Fire and land use
The most significant land use in the Mitchell Grassland is
cattle grazing and this is reflected in the approach to fire by
land managers. Of particular concern is the effect of fire on
native pastures. This relationship is still poorly understood, so
many land managers are hesitant in their use of fire as a
management tool.
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This 1999 satellite photo, centred on the
Mitchell Grasslands which run from the top left to the lower right
of the image shows few fires occur in the region. Blue regions show
fire from early in the year; red shows late fires—often
accidental wildfires
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In general, fire is excluded from Mitchell grasslands by
pastoral management so as to maintain forage throughout the dry
season. As a result this region of the tropical savannas probably
has the lowest rate of intentional, and managed, fires of any of
the regions. The majority of fires are accidental, often started by
lightning strikes. These fires can cause serious damage,
particularly after a series of good seasons when fuel loads are
high.
Burning as a management tool
For those concerned with the overall health of the region, there
is a consensus that greater controlled burning is required. There
is evidence that a judicious use of fire can increase tiller
production and therefore total grass yield as long as seasonal
conditions are favourable. (Scanlan 1980) Burning also promotes
seeding in Mitchell grass and, in the absence of grazing, may act
to maintain the dominance of Mitchell grass and keep invading
species at bay.
These positive outcomes of burning mitchell grass depend upon
seasonal rainfall—if the rains fail, then burning can have
distastrous results. Of all the savanna regions, the Mitchell grass
country is the one most prone to unseasonal weather fluctuations.
This translates into greater vulnerability overall for land
managers; that is, slimmer margins for error in land-management
decision-making. However, the ever-increasing invasion of woody
weeds into much of this country may soon compel land managers to
adopt fire as part of their pasture management regime.
At present the costs of burning for pastoralists, both in terms
of spelling required to allow fuel levels to build up, as well as
possible short term losses in animal production while grasses
recover, remain unclear. These uncertainties, in addition to
climatic variability, means that controlled burning is likely to
remain uncommon in the region until research and extension has
demonstrated that benefits outweigh costs.
