Fire is a key element of the Australian landscape, and has shaped the evolution of species and ecosystems since the continent first formed. Many plant species are adapted to regenerate after fire, and even rely on fire to trigger the release of their seeds. On the other hand, fires that are to frequent or intense can also seriously damage sensitive ecosystems.
The impact of fires on the landscape is determined by the fire regime, which is the complex interaction between three factors:
- Fire intensity – A fire’s intensity is a measure of the energy emitted during a burn, or ‘how hot it is’. The intensity of a fire is in turn influenced by wind speed, slope, temperature, humidity and fuel characteristics. The greater the intensity of a fire, the greater the damage which can potentially be done to native plants and animals.
- Fire frequency – Fire frequency refers to how often an area is burned. Some areas of native vegetation, especially around human businesses, settlements and infrastructure, are burned frequently with low intensity burns to reduce fuel loads. Frequent burning such as this can encourage ‘fire living’ species which add to fuel problems
- Fire season – The season in which a fire occurs also affects the likely impacts, as different plants and animals are likely to be at more or less sensitive parts of their annual life cycle. Also, fires in hotter months tend to burn more intensely and produce greater damage.
Variations in any of the elements of a fire regime will change the way that native species respond to the fire, and can have immediate, dramatic effects on native ecosystems and wildlife. In the longer term, altered fire regimes can change the types of species present in an area and affect the way that future fires behave in the area. Today’s fire regimes are significantly different to the natural fire regimes of the past due to planned burning or manual fuel removal, which is often carried out in order to suppress the danger of large fires. In addition, some invasive plant species, particularly grasses, are greatly increasing the fuel available for fires, thus increasing their frequency and intensity. Climate change is also affecting when and how native vegetation burns.
Fire in the GER corridor
Within the GER corridor, there have been significant alterations to fire regimes. Some areas of rainforest, such as the Gondwana rainforest communities in northern NSW, contain many fire-sensitive species and are threatened by increasing fire frequencies. Over time, these habitats may shrink significantly and be replaced by more fire-tolerant species and ecosystems. Regular and extensive hazard reduction burning is carried out in parts of the corridor to protect human livelihoods, property and life in large rural and peri-urban populations.
GER works with public and private land managers to implement long-term fire management that protects environmental and cultural values, as well as human life and property. Restoring connectivity across the landscape also plays an important role in helping native species and ecosystems cope with the effects of changed fire regimes. Animals are more likely to survive if they are able to move across the landscape to unburnt areas, either during or after fire events. Habitat linkages can also allow individuals from other populations to recolonise burnt areas, even if the original population has been seriously reduced or completely eliminated.