No place on the planet is truly isolated anymore, which means invasive species travel as easy as humans, hitchhiking on boats and planes with potentially devastating effects on the ecosystems they land in.

According to UC Berkeley insect ecologist Rosemary Gillespie, we are basically putting biodiversity in a blender and seeing what comes out.

Invasive non-native trees, for example, can silence forests once humming with bird and insect diversity. Alien insects can take over, she said, as happened in Tahiti when an obnoxious pest ravaged trees to the extent that feces rained down on residents.

Gillespie, a professor of environmental science, policy, and management and director of the Essig Museum of Entomology, studies islands to discover the secrets of a successful mix of species and clues about how to intervene when invasive species drop in to upset the balance.

“We want to see what makes a community stable to intrusion from outside,” she said in May during a talk at the Cal Future Forum.

These islands are microcosms of larger ecosystems, she says, and can tell scientists how to take the pulse of larger ecosystems.

In her 6-minute talk, Gillespie discussed the complex networks at play on islands and how what she learns could be applied more broadly.

—Robert Sanders