KENNEDY, M.S.; SPENCER, R-J.; BAXTER, G.S.; Univ. of Queensland, Gatton, Australia; Iowa State Univ.; Univ. of Queensland, Gatton, Australia: Using small mammals to test ecological processes driving population and community processes after fire in a nutrient poor environment.

Patterns of small mammal community responses to fire events are well documented in some regions of Australia. However, these patterns do not occur uniformly across ecosystems and the ecological mechanisms driving such patterns are rarely experimentally tested. We monitored the response of a small mammal community in the Eucalypt forests of Fraser Island to prescribed fire events and, using supplementary food and canid exclusion treatments, tested how trophic interactions influenced the community�s response to fire. The Bush Rat (Rattus fuscipes) was the dominant species and exhibited little immediate change in density as a result of the fire event. Small mammal communities in canid exclusion plots did not differ in composition or density from control plots at any stage in the 12 months after fire, indicating that canid predation has little effect on the community in the post-fire environment but food supplementation significantly increased the density of R. fuscipes (no effect on species composition). Top-down processes (predation) have little effect on R. fuscipes after fire, whereas resource availability (food) appears to drive the population for at least 12 months after fire. The responses to these experimental treatments are discussed with reference to top-down and bottom-up trophic interactions in the post-fire environment. The lack of response by other small mammals in the community strongly suggests that other processes such as competition with R. fuscipes are influencing their abundances.