A recent report produced by the Western Watersheds Project in collaboration with a retired Bureau of Land Management staff member and College of Idaho professor emeritus points to livestock as the key factor in cheatgrass spread.
The report claims livestock overgrazing is the reason for the spread of cheatgrass, an invasive weed that helps fuel wildfires and prevents native plants from growing.
“There is a massive and comprehensive body of scientific findings specific to cheatgrass invasions, showing that disturbance from commercial activities, most notably overgrazing by domestic livestock, is the key factor in causing the spread of this invasive and flammable weed,” said Erik Molvar of Western Watersheds Project.
The report said disturbance from livestock grazing is an “ecological switch” that is the key trigger of cheatgrass invasion. In addition to livestock grazing, the report also notes the impacts of road construction, oil and gas development, mining and fuelbreak construction.
“Livestock trampling, grazing, and surface disturbance are the key ecological switches that transitions healthy arid ecosystems to cheatgrass-invaded systems, by eliminating the native bunchgrasses and biological soil crusts that are the natural defense against weeds,” the report read.
The report continues that drought and fires are expected to increase as a result of climate change, further exacerbating the effects of livestock grazing.
“Blaming fire for our cheatgrass problems is a red herring,” said Don Mansfield, emeritus professor at the College of Idaho. “Building fire breaks is a wonderful way to develop corridors for the spread of weeds. Cheatgrass will be eternally grateful to us for that.”
The report reviews the difficulty of eliminating cheatgrass once it becomes established, and methods that while effective on small scales, prove to be inefficient at larger scales. The authors ultimately recommend removing livestock from large areas until native bunchgrasses are re-established.
“In an age of fads and short attention spans, it is critically important to take stock of all that scientists have learned about cheatgrass over the decades to prevent further cheatgrass spread and maximize our effectiveness at restoring infested areas back to healthy natural ecosystems,” Molvar concluded.
Funding for the report was provided through a grant from the Foundation for Sustainability and Innovation. — Anna Miller, WLJ managing editor
