The role of mound-building termites in the nitrogen economy of semi-arid ecosystems

Abstract

Termite mounds are a conspicuous feature of savanna ecosystems in semi-arid northern Australia. The mounds of two common species Amitermes laurensis and A. vitiosus were found to have average inorganic nitrogen concentrations which are 50 to 130 times higher than that of the surrounding surface soil. The use of ion exchange resin bags in the field, showed that inorganic nitrogen was leached from the mounds during rain events. A drip infiltrometer was used for leaching experiments with mounds in the laboratory. These experiments indicated that an average of 250 mg N would be leached from each mound for each 100 mm of rainfall. This would amount to only 6% of the standing stock of inorganic N in the soil, but could be a significant addition to the soil immediately adjacent to the mounds during the short wet season.