TERMITES, SOIL FERTILITY AND CARBON CYCLING IN DRY TROPICAL AFRICA - A HYPOTHESIS

Termites, particularly the mound building, fungus growing Macrotermitinae, reach densities of up to 400 termites m-2in soils of dry tropical Africa. The influence of Macrotermitinae in increasing certain soil nutrients in mounds compared to adjacent soils has been documented, but the links between litter harvesting by termites, soil fertility, and global C cycling have not been explored. This study reviews the evidence from soil science, ecology and atmospheric chemistry and generates hypotheses to explain the role of termites in dry tropical ecosystems. It is suggested that termite activity exhaustively partitions litterfall among adjacent competing colonies, where it is so thoroughly decomposed that little or no organic C is incorporated into the soils. Associated N, P, and cations build up in the mounds, but C apparently is emitted as CO, and CH4from the mounds. While not adequate to calculate nutrient fluxes through termites, the data available support the argument that termites contribute significantly to atmospheric fluxes of CO, and CH4. Moreover, they suggest a coupling of regional soil forming processes and the global C budget. © 1990, Cambridge University Press. All rights reserved.