Effects of bison grazing on Andropogon gerardii and Panicum virgatum in burned and unburned tallgrass prairie

TitleEffects of bison grazing on Andropogon gerardii and Panicum virgatum in burned and unburned tallgrass prairie
Publication TypeJournal Article
Year of Publication1992
AuthorsVinton, MA, Hartnett, DC
JournalOecologia
Volume90
Pagination374 -382
Accession NumberKNZ00384
Keywordstallgrass prairie
Abstract

Responses to clipping and bison grazing in different environmental contexts were examined in two perennial grass species, Andropogon gerardii and Panicum virgatum, on the Konza Prairie in northeastern Kansas. Grazed tillers had lower relative growth rates (RGR) than clipped tillers following defoliation but this difference was transient and final biomass was not affected by mode of defoliation. Grazed tillers of both species had higher RGR throughout the season than ungrazed tillers, resulting in exact compensation for tissue lost to defoliation. However, A. gerardii tillers which had been grazed repeatedly the previous year (1988) had reduced relative growth rates, tiller biomass and tiller survival in 1989. This suggests that the short-term increase in aboveground relative growth rates after defoliation had cost to future growth plant growth and tiller survival. In general, two species had similar responses to defoliation but their responses were altered differentially by fire. The increase in RGR following defoliation of A. gerardii was relatively greater on unburned than burned prairie, and was relatively greater on unburned than burned prairie, and was influenced by topographic position. P. virgatum responses to defoliation were similar in burned and unburned prairie. Thus grazing, fire, and topographical position all intreract to influence tiller growth dynamics and these two species respond differently to the fire and grazing pattern to influence a plants' grazing history and thus its long tern performance. Key words: grazing, bison, fire, Andropogon gerardii, Panicum virgatum

DOI10.1007/BF00317694