Professional alarmist and special interest groups, especially vegetarians, are blaming most of the world's ills and a forthcoming global catastrophe on livestock. Livestock, particularly cattle, are blamed for causing desertification, expending and polluting the earth's waters and contributing to global warming and depletion of the ozone layer. While scientists state that most of these spectacular and serious accusations are not based on fact, they nevertheless are being advanced and repeated mechanically, without understanding, by the media. The public is being misinformed and it is not surprising that many individuals are supportive of the extremists' call for an ecological renaissance and return to nature involving no domestic livestock grazing.
On the other hand, technologies which will allow man to better control his environment and to enhance and assure his quality of life are known and new ones are being continually developed. If the professional alarmists are serious, one would think that they would be more interested in supporting the implementation of these technologies, rather than making spectacular and illogical recommendations. However, it appears that they are either unaware of the technologies or prefer to ignore them.
To understand desertification on rangelands, its control and its reversal, one must have some knowledge of certain plant physiological, ecological and environmental phenomena and principles. An objective of this document is to describe and illustrate these phenomena and principles in a manner that can be readily understood by the uninformed. Moreover, to understand the role of domestic livestock in desertification control, one must know that livestock can be manipulated in order to achieve a desired effect for both the animals and the environment. Another objective of this document is to illustrate how this can be achieved. These objectives will pertain primarily to natural pastures or rangelands.
Principles are principles and while specifics will vary, most are applicable to all parts of the world. However, the practices for controlling desertification, will deal mainly with the livestock production situations in the Americas. The Near and Mid-East and Africa are not included because the vast majority of livestock are raised under a migratory system of production. Moreover, desertification control in these regions goes beyond technological implementation because a multitude of entangled sociological, economical, political and marketing factors that cannot be unravelled easily are involved. This does not mean that the problem cannot be solved. Readers interested in possible solutions in the Near East Region and possibly Africa are referred to Huss (1985).
This document emphasizes ruminant livestock. However, it is appropriate to say here that free-roaming pigs on pasturelands, as is the case in many Latin American countries, can be very destructive and the practice should be minimized as far as possible. Also, equines, kilo for kilo, put more pressure on grasslands than ruminant stock.
The Latin American and Caribbean region in this document is composed of those countries in FAO's South America, the Caribbean and North and Central America classifications with the exception of the United States of America and Canada. Specific references are made to the U.S. and to countries in other regions of the world merely to illustrate facts and/or points. Much of the information regarding the influence of grazing and vegetation on water yields, erosion and water quality comes from the United States because that is where the research is being conducted.