The next two Landsat scenes I include in the category of The Desperate.
Charleville and Bollon are areas of rangelands in southwest Queensland that,
after a century or so of pastoral use, are now so degraded that the landuse
is not sustainable. The background to this problem area is well described
in Chapter 4 of the book 'Recovering Ground': see Additional Reading.
The landcover is the semi-arid Acacia woodlands, the Mulga Country, which
has been grazed by sheep since occupation by European Australians. The degradation
of these landscapes can take many forms. The most common is actually an
increase in the amount of vegetation; a situation that does not easily fit
the commonly held view of degradation.
The key lies in changes in the fire regime. The open grassy mulga woodlands
that were so prized by the early pastoral settlers have changed into dense
woodlands with an understorey of shrubs but no grass. The open grassy woodlands
were only maintained by episodic fire, lit either by lightning or Aboriginal
Australian hunter-gatherers. With pastoral occupation, the grass fuel was
all eaten and fires suppressed. Over the decades, the woody component of
the landcover increased and further suppressed the growth of grass, lowering
the probability of fire thinning back the woody species and encouraging
the grass.
The situation was exacerbated by the edibility of the mulga tree. As the
pastoralists allowed the grass component to be eaten out, they created increasingly
frequent 'droughts'. These were temporarily overcome by cutting down the
mulga for sheep feed. This process, aided and abetted by government agencies,
kept sheep grazing pressure on an already bare landscape. Keeping up the
grazing pressure on an already stressed landscape ensured that soil erosion
was at a maximum and the probability of the recovery of the grass pasture
at a minimum.
