Beyond the War on Invasive Species by Tao Orion

I give this book 7 out of 10 acorns.

TL:DR: Some excellent material, which it's worth reading for, but some important flaws, which the reader needs to be aware of.

I spent a year studying habitat surveying for conservation, and I like to think I'm more aware than most of the implications of introducing opportunistic species into an ecosystem. There are endless discussions – some of them quite heated – about the point at which we might want to preserve or restore ecosystems, reintroduce extirpated species and introduce analogue species of extinct ones. Parts of this debate have turned to some very ugly language linked to xenophobic attitudes towards other human (Homo sapiens stultus-materfututor) beings. Sometimes, as with the reintroduction of beaver (Castor fiber), I have seen outright lies by those opposing the move (and this is before we even mention the word “wolf”).

I tend to take a radical position on this, as someone who consciously kept his mouth shut about beaver foraging signs on the River Tay in Scotland several years before they found their way into the newspapers, and who would be more than happy to see wolves (Canis lupus) again roaming the Highlands. I've also spent hours mapping non-native species in protected reserves, and micromapped extreme rarities in other reserves where opportunistic species needed to be controlled lest they destroy one of their last remaining habitats. I've beaten up rhododendrons (Rhododendron ponticum) and ripped up Japanese knotweed (Fallopia japonica) and Himalayan balsam (Impatiens glandulifera), all of which have been useful plants in what conservation biologists had concluded was the wrong place.

I also know there is no such thing as an undisturbed ecosystem, at least in Europe. The UK has no survey code for “natural woodland” because we don't need one. There is a strong argument that there is no need for a survey code for “natural woodland” anywhere, because manmade climate disruption has to some degree affected all of them. Here in Scotland attempts at “restoration” are complicated by the fact that most of the megafauna is gone and much of what remains is overpopulated (think red deer (Cervus elaphus)). I know of few sites (although there may be others of which I'm unaware) where there is a conscious attempt to restrict even the flora to “native” species. While there is a drive towards “rewilding” there is at least a tacit awareness that the inclusion of only native species and the exclusion of all non-native ones may well be a bad idea and is probably a lost cause. That said, unlicensed release of non-native species into the “wild” is illegal – and there is a very restricted definition of “non-native”, which includes even many extirpated species – a definition apparently designed to serve vested interests.

The right non-native species in the right place can help to restore ravaged ecosystems. The wrong one can do more ravaging. The myth of a non-native species coming to some sort of balance refers to a simplistic and discredited Gaianist perspective and, while it's possible to blame the damage caused by an opportunistic species on vulnerabilities caused by humans, here are fewer and fewer ecosystems that have not been damaged to the point of criticality by human interference, with the additional pressures of an increasingly disrupted climate and other boundaries we continue to push.

On the other hand, it's possible to create an entire novel ecosystem in badly degraded habitat. An exercise in Victorian-era terraforming converted Ascension Island from a barren wasteland that stared at a young Charles Darwin “with naked hideousness” into a thriving ecosystem, although with costs to the pre-existing biota. There is also, as I'm learning, a risk to overgeneralising from this case to a broader one. What happened on Ascension may have been an exception, on an island ecosystem, not a rule.

This book was my second look for a balanced perspective on introduced species that could be applied to Permaculture design and practice (the first is here: https://permies.com/t/53346/books/Wild-Invasive-Species-Nature-Salvation but I was even less impressed). In what circumstances is it appropriate to introduce a non-native potentially opportunistic species? The Foreword considers the case of Australia, with a relative paucity of native edibles, but a history of catastrophic introductions, from gorse (Ulex europaeus) to prickly pears (Opuntia stricta) to rabbits (Oryctolagus cuniculus) to cane toads (Rhinella marina).

David Holmgren's argument that the supremacy of the reductionist approach stems from a wholly unsustainable (not to mention deeply damaging) perspective – and set of practices – as regards agriculture is legitimate and fair. I want to be the last person to side with a view of invasion biology that sides with global agribusiness. The problem here, as in the US and elsewhere, is that the definition of an invasive species (and their management) is contingent on not so much human interests as those of a subset of human vested interests – usually rich, entitled ones, and this in itself is a reason to question the concept. The partnership of restoration ecology with corporate chemical interests stinks, and this needs to be faced. That said, many of the author's – entirely legitimate – criticisms of this partnership are specific to the United States, with its tradition of a refusal to regulate corporate interests. Parts of this book are well worth reading as an update to Silent Spring.

With all that said, I found the author's description of her experience of habitat restoration to be an interesting one. I'm familiar with what she knows as “moonscaping” only in the context of relatively rare habitats where one opportunist species has created a monoculture, mainly by Rhododendron ponticum (where I have, to be fair, seen the spot application of glyphosate used in order to prevent regrowth). I would not rule out bad practice at a local and regional level, especially where local authorities are concerned, but I'm not familiar with it in the context of restoration ecology. If her description is common practice in her area this is, indeed a disgrace.

It's certainly possible to take a position, as Orion does, that all (known) life is native to the planet. In terms of human relations I'd agree with her. In terms of ecology, I think the situation is more complicated, in that one needs to take into account the science of biogeography, which Orion simply ignores. Humans are all one species. Bioregionalism suggests to us that certain plants (and indeed certain concepts) may be better suited to some areas than others.

There is some excellent material in this book. Her specific criticisms of the failure of some habitat managers to look at an invasive species problem from an ecological perspective, and of the control by pesticide companies over perceived solutions are absolutely fair comment. Her desire to examine the context of the conditions in which they become invasive is also absolutely fair comment. Much of what she writes about feedback loops is also accurate.

Then she falls over her own feet by bringing it back to Gaia Theory. I've said this before, and I'll say it again: Lovelock's ideas are appealing, but there are some serious problems with the theory itself and the way it's interpreted. It's a potentially useful model, but the self-regulation aspects are not supported by observation, and are contradicted by work on tipping points. More to the point, her comment that life on Earth is “goal-seeking” is contradicted by Lovelock himself, who writes: “Nowhere in our writings do we express the idea that planetary self-regulation is purposeful, or involves foresight or planning by the biota".

It's an elementary mistake, and undermines her entire thesis. In this sense (although not in most others, and we need to be clear on this) it's faith, not science.

She then goes back to an excellent summary on the subject of ecological disturbance. Her observations on the way certain invasive species can only take hold where there has already been disturbance, and how these create novel ecosystems, are mostly fair. Her grasp of ecological principles seems solid, and her point that what actually underlies habitat degradation is factors other than invasive species is at least mostly true. I strongly concur with the author that, in many cases, “invasive” species are getting the blame as distraction from other human activity (a pattern also seen when human “immigrants” are blamed for other failings, such as inadequate infrastructure, the poor are blamed for the failings of capitalism, and so on). It's clear she should – and probably does – know better.

It is also fair to observe, as the author does, that if we want to address the problem of species extinction we need to be addressing the problem of climate change, which seems likely to do a great deal more damage than any individual “invasive” species.

She seems to argue that invasive species are opportunists when it comes to our mess, and can then be used to clean up our mess. She correctly observes that such species take the blame – often unfairly – for declines in native species. While this is a good point, if not always true, I would observe that a more appropriate solution would be to clean up our own mess, and limit the damage to biodiversity in that way. Many opportunist species do take advantage of habitats damaged by humans, but there are plenty of cases (such as the aforementioned rabbits) where a great deal less damage would have been done had they not been introduced, regardless of the underlying vulnerabilities.

Much of her analysis is primarily applicable to North America. As far as I can tell, it's mostly accurate, but many of her conclusions remain steadfastly anthropocentric, where a more ecocentric position might have led to different ones. A great deal of her analysis is excellent, but she again trips over her own feet when talking about mob grazing. Much of what she writes about soil improvement is at best ambiguous or unproven, and the claims about carbon that she cites without review are based on maths that just doesn't add up http://www.realclimate.org/index.php/archives/2013/11/cows-carbon-and-the-anthropocene-commentary-on-savory-ted-video/. This is someone who has a decent grasp of ecology, and yet doesn't know (or ignores) that domestic cattle and American bison have been consistently shown not to be ecological analogues (see, for example, with references: https://www.westernwatersheds.org/gw-cattle-v-bison/ ), and even reintroducing bison would not create biodiverse habitats in the absence of the trophic cascade effects of large predators such as wolves and mountain lions, which ranchers of all stripes insist on eradicating. In other words, what these ranchers are still doing is creating what's euphemistically called “improved grassland” while trying to pass it off as prairie. It might not be as bad as conventional alternatives, but it still doesn't support the full range of plants, animals and microbiota supported by prairie ecosystems – and one reason for this is that the fauna and microbes are not adapted to the novel flora. This comes after she has observed that the grasslands themselves in many cases developed after the boom in bison populations that followed the collapse in human populations in the Americas that followed the European invasion with their guns and diseases.

My biggest concern is that, in talking about North American ecosystems, of which my own knowledge remains patchy, that she may be making other, similar mistakes, basing conclusions on some poor science – and there is some abysmal (and some very good) ecological science out there. Much of the science surrounding mob grazing has been conducted by people with an agenda (on both sides). She seems to accept one side of this unconditionally, and seems to be based on the false assumption that you need to eat meat (and even mob grazing is responsible for significant methane emissions, worsening climate change, which she correctly regards as a threat). I'm led to conclude that much of the book may have been badly researched.

What's worse is the possibility that, in undermining the agenda of the agrochemical industry, for which she otherwise has my wholehearted support, she's reasoning in order to support other unsustainable practices, such as ranching. If it's okay to create similar polycultures in one place that exist elsewhere, regardless of the domestic biota, it becomes much easier to justify widespread grazing, despite its highly dubious environmental credentials.

It's frustrating, because I agree with many of her conclusions and recommendations. I agree wholeheartedly that we need to be addressing the conditions in which some invasive species become a problem, and that means systematic and systemic change in the way we live our lives and relate to the rest of Nature. Some of her ideas about how to live with non-native, even highly opportunistic species seem to be good ones, or at least are more constructive than the present paradigm. In many ways I like her radicalism, even where I disagree on details.

On the other hand, I think we need to be very careful about allowing, even encouraging, certain opportunistic species to take the place of less vigorous ones. This is the kind of thing liable to lead to less diversity, and less resilience. Many of these plants make excellent additions to a managed habitat in the right place where you can keep an eye on them and ensure they don't get out of hand. It's when they become part of an identikit ecosystem that might be identical in Europe or North America, or jump the hedge and become someone else's problem, that they can become an issue.

It's fair to observe that this could have been a really good book, instead of just a decent one. There is good material in this book, but it's another one that should not be read uncritically. This was my second attempt to find a balanced perspective on the introduction and use in Permaculture of non-native species, and my second failure to find it. This was better than the first one, in many important ways, but there are just too many critical flaws in this book for me to feel able to recommend it unreservedly.

There are important points to be made about the reintroduction of species that might have been extirpated as a result of previous bad management, even at the level of microbiota. There is also a case for considering introduction of non-native analogues, but care needs to be taken in each individual case, because there are few perfect analogues. Orion never makes the distinction between an introduced species and an invasive one, and the difference can be crucial when considering the safety of an introduction. A great deal of what she writes about land management makes a great deal of sense but here is what, to me, is the bottom line. We need to be very careful not to be responsible for a “green hell” situation, where another equivalent of kudzu (Pueraria lobata) (in North America) or Opuntia (in Australia) is responsible for ecological disaster. These changes are neither self-directed nor, in many cases, self-balancing (which may be one convenient distinction between an introduced species and an invasive one). Not only would this cause environmental damage and possibly even species extinction, but it would be exploited by those wishing to see Permaculture discredited, and we cannot afford that. It's the kind of thing they could, and would, use to destroy the movement and, whatever my disagreements with Tao Orion, I think we would both agree that this would be a very bad thing.

Neil Layton wrote:We need to be very careful not to be responsible for a “green hell” situation, where another equivalent of kudzu (Pueraria lobata) (in North America) or Opuntia (in Australia) is responsible for ecological disaster.

I wonder whether the cited examples are equivalent to "Ecological disaster"? I have heard plenty of similar language about local non-historical plants, but when I look at them with my own eyes, I observe them growing in a few ecological niches here or there. They haven't come anywhere near causing "disaster" to the local ecosystem. At least in the way that my experience and schooling have lead me to understand the meaning of "disaster".

Joseph Lofthouse wrote:

Neil Layton wrote:We need to be very careful not to be responsible for a “green hell” situation, where another equivalent of kudzu (Pueraria lobata) (in North America) or Opuntia (in Australia) is responsible for ecological disaster.

I wonder whether the cited examples are equivalent to "Ecological disaster"? I have heard plenty of similar language about local non-historical plants, but when I look at them with my own eyes, I observe them growing in a few ecological niches here or there. They haven't come anywhere near causing "disaster" to the local ecosystem. At least in the way that my experience and schooling have lead me to understand the meaning of "disaster".

The figure I keep seeing quoted for Opuntia in Australia is 260,000 km2 of farmland. That's without attribution, but if something like that were traced back to one of us you can be sure it would be used to destroy our reputation.

Gorse (Ulex europaeus) is mostly a petty nuisance here, but I know it's a serious nuisance elsewhere. Even locally it can turn into a monoculture: http://static.panoramio.com/photos/large/91802934.jpg This is a few kilometres away - and here it's a native species. The bees and a few birds love it, but it's still an opportunist monoculture. It's also a great nitrogen fixer and first-rate bee food, because it flowers more or less constantly. I wouldn't plant it, though - even here.

Joseph Lofthouse wrote:

Neil Layton wrote:We need to be very careful not to be responsible for a “green hell” situation, where another equivalent of kudzu (Pueraria lobata) (in North America) or Opuntia (in Australia) is responsible for ecological disaster.

I wonder whether the cited examples are equivalent to "Ecological disaster"? I have heard plenty of similar language about local non-historical plants, but when I look at them with my own eyes, I observe them growing in a few ecological niches here or there. They haven't come anywhere near causing "disaster" to the local ecosystem. At least in the way that my experience and schooling have lead me to understand the meaning of "disaster".

Douglas Fir, in the Pacific Northwest of the United States would be one such non-historical plants ---- an "invasive", if you looked at its more recent introduction into the ecosystem in the past 1000 years (or less).

Yet few people can imagine the NW without these vast "old growth" forests of Doug Fir—again, a relative newbe in the geological scheme of time.

There is a lot of diversity of opinion when it comes to these non-natives: one man's invasive, is another man's productive and beautiful novel eco-system. At the least, many of these so called invasives are pioneer species for succession that follows.

I don't think that anyone disputes that ecosystems naturally change over time, be it Douglass Fir or any other natural change.

I think what the conservationist school of thought has problem with is the rate of change and the lack of balance that human have on different ecological niches.

The example of the Douglass Fir is an excellent one (for both sides of the debate). Over a thousand years (or more, possibly), the tree gradually took over as the dominant, primary tree in the forests here, replacing a prior environment.

The information I have about this tree is conflicting. Some say it came in as a result of the last ice age, and gradually, through natural succession, took its place we know today. Others say it's a more recent addition. I don't think it matters which. The important thing is that the local species had a chance to adapt to the changes. Although the tree is 'new' geologically, it was a much slower change than we are seeing with some of the plant species humans bring with them which can become dominant in decades, or even less.


I don't know if the invasive species are good or bad. I have no moral judgement at this time. I do notice, however, that it has happened. We need to find a way to live with it. I'm very eager to read this book and see what Orion has to say about it.

The best idea that I have encountered in this thread is the vocabulary word "moonscaping". My primary objection to natives-only, or ecosystem restoration, has always been that so often the only tool in the restorers toolbox seems to be "moonscaping": Reducing the current ecosystem to bare/sterile earth so that something from a particular historical era can be planted in its place.

At my farm, there are no native species of land plants, since the land was hundreds of feet underwater during the last ice age.

I give this book 8 out of 10 acorns

For years, all I knew about invasive species was that they were bad. Then I began to stumble on the idea that they might not be so bad. But mostly it became apparent that these things were highly controversial with most people having a polarised view of them, and that that view might suddenly and irrevocably change. Which left me not really knowing what to think, as it became apparent that I had nowhere near enough background knowledge to come to an informed opinion. I'd also noticed that where discussion of invasives happens, discussion of pesticides and politics soon follows, and as those are pretty well taboo subjects on permies, my knowledge base wasn't expanding in hurry. So I decided to treat myself to a book on the subject, hopefully one which would fill me in on all the controversies and not be too dogmatic one way or the other about whether I should view them as 'good' or 'bad. And Tao Orion's book, Beyond the War on Invasive Species - A Permaculture Approach to Ecosystem Restoration, was the one I chose.

It fit the bill perfectly. It's an easy book to read, almost like a novel, though it's packed with information and the author's own experiences and opinions.

There are eight chapters

Against All Ethics talks about how many plants that are now considered invasive were originally introduced for ecological benefit but that once they began to affect business interests, then began to be targeted and used as a way to market toxic gick. The link between invasives, politics, and herbicides was made pretty clear to me in this chapter!

Getting to the Root of Invasive Species introduces us to the science of ecology with examples such as the relationship between oysters and spartina grass in Willapa Bay. It examines some of the definitions, or lack thereof, of words like 'invasive' Tao encourages us to adopt a whole systems approach and points out that "most primary research into invasion ecology is sound, objective science. It's the interpretation of the results that often lacks objectivity".

Thinking Like an Ecosystem begins with a quote from Fritjof Capra, one of my favourite authors from my younger years. I even named the donkey after one of his books... This chapter looks at more of the science, structure and characteristics of ecosystems, including feedback loops. It looks in some detail at how human activities have effected salinity of the Colorado river basin and the salt cedar which appears to be invading the area. But is the salt cedar really the canary in the coalmine?

A Matter of Time asks if exotics are more like the final nail in the coffin of a degrading ecosystem, and suggests that removing invasives might not solve anything as the root cause might be deterioration of water quality and overharvesting. Tao suggests that"we need to favor small, cooperatively owned woodlots that practice conscientious management for fuel, fiber, food, and medicine rather than multinational corporations that treat forest ecosystems as wood and pulp farms" and also that "we need a paradigm shift to save species from extinction, and it starts with the creative reimagining and redesigning of the ways we meet our needs" . Ash borers, for instance, take up residence in trees stressed by drought or pollution climate change and we should probably be concentrating on those root causes more than the borers.

Problems into Solutions is the chapter that really starts to bring permaculture thinking into the equation. Tao states that "invasive species provide opportunities to study the dynamics of ecosystem change given serious declines in ecological function engendered by modern land use practices" and that "an objective view of invasive species sees them in terms of patterns, processes, and functions that they represent, and it is important to acknowledge that they are not necessarily "good," just as they are not necessarily "bad" Examples used to illustrate this include watershed restoration, zebra mussels, beaver and giant reed.

Everyone Gardens explores the myth that what we see around us is 'nature', untouched by humans, but is "the result of consistent, thoughtful, and protracted stewardship by generations of people inhabiting an ecosystem full to the brim with edible, medicinal, and otherwise useful plants"

Here are a few more quotes from this chapter...

"Californian Indians believe that when humans are gone from an area long enough, they lose the practical knowledge about correct interaction, and the plants and animals retreat spiritually from the earth or hide from humans. When intimate interaction ceases. the continuity of knowledge, passed down through generations, is broken, and land becomes "wilderness" "

"Today, most native species are less abundant because we fail to manage them in a meaningful way"

"one of the best ways to ensure the health of native plant communities is to use them"

"Just as a conductor knows all of the parts in a symphony but does not play every instrument, people as stewards can see how all of the elements in an ecosystem relate."

Restoring Restoration looks at the idea that we need to acknowledge ourselves as part of a web of relationships - "we must move beyond short-term and short-sighted invasive species eradication measures and begin the necessary process of engaging the critical task of restoration on all fronts, from our homes and neighborhoods, to farms, forests, and the economic systems that support them - as well as to restoring our own way of thinking". In particular, Tao suggests that "rather than thinking of an invasive species as something that deprives an ecosystem and must therefore be eradicated, we must get into the habit of considering what an invasive species has to offer"

The tree of heaven, for instance"resprouts vigorously when cut and spreads well from prolific seeds...compared to cotton, cultivating tree of heaven for fiber helps mitigate climate change, reduces pesticide use, remediates heavy-metal laden soils, and has the potential to create economic outcomes for people living in invaded ecosystems"

She also points out that"caring for this land requires more work than can be accomplished by a handful of employees and is part of the reason that herbicides are considered necessary in the first place"

Putting Permaculture to Work in Restoration is the chapter that helps pull everything together. I'll let the quotes do the talking.

"ecosystem restoration also requires practical design decisions and management practices - not only a change in our thinking, but design and management decision that reflect the change in our thinking. This is where permaculture design - with its basis in applied systems thinking and integration between human and nonhuman needs - has so much to offer"

"If the individual is using ethics as a backdrop for her decision making, she'll encounter a roadblock when she considers using an herbicide"

"Permaculture design is not just about having a water tank, or a duck pond, or a greenhouse, but rather about how these elements both provide for and are supported by each other"

"invasive species can be seen as filling in the gaps in ecological systems that on the verge of severe impairment or phase change - systems teetering on the edge of "becoming unrecognizable" "

"The act of restoration implies that there is a goal for a site that moves it from a degraded state to something more beautiful, functional, and diverse"

"Invasion is a natural and predictable way that ecosystems change over time. Given the ongoing, imminent, and unknown effects of a changing climate, these factors must be taken into consideration before engaging in an eradication protocol" ; "we shouldn't be afraid of ecosystems tending towards complexity, instead we should feel comfortable diving right in and lending a hand to the process"

"a restoration plan could entail pulling out ivy and planting native forest understory species like Oregon grape and sword fern...However, this process does not address the larger picture of why the ivy is there in the first place, so it fails to ensure that the ivy will not come back"

And then a reminder social aspects are crucial, too. "The ultimate permaculture option for this site would be for all adjacent landowners to participate in collectively managing the space for their food, medicine, and firewood needs, through the use of fire and other methods of guiding succession that promote high diversity and achieve valuable yields"


To round the book off we also have

Appendix A - Species Identification List

Appendix B -Organisms that Moved around the World Prior to the Modern Colonial Era

Appendix C - Recommended Resources for Holistic Restoration and Invasive Species Management Alternatives


Overall, what I think I liked best about this book is that it didn't attempt to give a simplified overall picture with clear guidelines on how we should end up thinking. It provides us with enough background information to turn anyone from a 'yes' or a 'no' perspective into a resounding 'it depends'. For my own uses, I seriously doubt I'll be planting any known invasives on my own land, but I won't be attempting to eradicate any that are already here either. I will, however, be researching ways to use ones that are already here, and find ways to live in harmony with them.

Neil Layton, that is the most thorough book review I have seen in some time. The deficiencies that you point out are the same ones I have seen in several other publications. Thumbs up and an apple for Neil.

I want to elaborate on my comments above on low-diversity island ecoystems. I've proposed an edit, which I hope the mods will accept, but my more recent reading has led me to a better understanding of this question.

My expertise lies less in island ecosytems than in relatively local ones. I've seen a lot of heavily degraded habitats, through farming or other land use changes, that have benefited from selective reintroduction, typically of native flora. This then attracts native fauna, notably pollinators and birds that eat either them or the seeds provided by the plants. I had no idea how far the experience of Ascension Island could be generalised and I've been trying to find out.

The problem, and this is basic restoration ecology, is that plants, animals and soil microbiota have evolved as communities, not as isolated species. In the case of Ascension Island, there was not much of a community beyond a few seabirds. Plants, and with them microbiota, and a few animals have been introduced, and there is now a thriving ecosystem, including an invertebrate fauna - but to great cost to the nesting seabirds.

Most of us do not start with little more than barren rock.

Species that are not native, and again this is basic ecology, lack the connections with the other species in the habitat that evolved as part of similar communities. Some just won't cope, and will die out. Others will develop sufficient functional connections to, say provide nectar for pollinators and do well. If there are no plant-herbivore connections, and the plant is not managed, it may tend to monoculture and become "invasive", perhaps driving out native species that do have these connections, perhaps to the point of extinction, and taking the species that depended on them with them.

This, folks, is a problem. Current rates of extinction are at least a thousand times higher than the background rate, and humans are largely responsible.

Ascension Island, then, was an exception, not a rule.

This is why I'm increasingly tending towards a preference for native species over introduced ones. I don't have a problem with growing some particularly useful ones, but I'd rather go for a native species over an introduced one, and I'd want to keep a very close eye on the latter.

There is another important question about how we define a native species as species move as a result of climate disruption. We are already seeing plants flowering and fruiting out of synch with the animals that depend on them. Some are better able to move than others (which is one reason for the provision of wildlife corridors). This is a complex subject outside the scope of this post.

This, incidentally, is a good reason for learning to think of the land you are living on as a habitat, rather than as "property". "Property" is something you can do as you please with. A habitat requires a different mode of thinking, one of inhabitation, rather than ownership and domination. Once you start thinking of yourself as an inhabitant, with many other inhabitants, it becomes more straightforward to think about the connections you have with those other inhabitants and that they have with each other.

I think this is key to many of the disagreements I have with others on this site and elsewhere.

I love this article about Ascension Island.

I feel sick at heart when reading any of the official government plans to return the island to it's former status of moonscape.

Joseph Lofthouse wrote:I love this article about Ascension Island.

I feel sick at heart when reading any of the official government plans to return the island to it's former status of moonscape.

I'm not advocating, because we'd be here all night and I just do not have the energy, but there is the whole question of the endemic species on Ascension. This is the problem with "novel ecosystems": they tend to squeeze out the endemics. Push it far enough and you get extinction. E. O. Wilson's (since he's cited in this article) view of "novel ecosystems" is not a positive one.

Note that Pearce is a journalist, not an ecologist.

plants, animals and soil microbiota have evolved as communities, not as isolated species...
Species that are not native, and again this is basic ecology, lack the connections with the other species in the habitat that evolved as part of similar communities...
Ascension Island, then, was an exception, not a rule...
There is another important question about how we define a native species as species move as a result of climate disruption...

I want to take some time to respond to the concepts you've put forward here, as I believe they're central to developing a more holistic understanding of both invasive and native species. First, the idea that ecological communities are 'intact' entities that are destined to be together forever is one that has largely been disproven and abandoned within the framework of general ecology, though invasion ecology still clings to this antiquated idea. Consider the debate between Clements and Gleason I described in my book - Clements the 'father' of succession put forward the idea that ecosystems are tightly bound networks of interactions headed toward some predictable climax state, Gleason found that they are mixtures of species that forged relationships based on available resources and conditions, and that the end state of any ecosystem is unknown. CS Holling (perhaps one of the most visionary ecologists of recent times) brought this idea even further to explain how ecosystems behave in terms of systems theory as they progress through what he called the Adaptive Cycle - constantly changing in response to selection pressures, but in a pattern of increasingly complexity, networking, and information and resource exchange until all of the energy coming into the system is utilized by fewer, larger organisms. Eventually these late-successional systems are prone to disturbance, and the process begins again, though there's no telling who the characters will be that make use of post-disturbance conditions - most likely those best adapted to the current conditions. The pattern of the Adaptive Cycle can be seen throughout systems everywhere (and fyi, this is what is meant by 'goal-seeking' in systems theory in my book - different from Gaia Theory - systems tend toward higher degrees of complexity over time). If you believe the likes of Holling, Meadows, and Margulis (and I do), then there is no reason to believe that Ascension Island is an exception, but instead an opportunity to observe on a small scale how some of the finer features of natural selection in the context of the Adaptive Cycle work, even on a short time-frame.
There's no doubt that for a certain period following the last ice age, some species had time to develop associations with other species, and there are unique interactions based on isolation and time that are a result of the relatively stable climatic scenario of the last 10,000 years. However, climate change is happening, the process of which has both made possible and been exacerbated by the practice of agriculture, deforestation, and colonization, which have been underway for millennia. The ecological and cultural shifts associated with these practices are not without ramifications for plant and animal communities as we all know, and its impossible to separate out the intensification of activities related to human livelihood provision from shifts in surrounding ecologies. If we accept that ecosystems (like all systems) are constantly in flux and adapting to changes in local and global conditions, then we should be able to anticipate changes in their structure and composition. If we want to preserve and enhance the biodiversity that we've come to know and love, we have to develop management systems that facilitate the resilience of these systems. Holling also offers some great advice on how to manage complexity in constantly evolving systems. We have to move beyond the idea that ecosystems are static, and begin the long process of learning how and when to intervene to promote regenerative qualities and maximum diversity.

I'll go ahead and be a cad, and say that I don't care about the endemics of Ascension island. There are something like 200,000 to 300,000 species of plants in the world. I don't care if a handful of them die on a remote island in the Pacific. A few ferns and some spurge? There are plenty of closely related species in other places in the world. A million years from now, perhaps some of the introduced plants on the island will have become new species: endemic to the island. In my world view, I think that Ascension island would be better off with even more introduced species, even if it meant the complete extinction of every species that was living on the island in 1502. I tend to be a lumper, rather than a splitter. If there was an order of plants that were found only on Ascension Island, and they were incapable of growing anywhere else on Earth, then I might feel differently. But to me, a fern is a fern.

Unfortunately, I'm not in a position today to sit and take on the ecological science. I think a proper discussion of this would be generally extremely instructive.

I suspect, given the provisional, even controversial nature of much of the research (on both sides) that it may produce more heat than light, but it might be worth a try in circumstances I am not presently in.

Instead, I'm simply going to ask a question.

Just how many species is it acceptable to drive to extinction on the basis of what seems to me to be a highly perverse definition of "diversity"?

As it stands, on the basis of previous major extinction events, it's going to take about ten million years for Nature to recover from the bottleneck we've created. I'm horrified that some people in Permaculture are okay about making the situation worse.

There are, of course, several factors involved in species extinction: humans are responsible to some degree for all of them, and the introduction of invasive species is one of them.

I have no real issues with working with any species that might damage local ecosystems provided it can be kept contained, but over and over again containment has proved impossible.

Neil Layton wrote:Just how many species is it acceptable to drive to extinction on the basis of what seems to me to be a highly perverse definition of "diversity"?

I'll return a question for a question... How many new species are being or will be created by spreading propagules into places that they haven't been before?

As far as I can discern, life was created to jump the fence, and when I help it to do so, I believe that I am acting as a creator. As far as I can tell, when I spread propagules around, I am doing the work that mother nature created me to do. I cannot in any way separate myself from the natural world. I believe that I was born into a species that was designed by mother nature to disperse life into novel ecosystems.

All life is precious, and welcome to my farm and to the surrounding wildlands.

Estimates vary (quite widely) but it is clear that humans are responsible for far more extinctions than Nature is able to keep up with - and the release of invasive (not necessarily to be confused with non-native) species is part of the problem. In particular the background rate of speciation is a complicated subject (and there are two major models for this anyway: phyletic gradualism and punctuated evolution), but it's one **** of a lot less than the 27,000 species conservatively estimated to be being lost annually.

Some non-native species may even do some good, but it's hard to predict and certainly not something to be done more or less randomly.

Seriously, your response to the question is most likely doing much more harm, at least in terms of species diversity, than good.

I view native-only presentations as akin to a religion. Native-only enthusiasts tend to use fear-based persuasion, just like religions do. The best way that I know of to discuss religious ideas is by offering a spiritual sentiment... In my case, rather than using the vocabulary of fear, war, hostility, destruction, and separation to describe plants, I use words of love, peace, and inclusion. All plants are welcome on my farm and the surrounding wildlands. I believe that I am helping mother Gaia when I bring new species to my farm, even if they spread beyond my farm. When I spread species around, I feel like I am doing Gaia's work, and she smiles upon me, and blesses me with more plants, more diversity, and more beauty. I am similarly blessed when species that my neighbor's introduced make it to my farm. I simply can't observe any ecosystem being destroyed by a plant. Ecosystems might change, but change is always with us in every ecosystem, all the time.

I can't even sensibly define "native".

I don't want to use conflict vocabulary in this discussion. What I also don't want to be doing is risking damage to ecosystems by the uncontrolled release of organisms liable to tend to monoculture, whether that's based on some spiritual view or otherwise. That's not necessarily diversity - it can be, but it can also be the opposite.

I don't think you can know that "Gaia" smiles on you any more than "God" smiled on the crusades, but the Christian fundamentalist nutters involved believed it.

I tend to agree with the sentiment that it is impossible to even define words like "native", and "species". The archeology and physical evidence which could be used to help define those terms is fragmented, and even then open to subjective interpretation, and manipulation for political or economic purposes.

I used to be a research scientist doing chemistry for one of the national labs in the usa. It seems to me, like scientists as a profession have fallen into ill repute: That it's an occupation that is distrusted and looked down upon by most people, and the distrust becomes a bit deeper and a bit more widespread every year. The people watch as one medicine after another that scientists called "safe" is recalled because it has acquired a bad reputation for killing people rather than helping. We observe commercials in which the latest new drugs propose that they may inflict stoke, heart attack, pneumonia, suicide, etc... The pesticides that were declared "safe" end up decimating the local plant and animal communities. Dietary advice from scientists is constantly shifting. In many cases, the best current evidence is that previous recommendations by scientists were just plain wrong. Industrialized food as invented by food scientists and professional plant breeders seems unpalatable and unfit to eat. It is widely believed, that scientists have been colluding with government and corporations to produce results for commercial and political gain, and not to get at the truth of matters. Scientists knew that the water system was poisoning a major metropolitan area with lead, yet they said nothing and did nothing. Around here, government and corporations are among the most disrespected organizations. The local drug mafia enjoys a better reputation. So it seems to me, that when scientists hitched themselves to government and corporations to pay the bills, they also hitched themselves to being held in derision and suspicion.

So it's against that backdrop, that I enter the current discussion about moving plants around. My people generally hold scientists, governments, and corporations in ill repute. Therefore, since it's primarily government and chemical-corporations that are driving the natives-only agenda, we automatically distrust the recommendations, because of the long and current pattern of being wrong and/or untrustworthy. We automatically distrust the science behind invasion biology, because the research and action plan is paid for either by chemical companies or by governments. We distrust the recommendations of the chemical companies to moonscape the world in order to save it from a non-historical plant.

Without being able to depend on science to answer the questions surrounding this discussion, I might as well find comfort in a spiritual philosophy towards the topic, and that is that all life is precious, and welcome on my farm and in the surrounding wildlands. There are somewhere around 200,000 to 300,000 species of plants in the world. It is impossible for me to ever hope to identify even the thousand or so that are growing on my farm or in the surrounding badlands. Even straight-forward science like species names is denied to me. What I see with my own eyes is plants living in micro-environments, in niches in a wider ecosystem. I observe greater biodiversity in every ecosystem that contains non-historical plants. I can't observe mono-cultures, even in the most heavily sprayed field, and especially not in wild spaces in which non-historical plants are growing. So knowing the actual truth about this subject is denied to me by the sheer magnitude of the world, and by distrusting those that would purport to coerce me into living a certain way. The only thing that I am left with is following my heart. My heart says that all species are beautiful. And that all species are deserving of my love and admiration. All are welcome to my farm and the surrounding wildlands. I welcome all introductions by my neighbors.

I've just posted a review of a book which provides an interesting counter view to this one (Half Earth: Our Planet's Fight for Life by Edward O. Wilson): https://permies.com/t/55801/books/Earth-Planet-Fight-Life-Edward#465615

I give this book 10 out of 10 acorns.  It's the best book I've read on the subject of invasive species.  It's really helped bring together a lot of thoughts I had on this subject as well as brought forward many new thoughts.  After reading this book I look at invasion events with new eyes.  I've yet to have someone I recommended the book to come back to me without it having a similar effect on them.  Thank you Tao!

It is known that islands that are closer to other land where species disperse from end up with higher biodiversity, other factors being equal. This website on island biogeography sums it up with this quote,

A modified version of the classical island biogeography model proposed by MacArthur and Wilson (1963) is depicted above. The model considers the interaction of two main parameters, colonization and extinction, and then considers island size and distance from mainland as predictors of the species richness found on each island. Both colonization and extinction can be thought of in terms of rates or probabilities, and the size and isolation of islands impacts the probability of colonization and of extinction. Simply, Islands close to the mainland will more readily receive colonists from that mainland and, similarly, probability of colonization of large islands will be higher than that of small islands. Thus the larger the island and closer to the mainland, the more potential species will arrive. Species will also more readily go extinct on small islands than large, due to factors such as smaller population sizes and less available habitat. These parameters go hand in hand predicting that species richness will peak in large islands near mainlands, and be lowest in small islands far away from the mainland.

I have seen a few aggressive invasive species that do decrease biodiversity in the patches they take over, although oftentimes the claims are exaggerated (I've seen areas labeled monocultures of an exotic species that I can see quite a few other species growing in). However, we are glimpsing a very small period of time, as well as one with a lot of other human-induced factors that are changing the environment, so its no surprise that different species are thriving in the changed conditions. Humans have greatly accelerated the movement of species around the world, but there has always been a certain amount of movement, and I think the above example of island biogeography shows that more migration tends to increase biodiversity overall. That doesn't mean that none of the new species caused the extinction of species that were previously present, but the number driven extinct must end up fewer than the number of arrivals.

I've heard from some nativists the idea that certain exotic species will never find a balance and simply take over and leave much of the planet as near monocultures. If that were true, I'd think the islands with more migrating species would end up with less biodiversity, as periodically an aggressive species would come through and wipe out most of the others. Herbicide companies do love it when people have this view of exotic species, and have been known to support native plant groups and push them toward chemical use to eradicate exotics.

There was a time in early American history when peach trees were aggressive enough on parts of the east coast that some people worried they were taking over the landscape in places. That was before pests and diseases caught up with them, some imported themselves but others adapting from native wild stone fruits. Now there are occasional naturalized peaches but they don't appear on any invasive species list. I imagine the same will happen eventually to the invasives of most concern today, more pests and diseases will come after them and balance the populations out, how long that will take is the big question, my guess is that species that have native relatives will have more pests/diseases move to the new species more quickly.

While I'm generally not in the nativist camp, there are certain aggressive species that I would never spread to new areas, because even if they will eventually come into balance, in the meantime I wouldn't want to chance it by adding one more stress to all the others going on in this era.