Turning to Darwin to Solve the Mystery of Invasive Species

Carl Zimmer in the New York Times:

ScreenHunter_835 Oct. 14 16.09Invasive species are both a fact of life and a scientific puzzle. Humans transport animals and plants thousands of miles from where they first evolved — sometimes accidentally, sometimes intentionally. Many of those species die off in their new homes. Some barely eke out an existence.

But some become ecological nightmares. In the Northeast, emerald ash borers are destroying ash trees, while Japanese barberry is blanketing forest floors, outcompeting native plants. Scientists aren’t certain why species like these are proving superior so far from home.

“If natives are adapted to their environment and exotics are from somewhere else, why are they able to invade?” asked Dov F. Sax, an ecologist at Brown University.

A big part of the answer may be found in the habitats in which invasive species evolve. Many alien species in the northeastern United States, including the emerald ash borer and Japanese barberry, invaded from East Asia. But the opposite is not true. Few species from the northeastern United States have become problems in East Asia.

In a new study published in the journal Global Ecology and Biogeography, Dr. Sax and Jason D. Fridley, a biologist at Syracuse University, argue that this is not a coincidence. They offer evidence that some parts of the world have been evolutionary incubators, producing superior competitors primed to thrive in other environments.

More here.