Underpinnings of fire management for biodiversity conservation in ...

Underpinnings of fire management for biodiversity conservation in reserves
When regimes change, the effects may take many iterations (a series of successive fires) to reveal
ultimate changes (Gill and Bradstock 1995a). For example, a change in greater dominance of the
native grass Themeda triandra compared with Cymbopogon plurinodis, another grass, occurred with
a program of frequent burning in South Africa. The new quasi-equilibrium took about eight fires to
be achieved in the 16 years of observation (Trollope 1996).
Our knowledge of the effects of fire regimes on the biota is growing, but is still at an early stage on
a national scale in Australia. For example, explicit knowledge of the immediate responses of vascular
plant species to fires is incomplete, although no recent census has been conducted. There is a wide
variety of information on the direct and indirect effects of fire on animals in a variety of habitats,
from streams to forest and desert. The complexity of the food web and the effects of fire regimes
on individual components of it is a challenge to our understanding. Computer simulation is one way
of exploring possible effects of a fire regime, including prescribed fires (e.g. Bradstock et al. 1998a,
1998b, 2005), especially in a time of dynamic change of climate, fuels or fire regime. Also, effects can
be examined empirically using long-term fire experiments that are, by necessity, dominated by lowintensity
prescribed fires (e.g. Tolhurst and Flinn (1992) provide a progress report on a range of studies
related to the effects of prescribed fires on forest plots in Central Victoria).
Text Box 3.2 Literature on the effects of fire regimes
There is considerable literature on the effects of fires on biodiversity. Bradstock et al. (2002) and
Abbott and Burrows (2003) are recent multi-author books that tackle the subject in Australia.
Whelan (1995) is an Australian text on The Ecology of Fire. In the USA, there are substantial
recent reviews of the effects of fires on fauna (Smith 2000), flora (Brown and Smith 2000) and
air (Sandberg et al. 2002). A range of topics is considered in depth in Forest Fires: Behavior
and Ecological Effects (Johnson and Miyanishi 2001). Bond and Van Wilgen (1996) give an
authoritative account of the effects of fires on plants, based on their South African experience;
while Goldammer and Furyaev (1996) report on Eurasian Boreal forests. There are a number
of commentaries on the effects of fires and fire regimes on various Australian animal species,
including invertebrates (Brown et al. 1998; and various chapters in Bradstock et al. 2002;
especially Whelan et al. 2002; Abbott and Burrows 2003 and Anderson et al. 2003).
Despite many advances in our knowledge of fire regimes and their effects throughout the world,
a conservation manager may still not know how local species in the local jurisdiction respond to
fire regimes. There may be a general lack of local information and answers from one area do not
necessarily apply to another (Williams et al. 1994). It behoves the local manager to observe effects
of fire regimes on the local environment in light of the literature, and thereby draw and record
conclusions.
Conclusion
Prescribed fires are fires lit by managers of landscapes for specific purposes under specific conditions.
These can be contrasted with other fires that are not for management purposes, and which may
be ignited by unauthorised people or lightning. In forests, fires prescribed for broad-area fuel
modification are generally of low intensity. In some places they may occur at shorter intervals than
unplanned fires and occur in different seasons. In other areas they may be relatively rare. In some
shrublands fires may burn with a high intensity whenever a fire will carry satisfactorily, and some
grasslands may be burnt in mild weather during the usual fire season.
There are various methods for assessing a prescribed burning program, such as cost, influence
on ease of suppression and ecological effects. Various possible performance criteria for assessing
prescribed burning programs may be devised. Effectiveness may be viewed at a number of levels, such
as the proportion of area burned, effect on fire suppression or immediate effect on the landscape.
The ultimate measure of a program is its contribution to management aims.
Fire and adaptive management 55