed in any of my previous ecology classes. For the past four years, I’ve been told how beneficial earthworms and other soil organisms are to a range of habitat types, without any mention of the introduced heritage of many species. Like Professor Sayler, I don’t think the answer to habitat degradation by non-native worms is elimination. Instead, I advocate improved and comprehensive environmental education for farmers, gardeners, land managers, and other people who deal intimately with worms and the soils in which they live. Humans have changed the world irrevocably–the best we can do now is to broaden our knowledge bank so that we can avoid making the same mistakes we made in the past out of ignorance (like introducing non-native predators!).

  10. Margaret (Rosie) Dolen says:

    I found this article very interesting as I had never thought about earthworms being non-native, especially since they seem to be everywhere. Also that they can be detrimental in hardwood forests, since I’ve always thought that they were good for the soil.

  11. Trevor Austin says:

    This article was very fascinating to me because I never really realized how much of an impact worms have. I have always thought earthworms were good for our soils, but reading in the article it stating that the worms would change the habitat composition in the forest soils. The video was also very interesting to watch.

  12. Jasmine Sim says:

    All that information you shared on the earthworms blew me away. I did not ever think about worms that in-depth before and while a lot of that information was new to me, I was not surprised by their role in entire ecosystems. It makes sense that such a creature could have such a large impact on the environment. And for it to go unnoticed by people like myself. For me, I realize that organisms have their own special role in the environment and appreciate their contributions. Earthworms included. But to think that these introduced non-native ones are having a detrimental effect on our North American ecosystems is pretty horrific. It would be close to impossible to eradicate all the non-native, ecosystem ruining earthworms. So I believe we have to accept the fact that this was the fault of humans and just do our best to deal with the consequences until we can figure out another alternative (rather than eradication) to our worm problem.

  13. Eric Noel says:

    I never really gave much thought to many species of worms as being introduced to the area. This article was very interesting as it gave some background as to how these worms were most likely introduced and how many important historical figures held them in such high regards. The video about the giant earthworm in Australia was interesting because of the sheer size of the worm and the diameter of the tunnels it produced.

  14. Joel Demory says:

    This was a great reading. I’ve been told in classes before how beneficial earthworms, but I never was told they are actually introduced and the havoc they can produce on these ecosystems. Next time I bait my hook with a night crawler, I’ll definitely be thinking about them differently.

  15. Emily Haeuser says:

    I’ve heard a few anecdotes before about invasive earthworms, but before reading this article I didn’t quite realize how big of an issue they could be. Since as it stands eradication or at least reducing populations of these invasive worms without wreaking havoc on the rest of the system seems impossible, it seems clear that this issue needs more exposure. Increased public knowledge can at least prevent further introduction of invasives and help direct funding towards the development of possible solutions.

  16. Jake Frazier says:

    Before reading this article I had no idea how many non-native earth worms are underneath us and how they are changing the soil ecosystem. This article will make me think twice about the damage introduced species can have on non-native environments.

  17. Damon Cromar says:

    Having known that most of the worms are non-native, this was a good reminder just how much these worms don’t fit into the environment. I was really unaware of the harm these non-native worms do to forests.

  18. Emily Gray says:

    I guess that I just hadn’t given worms in general much thought. I had no idea there were even any introduced worms in the area because they live in the ground so I thought if they were here they must’ve just gotten here on their own or that these introduced worms might have such significantly different ecological roles that they could actually damage the ecosystem. This article was definitely interesting and not something that’s talked about all the time.

  19. Tanya Welborn says:

    I am surprised a little by the lecture. I did know that a lot of our worms are not native, and that they played an important role in the soil. I guess I never thought enough on the subject to think of what the ecological consequences would be and I most certainly did not think that they would be as drastic as described but when you think about what is happening the consequences make sense. I did know about the Giant Palouse Worm and people trying to get it on the endangered species list. And I do think that it is a valuable animal to have and should be preserved but as said above many of the information we have about the worms are at this point kind of lore. But on the other hand when I think about what organisms we are not putting on the endangered species list because they seem insignificant in most people’s eyes I find that terrifying. Like fungus can’t be put on the endangered species list, neither can viruses and whether or not they are appealing to the public they play a vital ecological role and need to be preserved.

  20. McKenzie Bomber says:

    I remember reading in 450 last year about if earthworms were natural or not, and being totally surprised by how much damage they did here. I had read the NatGeo article a few years before that, so I knew they were for the most part introduced. It does gets me thinking about protecting endangered, introduced species, at least in the case of those giant earthworms. As for that paper, I remember reaching the conclusion that where worms are introduced, they’ve had many positive anthropological benefits. It would be very interesting to see where we were ag and forest wise with out earthworms, for sure.

  21. Loni-Jean Rodrigo says:

    I remember reading about these worms that were put into an unnatural place about a year ago or so, and the idea still makes me wonder. The simple idea of worms makes me want to believe that they are the cream of the crop for soils, agriculture, trees, forests, etc. Though, because of this concept of unnatural worms (worms in an unnatural place), it makes what I believed as a child untrue. Nonetheless, information is more dynamic than is seems and completely ever-changing.

  22. Bobbilee Schuster says:

    I remember studying this very question in my previous conservation biology class. My conclusion was that earthworms were natural because they were part of the biological processes with the ecosystem, even if they are not native.

  23. Cody Watts says:

    This article was actually not surprising to me this time, because I studied this topic last year. However, when I did learn of these non-native ecosystem engineers I was very surprised. I never thought of earthworms as be invasive species, primarily because I grew up with them as part of the world I lived in. I do find this article to be very interesting to someone who was not aware of this.

  24. Justin Krohn says:

    I knew that most worms that you would find in your garden were non-native. I guess I never really paused to think about all the damage that they could do to our ecosystem. I also had no idea that there were giant worms of any kind anywhere in the world, and it’s pretty cool that we have one here in the palouse! I wish something could be done about the non-native species, but I agree that nothing practical could be done, I guess we’ll just have to see how this plays out.

  25. Kasey Parker says:

    This article was very interesting and is not something that you regularly think about when the topic of invasive species comes up. This is one of many factors that have caused ecosystems to change. It has really opened my eyes to taking below ground factors into account when thinking about how systems have changed over time

  26. Clayton Waller says:

    I wasn’t surprised by the information on worms. The most interesting idea that Rod brought up was the idea of “what is natural?” I never thought of something being natural just in an un-natural place. I also never thought of a walmart parking lot being anything near natural either. I thought this was a good twist to an out of the box type of idea.

  27. This article was veyr interesting. I learned a lot about worms and never knew they are dangerous to our ecosytems. However i did know that giant worms existed but i didnt know we had one right here in the Palouse. That is awesome. Knowing that most of the worms are non-native, this article reminded me a bunch how worms are not wanted nor or needed for our environments and ecosystems.

  28. Jordan Briggs says:

    I had always been told that a healthy garden has lots of worms in it, to hear that those worms are detrimental to the surrounding eco-system is rather shocking. Also just how many of them are around is also quite surprising. Perhaps the most interesting part though is the worm sounds. Although the worms aren’t making the sounds (like a cat’s purr) but are just the cause of it–Its still pretty cool stuff.
    Thanks for sharing!

  29. Ryan Johnson says:

    This article was surprising because I did not know that earth worms were introduced. Since early childhood family members and my science teachers always said that earth worms were a positive influence on soils because of nutrient rich casts and aeration and filtration processes. The fact that they were introduced and actually hurt certain ecosystems was never mentioned. Worms are not commonly thought of as invasive and certainly not destructive or damaging to ecosystems, but this misinformation highlights a growing need for invasive species awareness programs. It also represents how a human action can accumulate in an environment over time and create significant changes.

  30. Ursula Stegman says:

    I had no idea there were so many non-native worms in the Palouse. It also surprises me that I have never heard about this issue. My mom loves gardening and she taught me when I was very young how important the worms are, but I had no idea they could be harmful to the natural workings of the ecosystem. It’s too bad that we are all learning this too late and that nothing can really be done at this point.

  31. Taylor says:

    It really is fascinating that something as simple as earth worms aren’t indigenous to North America! I would have thought that something like that would have played a major role in the course of North American ecosystems, especially since we always hear about how important they are to soil and thus, pretty much all biota. It’s interesting to think that even something biologically simple (or so it seems) is still SO specialized in a particular area that it can do harm to certain ecosystems.

  32. Dan says:

    I had no idea we had global worming issues, I thought that worms were all kind of the same, just in different developmental stages. It is interesting to think how many worms are around us all of the time. Fishing worm dumping was something that I had wondered about in the past, those worms are usually a lot bigger than most worms that I dig up. It would be very difficult to worm out worms that we thought were harming our hardwood forests, probably nearly impossible. The only thing I can really see us do at this point is let it be.

  33. David Clippinger says:

    This lecture is very surprising. I would never have considered that a worm could be detrimental to the enviroment even if it wasn’t indigenous. However, if the non native species does a better job then the indigenous ones shouldn’t prefernce be given to the non native one. I mean evolution is the survial of the fittest, the living species today represent .000000..1% of all species that have existed on this earth. Society needs to get over the Disney created eco “harmony” where all species coexist in peace.

  34. Matt Schoonover says:

    I remember discussing this topic during my conservation biology course at WSU. Very interesting…

  35. Daniel Nyquist says:

    Yes I was rather surprised to about the article. I have always thought of worms as a beneficial part of the ecosystem, and with that I have had the notion that the more worms the better.

  36. Kevie-Lynn Pedersen says:

    I couldn’t believe that something many people consider disgusting and lowly was sacred to Cleopatra! While I have never disliked worms and am used to using them as fishing bate I never considered their ecological impact whether positive or negative. It seems preposterous that such a small organism can change a forest so easily just by existing and decreasing organic matter therefore lessening biodiversity in the area. I always thought they were very important for healthy soil therefore good gardens but now I know that they aren’t always beneficial. Who knew worms weren’t native to North America when they are so common!

  37. Justin Small says:

    I never had any clue that most of the worms we see on the side walk after a rain or while digging in the soil are invasive. I was shocked to learn how destructive non-native worms can be to a forest ecosystem. It definitely change my view in that worms are insignificant and harmless to the ecological order of nature.

  38. Karen Trebitz says:

    Not news to me, but I like how this information is presented in a reader-friendly article with interesting tidbits of trivia that make the facts memorable. David Attenborough’s videos are always fun to watch 🙂

  39. Neil McKellar says:

    I was pretty surprised by the worm lecture and was very much unaware that the earthworm I got from the store to go fishing is actually non-native. Worms haven’t really sparked my interest in the world of conservation or restoration though, but reading this lecture made me realize that they are not just a minor contributor to soil aeration and plant communities.

  40. Sean Stransky says:

    I remember reading about this. It is an interesting topic, in that worms are so very common every in the united states but they are most times considered non-native. While they are everywhere and very abundant, it is interesting to see how they effect positively and negatively known that they were introduced.

  41. charles macinnis says:

    do they increase the soil ph levels and decrease micro nutrients ? if so, do they weaken trees making them more prone to other infections such as the american chestnuts

  42. Bev Mowrer says:

    Help please. All I want to find the Genus and species of our local, indigenous earthworm. I want to add some worms to my new raised gardens, I suppose I can go out and gather them like I did as a kid but I’d rather find a supplier. There seem to be a lot of suppliers but I do not want to bring in a non-native and possibly invasive species. I do not need them for composting, only for keeping the soil aerated….can anyone help me out? Thanks!

    • Rod Sayler says:

      Hi, Bev. If you’ve got new raised gardens (which I’ve made myself a few times), the gardens will almost surely be colonized quickly by your local earthworms. I would really avoid buying worms from a supplier and having them shipped to you and accidentally introduce something that was undesirable. An alternative would be to simply pick up some of the worms you find in your yard “naturally” and put a few in your raised bed gardens to start things off. Once your raised bed gardens mature a little bit, as compost and soil additions decompose, you’ll likely have a thriving worm community there, as you will keep the soil moist and provide good conditions for the earthworms as long as you’re not using a lot of pesticides and herbicides. And that’s one of the advantages of having raised bed gardens, is that it is usually easier to manage these small plots organically.

  43. Richard says:

    So if i do a lot of worm composting, and want a worm i can release into my garden also, what would be a good native california earthworm? I live in zone 9b 92882

    • Rod Sayler says:

      Hello, Richard. That’s a good question. Research on earthworms is not readily available to the general public or popularized because many scientific publications are not available to the public. So it can be difficult to know what species of worms would be native to your area unless you were able to talk to someone in your region who has conducted research there. Also, it’s entirely possible that the conditions that you may have in your compost area or garden will not be the same conditions in which a native species of earthworm would thrive. So without knowing your regional earthworm species or exact environmental situation, my best guess would be that your site would be colonized by non-native earthworms. But that might be what to expect in those conditions. So I would just adopt the earthworms that you do have and mentally give them the status of Pilgrims in a new land!

  44. Ayo says:

    We lean new things everyday, most of the things I read and learn about worms by reading this article are news to me. my background is agriculture, during my undergraduate days we focused on the benefits of worms aerating the soil and improving soil fertility, we did look in details the negative impacts of worms on ecosystem. I was shocked when Cindy Hale, a scientist from Natural Resources Research Institute spelled out how non-native earthworms changed the soil structure, the soil chemistry, nutrient dynamics and the whole habitats making it difficult for other species to survive.

  45. Austin Bogard says:

    I was completely unaware that the most earthworms are actually non-native and technically invasive. I had never heard of this before reading this article. Very interesting!

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