Tuesday, December 01, 2009

Scientists say buffelgrass on unstoppable march—and the saguaro is on its way out

Buffelgrass is forcing us to think the unthinkable: A Sonoran Desert in which the saguaro cactus is no longer the master of the landscape. Is this really possible? Could Arizona's cherished icon vanish from a substantial portion of its range? Actually, yes. The problem is fire. The Nature Conservancy biologist Dale Turner says the density and distribution of buffelgrass is increasing dramatically, and in those places where it becomes the dominant plant, the number of fires will increase. "That means every other plant that's both slow-growing and fire-sensitive will disappear," says Turner. "That's certainly the saguaro. I don't think it will go extinct, but we'll see saguaro populations either lost or seriously degraded." Prior to buffelgrass, fire was never a major player in the Sonoran Desert. Old-fashioned fires—if we can use that term—didn't burn too hot or too long, because native grasses don't have the biomass to create big blazes. Buffelgrass does, and it won't pause to catch its breath after a fire. It regenerates quickly and thicker than before, making subsequent blazes more intense, with plenty of fuel to run across entire valleys and up grassy slopes...read more

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