In l995 wolves from Canada were reintroduced to Yellowstone National Park after a 70 year absence. They had been exterminated by ranchers wanting to protect their livestock and by trophy hunters. The reintroduction of wolves led to something called a "trophic cascade". This phenomena occurs when predators in a food web suppress the abundance or alter the behavior of their prey, thereby releasing the next lower trophic level from predation (or herbivory if the intermediate trophic level is a herbivore). Without wolves the population of deer and elk escalated which led to extreme overgrazing. Reintroduction of the wolves led to a myriad of beneficial consequences to a variety of species which the video below explains. One of the benefits to native bees is the increase in aspen and willow (great early season pollen) and the many varieties of fruit bushes and wildflowers (Wildflowers of Yellowstone) which had been overgrazed by the unchecked population of deer and elk. The video "How Wolves Change Rivers" describes how trophic cascade or removing the top predator, the wolf from Yellowstone effected the entire ecosystem and how the return of the wolf had remarkable beneficial effects.
A biological survey (Bioblitz) held on August 28-29th, 2009 in the northwest corner of Yellowstone National Park identified 46 species of native bees. Biologists estimate that there are between 400-500 species of native bees in Yellowstone.
My first experience with wolves was about 45 years ago when as a young man working on the railway in the Rocky Mountains I met my first wolf. I was alone in a blizzard, five miles from camp carrying about 80 lbs of equipment with the task of switching the rails. As a young greenhorn, unable to see because of the whiteout conditions, I felt my way along the tracks thinking for sure this was my last day on earth. The snow let up briefly enough for me to see a wolf come out of the woods. Spotting me the wolf froze about 10 meters from me and growled. In my anger and desperation I growled back wielding an 8 foot long iron pry bar. We starred at each other for what seemed like an eternity (probably 30 seconds), he turned and disappeared back into the woods. Since that moment I have always held a special love and admiration for wolves.