Bacteria and Cheatgrass

An organism that plagues range lands throughout the West is cheatgrass. Because it was was introduced in the late 19th century as a forage crop, it’s an aggressive invasive species. It’s a grass that has changed the ecology, if not the landscape, of much of the western United States. Cheatgrass crowds out other plants and changes the fire ecology of a region. Because it matures in early spring, it dries out and provides a hot-burning fuel for wildfires. The reason invasive species are so successful is they are out of context, out of their normal environment. When a plant does well in an environment and lacks native predators or enemies, then it can become aggressively invasive. Ann Kennedy, a USDA-Agricultural Research Service soil microbiologist at Washington State University, has isolated a native bacteria as a perfectly natural way to fight cheatgrass. Recently, she and her colleagues were awarded a large grant to test the effectiveness of this bacteria on cheatgrass in rangeland. Kennedy and her colleagues imported soil from Turkey and Kazakhstan and found that 90 percent of the organisms in it were inhibitory to cheatgrass. Only 50 percent of organisms in domestic soil are inhibitory. The bacteria do not kill the plant. Rather, by whatever means, they inhibit cell elongation, resulting in stunted root growth, stunting the whole plant and giving other plants a competitive advantage.