Does fire affect the ground-dwelling arthropod community through changes to fine-scale resource patches?

In semiarid ecosystems, perennial trees create resource patches beneath their canopies by providing shade and accumulating litter. These patches are often distinctly different from inter-tree areas, which support scattered hummock grasses. Although patchiness is regarded as an important driver of faunal diversity, it is not known how it is affected by disturbances such as fire. In this study, we tested how resource patches and fire affect the ground-dwelling arthropod community. We sampled ground-dwelling arthropods under the canopy of mallee (Eucalyptus trees), and in adjacent open areas in: (1) an area burnt over 30 years ago (long unburnt'), and (2) an area burnt 4 years ago (recently burnt). Five taxa (cockroaches, isopods, spiders, jumping spiders and wasps) were more abundant under the canopy than in the open across both burn treatments, whereas ants showed the opposite pattern. Irrespective of patch type, silverfish, wasps and isopods were more abundant in the long-unburnt stand than the recently burnt stand. Ants showed the opposite pattern. Both long unburnt and recently burnt stands supported a similar abundance of beetles, cockroaches and spiders. Our results demonstrate that many arthropod taxa are affected by the resources provided by trees (litter, shade), even in areas recently burnt by fire. This is likely to change over time and in relation to further disturbance.