Long-term effects of frequent low-intensity burning on ant communities in coastal blackbutt forests of southeastern Australia

Periodic low-intensity fire (hazard-reduction burning) is a conspicuous management strategy in virtually all of Australia's dry forest communities where it is primarily used to reduce fuel levels with the intention of minimising the extent and severity of wildfires. Little is known, however, about the effects of its repeated use on natural ecosystems over long periods of time. This study investigated the long-term effects of frequent low-intensity fire on forest ant communities by comparing frequently burnt sites with long-unburnt control sites. While the richness of ant communities remained largely unchanged, the composition of assemblages differed substantially between treatments. Although frequent burning apparently resulted in the loss of a substantial number of species, the overall richness of frequently burnt areas was maintained by the addition of species not present on unburnt sites. These changes in species composition were accompanied by major changes in community organisation (structure) and were considered to be a response to altered habitat conditions, particularly litter biomass, vegetation structure and patterns of insolation at ground level. Appropriate fire prescriptions could therefore be applied to manipulate these habitat elements at a landscape scale to meet both management and conservation goals. A comparison of pitfall trapping and litter extraction techniques revealed the importance of a composite sampling strategy, with 22% of ant species detected only by litter extraction.