The Palouse Prairie Balsam-root 



E. R. Bogusch 



The natural Palouse prairie of southeastern Washington has 

 rapidly disappeared during the last twenty years. This change 

 has been largely dependent upon the advance of agriculture in 

 search of increased acreage. Fortunately, for the student of 

 plant ecology there have been preserved for study a few typical 

 examples of the original Palouse vegetation that give us an ap- 

 proximation of what the climax vegetation consisted before the 

 advent of the white man. One such area has been set aside by 

 the State College of Washington, expressly for botanical study. 

 It was here that Weaver carried on a part of his investigations 

 of the root systems of prairie plants during 1914. 



Despite precautions in keeping this strip of ground secure 

 from stock and agriculture, this prairie remnant affords an ex- 

 cellent example of a unit of plants that is out of balance with its 

 surrounding biota. Extensive summer fallows in adjacent fields 

 have materially reduced the atmospheric moisture during the 

 growing season and the plants are dwarfed accordingly. 



The most profound influence, however, comes from the pres- 

 ence of ground squirrels, animals that are not components of 

 the true climax as indicated by the presence of Festaca idahoen- 

 sis and Agropyron spicatiim. The rodents belong to the larger 

 species {Citellus columbianus) and are found normally only in 

 the serai habitats induced by erosion and other factors and 

 therefore invade the climax marginally. Due to the increased 

 food supply and the introduction of much disturbed ground in- 

 cident to agriculture, coupled with the decimation of natural 

 enemies — chiefly coyotes and hawks — these rodents are present 

 in greatly increased numbers. 



The accompanying figure is a photograph of the spring as- 

 pect of the balsam-root (Balsamorhiza sagittata) and represents 

 a typical condition to be found in the preserved areas. This 

 plant, one of the major dominants of the Palouse vegetation, 

 is among the first to resume activity in the spring. The con- 

 tinued destruction of the early shoots results in a stimulation 

 of the radial ones so as to produce the peculiar ring-like growth. 



