I just want to post a lot of thoughts I have had about disturbance as it relates to
permaculture. I realize that my thoughts are simply my own, and that a lot of other pemies have other thoughts on disturbance, so it would be interesting to see if anybody else posts here.
1. Disturbances versus an integral part of the system is a hard call to make.
For instance, is a beaver building a dam a disturbance or just part of the system? From the point of view of a riparian system, it would be a disturbance I guess, but from the point of view of the whole ecosystem it would not. Is a human building a dam a disturbance? In other words, is the human part of the system?
2. Inputs = Disturbances.
Any input (from outside the system) is a disturbance as far as that system is concerned. For instance, fertilizer is a drastic disturbance of a system; look at what happens when acid rain adds nitrogen to a forest, or manure runoff adds nitrogen to a river. Mulch or seeding is a huge disturbance.
3. The
energy intensity of a disturbance does not necessarily relate directly to its impact.
A high energy disturbance may not produce much result, but a low energy disturbance may produce a lot of result.
4. The sequence and frequency of disturbances mean a lot more to a system then the disturbance itself.
For instance, a fire every hundred years will maintain a forest. A fire every few years will probably change the forest into a meadow.
5. A disturbance can only be judged by its results.
Every disturbance works to prevent or cause change, and depending on one's view point, a change is good or bad.
6. There is no such thing as an undisturbed system.
7. As
permaculture practitioners, we
should not necessarily minimize disturbances, unless we like the system as it is. Even then we may have to disturb it to maintain it. Instead, we should use as little energy as possible to disturb a system while still meeting our goals, and we should carefully evaluate a disturbance to see if it really meets those goals. Thus tilling is out on both counts; it uses a lot of energy, and it may not meet our goals.
8. Severity of impact is not necessarily a bad thing; it depends on our goals. For instance, in some ways sheet mulching has a more severe impact on some systems then tilling. Tilling often means that all the same plants are growing on the site within a year or so. Mulch, if done, right, prevents this. Also, mulching has a more long lived effect on soil biology, soil temperature, and nutrient availability and cycling.
9. More severe disturbances to prevent further disturbance latter is a good thing.
10. For every system, there is an optimum level of disturbance to maintain ecosystem health. (Though how that is judged is contentious; basically, we have to use various human constructs to judge, and they may be wrong.) There is also an optimum level to gain a human yield. Too little or too much disturbance can both effect system health and yield negatively. For instance, wildfire suppression in the Western states have had a very detrimental impact on the system. Removing grazers from a grassland is detrimental, if one wants a grassland.
11. The more
land one has available to meet human needs, the less disturbance one needs to use to achieve them.
12. It may be better for we permies to use slightly more disturbance in small, intensive systems on already disturbed land, and thus produce more yields, then to produce less with a less disturbed (less input) system and get the rest of our yield from land disturbed elsewhere, often with less care and attention.
13. There is no such thing as a pristine or original state of nature; all such notions come from a construct of separation and hubris.
At least, this is how I see things. Now that I've said all that, I would like to see how other people see it.