Underpinnings of fire management for biodiversity conservation in ...

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The fire-management concept – within the context of biodiversity conservation – is that track
networks, fire-suppression capacity and potential fire behaviours need to be considered together,
not alone, and in relation to the short- or long-term risk of extinction of plants and animals. Factors
that limit track effectiveness need to be addressed in the short- and long-term – e.g. funding, terrain,
environmental effects, equipment and knowledge.
Conclusion
Tracks and roads are seen as an integral part of any bushfire-fighting infrastructure, but they have
indirect and direct effects on the environment, including biodiversity. In short, these adverse effects
may relate to: drainage lines, erosion and sedimentation; native animals and plants; weeds, diseases
and feral animals; and unwanted ignitions. How can tracks be kept to a minimum and negative
impacts ameliorated? A first premise in examining this question is that suppression effectiveness
is maximised by high accessibility. When a grid of points is used to define a model area, the shape
of the shortest (cheapest?) model track network to reach all these points can be described. Having
done so, it becomes clear that factors other than access (e.g. fire fighter safety, ease of burning out
blocks and continuous perimeter protection) need to be considered. To accommodate these matters,
model networks can be revised to include perimeter tracks that define a series of areas of land suited
to prescribed burning. Tracks vary in their characteristics, width being particularly important to the
effectiveness of suppression in grassfires and for traffic flow during fires.
If aerial suppression is possible, are tracks needed at all? In forests, aircraft can construct control
lines at about half the rate of bulldozers and cost something like an order of magnitude more
per kilometre. Bare-earth breaks of some sort almost invariably accompany wet lines laid down
by aircraft as they only provide a temporary holding function for fire spread. Bare-earth perimeter
tracks around fires are usually necessary to prevent rekindling of the fire and further outbreaks.
From a biodiversity point of view, it would be a mistake to think that aerial suppression can have no
adverse effect, as effects of fire suppressants and infrastructure on the ground can be significant. All
methods of suppression have limitations. No system is totally effective unless it is a complete bareearth
system – an impractical, nonsensical extreme. For suppression alone, the concept is that track
networks, suppression capacities and fuel modification need to be considered in concert with the fire
characteristics expected. For the best possible outcomes, suppression operations need to be addressed
in relation to land management objectives.
There is no single simple answer to the question ‘What is the length of track is suited to fire
management of a reserve?’, partly because length is not the only criterion for the establishment of
a track network. Other criteria include: the activities that are to be serviced by tracks (e.g. access
to beauty spots, access to fires, egress from fires, prescribed burning, fire suppression, servicing of
boundary fencing and feral-animal control); the safety context of tracks (e.g. for firefighters, general
road users and park rangers); the establishment and servicing cost-implications of the track network;
and the limitations to local track networks imposed by the terrain (e.g. swamps, rivers, estuaries,
gorges, ridges and sand drifts).
Fire and adaptive management Underpinnings of fire management for biodiversity conservation in reserves