Invasive grass poised to take over Western fields

The invasive weed medusahead has growth advantages over most grass species and could devastate grasslands as it spreads across the west, says a new study. The research, by scientists from Oregon State University and the Agricultural Research Service, found that the weed "has a faster growth rate, a longer period of growth and produced more total biomass even than cheatgrass -- another invading species that is a major problem in its own right, but not as devastating as medusahead," ScienceDaily reports. (OSU photo)

"Medusahead is now spreading at about 12 percent a year over 17 Western states," said Seema Mangla, a researcher in the OSU College of Forestry. "Once established, it's very hard to get rid of. It displaces native grasses and even other invasive species that animals can still eat. Unless we do more to stop it, medusahead will take over much of the native grassland in the West." Mangla noted some research has identified candidates like crested wheatgrass and Sandberg's bluegrass that might be able to compete with medusahead.

"So far, medusahead has received very little attention compared to other threats such as cheatgrass, even though it ultimately poses a far greater threat to ecosystems across the West," ScienceDaily reports. Grazing animals can still eat cheatgrass, but medusahead eliminates more than 80 percent of the grazing value of land. Medusahead was imported to the U.S. in the 1880s but is now found on 2.5 million acres across the country. "This plant is easier to keep out than it is to get rid of," Mangla said. "The time to stop it from taking over the West is now, before it becomes much more widely established. And it has not gotten the attention it deserves." (Read more)