The Distribution and Abundance of Large Termite Mounds in Uganda

Abstract

Rapid estimates of termite mounds exceeding 1 m in height were made by roadside counts covering most of Uganda. The error in the counts was estimated at about 3% and the counts reflected the abundance of mounds in the local areas. The density of mounds in most parts of Uganda is 1-4 ha1, only a small proportion of the country having more. The total quantities of soil incorporated in the mounds were comparatively small, equivalent to a layer less than 1 mm thick over most of the country. Mounds were absent from higher ground, the upper limits corresponding to a mean minimum temperature of 90 C for Macrotermes subhyalinus and 120 C for M. bellicosus. There were several areas where M. subhyalinus occurred alone, but few were occupied exclusively by M. bellicosus. In most places both were present but it was usual for one to be dominant. The shape of mounds varies considerably, partly in response to climate. For example, 'turrets' on M. bellicosus mounds are more common where the mean maximum temperature exceeds 280 C and the ratio precipitation:evaporation is 0-6 or less. Mound shape in Uganda was not correlated with the sandiness of the soil.