Fire severity in a northern Australian savanna landscape: the importance of time since previous fire
Brett P. Murphy A D and Jeremy Russell-Smith B CA School of Plant Science, University of Tasmania, Hobart, TAS 7000, Australia.
B Bushfires NT, Northern Territory Government, Winnellie, NT 0822, Australia.
C Tropical Savannas Management Cooperative Research Centre, Darwin, NT 0909, Australia.
D Corresponding author. Email: brettpatrickmurphy@hotmail.com
International Journal of Wildland Fire 19(1) 46-51 https://doi.org/10.1071/WF08202
Submitted: 8 December 2008 Accepted: 30 July 2009 Published: 5 February 2010
Abstract
Using a detailed fire history collected over a 10-year period throughout a savanna landscape in northern Australia, we have addressed the question of whether fire severity, inferred from a semiquantitative fire severity index, increases with time since previous fire. There was a clear trend of fires becoming much more severe with increasing time since previous fire. Between 1 and 5 years following a fire, the probability of a subsequent fire being classified as ‘severe’ increased from 3 to 8% for early dry-season fires, and from 21 to 43% for late dry-season fires. It was clear that the strong increase in fire severity was not confined to the first 2–3 years following the previous fire, as previously suspected. These findings highlight the difficulty of reducing both fire frequency and severity in northern Australian savanna landscapes, as they imply that a negative feedback process exists between the two; that is, reducing fire frequency is likely to increase the severity of fires that do occur.
Additional keywords: fire intensity, fuel accumulation, tropical savanna.
Acknowledgements
We thank those who assisted with the fire-monitoring programs, especially the staff of the three national parks. We acknowledge the financial support of Parks Australia and the Northern Territory Parks and Wildlife Service. Brett Murphy was supported by an Australian Research Council grant (DP0878177). The comments of two anonymous referees greatly improved an earlier version of the manuscript.
Andersen AN, Cook GD, Corbett LK, Douglas MM, Eager RW, Russell-Smith J, Setterfield SA, Williams RJ , Woinarski JCZ (2005) Fire frequency and biodiversity conservation in Australian tropical savannas: implications from the Kapalga fire experiment. Austral Ecology 30, 155–167.
| Crossref | GoogleScholarGoogle Scholar |
Collins BM, Kelly M, van Wagtendonk JW , Stephens SL (2007) Spatial patterns of large natural fires in Sierra Nevada wilderness areas. Landscape Ecology 22, 545–557.
| Crossref | GoogleScholarGoogle Scholar |
Fernandes PAM, Loureiro CA , Botelho HNS (2004) Fire behaviour and severity in a maritime pine stand under differing fuel conditions. Annals of Forest Science 61, 537–544.
| Crossref | GoogleScholarGoogle Scholar |
Gill AM, Moore PHR , Williams RJ (1996) Fire weather in the wet–dry tropics of the World Heritage Kakadu National Park, Australia. Australian Journal of Ecology 21, 302–308.
| Crossref | GoogleScholarGoogle Scholar |
Russell-Smith J , Edwards AC (2006) Seasonality and fire severity in savanna landscapes of monsoonal northern Australia. International Journal of Wildland Fire 15, 541–550.
| Crossref | GoogleScholarGoogle Scholar |
Williams RJ, Wahren CH, Bradstock RA , Muller WJ (2006) Does alpine grazing reduce blazing? A landscape test of a widely held hypothesis. Austral Ecology 31, 925–936.
| Crossref | GoogleScholarGoogle Scholar |
Woinarski JCZ, Milne DJ , Wanganeen G (2001) Changes in mammal populations in relatively intact landscapes of Kakadu National Park, Northern Territory, Australia. Austral Ecology 26, 360–370.
| Crossref | GoogleScholarGoogle Scholar |
Woinarski JCZ, Risler J , Kean L (2004) Response of vegetation and vertebrate fauna to 23 years of fire exclusion in a tropical Eucalyptus open forest, Northern Territory, Australia. Austral Ecology 29, 156–176.
| Crossref | GoogleScholarGoogle Scholar |
