Post-fire survival and reproduction of rehabilitated and unburnt koalas

Fire can be a catastrophic event which causes high mortality and injury in wildlife. While rehabilitation of injured animals is common, no studies have measured the success of rehabilitated wildlife following fire. This study compared the long-term survival and reproduction of a group of injured, rehabilitated and released koalas ( n=16) with that of uninjured koalas ( n=23) following fires in fragmented forest in Port Stephens, Australia, in 1994. Individual koalas were monitored for up to three years following release. Survival rates were calculated using the Kaplan–Meier estimate, modified for the staggered-entry of new animals. There was no significant difference in the survival of rehabilitated and uninjured koalas after fire. Annual survival, derived by fitting an exponential decay function to the data, was estimated to be 58% for rehabilitated koalas and 67% for the uninjured koalas. Predation by dogs was the major cause of mortality for both groups. Reproduction did not differ significantly between the two groups over two breeding seasons following fire. It was concluded that rehabilitation of injured koalas was successful from the perspective of the individuals. Furthermore, such efforts have the potential to contribute to the recovery of populations depleted after fire and thus contribute to the long-term survival of koala populations.