物种入侵会破坏环境?

At Point Reyes National Seashore in Marin County, California, a plant called Tidestrom’s lupine is holding on for dear life. Its survival has been threatened by the appearance of another plant, an invasive species called European beachgrass. So, does the beachgrass simply outcompete the lupines for land and light? Not at all, according to researchers at Washington University in St. Louis.

Tiny deer mice have a taste for the seeds of the lupines. These critters would ordinarily think twice about approaching the plants. Because exposed out on the sand, they’re easy pickings for birds interested in a rodent repast. But the beachgrass provides excellent cover. The mice use the grass to get close enough to pilfer seeds before any hungry birds pilfer the mice. The research appears in the August issue of the journal Ecology.

The information may be useful for a proposed dune restoration project. And the unexpected consequences of the invading species bring to mind this well-known comment by ecologist Aldo Leopold: “To keep every cog and wheel is the first precaution of intelligent tinkering.”

—Steve Mirsky