This is an issue under the Biodiversity theme of the Data Reporting System.
Fire is a characteristic of many Australian environments and many native species have adapted to established fire regimes. Fire occurs in most of the plant communities of Australia and is as much a part of the natural environment as wind, sun and rain. It has been among the driving forces in the evolution of the Australian fauna and flora. Where one fire alone may determine the response of an organism, consideration of the fire regime (i.e. type, frequency, season and intensity of a fire experienced at a specified location) is necessary to better understand responses of species and assemblages of species.
However, changes in fire regimes - more frequent or less frequent fires, hotter or cooler fires, fires at different times of year, etc - have the potential to produce rapid and permanent changes in species composition, population and distribution.
Changes in fire regimes may result from changes in species composition (eg replacement of native species with agricultural or non-native plantation species) or may be associated with broader changes of climate. Fire and other environmental factors, such as life-history stage, plant condition, fire edge to area ratio, and the post-fire environment, interact to modify the mosaic of landscape and biological patterns. The complexity of fires and the way they may change native ecosystems can still be detected 20 to 30 years after a fire event. Much is still to be learnt about the long-term effects of both single and repeated fires on natural ecosystems.
Changed fire regimes may result from humans deliberately or accidentally lighting fires, either as a criminal action, or in the course of fire or agricultural management. For example, the changes in habitat structure that come with the decline and elimination of woody plant species subjected to more frequent fire regimes have implications for many groups of biota. Prescribed fires and wildfires can affect biodiversity differently and a fire regime for one ecosystem is likely to have a different outcome to a similar regime in another ecosystem.
In environments that are subjected to a range of other anthropogenic pressures, even the normal fire regimes to which native species are adapted may prove devastating.
- BD-11 Area burnt by frequency, intensity and season of burning
The 2001 State of the Environment (SoE) report indicated that large areas are burnt each year in northern Australia. In southern Australia, fires deliberately lit for fuel reduction purposes are common. Changes in area showing up as burnt at various points in time is a direct indicator of changes in the extent of fire occurence. It does not show changes in timing, temperature or frequency of fires, or the range of other variables which could affect the impacts of fire on biodiversity.
- BD-12 Examples of the impacts of fires on biodiversity
As there is no continent-wide method of measuring changes that can be directly attributed to fire across all species and habitats, examples of changes that appear to be directly attributable to this cause is at present the only useful indicator of the pressure of fire on biodiversity.
- LD-24 Severe drought and wildfire correlation
Climate driven changes in fire patterns have significant implications for viability of vegetation types and for biodiversity more generally.
- LD-35 Temporal and spatial correlation between changing fire regimes and species change
Changes in fire patterns have significant implications for viability of vegetation types and for biodiversity more generally.
- Atmosphere - Air quality - Urban air quality
- Atmosphere - Air quality - Regional air quality
- Land - Direct pressure of human activities on the land - Species introduction and species change
- Land - Contributions and pressures between the land and the atmosphere - Climate
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