Is Succession a Viable Concept in African Savanna Ecosystems?

Abstract

The savannas of Southern and East Africa have five major characteristics that together distinguish them from other ecosystems:

• 1. Both the herbaceous and woody layers contribute significantly to primary production, and they generally occur in an irregular mosaic.

• 2. The vegetation is spatially very heterogeneous.

• 3. They support, in their natural state, a high biomass of large ungulates.

• 4. Rainfall is very variable and, as a consequence, so is primary production.

• 5. Fires occur at irregular intervals, the frequency decreasing with aridity, from virtually annual in some of the wetter savannas (>750 mm rainfall per annum) to nil at the driest extremes. In the moister savannas, the vegetation would be closed woodland in the absence of fire.