The effect of varying fire regimes on ant diversity in a savanna ecosystem

Fire regimes are thought to have an important influence on biodiversity (in terms of
savanna ecosystems). This study aimed to investigate the effects of fire frequency on
faunal structure and composition, using ants as indicators. The plots in one site had
greater species richness and diversity (S=19, H’=2.327 and S=17, H’=1.818) than the
other (S=15, H’=0.6016 and S=15, H’=1.31). The overlap in species between the
plots at the more diverse site, and the proximity of the two plots, suggest that
immigration of species between the two plots could have resulted in elevated
diversity. The other site may have been less diverse as there was no refugia from fire
for species that prefer the structure of annually burnt plots, but are intolerant of
burning events. It is also possible that this site did not conform to our predictions as
a result of the unusually high density of a single species (Lankyblackass spp.) in the
annual plot samples, which could have caused the exclusion of other species.
Heterogeneity in terms of patchiness of different fire frequencies was deemed
important as it allows migration of species between patches, and creates refugia for
some species from either competition or disturbance.