INTRODUCTION
One of the greatest threats to global biodiversity is
species invasion. Biological invasions have been
considered to be one of the three most difficult environmental
problems in the world. Mikania micrantha
H.B.K., a climbing perennial weed of the family Asteraceae
native to Central and South America, has been
listed as one of the 100 worst invasive alien species in
the world (Lowe et al. 2001). The distribution of the
plant in Australia has been reviewed by Day (2012)
and the species has been put under high alert (Class
1 species) since 2002. The plant was introduced in
Indonesia as ground cover in the 1940s and then spread
to the Pacific islands, south-east Asia and New Guinea
(Waterhouse 1994) and is now one of the worst exotic
weeds in southwest and south Asia (Zhang et al. 2003).
In Asia, M. micrantha is known to be particularly
problematic in plantation crops, but also threatens
natural areas and disturbed ecosystems. After establishing
itself in a new habitat, the plant kills all the
other plants by smothering them and thus effectively
reducing light beneath its canopy (Huang et al. 2000).
Due to its high spreading and establishment capacity,
the plant has the ability to be a potent threat to a nation’s
biodiversity as well as its economy. In south
China, the plant causes problems to tropical fruit trees