While I don't have any facts to back me up, I would be willing to bet a years salary that there are still plenty of moose in Yellow stone. There is no way in the world that the wolves could wipe out an entire population of heathy moose in Yellowstone.

I think a bigger concern in the ticks, fleas and other parasites that cause the moose to loose and scrach off all of their hair during the summer and when winter rolls around they do not have the protection from the elements that they need and die of sevear cold.