Geographic variation in mammal and reptile responses to fire and livestock grazing regimes

1. Changes in land use and fire regimes are a major threat to species and ecosystems worldwide. Species' responses to altered fire and livestock grazing likely vary depending on the local ecosystem and the attributes of the disturbance regimes.

2. We used single-species, single-season occupancy modelling to investigate the responses of 15 commonly occurring mammal and reptile species to fire and grazing regime attributes in an Australian subtropical woodland. Thirty-one hypotheses were formed based on species' responses to these regime attributes reported in other studies conducted in Australia. We expected that our hypotheses would be more likely to be supported when based on results from studies closer to our study area.

3. Of the 31 relationships we tested for, only six were consistent with the hypothesized responses for each species, and we were unable to discern any geographic patterns that made this consistency more likely. Seven mammal species' occupancy changed in response to a fire or grazing regime attribute. Four small mammals (eastern chestnut mouse Pseudomys gracilicaudatus, pale field rat Rattus tunneyi, delicate mouse Pseudomys delicatulus, central shorttailed mouse Leggadina forresti) and two large mammals (eastern grey kangaroo Macropus giganteus, red-necked wallaby Macropus rufogriseus) responded to different fire regime attributes. Pigs (Sus scrofa) had higher occupancy in more heavily grazed areas.

4. Synthesis and applications. Based on our findings, conservation land managers should be cautious in using species' responses to disturbance regimes from studies done in other bioregions to inform conservation practices in their local area. Factors that may have influenced the response of species to fire and livestock grazing in this region include the unique climate of the bioregion, prior land use history, previous large wildfires and recent above-average rainfall. Given the interspecies variability to fire regime attributes in this study area, we recommend maintaining variation in time since fire, time since late-dry-season fire and fire frequency in the landscape to accommodate the different fire history needs of individual species.