Since "root cause" is defined as: "The fundamental reason for the occurrence of a problem," and such significant depredation/kill-off of elk & moose in places where the new wolves have become established following "reintroduction," that certainly appears to be a significant causal factor. While disease, hard winters, wild fires, loss of habitat, etc. can cause population fluctuations, it has only been since the advent of the populations of larger wolves that such has reached the monumental proportions realized today, but the introduction of a much larger & fiercer wolf species foreign to the northwestern US IS the root cause. Failure to control the wolf population early-on certainly was a contributing factor. Shortly after wolves became problematic in Montana, I found 2 fresh wolf kills (cow & calf). When I reported it to a state biologist, he was reluctant to believe me, saying: "How do you know it was a wolf?' "Because there were tracks & 4 wolves were standing in them." He still didn't believe it was a wolf kill. Had Canadian wolves NOT been introduced uncontrolled initially into the Northwest, we wouldn't be having this conversation would we . . .