TALLGRASS PRAIRIES: AN ECOLOGICAL ANALYSIS OF 77 REMNANTS (BOTANY, GRASSLANDS, INTERIOR HIGHLANDS, ARKANSAS, KANSAS, MISSOURI, OKLAHOMA)

Tallgrass prairie is a North American vegetation type with a preponderance of four main grasses little bluestem (Schizachyrium scoparium (Michx.) Nash), big bluestem (Andropogon gerardii Vitman), Indian grass (Sorghastrum nutans (L.) Nash), and switch grass (Panicum virgatum L.) , and a large assemblage of distinct forb species. The objective of this study was to quantitatively describe and analyze the vegetational composition of tallgrass prairie within a large geographical region. The study was conducted in the vicinity of the western Interior Highlands in portions of Arkansas, Kansas, Missouri, and Oklahoma where little previous research had been conducted. Data on species composition, management practices, and soils were gathered in addition to quantitative vegetational data obtained with line-intercept sampling.; These data demonstrated that tallgrass prairies in the region studied are qualitatively quite similar, but that quantitatively the Importance Values (IVs) of a number of species varied, including the importance of the four main grasses. A fifth grass, broomsedge (Andropogon virginicus L.), was also determined to be important, especially in prairie remnants in the eastern part of the study area. Although no conclusive explanation was established for the differential IVs of this fifth grass, it was demonstrated that broomsedge is negatively correlated with the four main grasses and with soil fertility, and that management practices are probably partially related to these differences.; Vegetational parameters were compared for three geographical sections of the study area (WEST, BORDER, EAST). Total percent basal cover was not significantly different between these three sections. However, species richness, species diversity, and the total IV of the four main grasses were statistically different in all three sections. Species richness and species diversity increased from WEST to EAST across the study area, while the importance of the four main grasses decreased from WEST to EAST. This is the first time that such patterns have been recognized in tallgrass prairie. Insufficient data on a number of environmental variables prevent adequate ecological explanation of these patterns.; This study can serve as the nucleus for further research because it is the only large data set that has been collected in a consistent manner over a large geographical area. Now that such data exist a number of additional hypotheses and relationships concerning prairie vegetation and environmental parameters can be tested and applied to prairie preservation and management.