Soil Modification by Termites in the Central Wheatbelt of Western Australia

Abstract

In a semi-arid region of Western Australia, in kwongan and open woodland, we examined the texture and selected chemical properties of two soil types, firstly in the mounds of two mound-building termite species (Drepanotermes tamminensis and Amitermes obeuntis) and secondly in the foraging galleries of D. tamminensis and A. neogermanus. The soil properties of the termite-modified soil were compared with soil unaffected by termite activity. It was found that both mounds and foraging galleries had significantly higher clay contents, increased organic carbon, and lower pH than the surface soil. The mean standing mass of D. tamminensis mounds was 5 Mg ha⁻¹ on yellow sand (under kwongan vegetation) and 7 Mg ha⁻¹ on grey sandy loam (under open woodland). However, this modified soil is predicted to be inaccessible for plant growth for a considerable period of time, since termite mound longevity could be as much as 70 years. In contrast, termite-modified soil from foraging galleries and chambers in the soil or soil sheetings covering food sources would be more readily accessible to the plant-soil ecosystem than modified soil materials in termite mounds.