Resilient, opportunistic plants are most invasive threat, study shows

Dec. 6 (UPI) -- What makes a plant successful as an invasive species? Previously, scientists thought plants with the fastest growth rates posed the greatest threat, but new research suggests plants that quickly rebound in the wake of disruption are most likely to invade foreign soil.

To better understand which plants make the best invaders, scientists surveyed a global database of plant life cycles.

"What we found was a real surprise," Dave Hodgson, professor of ecology at the University of Exeter, said in a news release. "Invasive plant populations grow fast in their invaded range, but not in their native range. So you can't use population growth to predict invasiveness."

But while plants with the greatest success as invaders don't grow quickly in their native environs, scientists found they are more resilient and opportunistic. Successful invaders are the species that quickly repopulate after plowing, flooding or drought.

"Invasive plant species have an amazing ability to bounce back from disturbances, and we can see this in both their native range and their invaded range," Hodgson said. "Based on this finding, we should avoid the export of plant species that grow well in disturbed environments."

Plants that tend to do well in the wake of disturbance and stress produce big flowers and lots of seeds. Unfortunately, gardeners like big flowers.

In their new paper on the subject -- published this week in the Nature Communications -- Hodgson and his colleagues call for an end to the international trade of large flowered species.

Additionally, the new research showed that the close relatives of invasive species are also likely to be successful invaders.

A lot of attention is paid to ecological damages caused by invasive animals, but researchers suggest invasive plants cause just as many problems. Scientists hope their latest efforts will help policy makers, regulators, conservationists and others locate and stop the the most harmful species before they have a chance to invade.

"The global battle against invasive species is made difficult because we have failed until now to predict which species will be a problem, and which will be benign, when they colonize new regions," Hodgson said. "For the first time, we have a strong clue to the identity of future invasive plants. Weedy plants of disturbed environments -- and their close relatives -- should not be exported."