Fire and The Australian Flora: A Review

SUMMARY Fire is a natural environmental variable over most of Australia. It is a unique environmental variable in that it: tends to be self propagating; occurs for extremely limited periods in any one locality; may have devastating effects; occurs over a wide range of environments and plant communities. In many ecosystems fire is a normal environmental variable. Its immediate effects on vegetation depend on fire intensity but longer-term effects depend also on fire frequency and season of occurrence. Using these three variables, various fire regimes may be defined. Species may be adapted to these fire regimes but not to fire per se. Interaction between fire and an adaptive trait may facilitate survival or reproduction of a species but this effect alone does not guarantee that the species is adapted to a certain fire regime—this depends on many characteristics of the life cycle. Much of the relevant Australian literature is concerned with adaptive traits while relatively little considers adaptations of species. A knowledge of species' adaptation is necessary if we are to predict species' behaviour under various natural or imposed fire regimes.