Conservation Conflicts Over Burning Bush In South-Eastern Australia
David A. Morrison, Rodney T. Buckney, Belinda J. Bewick
Department of Environmental Biology and Horticulture, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
Geoffrey J. Cary
Ecosystem Dynamics, Research School of Biological Sciences, Australian National University, ACT 0200, Australia
Current fire management practices in the fire-prone vegetation of south-eastern Australia are based mainly on the concept of hazard reduction via the use of periodic low- intensity fires to maintain the amount of flammable fuel within specified (low) limits. We examined the possible conflict between the requirements of fire management for hazard reduction and requirements for species conservation in the dry-sclerophyll shrublands and woodlands of the Sydney region. Our data indicate that potentially severe fire hazards (fine fuel loads of >10 t.ha -1) can reappear in the woodland and shrubland vegetation within 2-4 years after low-intensity fires, such as are typical of the fuel-reduction burns usually prescribed. Our data also show that low-intensity fires will have significant effects on the species composition of the communities if they occur with an inter-fire interval of less than 7~8 years, causing a significantly reduced abundance of long-lived woody shrub species. There is thus a clear conflict in south-eastern Australia between fire management practices based solely on prescribed burning for hazard reduction and the fire management practices necessary to maintain ecosystem biodiversity, and this conflict is greatest for fire-sensitive shrub species. The conflict between these two vegetation management objectives cannot be resolved by a simple compromise, as prescribed fires with inter-fire intervals any greater than 4 years will allow a potentially severe fire hazard to exist, while a burning regime with any interfire intervals less than 8 years will result in loss of biodiversity. This conflict means that it will probably not be possible to achieve simultaneously both hazard reduction and species conservation for any specified managed area.