Environmental Engineering Reference
In-Depth Information
biological control
Biological control has been used successfully to address some of the major invasive
species problems that have threatened countries or sometimes entire continents.
In natural ecosystems it is particularly appropriate as other control methods, such
as pesticides, may have a larger negative impact than the invasive species. Also, in
agriculture, there is a growing demand across the globe for pesticide-free crops and
biological control has been highlighted as a major means of providing ecologic-
ally safe management. Overall, the technology is particularly useful in develop-
ing countries where the needs for cheap and cost-effective management tools are
important as resources are limiting. An analysis of fi ve biological control projects
in developing countries showed the overwhelming benefi ts of those projects when
compared to the impacts and costs that the target species were causing (Cock
2002). However, it has been estimated that biological control has been used against
only about 5% of invasive species problems worldwide (Van Driesche and Ferro
1987) and the situation has not changed. A recent assessment of trends in bio-
logical control research and application suggest that there has been little growth
despite increased opportunities (Kairo 2005). This 'lack of adoption' is likely to be
due to several factors; as we have seen, the concerns about non-target effects have
made biological control implementation more diffi cult in some countries, but fac-
tors other than this are important.
In countries with long experience in biological control such as Australia, Canada,
New Zealand, South Africa, and the USA, national regulatory frameworks and
legislation for biological control are well advanced and many now have the involve-
ment of environment agencies in the assessment of agents process; this has been
brought about because of the greater awareness of the risks (see above) that all inva-
sive species (including biological control agents) might pose to natural ecosystems
(Sheppard
et al
. 2003). h ere is much variation between countries in the extent to
which the assessment processes meet a full ecological risk:benefi t-cost analysis. But
despite the benefi ts this has brought in terms of the broadening the consultation
process and criteria on which release decisions are made, it has lead to a greater cost
of eff ort and overall is at risk of reducing biological control initiatives (Sheppard
et al
. 2003). And regulatory restrictions, notably in the USA, have been enforced to
the extent that they 'have nearly eliminated classical biological control with exotic
pathogens of introduced insect pests' (Lacey
et al
. 2001).
In contrast, in many countries, especially in the developing world, there is no
national framework or responsibilities established for those who want to imple-
ment biological control. And with invasive species now high on the global agenda,
government organizations without experience of biological control have become
even more risk adverse. h e publication of the FAO Code of Conduct in 1996
for import and release of exotic biological control agents (FAO 1996) was a turn-
ing point as it provided important guidance for countries and this Code has
