Over the past several decades, the field of invasion biology has rapidly expanded as global trade and the spread of human populations have increasingly carried animal and plant species across natural barriers that have kept them ecologically separated for millions of years. Because some of these nonnative species thrive in their new homes and harm environments, economies, and human health, the prevention and management of invasive species has become a major policy goal from local to international levels.

Yet even though ecological research has led to public conversation and policy...