[greenonions]

I don't know much about the topic, but my understand was that bison graze more selectively, and have behaviors where they roll in grass, creating dirt ruts, which provides habitat for insects etc.

Bison are far more unruly though, so you need serious fencing to keep them contained, so it's less practical. I think they are lower maintenance than cattle, but bison just doesn't have the market.

[peteradio]

I just learned about "bison wallows", the dirt ruts you refer to. Some estimate that prior to European settlement and modern ag there were 5 small wallows per acre! That would be 500 or 1000 on a modest farm.