Extent of Communities and Abundance of the Most Common Grasses in Prairie

Abstract

1. Sixty-three typical prairies scattered throughout an area of 60,000 square miles of the central Missouri Valley region were carefully analyzed. The Andropogon scoparius and A. gerardi communities, respectively, composed 58 and 39% of the grassland. Other communities-Stipa spartea, Sporobolus heterolepis, and Spartina pectinata-together occupied the remaining 3%. The A. scoparius community occupied 6-11% more area in western Iowa than A. gerardi, 23% more in southeastern South Dakota, 12% more in eastern Nebraska, 14% more in northeastern Kansas, and 58% more in north-central Kansas and adjacent Nebraska. 2. In the sections with 32-34 inches of rainfall, average percentages for the two types were 54 and 44; in those with 24-26 inches precipitation, percentages were 69 and 29. In the 63 prairies, the Andropogon scoparius community was the most extensive in 67% and the A. gerardi community in 25%. They were approximately equal in area in the remaining 8%. 3. As individual species, Stipa spartea was present in nearly all of 70 prairies but was most abundant in northern areas. Koeleria cristata occurred in all, mostly in amounts of 1-3%. Sporobolus heterolepis was absent from northeastern Nebraska and northcentral Kansas. In many Iowa prairies and in northeastern Kansas it was common to abundant, but often it occurred only in amounts of 1-5%.