Biological invasions can fundamentally alter the structure,
composition, dynamics, and function of natural
ecosystems (D’Antonio & Vitousek 1992). Direct and indirect
effects of some invaders can be so pervasive and
strong that they reconfigure entire interaction networks
(Schoener & Spiller 1999), cause state changes in ecosystems
(Maron et al. 2006), and may even lead to invasional
“meltdown” (i.e., synergism between invaders increases
the pace, magnitude, and variety of ecological impacts
and facilitates additional invasions by alien species; Simberloff
& Von Holle 1999).