According to a new study, animals and plants that are introduced to nonnative habitats and thrive, pressuring the ecosystem that developed there in the first place, have done $423 billion in damage. But there’s still more that’s unknown. The World’s Marco Werman talks with Laura Meyerson, a professor in the department of natural resources at the University of Rhode Island, where she focuses on invasive species, and she’s one of the authors of these new findings about the global costs.