Soil modification by the harvester termite Hodotermes mossambicus (Isoptera; Hodotermitidae) in a semiarid savanna grassland of Namibia

Soil texture and chemical properties of soil dumps, brought up to the surfa ce by the harvester termite Hodotermes mossambicus (Hagen, 1853) during sub terranean building activity, were examined and compared with unmodified soi ls of different depths on three different study areas in the Etosha Nationa l Park, northern Namibia, Termites in these regions removed 372.9 kg on a t otal area of 2595 m(2) between February 1999 and September 2000. These term ite-affected soils were enriched in clay, brought up from deeper soil level s richer in day. Increased values of organic carbon and nitrogen were regis tered in soil dumps from two study sites, assuming that the termites incorp orated saliva and / or faeces to the central tube of the soil heap. The pH from one study site varied from acidic to basic. The soft soil dumps of H. mossambicus, in contrast to the longevity of termite mounds, were eroded ea sily by wind and the nutrients were washed out on to the soil surface by th e first heavy rains. Thus nutrients in soil dumps were more easily cycled t han those in the soils of termite mounds.