Global response for alien invasions Plants have no respect for boundaries. Nor, for that matter, do zebra mussels, crazy ants or Nile perch. When alien species invade, they wreak havoc on economies and ecosystems. Curbing the problem is an international task, says Harold Mooney, a Stanford University biologist who helped design a global plan to deal with the invaders. If we have a fire, then we send for the fire truck.
People respond right away.
Behind habitat destruction, alien invasion is the second greatest cause of species extinction worldwide, he says. The iwater hyacinth strangled the ecosystem and economics of Lake Victoria in Africa until a multimillion-dollar international control program went into effect, he says. Crazy ants formed supercolonies in the rain forests of Christmas Island, changing the habitat and preying on animals of the forest floor. In California, the alien star thistle out-competes native desert grasses. Currently there is no global network set up to deal with or prevent future ecosystem invasions.