Range Condition Classes of Native Midwestern Pasture: An Ecological Analysis

INTRODUCTION Many tracts of native vegetation still remain in the western portion of that vast North American grassland known as True Prairie. Some are mowed annually for the crop of excellent forage, but far greater areas are now in native pasture (Weaver & Fitzpatrick 1932, 1934). One result of the long years of study of the grazed portion of this grassland was the recognition of the manner in which the prairie vegetation degenerates under continued grazing (Weaver & Hansen 1941). A second was the classification of the resulting pastures into several grades or range conditions, each based upon the composition of its vegetation (Weaver & Hansen 1941). Further ecological analysis of the different conditions of pastures was not made because of the 7 years of severe drought (1934-40). But after 8 good years for recovery of the greatly depleted grasslands , the present study was carried out in 1949. The research was undertaken with a full knowledge that certain profound changes in prairie, which were also reflected in native pastures, had occurred both during and following the drought. There was a decrease in the amount of little bluestem (Andropo-gon scoparius)l which had been extremely abundant, and a resultant great increase in big bluestem (A. furcatus), formerly of much less abundance on up-land. Marked local increases in prairie dropseed (Sporobolus heterolepis) and tall dropseed (S. asper) had also occurred. Decrease or disappearance of