Key findings of the report include:
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Cheatgrass requires disturbance of native plant communities to gain a foothold.
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Disturbance from heavy grazing by domestic livestock is an “ecological switch” that is the key trigger of widespread cheatgrass invasions.
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Industrial disturbance from road construction, oil and gas development, mining, and fuelbreak construction can also cause localized cheatgrass irruptions.
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Once soils and vegetation are disturbed cheatgrass seedlings outcompete the seedlings of native grasses for soil nutrients and water.
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Because cheatgrass is an annual that dies in early summer providing highly combustible fuel, cheatgrass infestations fuel unnaturally large range fires.
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Fire itself is not a direct cause of cheatgrass spread, and fires that occur in healthy natural ecosystems result in native bunchgrass communities post-fire, not cheatgrass monocultures.
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Healthy perennial bunchgrasses and undisturbed biological soil crusts provide a natural defense against cheatgrass invasions.
Scientific report reveals livestock as the key factor in cheatgrass spread
“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,”
“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 spread of weeds. Cheatgrass will be eternally grateful to us for that.”
Wow, it is a tough customer and that map threw me for a loop. It is everywhere. I didn’t know that.