Precipitation mediates termite functional diversity and dominance in southern Africa

Abstract

Background: Termites are important ecosystem engineers in the tropics and sub-tropics, so understanding their diversity, particularly their functional diversity, across biogeographical scales is important for understanding where they alter the environment and deliver ecological services. Feeding groups combine phylogenetic and dietary information about termites into ecologically significant functional categories. Objectives: To characterise termite feeding group prevalence, distribution and diversity in southern Africa and assess the effect of precipitation on termite diversity and assemblage composition. Method: Termite genus and species-level occurrence data were acquired from the South African Termite Database and classified into one of five feeding groups. We evaluated the prevalence of each feeding group and assessed species and feeding group richness and dominance. Linear regressions were performed to determine the relationship between 1) species richness and precipitation; and 2) feeding group richness and precipitation. Results: We find that southern Africa 1) is dominated by FG-IIw (feeding group - II, wood feeding) termites; 2) is occupied by multiple feeding groups across the entirety of the rainfall gradient; and that precipitation 3) influences feeding group species diversity variably; and 4) causes notable shifts in termite community structure. Conclusion: Our results indicate that termites likely make substantial contributions to plant material decomposition across southern Africa and that while shifts in feeding group dominance are associated with rainfall gradients, the services unique to individual feeding groups are not isolated to certain regions, but rather are widespread regardless of the amount of precipitation received.