The importance of sampling intensity when assessing ecosystem restoration: ants as bioindicators in northern Australia

Insects are commonly used as bioindicators for assessing ecosystem restoration, but such assessments are potentially influenced by sampling intensity. Uncommon species are often late colonizers of sites undergoing restoration, so that sampling that is effective for only common species can under-represent differences between rehabilitation and reference sites. We found that differences in observed ant species richness and composition between rehabilitation and reference sites at a northern Australian uranium mine increased markedly with increasing sampling intensity (through repeat sampling), reflecting differences in the numbers of uncommon species. Ensuring appropriately high sampling intensity is important in assessments of restoration success using insect bioindicators.