Here are some thoughts I have about the philosophy and practice of disturbance in permaculture. I'd love to hear your thoughts!
A certain thread within the modern environmental movement is explicitly anti-human (for instance, the human extinction project) and a certain anti-human spirit pervades the wider movement; humans are seen, with some justification, as the problem; only land that is untouched by humans is seen as valuable or healthy. Land ceded to habitation or agriculture is seen as, (and often is) a loss for the biosphere. Environmentalists such as E.O. Wilson hope for a future in which humans are corralled within high density cities, letting the rest of the planet run wild, returning itself to health and beauty, not interacted with except by occasional tourism. In this view, the best we can hope for is to avoid causing damage; only the negatives that humans bring are considered.
Native people around the world saw themselves as part of the landscape, stewards or caretakers of it; for the California natives, for instance, "wild" land was a bad thing, the result of neglect by human beings; they saw "the wild" as a thing which needed them, even as they needed it. We've undoubtably stepped over our proper boundaries, but that does not mean that we have no role to play. No matter what philosophy one holds, to me it would seem strange if we were entirely alien and detrimental to the planet from which we came.
Permaculture is the science of designing permanent agriculture for sustainable human livelihood. Because of this, it is human centered. By definition, it escapes the anti-human mentality discussed above. It studies nature to enable the construction of sustainable human habitats.
In this study, Permaculture practitioners have abstracted certain general principles from nature. For instance "every element should perform multiple functions" "every function should be preformed by multiple elements" "use slow and small solutions" "capture and store energy and nutrients" "use biological and renewable resources" "value diversity" "apply self-regulation and respond to feedback" "integrate rather then segregate" "create edges" etc. These principles are widely true of any ecosystem; there are no single purpose elements in nature, and even the internal organs of animals often preform many functions; all ecosystems capture and store energy, as do all animals and plants; almost all ecosystems are staggeringly diverse, including that in our digestive system; edges, in the sense of a high surface area to volume, are found all across nature, from lungs to trees to estuaries; etc.
Permaculture also uses observations of particular patterns in natural systems. These observations show ways in which particular ecosystems or organisms obey the general principles mentioned above. They may be directly useful to our designs, and they help us to understand the principles better, but they do not have the universal relevance of the principles. For instance, coral reefs catch and store energy by using photosynthesis to power the building of fantastic shapes out of calcium carbonate, thus also creating edge and attracting more diversity. Our designs also need to catch and store energy, build edge, and gather diversity, but unless we are farming coral, they are unlikely to do so by using photosynthesis to build shapes out of calcium carbonate. In fact, our use of calcium compounds in cement is an environmental disaster.
Since permaculture is often seen as a subset of the wider environmental movement, it is not surprising that the anti-human mentality mentioned above tends to slip back in at times. Permaculturists tend to focus on observations of "undisturbed" areas, where animal and human disturbance is absent. For instance, when speaking of tilling, irrigation, or fertilization, the forest is often used as an example; we are told that nobody tills the forest, but it grows trees just fine. The massive size of redwoods or sequoias is sometimes used to further such arguments. Similarly, arguments are made that forests are heavily mulched with organic matter, and contain primarily perennial plants, and thus our designs should be un-tilled, heavily mulched with organic matter, and primarily perennial. Further, such techniques as mono-cultures, rows of crop plants, weeding, and confinement of animals sometimes come in for criticism, because "we don't find rows in nature."
I don't want to critique or defend these individual practices at this point; they may be valid in a particular design or detrimental in another; however, I do have a problem with the reasoning behind these ideas. For one thing, we may not be trying to design a forest. For another, no ecosystem on earth is mulched with a foot of wood chips, though this is often billed as mimicking the forest floor.
But a deeper concern is that we are not factoring our human activities into the picture. Humans are animals, even if rational animals. Animals disturb ecosystems in numerous ways in their search for livelihood, generally to the benefit of the ecosystems so disturbed. Undisturbed ecosystems tend to decline in diversity and productivity. If we don't find rows in nature, neither do we find beaver dams, beehives, bird nests, ant mounds, buffalo wallows, or termite nests; not until something builds them, that is! Beavers are a particularly good case. They would starve or be eaten by predators in an 'undisturbed' forest. So to suit their needs, they cut down groves of trees, and dam streams to create ponds and marshes. They dig canals to float tree branches to the dam, and divert streams into new channels, managing and converting huge areas of valley bottom. Some dams can grow to enormous sizes; the largest stretches for half a mile. This modification radically changes the species composition of the area. Pre-existing trees die as they are flooded, creating snags, and wetland plants move in. The swift flowing, relatively deep stream becomes a pond, spreading out to become shallower, warmer and higher in nutrients. Grazing animals are another good example. Their grazing and trampling tends to destroy woody plants and strengthen grass and forbs. The rapid nutrient cycling caused by grazing increases the rooting depth and carbon capture of grasslands, making them more resilient over time. Prairie dog towns once stretched for miles, creating a huge network of tunnels and disturbed ground, in effect "tilling" the prairie.
Fire is a unique case. It is important for many ecosystems, effecting plant structure, nutrient cycles, and species composition. And humans have a special relationship with fire; we are the only animals that start and maintain fires. Native peoples around the world have tended to use fire to modify the landscapes around them; post colonization, these landscapes have often changed, becoming both less useful and less healthy.
Once we realize that being animals, we are certain to cause disturbance, we can focus our observations in different directions; we should focus on how animals produce habitats for themselves. We won't build ourselves wax combs or live in ponds, but we can study beavers and bees and abstract general principles from their work. Even more importantly, we should study how various cultures have interacted with the land over time. And we shouldn't let cultural prejudice limit which cultures we study. European colonialism is rightly seen as a tragedy and a crime, and perhaps because of this, European traditional land use is sometimes ignored; we should study all land use traditions, with the caveat that those which developed with fairly dense populations in temperate climates will have the most applicability to designs in the USA. European coppice woodlands, small grain fields, pastures, laid hedges, thatched or turf roofs are all "unnatural" as are the slash and burn plots, chinampas, and terraces of Central American cultures, or the rice paddies and canals of Japan; but all could theoretically be used in our designs.
Instead of latching onto certain observations, we should be sure our designs follow the basic principles, and further, we should develop certain objective metrics which we can use to determine if our land use is promoting health or decay in the land. What these metrics should be I don't know; but they must be more sophisticated then gauging the amount of "disturbance" or the "naturalness" of the land. In the following paragraph I'll suggest just a few of the principles we can learn from studying animal activity.
The disturbance caused by some animals is intense; beavers probably cause the most intense disturbance of any non-human animal. On the other hand, some animals cause disturbance over a vast scale; the buffalo herds are a good example of this. But no animal causes extensive and intense disturbances, as we do. We shouldn't be afraid to spade up a few hundred square feet for a vegetable garden, for instance, or build a farm pond of a few acres, or set a controlled fire over a field; we should be wary of Hoover Dams, monoculture forests, and thousand acre fields. And we should "respond to feedback;" if our disturbance seems to be degrading the natural world, we should stop. Most of all, we should not disturb the whole face of the planet; we should leave some areas to be disturbed by other animals. To achieve this end, we may have to increase our disturbance of areas that we already use, while still staying within the bounds of the principles.
Do humans actually provide a benefit to the ecosystem as a whole? We definitely aid some particular species. A whole guild of creatures, from corn, tomatoes, and chickens to mice, dandelions, and purslane, are ecologically linked to human beings; garden writer Carol Deppe calls this "the grand alliance." We, even more then other animals, create disturbance, which is then exploited by the alliance. If we don't overdo it, could we add diversity to the overall picture? The meadows created by the natives of what is now California are diverse places, harboring many species that will not survive in the "natural" conifer monocultures now overrunning them. Similarly, the tilled ground and annual crops and weeds of a small farm provide a very different habitat then the forest or prairie which surrounds it; according to the edge principle, this difference may promote an overall increase in diversity. More then most animals, we transport nutrients; thriving stands of trees are now found on shell heaps piled by the native peoples of the Americas. The shells contain calcium and other minerals from the sea and provided a nutrient source in a relatively depleted environment. Could our importation of kelp meal or limestone for our gardens have similar effects? These are complicated questions, and the answers may be long in coming; but if we let an anti-human, anti-disturbance spirit constrain the range of questions asked, we will never know.
If all humans were to somehow abruptly vanish, the ecosystems in North America and the majority of the world would not revert to their pre-human state. The North American ecosystems before humans arrived were dominated by many species of megafauna that are now extinct and must have shaped the ecosystem in ways that we will never fully understand. Having certain areas be as undisturbed as possible is good to have a point of comparison with areas managed in various other ways in the same ecosystem, and since so much land is currently managed so badly, preserved areas are generally much healthier, but as Allan Savory has demonstrated, some brittle ecosystems need quite a bit of disturbance (his examples come from the actions of herds of animals) to thrive and will degrade from over-rest. Preserved areas in many regions of the country have no animals larger than a deer around, even in areas where wolves, bear, elk and buffalo still roam, that ecosystem developed alongside the native peoples of North America after the megafauna went extinct.
Your observations are spot on! We are both the problem and the solution.
I just read an article about a couple of writers from back in the 70's. One noted the population increasing and postulated that because of more demand and fewer resources there would be megafamines and shortages shortly. The other author contended that human ingenuity was the ultimate resource and we would adapt. The two authors agreed on a $1000 bet, where one author purchased $1000 dollars (at the time) of agreed upon raw resources. About 15 years later, whichever author was right (inflation corrected prices went up do to increased demand, or down due to alternatives being found) would pay the other author the difference in the money. About 1990, the bet came due and, sure enough, human ingenuity had triumphed and all of the raw materials (about 30 of them) had dropped in value) except for gold, silver and petroleum.
The problem is not people, it is stupid, short sighted behavior among people.
I agree that there is, for any species, a maximum amount an area can support without real and lasting damage, but there are areas that have supported large human populations for a long time without significant problems. There are also areas that have been distroyed by bad land management. Properly managed, much of the world can support large human populations AND promote a diverse environment.
A common theme in many arguments is "Anything introduced after this date, (often 1492 in the Americas) is invasive and must be removed. I have a problem with this. First of all, how do we really know what was around prior to 1492? Species can be in an area, but have a relatively minor footprint until something upsets the balance. Ancient historical records show that there were once lions in Turkey and Greece and kings once hunted elephants in the middle east. No real proof found in the bones in these areas (at least during historical times). I realize these are top species and so scarcer, but the principal is sound.
So, how do you know that your 'introduced' species wasn't here before and only started expanding when european settlement upset the existing balance. I've read that there is very little evidence of passenger pigeons in the middens of New England native villages until after european contact and disease upset the apple cart. Then the pigeon population evidently exploded.
In reality, there is probably no really "untouched, virgin wilderness" left, and there hasn't been for several thousand years except maybe on some remote islands. Humans are part of the environment and have been for quite a while.
Next, Species have been moving around the world, hybridizing, going extinct and new species coming into existence since life began. People have been moving species around for a very long time. I read a while back that there was some kind of gourd in the Americas that anthropologists think was brought by people from southeast asia several millenia ago. Nor is every particular "species" that different (sometimes it's just a variation in hair or leaf color), at best it should be called a subspecies or local variant. Not that we shouldn't look carefully, but sometimes the gene variations just aren't that different.
There is ample evidence of terrible results from introduced species (rabbits and prickly pear in australia; cats, dogs, goats and rats on any number of islands; kudzu in the southeast US). There are also thousands of examples of introduced species that cause little or no problems, actually increasing diversity in the system. (I think dandelions in North America qualify, although lawn enthusiasts might disagree. Feral fruit trees, corn, wheat, guinea pigs haven't really destroyed many ecosystems.)
As far as introduced species go, in most cases, the cat's out of the bag and it isn't going back in. We probably aren't going to be able to remove introduced species that have found a niche. The best we can hope for is that we can control them either by introducing some population limiter from their home environment, or with our behavior. There is growing concern in south Florida about introduced boa constrictors that are eating everything else. If we come up with some really good recipes for snake meat and promote it we may popularize hunting boas.
In the U.S. there is a growing problem with an expanding feral pig population. I've read articles where people are bemoaning this how this 'introduced' species is messing up things. It was introduced hundreds of years ago. Why wasn't it such a big problem decades ago. The answer is, farms were smaller, smaller wood lots and people hunted them (or at least shot them on sight) and kept pressure on their population. We have a similar problem in suburban areas with white tail deer (a native species in a non-native environment). Deer are living organisms, a prey species, and living organisms are programmed to reproduce. Prey species reproduce quite rapidly.The only population control the deer face in the suburbs are fast moving cars, so the population has exploded. The answer is, we either need to remove the food source (plants around the houses and yards) or we need predators. Since most parents of small children don't want large predators hanging around the house, we need to be the predators. Of course, this is socially unacceptable in some circles, but one things certain, the deer aren't going to change.
I firmly believe that permaculture is the wave of the future, simply because it is a recognition of true principals. It's not building as fast as I would like, mainly because it actually removes profit opportunities for big money, since it focuses on local production and removes things from the 'pipeline' that is big money's revenue source. In the end permaculture is going to be a big part of the solution to our problems, simply because it I think it is the only solution. It also promotes an egalitarian attitude and society. When the number of permaculture enthusiasts increases by 10 fold, the engenuity and creativity will increase by 100 fold and things will start to take off. We aren't currently tapping into anywhere near the potential we will in a generation. For most of history, advancement has occured because the rare individual got a burr under his saddle and developed a new variety of plant, etc. Once we get things going, that will be more organized, thanks permaculture education and to the internet. We lost a lot of diversity in our domesticated species over the last few hundred years. We will get it back, maybe with interest.
The dichotomy of 'regenerative vs. Degenerative' is growing on me. It's very hard to greenwash and is usually pretty straight forward: over time is this regenerating its functions, provisions and services (e.g. an agroecological family farm) or is it degenerating its functions, provisions and services (e.g. a thousand acre, external input intensive monoculture run by purely-profit-seeking mega corps)?
Humans inevitably have an impact. Even the most 'wild' among us, left to our own devices in wilderness, will make a tremendous impact at least on the order of magnitude of beavers if not far greater. What I sense and hope may be a sea change coming is that humans recognize this impact doesn't need to be degrading to the world upon which we rely and deep-down enjoy, rather we can regenerate and give gifts back to the world which provides for our needs.
I will suppress my every urge. But not this shameless plug:
Devious Experiments for a Truly Passive Greenhouse!