|Publication Type||Conference Paper|
|Year of Publication||2007|
|Authors||Scott, KA, Setterfield, SA, Douglas, MM, Andersen, AN|
|Conference Name||Proceedings of the 4th International Wildland Fire Conference|
|Date Published||13 -17 May, 2007|
|Publisher||Spanish Ministry of Environment, Madrid and Junta de Andalucia, Seville|
|Conference Location||Sevilla, SpainBarcelona, Spain|
Fire is a very frequent and extensive event in the tropical savannas of northern Australia. It has the ability to either directly instigate seed germination by breaking dormancy, or modify the physical environment in a way that enahnces seedling emergence from the soil seed bank. This study used a field sowing experiment to analyse the magnitude of Sarga intrans seedling emergence in different tropical savanna microsites and within different fire regimes of a manipulative fire experiment. Fire regimes were not a statistically significant factor overall in determining how many seedlings emerged in the field; biophysical factors such as canopy cover had a greater influence. At the start of the growing season 7 months after sowing, more seedlings emerged from areas away from the tree canopy than underneath it. In areas away from the tree canopy, and when seeds were sown on bare soil, the lowest number of seedlings emerged from unburnt plots. It is suggested that recent fire events remove competing vegetation, enhancing the number of seedlings that can emerge. However, having fire in the dry season before germination, rather than only in previous seasons, will result in some seed mortality and reduce the number of seedlings that later emerge. To some, S. intrans is regarded as a native weed where its distribution is thought to be expanding as a result of frequent fire. Leaving landscapes unburnt will limit the number of seedlings that emerge from the soil seed bank. 1 Bushfire Cooperative Research Centre, East Melbourne, Australia (www.bushfirecrc.com) and Faculty of Education, Health and Science, Charles Darwin University, Darwin, Northern Territory 0909, Australia. 2 Bushfire Cooperative Research Centre, East Melbourne, Australia (www.bushfirecrc.com) and CSIRO Sustainable Ecosystems, PMB 44, Winnellie 0821, Northern Territory, Australia.