Yes, Erin, it was the rabbits. Exactly the same thing happened to me last year, as mine what munched right down to the root. Not only that, but the little so-and-so's nailed my big beautiful variegated carex, rhododendrons, crocuses, some tulips, and two feet of green of the bottom of a columner juniper. Then cleaned me out of green beans later in the summer.
My yuccas did come back, but as a zillion mini shoots from the root, which I never got around to thinning out. They've been chewing on it a bit again this year, but I've been able to deter them somewhat with Critter Ridder.
Someone else recently suggested to me to try Vaseline on tulip shoots. Am going to try that too, and if all else fails, I just bought a trap from Lee Valley.