Termites of a South African savanna : IV. Subterranean populations, mass determinations and biomass estimations.

Shallow soil cores taken every four weeks for a year in broad-leaved savanna and in Acacia savanna at Nylsvley Reserve, northern Transvaal, supported evidence on termite distribution and abundance reported in earlier papers. Surface activity was markedly affected by soil moisture, and the extent to which the core results can be used to assess subterranean populations is discussed. Live and dry masses for 14 species of termite are reported, and these results plus epigeal nest populations published elsewhere are used to calculate termite density and biomass in the two vegetation types. Tentative figures are 3,00 workers m-1 (=8 g m-1 fresh mass; 2.5 g m-1 dry mass) in broad-leaved savanna, and 725 workers m-1 (=1 g m-1 fresh mass; 0.3 g m-1 dry mass) in Acacia savanna. Excluding the mass of soil in the guts of soil-feeding species, these masses are reduced to 3 g m-1 (fresh) and 1 g m-1 (dry) in broad-leaved savanna, and 0.5 g m-1 (fresh) and 0.15 g m-1 (dry) in Acacia.