Return of wolves to Yellowstone has led to a surge in aspen trees
26 comments
·July 23, 2025mkw5053
It's amazing the impact that the reintroduction has had. On a recent winter trip there I also learned that the reintroduction literally moved rivers [1]:
- Elk quit loitering along streams, so willow and cottonwood shot up, anchoring soil and narrowing channels.
- The new woody growth gave beavers lumber; their colonies jumped from one in 1996 to a dozen within fifteen years, raising water tables and rebuilding wetlands.
- With healthier riparian zones came deeper pools, colder water, and a surge in native trout and song-bird nests.
[1] https://phys.org/news/2025-02-predators-ecosystems-yellowsto...
owenthejumper
It's incredible how much damage we have done to ourselves in the past 250 years, and how much effort do we now need to spend to undo that damage
hagbard_c
It's incredible how much good we have done to ourselves in the past 250 years, and how much good we can do in the now and the future.
rgreek42
Surely this is the best of all possible worlds, Dr. Pangloss.
ysavir
Downvoted as this comment feels like it's trying to be witty/upshowing the parent comment without actually engaging with it or offering anything of substance. If the comment was along the lines of "yes, but we've also done a lot of good, let's reflect on both", great. But that's not what it was. Instead it feels like a statement that's trying to argue with the parent comment despite the parent comment never saying we haven't done any good.
mc32
It’s is! Just in medicine alone. And then economically, as well as justice. From 98% of the people living in abject poverty, no pairs of shoes, two changes of clothes, selling off relatives for money, dying from simple infections… to where we are today. It’s like the glory days of Rome but much better.
djoldman
The subtitle explains:
"Gray wolves were reintroduced ... to help control the numbers of elk that were eating young trees"
atentaten
How does returning wolves to ecosystem effect the mountain lion population? Can we balance things out or are we shuffling problems around?
flkenosad
They should try it in nfld
cadamsdotcom
Yellowstone seems like one of the most resilient ecosystems we do science on, seems it can reorganize to respond to changes in species.
Can other ecosystems do this? Or is Yellowstone the only one?
incomingpain
They only moved few dozen wolves, over 1000km from their homes, which is not going to have any significant consequences. Even today there's only about 100 wolves in the park?
2,200,000 acres, with 100 wolves.
Then they've made the claim that those 100 wolves in 2.2million acres has resulted in plants and fish returning? As opposed to their efforts doing nothing at all?
rustyconover
I'm not a biologist, but I grew up in West Yellowstone around the time wolves were reintroduced. Their return—and its impact—has been extensively studied by experts far more qualified than me.
That said, I believe wolves had a profound effect on the Yellowstone ecosystem, particularly on elk and deer populations. Before their reintroduction, those species had few natural predators beyond hunters, vehicles, bears, and the occasional mountain lion. The imbalance led to overgrazing and the spread of diseases like Chronic Wasting Disease (CWD) in elk.
williamdclt
> Then they've made the claim that those 100 wolves in 2.2million acres has resulted in plants and fish returning? As opposed to their efforts doing nothing at all?
They've studied it and came to these conclusions, yes. Have you studied it and come to different conclusions?
littlestymaar
You're responding to someone who believe that omnivorous animals don't exist[1], so you can assume that they will disregard whatever biologists say and trust their feelings rather than reality.
plemer
While I find your counter argument vague, it did prompt me to dig in and find that human hunting is arguably still the bigger suppressor of elk population. However, that’s been going on since the ‘40s.
The reintroduction of wolves is associated with an immediate, steady, and durable decline in elk - i.e. pushed the ecosystem past an inflection point into a new equilibrium.
bhaak
It’s also possible that wolves hunt in a different way than humans, or different types (regarding age, gender, or health maybe) of elks.
It’s an interesting question and this could be empirically tested if human hunting would be slowly reduced.
scott_w
That’s a good point: hunters probably prefer strong elk but wolves prefer weak elk. I recall going to a walking with wolves experience in the Lake District where she explained that predators strengthen their prey by removing sick and those with genetic issues from the gene pool.
rustyconover
Yellowstone is a national park, you can’t hunt anything inside the park’s boundaries. Wolves can.
specialist
IIRC:
Without risk of harm, elk and deer linger near water. This tramples the shoreline. And they love eating noshing on (aspen) saplings. Over time, the shorelines become barren.
With the reintroduction of wolves, shorelines are no longer safe havens. Aspens have returned. With aspens, song birds have returned. Trees shade the water (eg streams), so fish are happier. Trees stabilize the top soil, reducing erosion, allows other plants to become reestablished.
I dimly recall beavers returned too.
--
Aha. I was mostly right (or hallucinating). Here's perplexity link for "impact of return of wolves to yellowstone".
https://www.perplexity.ai/search/impact-of-return-of-wolves-...
I learned about the birds returning because of the wolves while volunteering at Audubon. That linked summary doesn't go into those details.
--
Update: I should've read the OC first. My bad. TIL: (too many) bison also negatively impact riverbanks. I had thought (misremembered) that overall impact of bison was positive. Does Yellowstone need more cougars?
laughingcurve
“I do not like the results!” Or “The result does not make sense to me!” are not valid criticisms of science. They are arguments made from emotion. And in your case, based on your account history, it’s clearly something political for you. I would encourage you to write that kind of commentary in a more appropriate venue. Like the bathroom stall of your local truck stop. Just not here.
mousethatroared
But it's perfectly valid to question results that don't make sense, and the role of the supposed expert is to explain why it does.
After all, off in a democracy an expert expects to be paid by taxpayers to make decisions that affect the taxpayer the expert should be, at the very least, be able to explain himself in an intelligible manner.
Thats the bare minimum of expectations. I also expect the taxpayer funded expert to provided full access to his data, notes and analysis software.
Im considered an expert in thermodynamics, materials science and E&M. The people that pay me routinely don't understand what I'm working on, but they expect me to explain myself.
sarchertech
>they expect me to explain themselves
But the experts did explain themselves. They’ve published numerous studies on how small wolf populations impact the larger ecosystem.
It’s not even that hard to understand. Yes Yellowstone is large, but there are a finite number of elk herds and the wolves move to follow and prey upon the elk herds.
Wolf packs can kill 20 elk per year per wolf, there are 120 wolves inside the park and 500 immediately around the park wandering inside it and killing elk that wander outside.
At the peak there were 18k elk in the park and now the numbers are down to 2000. There’s plenty of evidence that the decline is a direct result of the wolves.
Controlling elk population has tons of 2nd and 3rd order effects which have also been well documented.
scott_w
While I didn’t like the tone of OP I do understand where they’re coming from. Assuming what they’re saying is correct, it’s a valid question where explaining the mechanism is a solid response.
I’ll say that I’ve not read the article so if it’s in the article then I would rather you just point to that, rather than make this response.
asacrowflies
The science is pretty clear on this Im not sure what you exactly are criticizing other than you don't like the vibes or vaguely incredulous? It doesn't take many wolves to change the behavior of nearly every herbivore they prey upon. Which then changes the river bank erosion. Which causes hundreds of more species to change behavior.... Trophic Cascades are not really up for debate .
null
Not sure where opinion ended up on this, are there dissenting voices still?
https://www.accuweather.com/en/weather-news/scientists-debun...