History

Cheatgrass arrived in North America from Eurasia in the late 19th century. By the 1920s it had spread throughout the USA replacing native flora in over 40 millions hectares of the arid Intermountain West.

Biology

Cheatgrass is a self-fertile winter annual. Establishing itself in the fall, it flowers in early spring, has a large seed production, can occupy disturbed sites and all soil types, has 20 cm roots with extensive lateralization, and dies back in early summer.

Ecology

An early emergence reduces soil moisture, thereby competing with native perennials for water. The die-back in early summer and impact on natives increases fuel load and fire frequency. The cheatgrass re-establishes early in burned areas.

Impact

Cheatgrass changes the hydrological cycles and biogeochemical cycles, especially carbon and nitrogen, and alters the fire regimes at landscape scales. The species changes the landscape albedo, which affects energy budgets and climate.

Control

Herbicides are currently under development to try to control cheatgrass.

References on the Web:

Northern Prairie Wildlife Research Center

Colorado Weed Management Association