Applications of biogeochemical modelling in southern Africa

Abstract

Biogeochemical modelling is largely concerned with the cycling of carbon, nitrogen, phosphorus and sulphur in the biosphere. It offers a robust approach to modelling many aspects of ecosystem function at the regional scale, since it is not highly dependent on a detailed know ledge of species or organism-level processes. In southern Africa biogeochemical modelling has been used to provide new insight into the geographical distribution and underlying mechanisms of palatable (sweetveld) and unpalatable (sourveld) grasslands and high-herbivory and low- herbivory savannas. It has also been applied to the problem of estimating the emissions of trace gases and smoke particles from vegetation fires in the region, and suggests that the emissions are much lower than previously believed. Work in progress relates to the modelling of tropospheric ozone precursors produced by the soil and plants. Biogeochemical modelling has the potential to be an integrating tool, drawing together data collected at widely different scales in a way that allows hypotheses about the working of the biosphere to be rigorously tested.