308 GRAZING INDICATORS. 



pletely replaced bj' the mixed prairie of tall-grasses and short-grasses, which 

 was undoubtedly the original cUmax. 



Relations of tall-grasses and short-grasses. The explanation of the ap- 

 parent replacement of buffalo grass by the bluestems, as well as the general 

 replacement of tall-grasses by short-grasses, has been found in the effect of 

 grazing upon such a mixed community. This effect is naturally increased by 

 drought periods, and it is especially in connection with such periods that the 

 impression of a permanent change arises. Mixed prairies of tall Andropogon 

 or Stipa spariea with short Bulbilis and Bouteloua are found in central Ne- 

 braska and Kansas, and also in the eastern Dakotas, while in western Nebraska, 

 the Dakotas, Montana, and Wyoming they consist of Agropyrum or Stipa co- 

 mata with Bulbilis, Bouteloua, or both of them. It is in these regions that the 

 view has been more or less general that the tall-grasses have replaced the short- 

 grasses as a consequence of the disappearance of the buffalo and the coming 

 of man. This view has been held by so many keen observers, both practical 

 and scientific, as to indicate that it has an actual foundation of fact. This 

 has proved to be the case, but it was impossible to recognize the basic facts 

 until the principles of successions were brought into use. A particular study 

 of the effects of overgrazing upon mixed prairie with respect to wet and dry 

 periods has been made since 1914. Thi> quickly revealed the fact that the 

 short^rasses were often completely hidden by the tall ones in times of unusual 

 wetness, such as 1915, and that overgrazing regularly brought the tall-grasses 

 to the point of apparently complete disappearance during drought periods. 

 These facts have been repeatedly confirmed in adjacent grazed and ungrazed 

 areas throughout the mixed prairie from North Dakota to Kansas, and they 

 are regarded as furnishing a complete explanation of the apparent disappear- 

 ance of the short-grasses and the invasion of the tall ones. 



There is general agreement as to the damage done to the range by buffalo, 

 as well as to the enormous number found on the prairies and plains from 1865 

 to 1875, when settlement was taking place most rapidly. In fact, the appli- 

 cation of the term buffalo grass to the short-grasses is in harmony with the 

 action of overgrazing in suppressing or destroying the tall-grasses. The 

 westward movement of the buffalo and their decrease in numbers coincided 

 with the incoming of settlers and the decrease of prairie fires. The im- 

 mediate result was renewed growth of the tall-grasses, especially Andropogon, 

 in areas where it had not been completely killed, and its invasion into others 

 where it had disappeared. This tallies with the statement that the blue- 

 stems followed in the wake of the settlers, and drove out the buffalo grasses. 

 The error involved in this is best illustrated by the statements of Bell (1869: 

 1:26,43): 



"Before we reached Sahna, trees had become very scarce; but as we moved 

 farther, the short tender buffalo grass gradually appeared at first only here 

 and there, but at last it abounded everywhere; and ever and anon we crossed 

 the well-beaten path of the monarch of the plains. Doubtless no grass could 

 bear so well the heavy tramp of thousands of buffalo continually passing over 

 it; but it is a good thing for the land that, as settlers advance and domestic 

 herds take the place of big game, the coarser, more vigorous, and deeper- 

 rooted grasses destroy it and take its place. These new-comers grow with 

 great luxuriance, yielding very fine hay; and at the same time loosening the 

 sod, opening up the soil, and retaining the moisture in the ground. " 



