Environmental Engineering Reference
In-Depth Information
challenges to attempts to contain or control it. The most effi cient strategy in such
cases is to focus control at locations of high conservation value that are not used for
cattle production (e.g. conservation reserves).
A diff erent approach could be taken with gamba grass (
Andropogon gayanus
)
another species used by the cattle industry in northern Australia. It is currently
less widespread, less important to the grazing industry, and probably has even
more serious environmental impacts, especially through its eff ects on fi re regimes
(Rossiter
et al
.
2003). Containment, or even local eradication, may not only be
possible with this grass but it may also be more desirable from an environmental
perspective and more socially acceptable. h ese two examples illustrate how posi-
tive and negative economic, environmental, and social factors interplay to deter-
mine whether containment or control are the more feasible option, and indeed,
whether any management action is likely to be worthwhile.
In this chapter, 'containment' and 'control' have been defi ned as management
strategies that seek to reduce the impacts of invasive species that cannot be erad-
icated on a broad scale. 'Containment' is management that specifi cally attempts
to restrict the distribution of an invasive species to a fraction of the range that it
would otherwise occupy, while 'control' tries to reduce impacts without necessarily
limiting distribution. Sound decisions in relation to these two options will depend
on the characteristics of the invasive species, the landscape that it is invading, the
management regime imposed on that landscape, and the resources that are avail-
able. Both strategies require an indefi nite commitment of resources. They also
demand some assessment of the impacts of the target species, and knowledge of
its biology, ecology, distribution, abundance, and responses to management. This
knowledge can be used to set priorities in terms of both species and the spatial
distribution of management effort. It is important to consider the multi-species
nature of many invasions, and failure to do so may result in an ineffective use of
resources. Regardless of the objective (eradication, containment, or control), the
earlier in the invasion process action is taken, the more effi cient and effective that
action is likely to be. Socio-economic factors are critical in deciding what is possible
by way of containment or control and what are the most appropriate approaches;
it is critical that any confl icting interests are resolved. Finally, it is important that
the consequences of the efforts are monitored so that approaches can be modifi ed
as the containment or control programme proceeds.
I thank Dane Panetta, Lynise Wearne, and Peter Williams for useful comments on
a draft of this chapter.
