Environmental Engineering Reference
In-Depth Information
moth
Euclasta whalleyi
) (Tomley 1998), both of which are now well established
across much of rubber vine's Australian distribution and result in periodic severe
defoliation, greatly reduced seed output, and, in at least some areas, signifi cant
mortality (Vogler and Lindsay 2002).
h is example illustrates many of the principles outlined above. h e attempt to
contain rubber vine is facilitated by broad recognition (if not quantifi cation) of its
impacts and the fact that there are few confl icting interests surrounding it. General
knowledge of the species' biology/ecology is good, eff ective management tech-
niques (e.g. biological control and burning) are available, and the distribution has
been documented. It is the target of a nationally-coordinated campaign that has
strategic goals. h is eff ort to counter the invasion by rubber vine began many dec-
ades after the species fi rst naturalized in Australia so it does not provide an example
of early intervention. Also, little overt consideration is given to the consequences of
there being many other invasive plant species in the same ecosystems.
fodder shrub in Australia
The South American shrub leucaena (
Leucaena leucocephala
)
was deliberately
introduced to Australia and widely cultivated for use by the northern Australian
cattle industry. It naturalized in many areas and is now also perceived to be an
environmental weed (Walton 2003). There are, as a result, confl icting interests
surrounding this species. Its status as a weed has not been recognized in legislation
though a Queensland State departmental policy statement considers the issue and
provides recommendations in relation to management of the species (Queensland
Government 2004). Currently, management of leucaena as an invasive species is
voluntary. A Leucaena Network has developed a code of practice (Queensland
Government 2004) designed to help reduce the risk of new infestations arising
from existing plantations. Any other attempts to deal with existing infestations
and impacts are dependent upon local motivation. The situation with leucaena
contrasts with that of rubber vine, a far less controversial invasive species. The
approach to leucaena as an invasive plant is less strategic and there is little govern-
ment funding. Leucaena also illustrates the challenges of containing commercially
important species that are legally cultivated on a very large scale in widely dispersed
plantations. The leucaena code of practice does not address problems associated
with the many growers who operate outside the voluntary code, nor the issue of
naturalized populations that existed before the code of practice was prepared. This
means that many infestations remain untreated.
in New Zealand
Invasive mammalian predators are major threats to native species and ecosystems,
particularly on islands that lacked similar native predators. In New Zealand, intro-
duced mammalian predators, including cats (
Felis catus
), brush-tailed possums
