An invasive species of "devil" weed in range lands in the western United States could make millions of acres of grazing land worthless, researchers say.
Researchers at Oregon State University say the weed knows as medusahead has growth advantages over most other grass species that could allow it to continue to spread across much of the West and disrupt native ecosystems, a university release said Thursday.
Their study comparing the "relative growth rate" of this invasive annual grass to that of other competing species in natural field conditions found that medusahead has a faster growth rate, a longer period of growth and produced more total biomass than any native grasses.
"Medusahead is now spreading at about 12 percent a year over 17 western states," Seema Mangla, a researcher in the OSU College of Forestry, said. "Once established, it's very hard to get rid of.
"It displaces native grasses and even other invasive species that animals can still eat," she said.
"This is a devil species," she said.
Native to the Mediterranean region, medusahead was imported to the United States in the late 1880s.
The sharp and twisting points on the tips of medusahead can injure animals and give the plant its name, based on the female monster in Greek mythology who had hair composed of writhing snakes.
The plant takes up other soil resources and its deep root system soaks up limited moisture. It creates fuel for wildfires, is virtually inedible and prevents many other plants from germinating, researchers say.
Experts at the Oregon Department of Agriculture say once land is invaded by medusahead, it becomes largely worthless, incapable of supporting native animals, birds or livestock.
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