Fire
Fire in Savanna Woodlands
Bushfires have become more intense and frequent since european colonisation of northern Australia, and some of the wildlife is suffering. We need to manage fire more actively across the entire savanna region.
 A mild fire has little impact on wildlife |
Bushfires Then and Now
The indigenous people of the NT manage fire actively, either to aid hunting, or to look after the health of the country. Since european colonisation, there has been a reduction in this management because, in many areas, people are not living so actively on country and may be less likely to travel around their country.
The regime of bushfires that occur in the savanna woodlands has shifted from one dominated by mild fires mostly lit early in the dry season, to more intense fires later in the dry season. Fires have also become larger in area, and most places now burn more frequently that they used to. Another way to view the fire regime is as a mosaic of patches in the landscape, each with a different history of fire. Where these patches used to be small and variable, they are now larger and more similar.
 Intense, late dry season fires can kill many trees |
The Threat
The fauna and flora of savanna woodlands has evolved with fire: fires of themselves do not pose a great threat. The problem is the long-term change in the pattern, and it affects wildlife in complex ways:
- Some species are killed by intense, late dry season fires.
For example, the cypress pine (Callitris intratropica) has declined in many areas due to fire-death. Many rainforest boundaries are retreating because of intense fires. Many invertebrates, mammals and reptiles are killed by intense fires. - Some species need long fire-free intervals to complete their lifecycle. Many shrubs in the Arnhem Land Plateau need at least five fire-free years to seed.
- Some need a fine-scaled mosaic to provide food and shelter through the year. The frill-necked lizard, partridge pigeon and many mammal species are in this group.
- The composition of plant species changes, and this can affect animals that rely on a particular one that is declining. Intense regular fires promote Sorghum spear grasses at the expense of other grasses such as Alloteropsis semialata. The endangered Gouldian Finch relies on Alloteropsis for food in the early wet season, so changed fire regime may be the reason for the bird's decline.
- Some animals are lost or escape from burnt areas and return as the vegetation recovers. If the fires are large, the chances of escape are less, and the time to return will be greater.
What Can We Do?
There is now a consensus among scientists and indigenous people that we need to return fire regimes to something closer to the traditional practises. This will be difficult because it needs lots of people to be in remote parts of the Territory lighting fires early in the dry season, when the ground is still quite wet. It may be achieved by providing the resources for local indigenous communities to return to more active management. It may not be possible to change fire regimes everywhere. For example, many pastoralists prefer hot late dry season fires, to control vegetation thickening, and many rural landholders try to exclude fire altogether. In these circumstances, there is probably room to reach some compromise that is good for the landholders and the wildlife.
Read more about this publication... One word of warning. We do not fully understand the complex role of fire in shaping animal and plant communities, and the information given here is only the current state of our knowledge. We also need to conduct research and be prepared to change our management as our knowledge improves.
Further Reading
The book 'Savanna Burning' gives an excellent description of the issues relating to bushfires from many different perspectives. Full details: Dyer, R., Jacklyn, P., Partridge, I., Russell-Smith, J., and Williams, R. (2001). Savanna burning: understanding and using fire in northern Australia. Tropical Savannas CRC, Darwin.
