Environmental factors related to the occurrence of mound-building nasute termites in Trachypogon Savannas of the Orinoco Llanos

The incidence of termite mounds was determined in twenty-six sites in the Trachypogon savannas at the Orinoco Llanos, including a wide range of physionomic types. A multiple discriminate analysis was utilized to analyze ecological variables as the best indicators of a given area's suitability for support of terrestrial Velocitermes and/or Nasutitermes species. The variables included physical attributes (texture, ineffective soil mass, water holding capacity, and infiltration rate), chemical attributes (cation exchange capacity, base saturation, and organic matter content), soil characteristics, and the above-ground phytomass accumulated at each stand. Results indicated that soil physical variables determining water balance during critical dry periods were of paramount value for the successful establishment of mound-building nasute termites in Trachypogon savannas.