The resilience of sagebrush ecosystems following fire depends on a few things. Climate variation is important, since the climate in the great basin experiences drought quite often. The plants of the sagebrush ecosystem may not establish quickly if precipitation levels aren't favorable after a fire. Severity of the fire is also an important consideration--a less severe fire results in higher resilience of the ecosystem. Cheatgrass complicates this problem, because it forms continuous, fine fuels and is drought tolerant. It also produces seed early in the growing season that can germinate and establish before native plant populations have a chance to recover. Cheatgrass invaded areas experience an increase in fire frequency, further diminishing resilience of the ecosystem.
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Sage grouse populations suffer in areas dominated by cheatgrass. Without the invasive annual, sagebrush steppe would recover after fire to become sagebrush steppe again. Since sage grouse populations depend on sagebrush, and sagebrush can take a while to recover after fire while cheatgrass can invade quickly, the biggest threat to existing sage grouse habitat is in areas where cheatgrass is present but not yet dominant. Fire in these areas would be carried by the fine fuels, causing an intense fire that could wipe out native vegetation. Cheatgrass would subsequently become more dominant in this situation, resulting in a net loss of sage grouse habitat.
http://www.mcclatchydc.com/news/nation-world/national/article24782557.html
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