SOIL MODIFICATION BY TERMITES IN THE CENTRAL WHEAT-BELT OF WESTERN-AUSTRALIA

In a semi-arid region of Western Australia, in kwongan and open woodla nd, we examined the texture and selected chemical properties of two so il 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 pro perties of the termite-modified soil were compared with soil unaffecte d by termite activity. It was found that both mounds and foraging gall eries had significantly higher clay contents, increased organic carbon , and lower pH than the surface soil. The mean standing mass of D. tam minensis mounds was 5 Mg ha(-1) on yellow sand (under kwongan vegetati on) and 7 Mg ha(-1) on grey sandy loam (under open woodland). However, this modified soil is predicted to be inaccessible for plant growth f or a considerable period of time, since termite mound longevity could be as much as 70 years. In contrast, termite-modified soil from foragi ng galleries and chambers in the soil or soil sheetings covering food sources would be more readily accessible to the plant-soil ecosystem t han modified soil materials in termite mounds.