Meet Dalmation Toadflax, A Nasty Invader And Climate Change Winner

CREDIT: AP Photo/Wyoming Game and Fish Department

This July 2011 image provided by the Wyoming Game and Fish Department shows cattle grazing on the Fish Creek Ranch near Big Piney, Wyo.

With rising levels of atmospheric carbon, the invasive weeds may inherit the earth.

That’s at least the tentative conclusion of a long-running experiment in Wyoming, where a team led by U.S. Department of Agriculture researcher Dana M. Blumenthal found that a common non-native flowering perennial called Dalmation toadflax thrives under warmer temperatures and elevated carbon dioxide. They heated their test plots and pumped in higher levels of carbon dioxide and observed the effects on the invasive species.

Over a four-year period, the higher carbon levels “dramatically increased” the success of Dalmation toadflax, increasing its production of seeds by 32 times, and its size by 13 times. The study was published last year in the journal New Phytologist, and highlighted in a story aired March 25 on NPR’s “All Things Considered.”

The research may have some sobering implications for agriculture and ranching in arid and semi-arid regions of the U.S., including the southwest and Great Plains. As climate change increases levels of CO2 in the atmosphere, the study concluded, “water-limited ecosystems may be particularly vulnerable to colonization by fast-growing species…..including many invasive species.”

A native of Eurasia, Dalmation toadflax was introduced to the U.S. as an ornamental plant in the late 1800’s. It grows to two to three feet tall and has bright yellow flowers similar to snapdragon. It is an aggressive invader, occupying disturbed sites and then spreading to open rangelands where it out-competes native plants and limits forage for cattle and other livestock. A single plant can produce up to a half million seeds which remain viable for up to a decade.

“The simplest reason that invasive species are likely to do well under future conditions,” Blumenthal told NPR, “is that they are pretty much by definition good at dealing with change.”