Termite diversity in southern Africa: A test of biodiversity theory
Biodiversity is a fundamental characteristic of biological systems and has significant impacts on ecosystem function and sustainability. Although its protection is a primary management objective for conservation areas and land managers worldwide, the mechanisms producing and maintaining biodiversity remain poorly understood and are hotly debated in the ecological literature. The productivity-diversity hypothesis (PDH) and the intermediate disturbance hypothesis (IDH) are popular theories that offer contrasting predictions on patterns of biodiversity in the landscape.
This research uses biodiversity patterns of termites in southern African savannas to evaluate the merits of the PDH and IDH models. We address 1) how termite diversity (species richness) is affected by productivity, 2) How termite diversity is affected by disturbance (fire and herbivory), and 3) determine the main drivers of termite diversity. Presence – absence data for 119 species in 52 genera of termites was accessed from the South African Termite Database and analyzed in boosted regression tree framework.
Our analyses suggest that at a continental scale, termite diversity is controlled by temperature and not productivity as per the PDH. Termite diversity was positively influenced by fire at both continental and biome scales suggesting that the temporal heterogeneity introduced to the system by fire disturbance overrides the effect of productivity as per IDH. In savannas intermediate tree cover (structural heterogeneity) promoted termite diversity. The affect of disturbance from livestock on termite diversity was not apparent.