I'd like to get your take on Fred Pearce's, "The New Wild: Why Invasive Species Will Be Nature's Salvation". Some of what he said made a lot of sense to me - many "invasive" plants have been created by man's tendency to disturb nature directly and indirectly, and nature abhors a vacuum. I worry though, that neither extreme opinion - "all invasives are bad" and "nature will re-balance and recover from anything humans throw at it" - is valid.
I just read R. Ranson's thread on Scotch Broom and agree with much written there including the part about Pre-European Americans "managing the Gary Oak habitat" for productive human use. Similarly, I've been told that Doug Fir were considered an invasive weed by those cultures which considered it useless and they tried to limit it in favor of the Cedar trees which they found a multitude of uses for. Current forestry practices seem to disagree with that opinion!
How do permaculturalists balance these two extremes and find a way to live with the consequences of what is being done with our planet? Finding good uses for "invasive" plants, such as using them to mulch and build soil, animal feed when possible, etc seems a good first step to me. There are situations where I would cheerfully eradicate every scrap of a plant even if it has uses (Himalayan blackberry for one - yes, it makes a fine crumble and even better wine, but it's just too nasty and takes over too quickly for me to like the stuff.) There are other situations where I'm trying really hard to find a way to co-exist with a plant that is considered invasive, but which would take more time and resources than I'm willing to devote to the problem to do what the "experts" tell me needs doing (English Ivy - the experts insist it has to be removed and burned, but I haven't really had a sufficient explanation for the burning part that I understood - a permie suggested goats, but I don't currently have the fencing for that option).
I'm sorry if this seems to be a bit of a ramble, but that's exactly how my brain is feeling about this topic. I don't want to be guilty of letting the next "kudzu" invade Vancouver Island, but there are useful non-native perennial edible plants I would like to experiment with growing. How should we at Permies try to balance those two forces?
While I believe that invasive species offer important insights into how an ecosystem is transforming, and my understanding of these transformations is influenced by acknowledging the extensive influence that people have had in shaping plant and animal communities. Nancy Turner at the University of Victoria in BC has done amazing work cataloguing the role of indigenous people in creating the biodiverse ecosystems that are now filled with what are considered native plants. And there's evidence these ecosystem-shaping effects from throughout North, Central, and South America, Australia, SE Asia, and Africa - everywhere that indigenous people have been classified 'hunter-gatherers.' There's a lot of interesting discussions to be had in this regard, but when it comes to invasive species, much of what we're seeing today is a direct result of the collapse of these management systems and a change in mindset about the nature of 'nature.' Many of the people who work with Dr. Turner and Dr. Kat Anderson in California believe that a lack of relationship and stewardship with the world that surrounds our immediate homes is leading to declines in biodiversity - the world is retreating from us because of our lack of attention. I think this perspective is extremely important to consider, because it reframes the focus on invasive species to a larger perspective of how we are relating to our home landscapes. How are we contributing to the proliferation of the native species that we ostensibly care so deeply about?
On my homestead, I've been tending my patches of camas, mariposa lily, fawn lily, tarweed, brodiaea, and 'wild' strawberry with the same attention that I lavish in my garden of (non-native) crop plants. I dig them, eat them, save seed from them, and spread the around in places I think they'll grow. I cut out and selectively graze blackberries from their midst. I also cut out douglas fir to give them light. I believe that if we started to conceive of our immediate environs as resources for our daily needs and see how our day to day lives affect the quality and availability of these resources, many things would start to shift socially, ecologically, and economically. Many interesting conversations to be had in this regard as well, but for me, this is a key piece of deciding how and when to manage invasive species - looking not just toward their eradication, but crafting clear goals and management plans for supporting what remains when and if they are moved along to their next iteration as compost, mulch, or manure.
Thanks for that thoughtful post. It seems to mostly concern actively managed areas. I'd be interested in your thoughts about invasive species in less-managed areas. For example, in the Berkshires in western MA, there is some concern that hardy kiwi is "escaping" from managed areas into forests where human presence is too limited to track or arrest its spread.
Tao Orion wrote:
On my homestead, I've been tending my patches of camas, mariposa lily, fawn lily, tarweed, brodiaea, and 'wild' strawberry with the same attention that I lavish in my garden of (non-native) crop plants. I dig them, eat them, save seed from them, and spread the around in places I think they'll grow.
I'm working on re-establishing as many edible native plants as possible on my place as well. I'm only just beginning, but we already eat natives (and "weeds") regularly.
Geologically speaking, an ecosystem system will eventually adjust and find a balance point. But it may take a long time to happen. Also, the problem as I understand it is that the new balance may not bear much resemblance to the old balance. I am unable to find the link now, but I recall reading an article a while back about an area of the black sea that had been pretty much killed off by oxygen deprivation (fertilizers washed in from the Danube I think). When they got the fertilizer issue under a little control and the ecosystem started recovering, the system that came back seemed to favor jellyfish rather than scaly fish. At the time the article was written a sizable chunk of the Black Sea was producing millions of tons of jellyfish rather than the fish species that had been there before. The concern at the time was that the jelly fish producing area seemed to be expanding and might eventually take over the Black Sea. We need to realize that there might be multiple balance points and that if you knock the system severely out of whack, it may come back to a different, possibly less favorable balance. (the example that comes to mind is tossing the dice. Each Die has six stable points (a flat side down). If you upset it (toss it into the air), you can pretty much count on it coming to a stop at a stable point, but you don't know which point,, if you had a 4 or 5 and were hoping for a six are just as likely to be looking at a 1 when all is said and done).
Not to be a scare monger but throwing things far out of kilter with an extremely aggressive invasive is one of those things where some of the consequences are potentially too disastrous for any intelligent person to risk (other examples include, fracking (love the gas and oil availability, not willing to risk losing aquafers), playing nuclear tag with Russia or any other country and finally, on a more personal level, sleeping with someone with AIDS (hey, the chances of infection are pretty low for a single contact but who wants to risk it). Come to think of it, with the rates of VD, maybe we are just short on intelligent people.
The only invasives that we have on this island that I'm really concerned about, are English ivy and Japanese hogweed. Both are capable of doing immense harm to treed areas. Ivy can climb up the trees, depriving them of light and creating a much greater sail area, so that they are more likely to blow down in a windstorm. Both Ivy and hogweed are capable of preventing new trees from coming up without human assistance. Currently, I don't have to do anything to make my forest regenerate. When an old tree comes down , there are many young ones available to take its place. When I make a new trail through my forest, it is very easy to maintain with foot traffic and an occasional snip. If my paths were crawling with ivy, I would let the paths grow in, and no longer go for walks on the property.
The presence of either of these two plants would make a whole lot of work for me without adding one positive thing.
My seven and a half acres are worth somewhere around $225,000. If it was completely infested with English ivy, I would put it up for sale today and I would take half that much. That's a pretty rough way of quantifying the economic disaster that this plant would cause me, but I think it's about right.
The determining factor to my mind is that we should not make a decision with out taking into account all that could happen.
As an example, consider the lion fish invasion in Florida, USA.
This is a species that never has and never would live in this particular environment if it was not a popular aquarium species.
This species also does not have any natural predators. It does have a voracious appetite for developing sea dwelling species, babies if you will.
Now since the lion fish eats babies and has no predator to keep its population under control, the probability of this one "invasive species" creating the situation of causing the extinction of other species is rather high.
A Reef with out the many species that normally thrive there and provide the healthy environment so all thrive, would end up desolate, since eventually the only species of fish there would be the Lion fish.
Such a reef would end up without any fish life because with all the "food" gone for the lion fish to eat, it too would perish or move on and now you have a reef devoid of fish life.
This is not a good thing, any way you look at it, the invasive species has killed a whole ecosystem. It would be easy to say that this probably would not happen except that it is indeed in progress as I write this.
When a forest is taken over by one tree species, the number of types of animal and vegetative life diminishes because of the vast change in the overall ecosystem.
Look at how the invasive species Humans have changed forever some areas of the planet. Bison used to be thick on the great plains, they were almost made extinct by the humans, and it will never recover.
There used to be massive forests of ancient trees all over the east coast all the way to the west coast, now there are only little pockets of these majestic trees left and that is only because they are now protected by being in a National Park.
The only way to not be concerned with invasive species is to not care if many flora and fauna go extinct. That leaves the question of what happens to humans once we have allowed things to go that wrong and we have no way of correcting the problem that was created?
One other example is the snake fish, it too will most likely devour all the other species of fish and end up the only one left in the canals it has found its way into because some one thought it would be good to grow them thousands of miles from the natural habitat.
There are already areas here that have fewer numbers and have already lost species to the point of it now being necessary to stock back the species that are disappearing because the "locals" have all been eaten by the invader.
Invasive species may be considered ok, but it needs to be looked at from all angles. If you had your farm invaded by a plant that could destroy all your current food plants, and the invading plant was not good to eat, would you think the same way about invasive species ?
At the risk of stirring up a firestorm, it's kind of like the current immigration debate (ignoring humanitarian concerns for the minute). We have the 'don't cares' (who are getting fewer as the problem gets more publicized), we have the xenophobes (who may be worried about competition for resources and changing the human ecosystem) and then those who refuse to accept that anyone should be kept out (maybe they just like more variety in their restaurant availability and have huge faith in the ability of the human ecosystem to absorb all comers).
It's hard to look at any of this dispassionately. As a descendant of an earlier introduction of an invasive variety, I realize I am not nearly as upset about the results as the descendants of the people my ancestors displaced.
In reality, in both situations, there are some bad players who really need to be excluded, often because they are excellent predators (criminals in the human comparison). We also have many who are not going to cause a problem. Their presence will cause some shifting around as room is made, but not be terribly intrusive. Often documentation is lacking, or doesn't really tell you what you need to know. Without the proper data it's hard to make the proper informed decision. (The harmless looking fish there is really kind of cute, isn't a problem in it's home area is it? Ok, bring it in.) Our history of introducing foreign species to an area seems to me to be one part apathetic carelessness, one part individual greed (they see a personal advantage to the introduction and look no further), and one part govt arrogance or incompetence (govt. experts have introduced lots of problem children to the ecosystem)
Of course the immigration issue is vastly more complicated by the real, humanitarian crisis it is part of (I can be pretty heartless about the fate of a single lionfish, not so much with people), so please don't think I'm drawing a direct parallel in any way, but it helps me to see things clearer if I draw comparisons.
Mick Fisch wrote:wanting to keep all non-native species out
I have to wonder what they eat.
Many of the food plants we now grow either are or came from "invasive species", they are however usually found in controlled situations (garden beds or food forests, etc.)
It is only when items either escape to the wild or are intentionally let loose in the wild that we see the problems that can arise.
It is an issue that must be taken seriously but it must also be handled with some sort of control so it doesn't become a "monster" on the loose.
Even when things like animals in a zoo, usually no problem at all but let a hurricane destroy the zoo thus letting those animals out into the wild can create a very bad situation.
That is part of what happened in Florida, much of the new population of Burmese Pythons happened because of the destruction of a hurricane, several zoos were destroyed enough that the animals escaped. Add to that the Pet industry buildings that went the same way and a whole lot of critters that don't belong in the everglades and other places now call these spots home.