Plants and animals which get imported from other locations, known as “exotics,” can sometimes dominate new ecosystems that do not have the necessary predators, or other checks and balances, in place to protect against them. Invader species can threaten biodiversity by killing off the other species in their path. Chris Bright of the World Watch Institute, has written a new book called “Life Out of Bounds: Bioinvasion in a Borderless World.” Steve Curwood speaks with Mr. Bright about how contemporary travel and technology have increased the odds of such exchange and contact.