North American tallgrass prairie is dominated by a small number of matrix-forming grasses, between which are found a large number of less abundant interstitial species. Distributions of these species are influenced by disturbance regime and soil variability, resulting in a patchy mosaic. Patches, as defined by interstitial species, have been defined in tallgrass prairies in Kansas and Oklahoma, and vary unpredictably within and between growing seasons. The importance of matrix-forming species on the unpredictable variability of these patches will be tested experimentally. Schizachyrium scoparium, a matrix-forming species, will be removed form half of five 10x10 m2 study blocks, leaving the remaining halves as controls. Patch structure in each block will be analyzed from cover data form each square meter. Samples will be taken three times over the growing season. If a matrix- forming species colonizes the space, patch composition and spatial structure will not change. If interstitial species already occupying the patch type colonize the space, patch composition and spatial structure will change. Inter-site comparisons will be possible by applying treatments to eastern Kansas. This study will aid in understanding effects of unpredictable, Interstitial components on spatial-temporal dynamics in tallgrass prairies.
