In Oregon, only generalist insects are the enemy. "Generalists can cause a lot of damage, too," Roy said. "We found that this grass actually gets eaten more by insects in its invaded range than it does in its home range."
While such insect damage may slow its growth, false brome now appears to be entrenched among the more than 25 percent of non-native plants now growing across the state, Roy said.
"There has been extraordinary, exponential growth, especially since 1989. The conditions are now perfect to spread, because it has had time to genetically evolve and adapt. We carry things around with us -- sometimes accidentally, sometimes on purpose. Then they become our nemeses. This really is a case of 'this is the house that Jack built,'" Roy said, referring to a British nursery rhyme. "Once something gets here, it's really difficult to control it."
False brome also has been confirmed in both Washington state and northern California, the spread of which is monitored by the states' agricultural departments. It has also recently shown up on the East coast. "Grasses are particularly dangerous invaders. They tend to do wholesale ecosystem change," Roy said. Brachypodium sylvaticum grows really well in the shade and in the forests."
Where it grows, it blocks forests' floors, keeping tree seeds from falling to the ground and germinating. It stays green throughout even dry summers. Its impact in encouraging or retarding the spread of wildfires is currently being pursued in controlled burn studies underway by one of Roy's students in a project with the U.S. Forest Service.
There is no easy answer on how to stop the spread, Roy said. Biological control, in which another non-native species is introduced to kill an invasive plan, can backfire, she said, recalling when Oregon agricultural officials imported moths to attack tansy ragwort in the 1970s. Because the ragwort was related to native r
|Contact: Jim Barlow|
University of Oregon