Wolves and Rivers


Just a few days ago, on May 1st to be precise, I published the post Dogs and Humans.

Colin Reynolds, he of the blog Wibble, left the following comment:

Good to see you back, glad to hear you had an enjoyable trip.
Those goslings are really cute 🙂
At risk of self-promotion: I was thinking of you when I wrote my latest blog post. Granted, wolves aren’t dogs, but they almost are… 🙂

I went across to Colin’s latest blog post and immediately wanted to share it with you all in this place.

It also seemed appropriate to ask Colin for his introduction. But here’s what he offered: “When Paul asked me if I would be willing to turn this post into a guest post for Learning from Dogs, I was more puzzled than anything else. The only words here that aren’t my own are those where I explain that all I did was transcribe George Monbiot’s words from the video.” I’m bound to say that the transcription was a grand job!

Anyway, here is Colin’s post.


How Wolves Change Rivers

by Colin Reynolds

When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” — John Muir

When wolves were reintroduced to Yellowstone National Park in the United States after being absent for nearly 70 years, the most remarkable ‘trophic cascade‘ occurred. In this short film, George Monbiot explains what a trophic cascade is, and how wolves do actually change rivers.

I found this so remarkable that I took the time to transcribe George’s words:

One of the most exciting scientific findings of the past half century has been the discovery of widespread ‘trophic cascades’. A trophic cascade is an ecological process which starts at the top of the food chain and tumbles all the way down to the bottom, and the classic example is what happened in the Yellowstone National Park in the United States when wolves were reintroduced in 1995. Now, we all know that wolves kill various species of animals, but perhaps we’re slightly less aware that they give life to many others.

Before the wolves turned up, they’d been absent for seventy years, but the numbers of deer — because there’d been nothing to hunt them — had built up and built up in the Yellowstone Park and despite the efforts by humans to control them, they’d reduced much of the vegetation there to almost nothing; they’d just grazed it away. But as soon as the wolves arrived, even though they were few in number, they started to have the most remarkable effects.

First, of course, they killed some of the deer. But that wasn’t the major thing: much more significantly, they radically changed the behaviour of the deer. The deer started avoiding certain parts of the park: the places where they could be trapped most easily, particularly the valleys and the gorges — and immediately, those places started to regenerate. In some areas, the height of the trees quintupled in just six years; bare valley sides quickly became forests of aspen, and willow, and cottonwood.

And as soon as that happened, the birds started moving in. The number of songbirds and migratory birds started to increase greatly. The number of beavers started to increase because beavers liked to eat the trees; and beavers, like wolves, are ecosystem engineers, they create niches for other species. And the dams they built in the rivers provided habitats for otters and musk-rats and ducks and fish and reptiles and amphibians.

The wolves killed coyotes, and as a result of that, the number of rabbits and mice began to rise, which meant more hawks, more weasels, more foxes, more badgers. Ravens and bald eagles came down to feed on the carrion that the wolves had left. Bears fed on it too, and their population began to rise as well, partly also because there were more berries growing on the regenerating shrubs. And the bears reinforced the impact of the wolves by killing some of the calves of the deer.

But here’s where it gets really interesting: the wolves changed the behaviour of the rivers. They began to meander less, there was less erosion, the channels narrowed, more pools formed, more riffle sections, all of which was great for wildlife habitats. The rivers changed in response to the wolves. And the reason was that the regenerating forests stabilised the banks so that they collapsed less often, so that the rivers became more fixed in their course. Similarly, by driving the deer out of some places and the vegetation recovering on the valley sides there was less soil erosion, because the vegetation stabilised that as well.

So the wolves, small in number, transformed not just the ecosystem of the Yellowstone National Park, this huge area of land, but also its physical geography.

Note from the video’s publisher (Sustainable Human): “There are ‘elk’ pictured in this video when the narrator is referring to ‘deer.’ This is because the narrator is British and the British word for ‘elk’ is ‘red deer’, or ‘deer’ for short. The scientific report this is based on refers to elk so we wanted to be accurate with the truth of the story.”


As that quote from John Muir infers, we are all connected. No better illustrated by a very sad piece of research news that will be the topic for tomorrow’s post.

33 thoughts on “Wolves and Rivers

      1. That is from chaos theory. A butterfly flaps his wings on the other side of the world and we get a hurricane. Something like that.


  1. Excellent quote. “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.” — John Muir. My cat came in a looked at the computer when I played the video and the wolves were howling!

    Liked by 1 person

    1. I am going to replay that video in the next few minutes to see what reaction we get from all of our dogs who are in the bedroom just now! That profoundly wise quote from John Muir says it all!

      Liked by 1 person

      1. The dogs sleeping on the bed, four of them, casually looked across at me! Guess they have got well past the point of being surprised at what they see and hear!


  2. I have seen that documentary by George Monbiot, some time ago now. I think that it might be available on YouTube, but I can’t check because I am on very limited satellite WiFi right now (House sitting in very remote part of Alpujarras in Spain). I do recommend it as a ‘Must Watch’ though. It is extraordinary to see the evidence with your own eyes.
    If I have one wish, it is that people wake up to the connectedness of all life.
    I once watched (with horror) as a good friend absent mindedly took his knife and cut a wasp, that was crawling on our restaurant table, in half! I berated him for a full hour on the thoughtless cruel act. He shrugged and said, ‘it can’t feel anything, it’s an insect with no brain and we don’t need ’em!’ His statement made me as angry as the act itself.
    Folks, we need everything… whether we know it or not. We are so stupid about the role every life form plays… I think it’s high time we wised up!

    Liked by 1 person

    1. Oh, dear Colette, not only are we, as a species, way past the point of wising up but running out of options! Don’t mean to sound gloomy but talk about fiddling while Rome burns! Completely agree with you regarding your anger towards your ‘good friend ‘! Thank you!

      Liked by 1 person

    2. I think that it might be available on YouTube…
      It is — that’s where I found it. If you right-click on the video above you can ‘copy Video URL’ and then paste into your browser’s address bar to view it on YouTube.

      Liked by 1 person

  3. Awesome! Thanks Colin and Paul. Everyone needs to see this. George Monbiot is one of my very favourite journalists and deserves a Pulitzer Prize (or UK equivalent). I do hope he will be with us for a long time yet.
    Btw, the following video was on the side bar – about the relationship between a certain wild wolf and the dogs (and people) he met. https://youtu.be/eie7WJF0aY0


    1. I’ve seen Romeo’s story before… [spoiler]Such a shame, and so typical, that the friendly wolf was shot by humans… I suspect it was an easy kill, as it had foolishly come to trust our species.[/spoiler]


  4. I love the Yellowstone example. Everything has evolved into its proper place for a reason. I remember a dam being built years ago and the lawmakers were making a joke about displacing the pickle fish. They built the dam and destroyed the species, but at what cost. These are naturally occurring creatures that are there for a reason. Each one is important.

    Liked by 1 person

  5. I heard about this and have always thought it was wrong to try to mess with the ecosystem already working well without human interference. Good post. Loved seeing the video. Poachers, now that’s something we should manage better.


  6. It is only Man who by his actions thinks he knows better than nature and comes along to upset the ecosystem by imposing his behaviour and ways on the natural world.. Nature knows what it is doing and has a pecking order, where everything is in perfect order.
    I am pleased that at last this is being recognised. And that it has been clearly shown that Wolves are not the big bad wolves at all.. But are part of the system that ensures that the rest of nature also thrives..
    Great Post Paul.. 🙂


  7. Amazing. Being a lover of wolves since I can remember myself! It breaks my heart when I hear they’re hunted down by humans in certain areas! We need wolves, the ecosystem needs wolves!


    1. First, let me offer you a very warm welcome to this place and, secondly, thank you for your very lovely response. Yes, you are so correct in saying that we need wolves. Indeed, we need the totality of nature more than we can even imagine!

      Liked by 1 person

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