Review of the management of feral animals and their impact on ...

Indigenous l<strong>and</strong>s
Indigenous l<strong>and</strong>s are unusual in being private l<strong>and</strong>s by tenure but public l<strong>and</strong>s by
<strong>management</strong>.
Aboriginal communities <strong>of</strong>ten come to value <strong>feral</strong> pests (camels, cats <strong>and</strong> rabbits) <strong>and</strong>
may oppose <strong>the</strong>ir control.
What don’t we know?
Lack <strong>of</strong> information emerged as a key <strong>the</strong>me for <strong>the</strong> workshop. The information gaps
fell into four main categories:
1. All too <strong>of</strong>ten we don’t know what <strong>impact</strong> <strong>feral</strong> <strong>animals</strong> are having. Very little is
known, for example, about <strong>the</strong> <strong>impact</strong>s <strong>of</strong> deer, camels <strong>and</strong> donkeys. We don’t
know enough about cats. Even among those species that are well-studied, major
information gaps remain. For example, <strong>the</strong>re is clear evidence that foxes suppress
certain rare species (e.g. rock wallabies), but that does not mean that foxes are
causing biodiversity losses everywhere <strong>the</strong>y occur. Unrealistic assumptions are
<strong>of</strong>ten made, for example that foxes threaten black cockatoos.
2. We don’t know enough about interactions between species. Do dingoes suppress
foxes or is that a myth? Do foxes help in some situations by eating rabbits which
might o<strong>the</strong>rwise eliminate rare plants? Does dingo control increase rabbit
numbers? How do overabundant kangaroos influence <strong>feral</strong> animal <strong>impact</strong>s <strong>and</strong>
contribute to <strong>the</strong>m?
3. There is too little monitoring <strong>of</strong> control programs. Baits are laid <strong>and</strong> pests die but
all too <strong>of</strong>ten without any quantified benefit to biodiversity. We are <strong>of</strong>ten unable to
say that this baiting regime delivers better biodiversity outcomes than some o<strong>the</strong>r
regime, because no monitoring is undertaken, or it does not last long enough.
Monitoring can be very difficult, e.g. how to count cats when <strong>the</strong>y are shy <strong>and</strong>
<strong>the</strong>ir numbers are low, <strong>and</strong> is thus expensive. And where biodiversity monitoring
is undertaken it is sometimes inconsistent between states. Because monitoring is
expensive, innovative monitoring techniques involving community observers
would be desirable, but community members are difficult to motivate <strong>and</strong> <strong>the</strong> data
<strong>the</strong>y submit might not be reliable.
4. While <strong>the</strong>re are many methods <strong>of</strong> control available, gaps remain. Protocols for
controlling deer have not been developed, cat control in some states ‘remains in
<strong>the</strong> too hard basket’, methods are needed for controlling rabbits at very low
densities, <strong>and</strong> better baits are needed for pigs.
Of <strong>the</strong>se four categories: 1 <strong>and</strong> 3 were emphasised strongly during <strong>the</strong> workshop. We
do not know enough about <strong>the</strong> <strong>impact</strong>s <strong>of</strong> <strong>feral</strong> <strong>animals</strong> on biodiversity, <strong>and</strong> we do not
know enough about <strong>the</strong> <strong>impact</strong>s on biodiversity <strong>of</strong> <strong>feral</strong> animal control. We <strong>of</strong>ten
operate on ‘best bet’ ra<strong>the</strong>r than ‘best practice’. Good results are <strong>of</strong>ten achieved
despite lack <strong>of</strong> precise information, but all too <strong>of</strong>ten control efforts are wasted.
Some comments
The workshop was undertaken largely to help guide DEH funding into pest
<strong>management</strong>.
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