Post-fire changes in feral cat density across burnt and unburnt landscapes, Kangaroo Island

The impacts of wildfire upon biodiversity can be compounded by other factors. There is some evidence that feral cats Felis catus may move to, or occur in increased abundance in, recently burnt areas. As such, wildlife that have survived fire may be at increased predation risk, in part because the burnt landscape offers less shelter from predation. However, the response by cats may depend upon the severity and scale of fire: the only previous study of the impacts of a severe wildfire in temperate Australia found that cat abundance declined substantially in burnt areas.

Consistent with the previous study of cat responses to severe wildfire, we found that cat abundance declined markedly in burnt sites, but showed no consistent change in sites that were unburnt. In contrast, changes in the abundance of the common brush-tailed possum Trichosurus vulpecula showed a less consistent pattern, although this species declined markedly (at a rate comparable to that shown by cats) at two severely burnt sites.

Although we found that cat density was reduced in burnt areas, the likely reduced populations of many native species in burnt areas, and the fire-caused reduction in vegetation cover, may mean that predation rates are no less post-fire than pre-fire, and if the population sizes of native species have been substantially depleted by fire, even small numbers of predation events may jeopardise persistence and recovery. Management that reduces predation pressure on wildlife surviving severe wildfires is likely to enhance the likelihood of their persistence and recovery.