THORNY PROBLEMS - Rethinking Invasion Ecologies from the Environmental Humanities - page 124

purpose of providing shade and fodder for the animals, they behaved differently in
a landscape grazed by cattle instead of sheep. As far back as 1926, the Queensland
Agricultural Journal observed that A. nilotica was likely to spread more vigorously
with cattle grazing, noting:
There, is, however, a drawback to this tree in cattle country, in that cattle
consume the pods, the seeds are not masticated and pass whole through the
digestive tract, thus causing numbers of young trees to appear where they are
not wanted.
(quoted in Spies and March, 2004)
Several other studies have supported this observation, noting that cattle and sheep
graze and process hard seeds differently. Sheep chew leguminous pods with hard
(acacia) seeds to a point that makes them unviable for germination when passed
through droppings. Cattle do not break down seed pods in the same way, which
results in more undigested seeds passing through the animal and remaining in the
dung until appropriate conditions for germination arise (Simao-Neto et al ., 1987;
Tiver et al ., 2001).
The second reason for the growing condemnation of prickle bushes was the shift
to more machine-reliant methods of mustering cattle. Mustering has long been the
most iconic representation of Outback Australian life, an activity that evokes
enormous pride and sense of identity for pastoralists in the region (March, 1995).
In the past, mustering was a labour-intensive logistical operation involving a large
number of stockmen on horseback, who rounded up cattle for drovers who would
to take them to stockyards for sale. But the new industrial pastoralism has largely
replaced horses with quad-bikes, motorbikes, 4WD vehicles, helicopters and small
aircraft for mustering cattle. Many pastoral properties have invested in such
equipment to manage large herds and muster cattle with fewer people. These new
machine-based mustering methods are more affected by the spread of prickle bushes
than mustering on horseback. Vehicle tyres experience substantial damage from the
long and sharp acacia thorns, and aerial mustering becomes more difficult when
cattle run into and hide in dense thickets of prickle bush. It is in this context that
prickle bushes have become the villains of pastoralism and targeted as alien invasive
species that need to be eradicated from the landscape.
Tackling prickle bushes
An old farmer went to a Landcare conference, an old fella, about 75, and he
went along and he stood up at the end of that conference and he said: 'I just
hope this Landcare works because I'm sick to death of poisoning the things
that want to live here and trying to raise the things that want to die.'
(Pastoralist A, interviews, 2007)
The rise of industrial pastoralism has added to the many pressures that affect the
viability of family-run pastoral businesses in northwest Queensland. Globally linked