Are Wolves’ Footprints On Ecosystems Overstated?

Pantheraman

Well-Known Member
Are wolves’ footprints on ecosystems overstated? | International Wolf Center

"But researchers recently found wolves (Canis lupus)—and other predators—aren’t singlehandedly responsible for many of these events. There is still a place for them in the ecosystem, they argue, but not because they’re engineers."

Not engineers? I beg to differ, as mountain lions for example, are ecosystem engineers because their kills provide food for many different species and are even homes for 216 species of beetles. And that's just one example.

"Blossey originally worked as an entomologist, studying the use of insects as biocontrol for invasive plants. He noticed that introduced plant species were super competitive with native species in the Northeast. But he soon found out that the introduced plants weren’t the main driver of changes in the ecosystem, but white-tailed deer (Odocoileus virginianus) were. As he researched the issue, he found that sterilization and hunting wouldn’t significantly bring down deer numbers. That prompted other suggestions."

Given how the system of wildlife management works in this country, of course, recreational hunting won't lower deer numbers. The system simply doesn't work that way.

"Blossey and his co-author, Darragh Hare, with the Wildlife Conservation Research Unit at Oxford University, concluded that based on the available evidence, wolves by themselves would probably not restore the landscape the way conservationists might hope. They also probably would not cause the devastation to livestock that some ranchers fear.

“One of the big things that we see is that the data that we have is not good enough for us to actually make these bold claims,” he said.

Looking at wolves’ effects on deer, Blossey and Hare argue that that past research didn’t take into account other ungulates that wolves prey on, and it didn’t consider a lack of forage due to excessive deer browse itself and other factors like cattle grazing, feral horses and drought, which could play important role of deer abundance declines."

"Instead of reintroducing wolves, Blossey suggests they be allowed to disperse naturally. They might even be able to help stabilize deer and elk numbers, he said, but they probably can’t do without the help of recreational hunting. Wolves have a role to play, he said, but they won’t likely restore ecosystems."

Two things to take away from this.

1. What's wrong with reintroducing them? I'm not really sure how letting them dispserse on their own is any better than a reintroduction since either way you'll have a newly established wolf population, but a reintroduction is quicker and thus one can help deal with ungulate overpopulations much sooner.

2. When it comes to deer control the only thing they seem to be looking at is the ability of predators to reduce prey numbers, what they're failing to even bring up is the true main job of top predators: The Ecology of Fear, where the presence of predators makes the prey use the landscape in a way that prevents them from basically destroying the ecosystem. That's what happened in Yellowstone National Park, when wolves were reintroduced, now all the cogs of the wheel were in place, and now both the wolves and cougars kinda work together to keep elk on the move.

And this is something they can and have done without the help of hunters.
 
2. When it comes to deer control the only thing they seem to be looking at is the ability of predators to reduce prey numbers, what they're failing to even bring up is the true main job of top predators: The Ecology of Fear, where the presence of predators makes the prey use the landscape in a way that prevents them from basically destroying the ecosystem. That's what happened in Yellowstone National Park, when wolves were reintroduced, now all the cogs of the wheel were in place, and now both the wolves and cougars kinda work together to keep elk on the move.

If you read the actual article:

Myths, Wishful Thinking, and Accountability in Predator Conservation and Management in the United States

This is clearly mentioned and they state based on several studies that there is a lack of evidence for that claim too.

Not engineers? I beg to differ, as mountain lions for example, are ecosystem engineers because their kills provide food for many different species and are even homes for 216 species of beetles. And that's just one example.

I would be highly surprised if a natural death of an ungulate wouldn't provide the same food chain....
 
1. This quote in that article:

"Instead, large herbivores, in response to presence of large predators, change their activity patterns and graze in risky areas of high nutritional value when predation risk is low, for example when wolves rest (Kohl et al., 2018)"

So the ecology of fear does actually exist, just not in the way exact way people once thought. So I'm not really sure what they were really trying to prove. In fact, Kohl et al in another study found elk avoid both wolves and cougars by being in the right areas in the right times: Relationship between predators, prey is complicated

2. Predation simply makes carcasses more available, as has been shown in Malawi with the reintroduction of lions and cheetahs aiding in vulture recovery: Cheetah reintroduction in Malawi brings vultures back to the skies


And when it comes to landscapes of fear, I believe conservationists working to restore Gorongosa National Park, Mozambique would happily disagree: Science | AAAS
 
This is a quote from John Laundre (RIP), one of the people who came up with the idea of a landscape of fear in response to a study cited by this one, figured it would be appropriate:

"I have several problems with this article and the research it reports. The first one is that they used a simulation to estimate how elk might move without risk from wolves. As far as I am concerned all simulations are really just statistical lies. There are so many variables that can be altered to produce a favored outcome that there really is no way of knowing just how close to reality they are. It indeed is just the manufacture of data. In most cases, the basis of the simulation is some degree of randomness, or random walk. Ironically, if this is what they used, I would predict that yes indeed they would indeed get a pattern similar to elk living under the fear of predation. What many people fail to remember is that random patterns are NOT uniform patterns. They will produce clumps and dispersion. In the case of these random walks, just by chance alone there will be areas that are more used than others; the EXACT pattern one would get in a landscape of fear! Avoidance of high risk places, use of low risk ones. What they should do is compare how elk are using the landscape with wolves to a uniform use pattern. So in my mind, their analysis was flawed from the beginning.
"Another problem with simulations is that they treat the system as a mass action model (which of course is what they truly believe all ecology is). It is almost impossible to incorporate behavior in mathematical models and that is why ecological modelers don't like behavior ecology. Elk and wolves are NOT marbles rolling around the landscape where they accidentally, based on probability, run into each other. So their simulation is based on elk marbles rolling around the landscape without wolves compared to actual data that reflects actual behavioral interactions but those interactions are not incorporated.
"Another problem I have with this all is that these researchers are really johnny come lately's to this all. They have NO pre wolf data regarding movements of elk (if they did, they would have used that instead of simulations!). We specifically state in our work, which does include the ONLY pre-wolf data I am aware of, that as elk adjust to the presence of wolves, driven by fear of predation, they will try to minimize the risk they face, if not they are stupid! This shift from pre-wolf use to post wolf use reflects that attempt but can only be documented by comparing how elk used the environment before and then after wolves. Again, we are the only ones I am aware of who actually did this. And we saw significant changes in both behavior and landscape use. They are studying elk in the post wolf adjusted landscape of fear where elk have already made those adjustments to both reduce predation risk levels as well as fear levels! So how can they document the change that occurred when they are studying it after it has been made? They are studying an adjusted landscape of fear where out of necessity, elk have already made the changes needed to survive!
"Lastly, ironically, though they say that they think their data show elk are not afraid of wolves, they do document that, not just a few, by many elk have switched to foraging at night because wolves are not as active then. In response, I would ask, what keeps them from going back to the day time when wolves are active? If they are not afraid of wolves, why don't they continue to forage through out the day as they did before wolves? The only answer is fear! So in my mind, their study actually quite nicely demonstrates that yes in deed elk are afraid of wolves and it keeps them in the specific use pattern they have adapted to try and reduce/manage that fear at an acceptable level. Only a stupid prey doesn't know when the be afraid and when not to be!
"Overall it is an attempt by the mass action people to discredit the possibility of behavioral interactions and though they say they did, reading between the lines I find plenty of support for the ecology of fear and behaviorally mediated trophic cascades."
 
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