Associations between occupancy and habitat structure can predict avian responses to disturbance: Implications for conservation management

• We investigated bird responses to habitat structure and time since fire.
• All but two of the 15 modelled species responded to habitat structure.
• Four of the species that responded to structure also responded to time.
• Time since fire is likely to be a poor universal surrogate for avian occurrence.
• Results aid prediction of faunal responses to time since disturbance.

Increasingly, fire is used as a management tool to mitigate wildfire risk and conserve biodiversity. Use of time since disturbance as a surrogate for faunal occurrence presents an appealing basis for biodiversity conservation; however, successional change in resource availability is often the direct driver of change in animal occurrence rather than time per se, and rates of resource development can be highly variable. To facilitate prediction of animal responses to disturbance, we sought to test whether time since fire (TSF) and habitat structure can predict bird occurrence. Time is only expected to predict occurrence if (i) species respond to structural resources and (ii) the abundance of these resources can be predicted by time. We examined the responses of 15 bird species to habitat structure and TSF using a 70-year chronosequence spanning three forest types in southeast Australia. Habitat structure variables predicted the occurrence of 13 species, four of which also responded to TSF. The levels of associations between occurrence, structure and TSF varied among vegetation types but response shapes were generally consistent. The fact that the majority of species did not respond to TSF indicates that TSF is an inappropriate surrogate for avian occurrence in our study system. Further, it is unlikely to be a reliable surrogate for faunal occurrence in forests that exhibit variable rates of post-fire structural development. We suggest that relationships between TSF and structure can provide insight into the capacity of TSF to predict animal occurrence. They will also reveal the extent to which fire can be used as a tool for managing biodiversity, and species likely to benefit or be at risk from particular fire regimes. This is critical given projected increases in the frequency and extent of fire in many regions.