I recently watched an excellent zoom presentation by Dan MacNulty entitled “New insights into the ecological effects of wolves in Yellowstone National Park.” MacNulty is a professor at Utah State University who has done extensive work in Yellowstone since 1995 on the effect predators have on the ecosystem. MacNulty presented an historical view of wolves and elk in Yellowstone, concentrating particularly on the effect wolves have had on elk and on aspen growth. The two summary take-aways are that:
1.a whole suite of predators (wolves, bears, cougars, and humans) have affected elk in the Northern Range (the study is inside and outside the northern border of the Park as elk migrate with the seasons), and that
2. wolves really have not had a significant trophic cascade effect on aspen (i.e. elk were pushed by wolves so that they were no longer over-browsing aspen sometimes called the Landscape of Fear) that these previous studies suggested. MacNulty did a long-term extensive study on a variety of aspen plots inside the Park which showed the Landscape of Fear theory did not hold up.
Much of the zoom presentation material wasn’t new, but several things caught my attention. A chart MacNulty presented showed that wolves take older elk, those aging out of fertility. (Chart screen capture below). He presented another chart showing that hunters tend to take younger aged female elk, the most reproductively fertile in a herd (screen capture not shown). Add that to calf predation which is mostly by black and grizzly bears, followed by wolves, coyotes, and cougars, and you have an all-age class predation by all predators (humans included). One other chart MacNulty showed was that if we eliminated the hunt on cow elk, the Northern Range population would rise to around 11,000-12,000, about double what it is now.
But what interested me was MacNulty’s comments on how elk are not disturbed by wolves unless they are actually hunting. Arthur Middleton’s study on the two Cody herds also showed the same information. Interns spent countless hours observing elk feeding. Middleton’s conclusions were that elk showed no concern for wolves unless they were within about 1/2 mile. Middleton also told me that he spent time observing elk calmly grazing on a hillside in front of an active wolf den.
When the idea of a Landscape of Fear came out several years ago, it never sat right with me. Certainly elk have changed their habits since wolves appeared, their age-old predator. Elk in Colorado for instance, where no wolves exist, will chomp on grass on golf courses, hang around roads, and show no concern. Why should they? They have become like cattle, unhinged from their natural wild instincts. Yet here in the Yellowstone ecosystem, having now adjusted to wolves returning (along with cougars and grizzlies) doesn’t mean elk are now living in a state of fear.
To me, the idea of a Landscape of Fear applies to us humans who rarely enter into an ecosystem where we are not the top predator. We take a walk or hike in grizzly country, thinking all the while there is a bear behind every bush. Or in cougar country where we have a gnawing fear for our lives. We are visitors and have no real knowledge of the habits of what would be our neighbors if we lived in daily contact with them. For wildlife, the natural world IS their home and they know their territories very well. Even migratory herds, like elk and deer, are not only following eons-old routes, but they are faithful to them. They know the habits of their animal neighbors and are well aware of the wildlife that are nearby at any time. Wildlife do not live in constant fear; they live in an Awareness of their surroundings.
Living in fear is not a useful emotion, for humans nor for wildlife. Living with Awareness is. So when MacNulty said their findings did not suggest elk were triggered by wolves (except of course when they are actively hunting them), this made sense. And then it would follow that aspen recruitment isn’t especially affected; that there are many other factors at work relative to aspen regeneration.
One very interesting comment by MacNulty was that was mountain lions, not wolves, changed elk behavior. MacNulty didn’t go into this much further. I certainly would like to hear more about this, but my guess, based on speaking with Dr. Toni Ruth for my book Ghostwalker, is that cougars of course are ambush predators and are quite competent of killing an elk wandering off into the trees. It is more risky and difficult for cougars to take down an elk in the open where elk have the advantage.
I just want to end on another note. The short youtube video called How Wolves Change Rivers went viral many years ago. Although wolves don’t change rivers nor especially help regenerate aspen, I don’t object or fault this story. Humans are storytellers and story driven. False stories like the wolves that were reintroduced are non-native Canadian wolves motivated an entire group of wolf-haters to believe and spread that narrative. On the other hand, wolves changing rivers and enhancing wildlife is a positive story that stirs our appreciation for wolves. Good stories will help foster an appreciation for wolves and other predators.
If you want to listen to a recording of the meeting, it was hosted by Western Wildlife Conservancy and look for the passcode and link