What makes Prairie remnants so fragile, is it GW?

Question

What makes Prairie remnants so fragile, is it GW?

Answer 1

they wont let us burn any more so grasses like fescue are slowly crowding the blue stem, gamma grass & other prairie plants out.

back when we used to burn every year there was prairie every where. now its all weeds, brush & cedar trees.

Answer 2

No, it is that there is so little of it left.  During the farming boom after WWII nearly all arable land on the great plains was farmed or developed.  That which was farmed, but is now long fallow are called "old fields".  The biggest piece of virgin prairie left is the stretch from eastern OK, KS and NE called the flint hills.  It was too rocky, for the most part, for row crops.  The little pieces left are susceptable to non-native invasion and must be managed.