Return of the non-natives

Soon the false promise of green will sweep through the brown hills of Reno and Sparks. Then it will all be gone, replaced by a vast yellow rug of creepy knee-high soldiers. This is the way of Bromus tectorum, a noxious weed more commonly known as cheatgrass.

Cheatgrass is a non-native annual grass that was originally and accidentally introduced to the United States in livestock seed in the 1880s. Now it’s growing in every state. In Nevada, it’s in every county.

“It’s found almost everywhere, but it’s concentrated in the West,” says Earl Creech, state weed specialist for the University of Nevada Cooperative Extension. “In Nevada, it’s just about every square inch that’s been disturbed by fire or grazing.”

Cheatgrass is a problem because it displaces native vegetation like sagebrush and perennial bunch grasses. It germinates early and establishes an extensive root system before other plants in the area have a chance to take up soil nutrients or water, thus “cheating” native species out of scarce natural resources. It’s nearly impossible to destroy without intensive management that includes repeated herbicide application and perfectly timed fire and re-seeding. But cheatgrass’s main competitive advantage, particularly in the arid West, is that it proliferates in areas that have burned.

Walk the hills west of Reno where recent blazes have occurred or anywhere on Peavine mountain, and you can see the results. Where fires have ravaged during the past decade, cheatgrass is flourishing. The 20- to 24-inch tall plant has a slender stem and protruding panicles with hairy-looking purple or straw-colored “spikelets” that will stick in fur, socks and pants. It scatters via travelers or the wind, defiantly extending its domain.

Creech says a clear example of the weed’s domination in the Western U.S. is along firebreaks, where swaths of shrubs and trees have been removed to prevent fires from spreading. Ironically, the man-made path from road to ridge acts like a wick since cheatgrass takes over almost immediately and is so flammable.

Cheatgrass dies in the spring, dries up, and by summertime it’s a 9 million square mile Nevada fuel hazard. Fire is a natural part of the sagebrush grassland ecosystem, but historically, Western fires burned every 60 to 100 years. Cheatgrass-infested areas burn every three to five years, a frequency at which native shrubs and perennial grasses can’t recover. After a few wildfire cycles, a cheatgrass monoculture develops. This monoculture increases the risk of fire, and so the Catch-22 begins.

To make matters worse, cheatgrass offers marginal benefits to cattle and almost none to wildlife. During the growing season, grazers can gain some nutritional value from cheatgrass. However, according to the Nevada Department of Conservation and Natural Resources, “after cheatgrass cures in the spring, the nutritional value and edibility of the plants declines. Domestic and wild grazing animals, upland birds, and other wildlife must go elsewhere to meet their nutritional and other habitat needs.”

Cheatgrass grows easily, thrives in fire, out-competes native flora, resists eradication, and disperses without difficulty. It’s a miracle of nature really, survival of the fittest at its best. Unfortunately, nothing happens in a vacuum, and Nevada’s landscape is paying the price.