Termites, soil fertility and carbon cycling in dry tropical Africa: a hypothesis

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Abstract
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 Macrotermi tinae 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 atmos pheric chemistry and generates hypotheses to explain the role of termites in dry tropical eco systems. It is suggested that termite activity exhaustively partitions litterfall among adjacent com peting 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 CO2and 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 CO2and CH4. Moreover, they suggest a coupling of regional soil forming processes and the global C budget.