|dc.description.abstract||The transition from a species introduction to an invasion often spans many decades (a lag phase).
However, few studies have determined the mechanisms underlying lag phases. Such a mechanistic understanding
is vital if the potential ecosystem-level impacts are to be predicted and the invasion risks to be managed proactively.
Here we examine Banksia ericifolia, introduced for floriculture to South Africa, as a case study.We found 18 sites
where the species has been planted, with self-sustaining (naturalized) populations at four sites, and an invasive
population at one site.The invasion originated from around 100 individuals planted 35 years ago; after several fires
this population has grown to approximately 10 000 plants covering about 127 ha. The current invasion of
B. ericifolia already has ecosystem-level impacts, for example the nectar available to bird pollinators has more than
doubled, potentially disrupting native pollination networks. If fires occurred at the other naturalized sites we
anticipate populations would rapidly spread and densify with invaded areas ultimately become banksia-dominated
woodlands. Indeed the only site other than the invasive site where fire has occurred regularly is already showing
signs of rapid population growth and spread. However, recruitment is mainly immediately post fire and no seed
bank accumulates in the soil, mechanical control of adult plants is cheap and effective, and immature plants are
easily detected.This study is a first in illustrating the importance of fire in driving lag phases and provides a valuable
example for why it is essential to determine the mechanisms that mediate lag phases in introduced plant species.
Serotinous species that have been introduced to areas where fire is suppressed could easily be misinterpreted as low
risk species whilst they remain in a lag phase, but they can represent a major invasion risk.||en