While some invasive exotics display a propensity for rapid range expansion, not all biological invasions proceed rapidly from introduction to range expansion.   Many invaders, especially long-lived woody perennials, have long establishment phases which may initially obscure their potential to radically alter forest ecosystems.  One such invader is the ubiquitous ornamental shade tree Acer platanoides.

Results/Conclusions

Research on an insular population of this species on Mackinac Island has provided valuable insights into the invasion ecology of this as well as other “slow” invaders.  These invaders benefit from their apparent innocuousness during early invasion stages; allowing them to build up large sapling banks in forest understories proximate to source populations.  These sapling banks respond readily to release and can result in rapid transitions to invasive dominance following canopy disturbance.  Effective risk assessment requires a long-term perspective on lag-phases as they relate to both “fast” and “slow” invaders.