Biodiversity publications archive

Biodiversity and Fire: The effects and effectiveness of fire management

Proceedings of the conference held 8-9 October 1994, Footscray, Melbourne
Biodiversity Series, Paper No. 8

Biodiversity Unit
Department of the Environment, Sport and Territories, 1996

Introduction

The National Strategy for the Conservation of Australia's Biological Diversity recognises the importance of fire management for biodiversity conservation, and inappropriate fire regimes are recognised in the Strategy as a key threat to Australia's biodiversity. Fire management potentially affects more flora and fauna, both on publicly and privately owned land, than any other management practice. These effects can be positive or negative.

Biodiversity and Fire: the conference

The Biodiversity Unit funded, through the Victorian National Parks Association (VNPA), a two day conference "Biodiversity and Fire: the effects and effectiveness of fire management", on 8 to 9 October 1994. The conference was co-sponsored by the Victorian Department of Conservation and Natural Resources (DCNR). This paper consists of the Proceedings of the Conference.

The conference was an unqualified success, with more than 300 people attending, from Western Australia, South Australia, Queensland, New South Wales, Victoria and the ACT. Delegates represented research institutions, conservation and land management agencies, fire control organisations, conservation NGOs, and the general public.

It was seen as a particularly appropriate time for such a meeting, in the aftermath of the major NSW fires in January 1994, and given the public review of fire management being conducted by the DCNR. The conference dealt with a broad range of concerns relating to fire management in temperate Australia, including the effects of fuels on fire behaviour, the effects of fire management regimes on flora, vertebrates and invertebrates, fire protection of humans and human property, and the integration of fire protection and biodiversity management. The atmosphere at the entire conference was cooperative and very positive, with a general agreement on many issues, and marked scientific rigour during the discussions.

The Conference dealt with the following issues and concepts:

Fire regimes

The general acceptance of these ideas at such a broadly representative conference is a noteworthy achievement, and marks a significant step forward in perceptions of fire management regimes.

Integration

These ideas place this conference at the cutting edge of the fire management debate, and have the potential to make a major contribution to the assessment of recent major fire events.

Knowledge

The general acceptance of this principle is another significant step forward for the understanding of the interrelationship between biodiversity and fire.

Current practice

It is of great significance that land managers are now seeking to incorporate ecological requirements into their fire management plans, and also that rancour was absent from the conference.

The proceedings

The papers are in the same order as at the conference and are presented as submitted with only minor editorial changes. A transcript of the questions and answers follows each paper where time permitted audience discussion.

The first session looked at the physical side of fire including relationships between various fuel parameters and fire behaviour (Phil Cheney), the rate of fuel accumulation following fuel reduction burning in different seasons (Kevin Tolhurst) and effects of different intensities of fire (Dianne Symonds). Significant findings included that autumn burns reduced litter fuels longer than spring burns, that litter levels accumulated more rapidly following a low intensity fire and that bark and shrubs were important components of the fuel complex. It was concluded simple direct relationships cannot be applied to all fuel types and further research is required to better predict fire behaviour and the duration of benefits from fuel reduction burns.

The second session explored interactions between fire and flora. It encompassed effects on biodiversity (Malcolm Gill), computer modelling to predict long term effects of prescribed fire (Brian Lord), complexities of heathland management (David Cheal), fire as a management tool to counter woody weed invasion (Andrew McMahon) and the effects of prescribed burning in dry sclerophyll forests (Mark Neyland and Kevin Tolhurst). It was demonstrated that relationships between fires, fuels and ecosystems are varied and complex, and better knowledge is required for most organisms even in relatively well studied communities such as heathlands. Potential recovery of heath from woody weeds through use of fire worked better with more recent invasions. For dry sclerophyll forests, a single spring or autumn burn seemed to have no lasting effect, but frequent rotational burning appeared detrimental in the long term to nutrient cycling and flora and fauna, especially longer lived and slower reproducing species. Spring burning had a longer impact on soil invertebrates and the decomposer cycle and unburnt patches were important to assist biodiversity conservation. Computer modelling using already available data can help in relation to management goals, especially where conservation is a major consideration.

[Kevin Tolhurst's paper dealt with flora and fauna issues, and for the Proceedings, has been spilt into two separate papers. Note that the discussion on flora is found after the second Tolhurst paper, which has been inserted in the section "Effects on Vertebrates".]

The response of vertebrates to fire was reviewed in the third session (Barbara Wilson) together with the use of predictive modelling including population viability analysis (PVA) to predict consequences of different fire regimes and assess options for rare fauna management (Hugh Possingham). Small mammals were considered to be highly predictable from life history patterns, reptiles are less so, with data for amphibians largely lacking. Implications of current fuel reduction practices and possible incorporation of ecological burning practices into fire management planning were discussed including the use of zones with burning regimes for different purposes. Modelling using data from the southern brown bandicoot, a threatened species in South Australia, suggested that a longer average fire-free period is required than is obvious from the data and that variety of fire regime is of value.

The fourth session examined effects of fire on invertebrates in mallee-heath shrublands (Gordon Friend), in dry sclerophyll forest subject to frequent prescribed burning (Alan York), in mountain ash forests following wildfire (Robyn Coy), and on soils in Victorian dry sclerophyll forest (Ross Hall). A key finding was that if invertebrate samples were only classified to Order level, results were highly variable and classification to species or morphospecies level is essential to properly elucidate changes due to fire. Research on ants presented clear evidence of community changes in response to some fire regimes; with frequent fuel reduction, rarer species with more specialised requirements tended to be replaced by species with broader environmental tolerances. In mountain ash forest, fire intensity was found to affect the rate of recovery of soil invertebrates. Most taxa appeared to recover within 11 months following wildfire but Crustacea, particularly Amphipoda, were the most adversely affected. The study on soils indicated that erosion hazard was increased, significant nutrient movement occurred and that some important physical properties were affected following a fuel reduction burn. Volatilisation and disruption of litter decomposition by regular fire may also affect nutrients. Overall the speakers identified a number of potential invertebrate indicator groups and a need for care in the application of high frequency and large scale fire regimes.

Repeated themes amongst many of the speakers on flora and fauna were firstly that, given the current lack of knowledge relating to many groups, a variety of fire frequency, intensity, patch size and burn season, within the known tolerances of particular habitats, will help maximise biodiversity retention, and secondly that initiation of prescribed burns for ecological purpose must be better facilitated to be more in line with fire protection burn procedures. Thirdly, the need was emphasised for flexibility so that burning plans can be changed in accordance with changed circumstances or climatic variations rather than simply conducted according to rigid scheduling of season and frequency.

Fire protection needs and effectiveness were discussed in the fifth session including statutory and practical aspects of fire prevention and suppression (Rod Incoll), use of the "Wildfire Threat Assessment Program" to model likely fire impact and plan fire protection (Mark Garvey), and a challenging talk on the assumptions behind prescribed burning in forests (Charles Meredith). It was suggested that more information is needed on the costs and benefits of fire management practices including duration of effectiveness and whether sufficient coverage and frequency is achievable, that better understanding of natural fire regimes may enable mutual benefits where ecological needs and fire protection overlap and that computer modelling can provide the information to assess proposed residential development and avoid future problems.

The final session looked at the critical area of resolving conflict between fire management and biodiversity protection. Possible mechanisms included local management plans to better integrate burning for fire protection purposes with ecologically based fire regimes and species requirements (Michael Wouters), and the "Community Fireguard" program to involve local residents in the development of bushfire survival strategies that maximise protection of environmental assets of private land in the urban-forest interface (Jon Boura). Practicalities that need to be considered when planning burns for environmental purposes were explained (John Fisher) and the need emphasised for fire management planning to be based on a clear understanding of ecology, fuels, and proper hazard and risk assessment (Roger Good). Speakers emphasised the need for adequate pre-burn and post-burn monitoring to assess the achievement of objectives and improve understanding of fire behaviour and ecological effects, and the general need for more research and communication between researchers.

From many of the speakers throughout the conference, it is apparent that fire management is changing to take into account ecological requirements. The use of zonation to encompass burning regimes for different purposes, sufficient flexibility to deal with changed circumstances and climatic conditions, and the use of local management plans to better integrate burning for fire protection with ecologically based fire regimes and species requirements are the way of the future.

The final section of these proceedings includes a summary of the points raised from the audience at the conclusion of the final day of the conference. Some of the stronger themes included the importance of more research including invertebrate studies, the need for ecologically based fire management planning, including better facilitated environmental burns, and the need for better communication between scientists, land managers and the public.

The workshop

A workshop involving interested conference participants, was held three weeks after the Conference, to examine possible solutions to problems identified during the Conferenece. While attendees were from Victoria, many of the issues discussed have broad application in temperate Australia, and are presented with a series of recommendations, in Appendix 1 of this publication.