The biology of pastoral man as a factor in conservation

This paper discusses the basic relationship between the dietetic needs of pastoral people, the number of stock they must keep to supply these needs, and the productive capacity of the environment. While overgrazing and erosion in pastoral areas is usually attributed to ‘prestige’ overstocking, it is shown here that there is a basic minimum number of animals required to support a human family. This requirement is usually about 3 Standard Stock Units each of 500 kg live-weight per head, but varies from 2·5–4·5 according to the ecological conditions, and is made up of various classes of stock that are kept for meat or milk. Where rising human population becomes too great to permit each family to maintain this necessary minimum herd, damage to the environment through overstocking becomes inevitable. In addition, by competing for the available milk supply, the pastoral peoples inevitably starve the calves and depress the quality of their stock, especially where human populations are high. The prevalent ‘overgrazing’ situation is seen as one of human over-population in many areas—requiring the removal of humans, or alteration of their dietetic habits, as well as mere reduction of stock numbers. Possible methods of alleviating the situation include partial dependence on bought grain, or settlement on irrigation schemes, but none are easy or short-term.