Fire Ecology
For millennia, fire has been a natural feature of many Australian environments, and a major driver of vegetation change. Some vegetation communities are well adapted to, and benefit from, regular fire, while other vegetation communities exist only because they are rarely burnt. Similarly, the effects of fire on fauna may be positive or negative, and direct or indirect, depending heavily on the scale and intensity of the burn.
Fire also has the potential to cause changes in aquatic ecosystems, particularly when a large volume of post-fire sediment is washed into rivers and streams. Large-scale fires in our alpine region have been historically infrequent, but two major fires have now occurred within four years. However, the ability of alpine vegetation and fauna to recover from fires in such rapid succession is relatively unknown.
Research into the responses of flora and fauna to fire, both planned and unplanned, and from a wide range of ecosystems, will increase our knowledge of the effects and role of fire management in those ecosystems.
Key projects
| Alpine Mossbed Assessment and Rehabilitation Alpine mossbeds, also known as bogs or peatlands, are rare in Australia, being mostly restricted to the highlands in the south-east corner of the mainland, and in Tasmania. They occur in areas of impeded drainage with the water table constantly at, or near, the soil surface, where a thick mat of peat moss (Sphagnum) and other species leads to the slow accumulation of peat. Mossbeds are sensitive to fire, and many have been burnt several times in recent decades, with particularly large areas being burnt in 2003 and 2007. Recovery of these mossbeds will be slow, and many that have been burnt, particularly those that have experienced multiple fires or a long history of grazing, will require active rehabilitation work. Without such work they may not fully recover. This is a cause of concern for research staff and land managers alike as mossbeds play an important functional role in water filtration and regulation. Long-term monitoring by ARI and La Trobe University has commenced in several demonstration sites to determine the rate and patterns of recovery of Sphagnum and other mossbed species. Early results show that recovery is very slow, and may require decades. Information gathered from this study will be important for the management of this rare vegetation community, and for informing future rehabilitation works. For more information, contact Arn.Tolsma@dse.vic.gov.au Page Top |    |
Survey for Threatened Alpine Stoneflies after the 2006-2007 Fires A survey of high altitude streams was conducted in February 2008 to try to locate two threatened stoneflies in areas affected by the 2006-2007 wildfires in the north-east and Gippsland regions of Victoria. Some of these areas had also been burnt in 2003 (link to past projects). Populations of the Alpine Stonefly Thaumatoperla alpina (restricted to the Bogong High Plains near Falls Creek) and Mount Stirling Stonefly Thaumatoperla flaveola (restricted to the Mount Buller-Stirling area) are potentially vulnerable to disturbances such as fire, due to their poor flight capability and limited distribution. Sediment washed into streams after fires can lead to smothering of aquatic habitat and direct toxic effects on nymphs (juvenile life stage). Loss of streamside (riparian) vegetation can lead to increased water temperatures which may limit the ability of nymphs to survive. The riparian vegetation also provides critical shelter and foraging areas for the terrestrial adult life stage and any damage or loss of this habitat may adversely affect the adult through increased predation, exposure to high temperatures and loss of food sources. Both species were found to be abundant in fire-affected areas during the surveys, with both nymphs and adults detected. This suggests that populations were not significantly impacted by the fires. Additionally, their presence in some sites which were affected by both the 2003 and 2006-2007 fires, indicate that they are able to survive multiple fire events. However, as there is very limited data on population sizes and trends, it is difficult to ascertain the status of current populations. There are other processes and threats occurring in these areas, such as drought, timber harvesting and the emerging threat of climate change that also have the potential to impact on these species, and may contribute to changes in population numbers. Regular surveys of these species, and threatened invertebrate species in general, would allow a more accurate assessment of population viability. For more information, contact Shanaugh.Lyon@dse.vic.gov.au The following report is available:  ARI Technical Report 179 - The response of threatened aquatic invertebrates to the 2006 fire in north-eastern Victoria (PDF - 2.2 MB)Page Top |    |
| Ecological Fire Regimes for Box-Ironbark Forest Remnants In Victoria, Box-Ironbark ecosystems occupy around 250 000 hectares of dry sclerophyll forest inland of the Great Dividing Range. They are home to a diverse range of flora and fauna species. However, since European settlement, these forests have been extensively cleared for agriculture, urban development, timber cutting and mining. Some large areas of public forest still remain, but privately owned vegetation often exists as small remnants of multi-stemmed regrowth with depleted understorey in areas of poorer soil, and this has had serious implications for ecosystem biodiversity. Box-Ironbark forests are considered not prone to recurrent fires, and the extent of previous indigenous burning is largely unknown. Nonetheless, based on evidence from similar vegetation types, it has been commonly assumed that ecological burning (as opposed to fuel-reduction burning) might be a useful tool for promoting germination of native flora species. This should improve the condition of degraded native vegetation remnants, enhancing flora species biodiversity and the vegetation structure that some fauna species need. ARI has recently completed a project with the North Central Catchment Management Authority that developed appropriate ecological fire management regimes in key remnants on private land. An extensive literature review was undertaken to estimate the effects of fire on Box-Ironbark flora and fauna (as this was largely unknown), determine appropriate fire intervals (also largely unknown), and establish protocols for assessing the need for fire in individual sites. The review showed that few flora species in Box-Ironbark forest require fire for germination. Most species should persist provided the inter-fire period allows all species to reach reproductive maturity (10 to 20 years), and will continue to be present even when the interval between fires exceeds 50 years. Some flora and fauna species are particularly sensitive to fire, such as the ground-foraging Brown Treecreeper which would be affected in the short-medium term after a fire by the reduction of litter, and Daphne Heath Brachyloma daphnoides which may face local extinction if burnt twice within 5-10 years. However, occasional fire may benefit some shrub species and maintain vegetation complexity. A management strategy was developed using the knowledge gained from the project. For more information, contact Arn.Tolsma@dse.vic.gov.au The following report is available: ARI Technical Report 192 -Towards a process for integrating vertebrate fauna into fire management planning (PDF - 1.9 MB)Page Top Please note: Document(s) on this page are presented in PDF format. If you do not have the Adobe Reader, you can download a copy free from the Adobe web site. |    |