In addition to the positive potential of native prairie plantings being used for cellulosic biofuel, there is also risk to native prairies: that existing prairie remnants might be plowed up to plant corn or another biofuel crop. With so little tallgrass prairie remaining (estimates in Texas are less than 1%) and the potential for prairie biofuel and carbon sequestration, this would be a travesty in my opinion.
Loosing more tallgrass prairie to plowing is a higher risk in the near future with corn ethanol increasing corn prices. Ducks Unlimited and others have already reported on native grassland plantings being plowed up when their CRP (Conservation Reserve Program) agreements expire, leading to loss for grassland bird and duck habitat.
This is bad for grassland birds, but I think CRP plantings tend to be low diversity plantings so plowing of prairie remnants would be even worse for native plant communities than loss of CRP plantings.
An article from BBC News, "Biofuels ‘are not a magic bullet’", says:
"Biofuels could play an important role in cutting greenhouse gas emissions from transport, both in Britain and globally," said Professor John Pickett from Rothamsted Research, who chaired the Royal Society’s study.
"But it would be disastrous if biofuel production made further inroads into biological diversity and natural ecosystems.
"We must not create new environmental or social problems in our efforts to deal with climate change."