THE INFLUENCE OF SOIL FERTILITY ON THE ECOLOGY OF SOUTHERN AFRICAN DRY SAVANNAS

In dry savannas there is a wide range in soil fertility status, related at a regional scale to differences in parent material and the age of the land surface. At a landscape scale, catenal processes result in large fertility contrasts between ridgetop and bottomland positions. Several other processes lead to the creation and maintenance of nutrient-rich and nutrient-poor patches within the landscape, including patterns of herbivory, activities of prehistoric man and nutrient cycling through trees and termite mounds. While the base-richness of the parent material is initially important in determining soil fertility, biological activities involving P, C and N appear to be important in the creation and maintenance of localized areas of enhanced soil fertility on base-poor substrates. -from Author