Environmental Engineering Reference
In-Depth Information
that matter abandoned, if it is found to be ineffective. Monitoring could attempt
to document changes in the distribution and/or abundance of an invasive species,
or changes in components of the system it is invading. In the latter case, monitor-
ing should focus on those elements known to be affected by the invasive species.
Invasive species other than those targeted could be monitored to assist in under-
standing whether control of the target species facilitated population growth or
range expansion of others. Well-designed monitoring programmes will contribute
to knowledge of the impacts of particular invasive species, and of the value of the
containment and control programmes used to help manage them.
Rubber vine (
Cryptostegia grandifl ora
) was introduced to Australia from Madagascar
as an ornamental shrub/vine in the late 1800s. In the 1940s it was also grown
experimentally in plantations as a possible source of commercial rubber. It is now
widely naturalized. Its current distribution occupies a large part of tropical north-
eastern Australia but it is predicted to have a potential range covering 20% of
the northern half of the continent. The species is problematic from two perspec-
tives: it forms dense stands that out-compete native species, radically changing the
structure and composition of the vegetation and having fl ow-on effects for other
components of invaded communities; it is detrimental to grazing industries that
rely on these systems because it replaces plants that are palatable to cattle, is toxic
to livestock, interferes with animal husbandry, blocks access to water, and harbours
invasive animals such as feral pigs. Rubber vine is especially prevalent in riparian
zones and other low-lying parts of the landscape (Tomley 1998).
Rubber vine is universally recognized as a problematic plant and has been
declared a 'Weed of National Signifi cance' in Australia's National Weed Strategy
(h orp and Lynch 2000). h is status prompted and facilitated the development
of a national strategy for the management of rubber vine involving considerable
funding support from the Commonwealth Government of Australia, coordin-
ation by a department of the Queensland State Government of on-ground action
by multiple stakeholders, as well as research and education activities (QNRME
2004b). A key objective of this national strategy has been to contain rubber vine
within its current distribution in north Queensland. h is aims to prevent the
westward spread of rubber vine into extensive areas of potential habitat. Eff ort
has focused on the southern and western areas of the species' Australian distribu-
tion. It has required detection of infestations outside the designated containment
line and targeting those infestations for control. Previously unknown infestations
were located in Western Australia and the Northern Territory, well outside the
containment zone and have been the target of control operations. Prior to the
development of the national strategy, biological control research was undertaken.
h is yielded two biological control agents (the rust
Maravalia cryptostegiae
and the
