Savory brittleness scale

The Savory brittleness scale is a measure of the year round distribution of humidity in a particular environment. It was developed by Allan Savory a Zimbabwean biologist.A rainforest would be 1 on the scale and a desert would be 10.

The scale reflects year round humidity distribution and not simply amount of rainfall. Thus some high rainfall environments, for example Zambia with 2,000 mm rainfall can be high on the brittleness scale. At the same time environments with lower rainfall such as parts of England with 600 mm can be low on the brittleness scale. Hence it differs from an Aridity index. Brittle landscapes have erratic distribution of moisture throughout the year. The main significance of this scale is that the "tool" of resting land in either form - total rest or partial rest - leads to grasslands weakening and being replaced by either woody vegetation or bare soil covered with algae and lichens depending on the amount of rainfall. Partial rest a new concept named by Savory describes situations in which there are large herbivores, wild or domestic, on the land but scattered and with calm unbunching behaviour. Research plots across the brittleness scale indicate that the effects of partial and total rest are almost identical in grasslands and savannas. Partial rest in high end brittle environments, particularly where combined with overgrazing of plants, is the single greatest influence leading to desertification. Summarized, the most powerful tool with which to restore biodiversity and land health in non-brittle environments is rest in either form. The most destructive tool leading to a loss of biodiversity and consequent desertification in brittle environments is resting land in either form. Thus we witness one tool used in land management flipping its role across the brittleness scale.

References

*Citation
last =Edge
first =Aspen
title =Lessons from a Brittle Landscape
journal =Permaculture Magazine
issue =53
pages =47-50
date =Autumn
year =2007
*Citation
last =Keppel
first =Wilma
title =Landscape brittleness: how "good" management can harm land
date =
year =
url =http://managingwholes.com/brittle.htm
accessdate = August 5 2007
*Savory, Allan "Holistic Management: A New Decision Making Framework" Second edition 1998 Island Press.