Human Introduction and Dissemination of Invasive Species
The introduction of species into new environments has occurred throughout human history. Over the last century, however, the rate of new introductions has exponentially increased as a function of human population growth and the globalization of trade. While most introductions fail and most of those few that establish remain environmentally innocuous, a notable minority wildly proliferates in their new ranges. These invaders disrupt ecosystems and burden economies. Environmental impacts associated with invasions are hard to predict and vary in space and time but include ecosystem-level disruptions, species extinctions, and the homogenization of biodiversity. Economic costs, while challenging to quantify, are enormous and growing. Given that established invaders are difficult to eradicate, let alone manage, stopping invasions before they start remains the most effective strategy to limit further costs resulting from invasions. Challenges to implementing this approach include regulating trade and coordinating rapid governmental responses to emerging threats.