Blacks bears aren't considered main predators of deer, they will take a meal of opportunity on a young fawn but highly unlikely they will stalk or pursue a deer. Wolves and grizzlies yes but not blackie's. I have seen deer, elk, moose and black bear all sitting in the same spot the bears pay little attention to the other game but they all are aware and wary of each others presence non the less even where their is little to no threat.

Like mentioned the whitetail is not built for mountain terrain, so if steep, rocky, etc that could be a reason for the difference between the lower vs higher. It could also be a wolf density issue as well.