Rabbits got to my grafted plumerias

This past winter rabbits got into my greehouse and went wild. We have been in a drought since September 2007. Much of their forage just didn't come up this winter. Most of my Brugmansias recovered, but they distroyed a number of my plumeria cuttings. A few escaped but are almost completely chewed through below the graft. Should I cut the top off and re-root re rootstock or can I just bury the rootstock a bit deeper so the damaged portion sends out new roots? Please excuse the photo orientation. It's upright in my application, but Save's insists on turning it sideways.

What a bummer.
I would personally bury it deeper. It will almost certainly re-root.

This one suffered a double whammy. The bottom was whacked by a rabbit and the top by grasshoppers.

The top will recover, and the bottom might as well. The cambium will grow and fill in the gap eventually. You could take a wait-and-see attitude, or you could add more soil and bury the area. I've been surprised at how well wounds heal themselves when it comes to both brugmansias and plumerias.