NSW Bitou Bush Threat Abatement Plan - Department of ...

Threat Abatement Plan - Invasion of native plant communities by Chrysanthemoides monilifera
northern New South Wales, from Port Macquarie to the NSW/Qld border (Moss pers. comm.), but
no data are available to determine the impacts. If data shows that V. betonicifolia is threatened by
bitou bush then any reduction in bitou bush should have positive outcomes for this species as well
as for the endangered butterfly.
Performance criteria for Action 6.1
< Establish a system to prioritise fauna species (or groups of species, e.g. waders) that are at risk
from bitou bush invasions.
< Develop research projects on the effects of bitou bush invasions on priority fauna species.
< Initiate these research projects during the TAP. The results of these works could then inform
subsequent Bitou TAP’s.
9.9 Objective 7: Effect of bitou bush control on fauna
Objective 7 Determine the effects of bitou bush control on fauna.
9.9.1 Action 7.1
Action 7.1 DEC will foster research into the effects of bitou bush control on fauna.
There have been a few studies on the effects of removing a weed from an ecosystem on fauna (see
review in Gosper 2004b), especially when the weed has become dominant and may have been so
for many years or decades. Weed infestations may change the density and/or abundance of fauna
as well as how they interact with their ‘new’ environment containing these weeds, and as such
they may be seriously affected if these weeds are suddenly removed. Some weeds may play an
important role in the conservation of some threatened species, e.g. the southern brown bandicoot
(see Regel et al. 1996), and thus their removal could further threaten them. The disturbance
involved in removing weeds may also affect many fauna species long after the actual control
event has taken place (e.g. from increased light, soil disturbance, trampling of the ground and/or
the effects of management techniques like fire). Also, some native species may take many years to
recover following control (i.e. Turner and Virtue in press). The vast majority of bitou bush control
programs, like those for most other weed species, have operated on the assumption that the
removal of the weed and restoration of native vegetation will result in improved habitats for
native species (see Downey submitted).
The techniques used to control bitou bush may also impact on fauna. For example, as has already
been discussed in Chapter 7, the surfactants used with some herbicides may have adverse effects
on some frog species. Information on such impacts is scarce. A preliminary list of the species
likely to be affected is presented in Appendix 10A. Some frog species (e.g. green and gold bell
frogs) are known to utilise bitou bush in their habitat, and the removal of bitou bush may therefore
have adverse effects especially during broad scale control programs (Wellington pers. comm.).
The draft green and gold bell frog recovery plan raises the concern that the control of bitou bush
with herbicide could pose a real threat to the species and warrants further investigation (NPWS
2003b).
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