Not Fire, Not Rest: Animals for Improved Rangelands
Savory, Allan, Whole Earth
A letter from Allan Savory
I commend you on your excellent coverage of fire [Whole Earth, Winter 1999].
As global climate change looms, the issue of biomass burning--rangelands, forests, and croplands--will require even more serious attention. At present, only three main "tools" for land management are ever considered by ecologists: fire, resting land, or some form of technology. I believe one of the most vital things for humans to learn in this new millennium is how to return to what I call "animal-maintained rangelands, croplands, and forests," as opposed to rest and fire.
In Africa alone, over two billion acres of grasslands and savannas are burnt annually because there are too few animals to maintain them. National parks like Kruger are burnt frequently, while thousands of animals are shot in the false belief that there are too many! These fires burn, at times, for hours, and the average 1.5-acre fire apparently releases more noxious gases per second than 4,000 cars. Lately it has been discovered that such fires in Africa and America are also releasing methyl bromide, a compound with apparently far greater ozone-destructive powers than the CFCs which we much condemn.
Desertification, biodiversity loss, and global climate change are closely linked. In "brittle environments"--environments that alternate between seasonally humid and arid--only two things cause widespread exposure of the bare soil between plants. The first is too few large herbivores wandering around, grazing plants that developed with herbivore populations. The second is fire, which tends to destroy soil cover and expose the surface. Bare soil results in decreasing the effectiveness of rainfall moisture, increasing drought and flood frequency, and drying up water sources underground and in rivers--desertification.
Brittle environments developed with populations of large herbivores; unlike the perennially humid environments (non-brittle), where most herbivores were, and still are, insects. In the Americas, the bulk of large herbivorous mammals died off about 10,000 years ago. Much the same occurred in Australia following the arrival of humans: skilled hunters using fire changed an entire continent. All over Africa and Eurasia we see a similar situation, although due to the vastness of those continents not as many species were exterminated. It is highly likely that the desertification and global climate change we are experiencing today began with excessive human hunting and burning thousands of years ago.
The guts of large herbivores are essential for carbon to cycle and be sequestered in the soils of brittle environments (counteracting global warming). Gut bacteria break down billions of tons of dead plant material. In these environments, microorganisms experience considerable die-off during the arid months--except in the moist digestive systems of large herbivores! That seasonal symbiosis between large-animal guts, microorganisms, and alternating dry/wet soils was (is) essential to the breakdown of massive amounts of dead and lignified vegetation. …