Reed Noss' new book, Forgotten Grasslands of the South is quite good. At least the first half.
I try to review books about halfway through because the last half usually drags on. This might prove an exception, but I'll see.
Noss' main point is that grassland of the SE US are the true ancient grasslands of North America.
While the Great Plains were under ice or spruce, the SE was the refugia for much of the grassland biome. And has been for millions of years.
The high levels of endemism of species is a primary line of evidence. For example, he has a short table comparing the number of species of different plants in the Great Plains vs. Florida. Andropogon? 2 species in the plains. 9 in Florida.
Noss also argues for reconsideration of the longleaf pine ecosystem as a grassland.
His best writing is the natural history when he takes you through a tour of places he's visited. Dolomite glades, longleaf pine savannas, ancient salt licks.
I would say that this is one book that deserves to be a documentary. His descriptions are good, but video would do it more justice.