An exotic invasive plant selects for increased competitive tolerance, but not competitive suppression, in a native grass

Fletcher, Callaway & Atwater (pdf)

At each of four sites, bluebunch from knapweed invaded plots (I) had much better ability to tolerate knapweed than those from uninvaded plots (U). However they were not better at suppressing knapweed.

Many congratulations to Rebecca Fletcher, who just had a paper accepted into Oecologia. Her paper shows that spotted knapweed, an invasive plant, selects for bluebunch wheatgrass plants that are tolerant of knapweed competition, but not for ones that are better at competitively suppressing knapweed.

This is the first direct test of the hypothesis that neighbor suppression does not provide fitness benefits to competing plants. Her finding is important because it challenges long-held notions of what makes a plant a good competitor. Becky performed this research as an undergraduate student at the University of Montana, on a grant she wrote for the Montana Integrative Research Experience for Students (MILES) program.