Microhabitat selection by antechinus agilis and rattus fuscipes in response to fire

Context. Small mammals select resources in a non-random fashion to maximise their chances of survival and reproductive success. Understanding how they use and perceive their immediate environment provides insights into their distribution and abundance, predator avoidance and responses to disturbance regimes such as fire. In turn, this knowledge can aid conservation and land management. Aims. This study aimed to assess microhabitat selection by two small mammal species, the bush rat (Rattus fuscipes) and agile antechinus (Antechinus agilis) in response to prescribed fire. We addressed three study questions: 1) Does each species exhibit microhabitat selection in unburnt habitat? 2) Does each species exhibit microhabitat selection in burnt areas? and 3) Does agile antechinus microhabitat selection change in response to fire? Methods. Under a modified before-after, control-impact (BACI) study design, we used spool and line tracking and touch pole vegetation surveys to measure microhabitat selection along 21 trails for bush rats and 22 for antechinus. Key results. In unburnt habitat, bush rats showed positive selection for sedges, logs and habitat complexity, whereas no significant associations were observed for the agile antechinus. In burnt areas, bush rats showed increased selection for sedges, ferns, shrubs, habitat complexity and unburnt patches. Similar to pre-fire, antechinus showed no significant microhabitat selection in burnt areas and no change in response to fire. Conclusions. Bush rats appear to have more specific microhabitat requirements than agile antechinuses, both pre- and post-fire, particularly for dense vegetation. This could be due to factors such as loss of food and shelter from a reduction in understorey cover and subsequent increased risk of predation. Antechinus are more flexible in their use of habitat features, possibly due to their semi arboreal habit. Implications. Our results suggest that bush rats may be more susceptible than agile antechinuses to the short-term effects of fire. Strong selection by bush rats for small unburnt patches within burnt areas suggests that low intensity, patchy fires may help bush rats persist in recently burnt areas. Future prescribed burning should consider localised fauna responses when implementing fire regimes.