The Relation of Jack Rabbits to Grazing in Southern Arizona

Jack rabbits feed on valuable range vegetation. A preference was found for areas on which livestock grazing had reduced the vegetative stand, provided a moderate forage supply was still available. Similarly, a much greater insect population has been found on overgrazed than on lightly grazed range in Oklahoma. Earlier investigators have traced relationships between vegetative depletion by livestock and a multiplication of grasshoppers and white grubs, and have noted increases of certain small mammals following the disturbance of the native prairies of the Middle West. The results of altered character of plant cover are expressed in terms not only of plant succession but also of animal succession; the associative complex is not merely botanical but is also zoological and therefore inclusively biological; Increases of insects and certain vegetation-consuming mammals may be an effect of vegetative depletion rather than primarily a cause, or may be both an effect and in turn a cause; and maintaining in the right balance range use and range vegetation may be a problem into which should be integrated the control of animal life through the kind and amount of vegetation. For foresters, already accustomed to think of the forest as a biological complex comprising the animal as well as the plant life of the area, new vistas are brought into view by this highly suggestive paper relating to the range.