Results/Conclusions

At Konza, grazing increased small scale total species richness in both burned and unburned grassland. In the absence of grazing, fire did not play a dominant role in maintaining species richness; in the presence of grazing fire reduced total richness. At Kruger, grazing without fire increased richness. However, in annually burned sites, grazing by Cape buffalo alone led to higher richness than sites open to multiple grazers. All semi-variograms had relatively large ratios of spatially structured variance to sill (overall mean: 0.796), indicating that much of the variation is found at scales greater than 0.25m². The unburned site with multiple grazers exhibited the largest ranges for two dominant grasses indicating a larger patch structure at this site compared to the other treatments. At neither site was forb cover and richness related to grass cover. Large scale patch structure at Konza was similar to small scale structure; however, patch structure at Kruger responded differently depending on the scale of analysis. These analyses indicate that North American and South African grasslands respond differently to fire and grazing, and that these differences are a function of system-specific differences in patch size.