Continuing our examination of Alan Savory’s Four Key Insights:
Key Insight Number 2: The Brittleness Scale: Environments can be classified on a continuum. This classification is based on how moisture is distributed throughout the year and how quickly dead vegetation breaks down. On opposite ends of this continuum are two broad categories of environments (brittle and non-brittle) that will respond differently to the same treatments. For example: Rest will restore non-brittle land but will damage it in very brittle environments.
This second insight flies in the face of the belief that all environments respond in the same manner to the same influences. They don’t.
It has been long recognized that some environments readily deteriorated under human management. The world’s arid and semi-arid areas are mostly some type of grassland with livestock production being the primary economic activity. When livestock management produced bare ground, moisture either evaporated or ran off. Common sense dictated that the best remedy is to rest the land from human disturbance. That would seem to be a logical assumption.
However, Savory’s experience in the Rhodesian game department led to his suspecting a fundamental flaw in this belief. He could not explain what he saw because it did not fit the neat scientific theories. He knew that fire maintained grassland. The only other influence he knew that could cause such damage was overgrazing. Yet, when the game populations were decimated and the incidence of fire increased, the land actually deteriorated. Neither game nor domestic animals were present—there was no overgrazing.
He once published a paper in which he concluded that, once land was so badly damaged, it reached a point of no return and would never recover. It was years later before he realized how wrong he had been.
What had eluded him was that there are two broad types of environments that react differently to management. Practices that benefit one damage the other. It was from this insight that he coined the terms “brittle” and “non-brittle” with true jungle being a 1 on the brittleness scale and true deserts being a 10. Everything else is somewhere in between.
Brittleness is not the same as fragility. You can actually have a fragile community within a non-brittle environment (such as a delicate fern glade within a forest).
Brittleness is derived, not so much from total rainfall as from the distribution of moisture over the year. Brittle environments are typically characterized by erratic precipitation and humidity during the year. For example, a 30 to 50 inch rainfall area that has a very dry period in the middle of the growing season is likely to be very brittle. On the other hand, a 20 inch rainfall zone where the moisture reliably comes during the growing season would be non-brittle. In a completely non-brittle environment, precipitation and humidity would be constant and high.
The poorer the distribution of moisture, particularly in the growing season, the more brittle the area tends to be, even though total rainfall may be high. Brittle environments commonly have a long period of non-growth that can be very arid.
Where moisture is erratic (brittle environment), vegetation, insect, and microorganism populations build up during the rainy months. However, when the rain stops, the vegetation dies and the insect and microorganism populations decline drastically. The plant’s stems and leaves are dead and of no use to the plant. In fact, this remaining material is a liability in that it blocks sunlight from the ground level growth points of the plants.
For millions of years in the past, lightning had some influence but this occurred over relatively few areas in any one year. The difference is that there were lots of grazing animals that continued to consume the plant material long after growth had stopped. The microorganisms in their digestive tracts reduced the material to dung. In the following rainy season, insects and microorganisms became numerous and consumed the dung and dead vegetation that had been trampled onto the soil.
Today, there are no more vast herds. As a result, only a small portion of the vegetation produced is able to decay. Thus, the old belief that all land should be rested is wrong. Although non-brittle environments do, in fact, respond to rest, in brittle environments rest will lead to further deterioration and instability.
Bare ground is another indicator of brittleness. In non-brittle environments it is difficult, if not impossible, to create large areas of bare ground whereas in brittle environments bare ground is easily created.
In sum, different environments respond differently to the same influences. Rest restores non-brittle environments but damages brittle ones. The answer to how grazing animals might provide the necessary disturbance lies in the remaining two insights.
Source: Holistic Management: A New Framework for Decision Making By Allan Savory and Jody Butterfield
- And the Myths Live on: Thoughts on the 2010 Meeting of the Texas Section of the Society for Range Management (landandlivestock.wordpress.com)
- Managing the Ranch as a Business: Strategic Planning (landandlivestock.wordpress.com)
- The Myth that is Conventional Range Management (landandlivestock.wordpress.com)