Monday, August 6, 2007

PS 7-80: Plant community responses to fire and grazing in savanna grasslands: A cross continental comparison

Sally E. Koerner and Scott L. Collins. University of New Mexico

Savanna grasslands are one of the world’s major biomes covering almost 40% of the terrestrial land surface. Fire and grazing have both independently been shown to play an important role in savanna vegetation composition, yet rarely have their combined effects on vegetation been studied. It is my goal through the course of this study to determine the community responses to the key ecological drivers of fire and grazing in savanna grasslands located in southern Africa and North America. I will be determining how species abundances of the herbaceous vegetation change with varying degrees of grazing pressure and fire frequency. This project consists of two field experiments each occurring for a three year period, one in Kruger National Park (KNP), South Africa, and one in the Konza Prairie, Kansas. Each site has five experimental plots with varying grazing pressures and fire regimes. Initial results from the first sampling season suggest that both fire and grazing differ in their effects on plant community composition in NA and SA savanna grasslands. By comparing across continents, the results of this study will have global implications and help to establish a generalized model of the effects of grazing and fire on savanna grasslands.