Cheatgrass and the INL

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Cheatgrass and the INL

The scourge goes by many names: cheatgrass, cheat, chess, downy brome, downy chess, Junegrass, bronco grass, 100-days grass and Mormon oats. To scientists it’s known as Bromus tectorum. Ranchers and managers have called it the most significant ecological problem facing rangelands of the western United States.

A native of the Mediterranean, cheatgrass was first introduced to western North America in 1889. It is an aggressive invader that can adapt to a wide range of climates, often out-competing native plants. Cheatgrass may now be the most common grass in the Northwest. Once cheatgrass begins to invade, the end result is often a rangeland that is dominated by this species and one that no longer provides healthy habitat. Not only can cattle and sheep be negatively affected, but also big game, sage grouse and other wildlife.

Cheatgrass is an annual plant, but it matures fast enough that more than one generation can grow in a single growing season. This rapid maturity creates an abundance of dead foliage in later summer. Wind and sun cure the grass into a highly flammable fuel that blankets the desert floor. Wildfires are then able to burn much larger expanses and to burn more frequently.

In their aftermath, such fires change the nature of the sagebrush desert, perhaps forever. Following cheatgrass-fueled fires, burned patches are larger and appear more often, making it less likely sagebrush, which can only regrow from seeds, will recolonize. Increased frequency of fires makes this problem worse. Once cheatgrass makes up a large part of the plant community, fires can return at intervals of less than 10 years, as opposed to 50 to 70 years in a healthy sagebrush desert.

The conversion of shrub land to cheatgrass is thought to be final and irreversible by natural processes. The amount of land currently covered by cheatgrass is too large to economically reseed back to native species. This makes it all the more important that our remaining shrub lands, particularly those in reserved lands like the INL, be protected from this invasion.

But, this does not necessarily mean protection from fires. Fires are a natural process in the shrub steppe ecosystem. On the INL, where cheatgrass does not have a dominant foothold, fires burned more than 50,000 acres of sagebrush desert during the 1994, 1995 and 1996 fire seasons. Yet, these areas are recovering well. The speed of this recovery was due to extensive, healthy populations of native plants which resprouted vigorously, above-normal precipitation received at the INL since then, and the lack of any additional disturbances in these areas after the fires.

Will areas burned in the future on the INL fare as well? The answer will depend on the absence of activities that disturb vegetation and soil. Where robust populations of native plants exist, cheatgrass probably will not be able to displace them following fire. Fire is part of what makes for a healthy, diverse natural community. The key is to allow the land to heal itself.