Invasive Species Paradigm Shift Underway

There’s a big conversation going around in the ecology world right now, sparked by a two-page article in the journal Nature by 19 (!) co-authors, all prominent ecologists.  They argue for a change in the paradigm around introduced species to reflect ecosystem functions rather than categorization as “invasive”:

We are not suggesting that conservationists abandon their efforts to mitigate serious problems caused by some introduced species, or that governments should stop trying to prevent potentially harmful species from entering their countries. But we urge conservationists and land managers to organize priorities around whether species are producing benefits or harm to biodiversity, human health, ecological services and economies. Nearly two centuries on from the introduction of the concept of native-ness, it is time for conservationists to focus much more on the functions of species, and much less on where they originated.

The article is receiving a fair bit of criticism from within the academic world, such as this from restoration ecologist Nate Hough-Snee.  More conversation at the Ecological Society of America here and at Smithsonian Science here.

A few points I’d like to make.

–The full article is available here for $32.  I have to say I don’t understand the economics of academic writing – they seem grossly distorted, and like a barrier to access.  (Yes, I’m sure there are structural reasons for this…)

–The permaculture teaching community, especially in the Northeast, has been beating the drum around changing the invasive species paradigm for many years.  Dave Jacke, Jono Neiger, and Eric Toensmeier have, in particular, taken leadership around bringing similar lines of thinking forward publicly.  It’s exciting to see these arguments laid out clearly in a more mainstream publication.

–The core point the authors are making should, I think, be uncontroversial – that introduced species should be assessed on a case-by-case and landscape-by-landscape basis rather than through the lens of a blanket categorization of a whole species as “invasive”.  I would like to add that: the reason land use changes create favorable conditions for introduction of new species, is that the wholescale landscape alteration and intense soil disturbance of the modern world’s infrastructure and economy create new available niches for the usually disturbance-adapted introduced species to establish in.  And, those intensive levels of disturbance are not inevitable, but reflect choices of individuals and groups about how to manage landscapes.  And those choices can change with education, training, and living models of how to manage landscapes in a more regenerative manner.

–I really like the systems thinking revealed in the authors pointing out that biological islands – whether literal islands or figurative ones like lakes and ponds – are, in fact, quite vulnerable to disruption and extinction/extirpation from introduced species.  That’s a super important “weakest-link” factor for all of us to keep in mind.

Hough-Snee’s concluding criticism of the article seems to be that the invasive species paradigm shouldn’t be questioned publicly, because it will be misinterpreted by the public as “invasives are fine” and will lead to decreased funding for restoration and removal-of-invasives projects.  I think this is more than a little disingenuous.  Warning that certain points the article makes are “dangerous…in a day and age of limited money, personnel, and resources” has nothing to do with whether the article represents clear and accurate thinking.

–Also, Hough-Snee may be correct that most restoration ecologists are already focusing on the highest-impact introduced species, but there’s a significant private industry as well around introduced species removal – home-use pesticides, landscaping companies, etc. – that’s responding to the available market for those products and services, which is based in large part on the semi-informed perceptions of private landowners.  Which are, in my experience, not necessarily likely to be focused on the highest-impact species, but are often focused instead on the “nuisance” species like Japanese Knotweed, Autumn-Olive, and Japanese Barberry, to name a few.  All of these examples are filling very clear ecological niches in highly disturbed environments, offering significant uses and functions to people (food and medicine for Japanese Knotweed, nitrogen fixation and major fall food source for Autumn-Olive, medicine for Japanese Barberry), AND are very manageable within a context of creating a productive landscape mosaic.

–I think the ultimate question here is not actually about science and policy, but about worldviews, and about our relationships to our landscapes and ecosystems.  More difficult to respond to, because it defies any technological or political “solution” – but probably a more effective (and much more peer-to-peer and community-based) leverage point for those of us who aren’t already within the existing larger decision-making system.

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12 Responses to Invasive Species Paradigm Shift Underway

  1. sophie quest says:

    I wonder about hardy kiwi. They say it’s really invasive sound of her (Vermont). Seems like a fine invader.

  2. Thomas Meli says:

    Hi There,

    I appreciate your publicizing this article and giving a review of the themes you find most dominant. I have several questions and concerns about the way this is framed and hope to engage in some dialog with you about this.

    I want to acknowledge first off both my gratitude for your interest in this, it has inspired much research on my end, and has got me somewhat fired up about learning more about this. I also want to acknowledge that we have similar intentions – to care for the earth and ourselves in it for future generations.

    With that in mind, there are several things you say that have struck me as problematic and I hope to discuss them with you further.

    1.
    “The core point the authors are making should, I think, be uncontroversial – that introduced species should be assessed on a case-by-case and landscape-by-landscape basis rather than through the lens of a blanket categorization of a whole species as “invasive”.”

    This is, in fact, extremely controversial to me. A consequence of this s that before we decide on any particular strategy to deal with invasive plants with the knowledge we already have in general about them, we must research each particular case. This entails enormous resources and research, and indeed, if we take this logic to its conclusion, then each particular site must be investigated as the “invasiveness” of the site is a crucial variable in invasive species success (including variables such as path heterogeneity, bioclimatic suitability, local vector presence, predation / consumer pressure, etc.).

    If the issue is prioritizing those strategies that are certainly effective for a specific site, but this itself requires intense site-specific research every time, I don’t see how this can contribute to increased efficiency or effectiveness above and beyond mindfully and carefully extrapolating from data we already have.

    There is a risk either way, and pros and cons to both. I am merely pointing out that this is not at all an uncontroversial point, and itself has consequences.

    2.
    “All of these examples are filling very clear ecological niches in highly disturbed environments, offering significant uses and functions to people (food and medicine for Japanese Knotweed, nitrogen fixation and major fall food source for Autumn-Olive, medicine for Japanese Barberry), AND are very manageable within a context of creating a productive landscape mosaic.”

    I am uncertain where the factual evidence for this statement is derived. My research indicates quite clearly that any ecological benefits that may accrue from these species also come with many ecologically unproductive side-effects. Because they are so detailed, I will only pay attention to one, though the others are equally problematic (especially barberry).

    The main problem is that every plant will have its benefit(s). If we paid attention to only the benefits of each invasive plant, this would lead to an extremely one-sided and incomplete evaluation of the totality of their consequences. The point is to see that natives already perform many of these same functions (like Alders or native viburnums) without the negative consequences associated with non-natives. We cannot solve a problem with another problem, and I’m afraid pointing out the “positive uses” of the plants without fully evaluating all of their consequences can only lead to uninformed caretaking or unqualified acceptance.

    Example: Knotweed:
    (mainly based on article: “Community and ecosystem consequences of giant knotweed (Polygonum
    sachalinense,) invasion into riparian forests of western Washington, USA”, By Lauren S. Urgenson a,b,*, Sarah H. Reichard b, Charles B. Halpern a)

    For example, with regard to Japanese knotweed – Since Knotweed tends to colonize and monopolize riparian habitats, the question emerges as to how this affects the riparian ecosystems. Here is a summary of some effects.

    a. Knotweed has lower quality leaf nitrogen quality than natives.

    “In knotweed, resorption of >75% of foliar nitrogen
    suggests that most N is transported to rhizomes for storage (and
    subsequent use) before leaf fall. In contrast, lower resorption in native
    species (only 5% in N-fixing red alder) results in the transfer of
    a greater proportion of foliar N to riparian soils and aquatic environments”

    b. This likely reduces the productivity of macro-invert communities

    “By reducing litter from native
    species and replacing it with litter of lower nutritional quality,
    knotweed invasion could affect the productivity of macro-invertebrate
    communities and in turn, the fish that use these invertebrates
    as a primary food source”

    Another study concludes that
    “Green frogs show reduced foraging success in habitats invaded by Japanese knotweed”
    (That is the name of the article if you are interested).

    They end with the statement:
    “We hypothesize that Japanese knotweed invasions degrade terrestrial habitat quality for frogs by indirectly reducing arthropod abundance. Nonnative plant invasions may be another factor contributing to amphibian population declines. ”

    So these two studies converge and support the evidence of the other.

    c. reduced recruitment of natives negatively impacts nitrogen cycling

    “Among the species displaced in
    our study system are regenerating trees that, as adults, are key
    components of the structure and functioning of terrestrial and
    aquatic systems. Reduced regeneration of red alder has important
    implications for nitrogen cycling in these environments, where N is
    limiting.”

    The study concludes with the statement:
    “our findings suggest that removal of P. sachalinense
    should be a primary goal of riparian restoration initiatives.”

    Limited nitrogen cycling can slow down the entire productivity of an ecosystem since nitrogen is so important to the construction of proteins (both plant and animal).

    d. Caretaking Possibility – Increased nutrient density in topsoil.

    In another study (http://www.bioone.org/doi/abs/10.2980/1195-6860%282007%2914%5B230:IBFJIT%5D2.0.CO;2), increased nutrient cycling of other elements besides Nitrogen was measured.

    “We conclude that F. japonica enhances nutrient cycling rates and topsoil fertility, probably due to nutrient uplift. The impacts were greatest in sites with low nutrient concentrations in uninvaded plots, suggesting that F. japonica may contribute to soil homogenization in invaded landscapes.”

    Now we see that again this is a double sided sword. On the one hand, nutrient density increases, on the other, it promotes soil homogenization. Yet, as caretakers tending the wild, this actually affords a certain caretaking possibility.

    Since Knotweed has the previously mentioned negative impacts, though can also temporarily boost soil productivity (though of course this is meaningless if ONLY knotweed grows there), we can caretake the plants in a way that uses this soil productivity to enhance natives that would solve the other problems knotweed creates.

    So putting this all together, are we really willing to endorse knotweed on behalf of its supposed edibility and medicinal qualities (both of these attributes I might add, are short term benefits for humans and pay no heed to ecological consequences)?

    I also want to ask, have any of the people endorsing this actually one out to harvest knotweed? Do people know how much work it takes to harvest, process, clean, and cook it? The meristematic shoots can be pretty delicious, but this is hardly a reason for me to endorse not controlling the plant. So do so many other plants.

    And with regard to medicines, Knotweed is apparently a laxative and contains reversatol. My Peterson’s guide to medicinal plants indicates over 60+ plants that have the same effect, many of which are not native. Grape leaves have extremely high amounts of reversatol and a simple tea can give the same effect.

    Again, these qualities of the plant can be used to caretake it more effectively. Using invasives as meals and medicines is a carteking strategy that can be used to get rid of them, NOT to save them or promote them.

    So I’m fairly concerned about the way this article has been presented for the reasons I have mentioned in my writing, and I’m curious to hear how this lands in you and how you respond.

    Thanks for reading and hope to hear from you soon
    -Thomas Meli

    Blog: http://www.interdependentsoul.com

  3. Thomas Meli says:

    Important Correction
    “My Peterson’s guide to medicinal plants indicates over 60+ plants that have the same effect, many of which are not native.”
    I meant to say “not invasive.”

  4. grousedrum says:

    Thanks for such an in-depth response, Thomas.  I really appreciate you sharing your perspective. I also judge, as you said, that we both care a lot about the planet and the future generations. In that spirit, here is some more of my thinking about the overall invasive species conversation, as well as a few specific responses to things you wrote.

    My overall basic message about introduced species would be, “it’s complicated.”  I think it’s complicated both because the ecology at work is complicated, and because the economic and cultural situation we’re in at this moment in history is complicated.  What I think is problematic about the current I.S. paradigm is that it’s so often portrayed as simple – these species are invasive and bad, “shouldn’t” be here, and need to be removed.  I’m definitely not “endorsing” knotweed, or barberry, or any other expansive and/or dispersive species, as something that we should encourage and cause to increase – the plants are doing that plenty well on their own! And no, I don’t think (to respond to your specific question) that knotweed is a super-high-use species for most people in most situations.  What I do want is for people to think realistically and non-dogmatically about how to manage our landscapes given those landscapes’ history, our available resources, and our complex current global situation.

    One starting point I have in my thinking is that our ecosystems have already changed significantly from their “native” state (whatever that means) and will continue to.   Climate change alone is ensuring that the landscapes our grandchildren grow up in will differ in many important ways from the ones we live in now.  And the modern ecologies of the Northeast are themselves significantly different from the landscapes that European people found at the beginning of the colonial period.    And those pre-colonial ecosystems – featuring a different suite of dominant species; extensively managed by native people using fire, clearing, planting, seeding, selective harvests, etc; lacking anything like the level of soil disturbance we experience today; etc. – bore very little resemblance to the post-glacial landscapes that those people first inhabited.  And so on.  So to me, that begs the question, “what are we restoring to?” and causes me to notice emerging new ecosystems in rapidly changing landscapes (such as urban spaces, highway medians, abandoned mines and industrial sites, etc.) rather than “invasives” to remove. And looking at the long view of land history also points out to me that the definition of “non-native” is arbitrary, as is the conflation of “non-native” and “invasive”. To say that “all species that weren’t present in our region before 1492 are ecologically detrimental” seems inaccurate and extreme to me – but I think that’s what’s usually implied when people refer to “invasive species” as a category. And all of this doesn’t, in my mind, mean that we shouldn’t value and preserve “native” species and communities; it just means that those communities are already changing and preservation may not always be realistic (or even necessarily always desirable given rapidly changing range maps) as a singular goal.

    Your point about how much time and money it takes to fully research each site and each situation is well taken; I agree.  I don’t advocate for doing assessment that extensively in most circumstances, and I’m definitely in favor of developing basic best practices and then learning as we go.  I also don’t think holistic landscape assessment necessarily has to be time- and resource-intensive – most people and institutions, as you point out, have limited time and resources anyway.  What I would suggest as a starting point is asking: “what’s the ecological niche this plant is filling?  Why is this plant here?”  That places the question in terms of the patterns of the whole landscape rather than all the details surrounding one or two elements in it.  And I definitely see that, after some best-guess assessment of our goals, site conditions, and available resources, we might end up deciding to remove many of the introduced species anyway. That might be the outcome in many cases!  But I think that “it’s invasive, let’s remove it” as a starting point in our thinking is knee-jerk and ideological, and can be a barrier to people reading the landscape more deeply and understanding the ecosystem dynamics at work.

    The research you cite about ecological impacts of knotweed is good to read about, and an important part of a holistic assessment of knotweed and the landscapes it grows in. I definitely don’t dispute that there can be detrimental impacts on other species from introduced plants and animals (especially in “island”-type systems and with isolated or endangered populations). Many studies that purport to document those impacts, however, such as the frog-knotweed study you cite, draw broad conclusions from very limited data sets over small areas and short time frames, and more and more scientists (such as the 19 co-authors of the originally linked article) are questioning their colleagues’ broader conclusions from those limited studies.

    Given that removal is a likely potential response to the presence of many of these species, I think another part of an assessment should be the impacts of the removal process.  I.S. removal is often carried out with Roundup and other seriously toxic chemicals, and/or creates more of the soil disturbance that invited in the expansive/dispersive plants in the first place.  I’ve heard of people in the landscaping industry saying that “we should level all of Cape Cod and start over” because of introduced species, and heard stories of 2-3 feet of topsoil being scraped off sites to remove barberry and bittersweet seeds from the seed bank.  Examples like that make me think, really?  Does that really pass an ecological or an economic cost-benefit analysis?  Because we know from succession ecology that those expansive/dispersive plants are there for a “reason” – they’re inhabiting an available niche.  Removing them chemically or mechanically at great expense will still leave that niche open, unless the whole landscape is replanted at extraordinary cost.  

    And that gets at another piece of context for me, which is that in this time in history (climate change, resource depletion, economic crises, famine, mass extinctions, etc.), in my mind there might be higher priorities in land use decision-making than the often-never-ending treadmill of removing invasive species.  Priorities like: creating resilient local production of food and medicine and fuel; helping ecosystems adapt to climate change; shifting agriculture and forestry from the 20th century extraction model into ecologically and economically regenerative practices; etc.  Removing recently-introduced expansive and dispersive species may help with those priorities some times in some landscapes, and not in others.  That’s another reason why I disagree with a blanket categorization as “invasive” – I think it creates a “monoculture” response even when it’s really a polyculture of land use strategies that are (I think) called for if we want food security, long-term healthy ecosystems, etc.

    I hope that sheds some more light on why I see the issue in the way that I’ve portrayed. I again want to emphasize that I’m not “endorsing” these species as necessarily highly ecologically beneficial or economically useful; in plenty of cases, they’re not. The focus for me is really on the paradigm and mindset around invasive species, and the assumptions that those reveal. I want to create a broader context around introduced species related to succession, ecological niches, and overall land use choices at this time in history, rather than a narrow context of “invasiveness” as the species’ defining characteristic, and removal as the only option.

    That was quite a mouthful, and I think I’ll be done for now. :) Thank you again for sharing your thinking; I think it’s all really important to talk about.  And please feel free to continue the conversation in this thread if you’d like to.

    ~Connor

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  6. Sven Pihl says:

    Hi Connor, I was having a discussion recently and several issues came up and they presented a seemingly common issue; professional communication on invasives and/or disease.

    1. Hardy Kiwi as an invasive. This came up as I mentioned I had just planted two seedlings. I received this email the next day. (http://www.massaudubon.org/PDF/invasive_species/hardykiwipestalert.pdf)

    2. White Pine Blister Rust and Ribes spp. This came up as I was on a tour of the UMass Permaculture Garden, and it was observed that several Ribes varieties had been planted. Prior to planting, it had been discussed that Ribes can play a role in the continuing infection of White Pines. While we were at the site, we did not document varieties, but when home, I sent out this report (www.nh.gov/agric/documents/ribes.pdf ). It was later verified that the Ribes spp. planted there were disease resistant.

    3. And a while back, I was speaking to a gardener who had completed the NOFA OLC and brought up Forest Gardening. She chewed my head off regarding some of the plants being used and their characteristics.

    I bring all of this up, including the Ribes issue to make a point. Whether we are a forester, a Forest Gardener, or another professional of some sort, communicating between different disciplines is incredibly important. I fully understand where both you and Thomas are coming from, and it is great that you two are having this discussion.

    In closing, I wish to thank you two for an intriguing discussion and long for more professional interdisciplinary involvement on this topic.

    Thank you,

    Sven

  7. This is a discussion I run into time after time in my field of work — mainly because very few of the food plants humans now rely on are not native to our particular location in space and time ( Post-industrial Upper midwest). So in my design work I field many questions on whether the plants I am planting in a client’s garden are “native” or “invasive”. This has had me deep in thought on the subject and recently drew me into presenting my theories and ideas to a local native plants group.

    Adding to what Connor’s outlined — which reflects very well the thought patterns I have developed — there are two big points missing from the “invasive” vs. “native” debates and activism.

    #1 is FOOD. What did you eat today? Did you eat bread? Did you eat processed food? Did you open a box to get your calories? Corn, wheat, and soybeans are planted to a cumulative total of almost 200 millions acres in the United States. None of these plants are “native” to North America (corn might be debated by some), and certainly the cultural practices of land clearing, soil management, pest management, harvesting, storage, and transportation (etc.) are not native or indigenous — not by a long stretch. Then there’s the extractive economy surrounding packaging, marketing, and distribution of the seed of these “invasive” plants and foodstuff made from them. In short, the point I want to make is that our food system — the way in which we “earn our bread” is a huge reason for ecosystem destruction. And that’s what the “native” vs. “invasive” debate’s main focus seems to be — the disturbance of ecosystems due to “invasive” plant species. I suggest we look a little closer at what we put into our mouths.

    #2 is how we live on our home-fronts. Lawns cover 40 some million acres in America. And they’re not grazed paddocks, manured by ruminants, with deep loamy topsoil and polycultures of grasses and herbs. For the most part they’re relative monocultures of “kentucky blue” or other species of lawn grass — fertilized, kept on life support & “weed” and “pest” free via (very toxic) petroleum derivatives — then unrelentingly “grazed” by blade wielding beasts, powered by ancient, not current, solar income (oil and it’s derivatives). Many native plant activist turn their lawn into a native plant habitat — which is great. But what about our food production? Is it “native” to not grow even a small amount of food where we live, all the while driving to the store to purchase foodstuffs to stay alive? Sure the front or backyard now has habitat for plants, animals and insects… But what about the farms we’re gaining our sustenance from? Are their practices doing this?

    To add to this, it seems that these plants deemed “invasive” are nothing more than signposts. They’re mother nature’s attempts to heal what’s been damaged and signals that the way we interact with the living world around us is entirely imbalanced. We must keep in mind that the external world is merely a reflection of an internal state. In this case it’s the reflection of the collective human condition of our era.

    So long as the discussion focuses on elements and not the entire system, we will see too much time, money, and attention wasted fighting a battle that has no chance of a snowball in beezlebubs backyard of succeeding. Nature bat’s last. Let’s join her.

  8. Thomas Meli says:

    Mark,

    Thanks for this contribution I’m a bit confused by your response. I currently see your contribution in 4 ways.

    If I read you correctly, you are wanting to draw attention to the fact that much of what we eat is technically non-native. To you, our current agriculture and extractive economy is a big contributor to ecosystem destruction.

    Your second point concerns the use of lawns and both the possibility of growing food on them (that is domesticated), and what you see as a kind of habitat destruction by having grass everywhere.

    Your third point is involved in seeing the outside as a mirror for the inside. Your last wanting to be focused on whole systems and not just parts. Do I understand you correctly?

    While I agree to some extent with all of your claims. I’m confused about how they apply to the conversation we are having.

    A distinction which seems crucial here is the distinction between “invasive” and “exotic.” non-native domesticates, while being exotic, are rarely if ever invasive (precisely because they are domesticated and can hardly survive without human care). So the food question you pose is to me, quite important for sustainability in general, but I don’t see how it has anything to do with a conversation about invasive.

    The situation is even more complicated if we measure the “amount of domesticated-ness” (which can be measured through the plants’ capacity to survive or not by itself) and we find that some of the more “permacultury” exotics are domesticates that also have invasive attributes.

    My question is focused on solving a simple question: If I walk around land I frequent often with pruners, and cut all the invasives, over time, will the landscape be more healthy? I am not interested in industrial scale solutions to this, to which an idea like “tending the wild” becomes quite tenuous, though I also see its necessity in some respects.

    So I hope this clarifies this discussion, as to me, it is important to be quite clear about how all these things are related, not just noticing that they are.

    Connor I plan on responding to your comment too sometime soon.

    Blessings all,
    -Tom
    http://www.interdependentsoul.com

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  10. This is one of my favorite topics and we’ll have to talk about it over a beer sometime.

    I had some major issues with this paper also, though I think it brought up some good points. I would argue that a plant that is colonizing an unused niche created by humans is not actually invasive… and that many invasives are doing more than that. However, a plant species can do more than one thing. For instance, tamarisk (as mentioned in some of these articles) is doing two things… The massive tamarisk monocultures we see in mainstem rivers of the southwestern US are indeed related to changes we have caused in the ecosystem – in this case, installation of dams and alteration of hydrologic regimes. In this case, the plant IS colonizing an unnatural and unused niche, and is probably ‘better’ than the niche being unfilled. But THEN we have patches popping up high in watersheds, along springs and places of rare surface water in the desert. Tamarisk jumps into these places, ‘drills’ to the water table with its taproot, uses up all the water, kills the cottonwoods, dries up the spring, and causes a whole bunch of different animal species to die or have to leave the area.

    So what do you do when a plant is not invasive in some settings but is in others? Do you get rid of all of them? Do you let the springs dry up and let the animals die? Do you manage only the upper watershed areas? The beetle biocontrol being used in some areas is more effective on killing the larger patches on the mainstem river, that animals are actually using, and is not effective in finding all the little seeps and springs. All rivers are fed by seeps and springs and little tributaries, so how do we deal with the loss of all that water, especially when combined with climate change and general watershed degradation?

    I think the big backlash to invasive species management is caused by people using invasive and non-native interchangeably (as was mentioned above). In fact, most non-native species are not invasive, and native species can even become invasive when humans alter the environment. However, this doesn’t mean that INVASIVE species aren’t causing a vast amount of ecosystem damage. Some, like you said, are simply indicators of human disturbance (I’ve been mapping some Vermont invasives on my Iphone and have noticed that Morrow’s honeysuckle is very abundant in disturbed areas but isn’t really coming into dense intact forests that i’ve noticed yet). But others are quite different indeed. Tamarisk is invading upper watersheds of the Southwest, and cheatgrass, buffelgrass, and fire are converting the diverse deserts we know and love to vast, erodable, biologically sparse monocultures. It’s possible that over time glossy buckthorn will choke out the New England forests too… we won’t know until it’s happening (or isn’t).

    Ultimately, we’re looking at an equilibrium in an incredibly complex system that is being disrupted by invasive species, probably because they are not being controlled by insect predators, or in some cases because they are abusing the mycorrhizal network. Ruderals that evolved with the mycorrhizae and insects of an area will act very differently from a ruderal ‘set loose’ in a new area. Also, there is a HUGE factor here that you have probably considered but most people don’t. Almost all of the land in the modern United States was intensively (and largely sustainably) managed by Native Americans for many thousands of years. The management technique used in many cases allowed for immense diversity and complexity, but was management nonetheless. What happens when you abandon a cornfield? It becomes filled with weeds. I suspect much the same is true on a large scale in ecosystems of much of the United States. California, for instance, has been managed for diversity and abundance of seed-producing annual and geophytic wildflowers (among other things) for probably 10,000 years. The management ended, annual grasses and forbs were introduced, and next thing you know you get ecosystem collapse. Since the last ice age, Vermont has probably had people in it for longer than trees. What they were doing is very poorly understood even today. The real answer is probably to return humans to the landscape in a similar way. If we were as close to the land as people were back then, we could cause most invasives to ‘play fair’ again, especially the ones we can eat or find uses for. We could control most invasives, without having to use herbicides or other potentially harmful tools. It would probably solve a lot of other ecological (and social) problems as well. It’s a pretty lofty goal, and maybe not feasible, but then again…

    ~Charlie

  11. Hi Tom,

    Glad I made it back to this dialogue. It seems like my initial post wasn’t very clear to you.

    I think if I strip away the specific examples of the commodity crops, victory gardens/yardens and internal health my point can be made more easily comprehended.

    The underlying point I aim to make is that the mind-frame we view plants, their growth habits, vectors of distribution, and various intrinsic characteristics, is heavily biased by the way we think about ecosystem health and succession. If we look at the whole-system of ecosystems and species migration, “invasive” or “exotic/non-native” plants are, on a very basic level, taking advantage of soil disturbance and more widespread vectors for seed distribution (and any other connections between those two regarding seed banks in ecosystems).

    When I use corn, or soybeans, or lawns, or the internal dissonance these may represent, I aim to convey that these realities are larger and probably more systemic issues or causes of ecosystem disruption and destruction than any mention of the species that are so often branded as “invasive”, habitat, ecosystem, destroying species. My thinking on this comes from my observations of native plant activists and invasive plant antagonists exerting large amounts of human or other energy to eradicate species without much thought or reflection on what their appearance indicates in the larger picture of modern human activities and the impacts of these activities on ecosystem succession — and to then either leave bare soil (in the case of large-scale garlic mustard removal, for example) or replacement with a human selected species. I’ve seen acres of previously eradicated garlic mustard return as more dispersed, dense colonies of the very same species, for example.

    Do we, as humans, have enough foresight, knowledge, wisdom, and awareness to “tell” mother nature how to assemble species and respond to disturbances in the ecosystem? Personally, I think not. But in my opinion, we can have enough foresight, wisdom, and awareness to assemble species on farms, home-fronts, and regularly visited wild gardens (tending the wild, foraging) to produce yields that slowly, and over time, ease the damage of modern agricultural practices, industry, etc., all the while providing habitat, ecosystems services, and calories and nutrition to fuel the larger work.

    Some side notes:

    – I use food as an example because it is probably one of the more pressing issues of our time; the way we grow and source calories and nutrients exerts much more strain, contamination and soil erosion on ecosystems than any “exotic” or “invasive” species I’ve observed. It’s also a very strategic place to intervene, as opposed to tackling species whose purpose we’ve yet to comprehend.

    – Have you ever gotten terribly ill, to the point where you were bed ridden, or sweating, for a length of time? Afterwards your body balanced itself and you began to recover. I feel that disturbed ecosystems, over-run with species we don’t see as native or appropriate, as a means for mother nature to sweat off the fever caused by humans poor choices.

    – None of this is mentioned as way of saying something like, “Don’t talk about or do anything about “invasive” species.” I regularly pick and choose species in my garden and other work. My addition to this dialogue deals more with the larger issue of how we perceive ecosystem succession and the place for species in time and space.

    I hope this makes my point more clear.

    Cheers

  12. Pingback: Invasive Species Follow-up | Renewing the Commons

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