
How Wolves Change Rivers [video] - enraged_camel
https://vimeo.com/86466357
======
nkurz
I always wonder how much weight should be given to the accuracy of
"irrelevant" details. I tend to believe that spotting small errors that seem
obvious to me mean that there are likely other larger errors that I would
recognize if I were more knowledgeable about the subject. I presume that if
the author isn't concerned or knowledgeable enough to strive for accuracy in
the minor details, they are more likely (intentionally or not) to make errors
in the major details.

In the case of this video, Monbiot speaks of 'deer' and then shows pictures of
American Elk (Cervus canadensis). This is defensible, as he's British, and the
European Red Deer (Cervus elaphus) is very closely related and likely more
familiar to his anticipated viewers. But midway through, the video cuts to
pictures of a Mule Deer (Odocoileus hemionus), which an expert is unlikely to
conflate with an elk.

This could be considered an "irrelevant" detail, but one of the major
differences is that the American Elk primarily graze as they have a digestive
system that allows them to efficiently digest grasses, but the Mule Deer do
not: they eat some grass, but primarily "browse" on woody vegetation. So while
they will both have an effect on streamside vegetation, it's going to be a
very different effect.

In a piece that purports to explain the science behind the cascading effects
of wolves on the ecosystem, this feels like a disconcerting blunder. Should it
cause me to doubt the credibility of the piece as a whole? I don't know. But
it makes it more difficult for me to treat Monbiot as an authority on the
topic.

~~~
waterlesscloud
It's pretty clear from the audio that he's lecturing somewhere, so it seems
likely the filmmakers selected images to go along with his pre-existing
speech.

~~~
nkurz
You are right, the audio is from Monbiot's 2013 Ted talk:
[http://www.ted.com/talks/george_monbiot_for_more_wonder_rewi...](http://www.ted.com/talks/george_monbiot_for_more_wonder_rewild_the_world)

That wasn't clear to me. Rather, I presumed (I think reasonably) from the tag
"Sustainable Man Original" that it was something that that Monbiot had
participated in the creation of. I've now read the comments on the Sustainable
Man page ([http://sustainableman.org/blog/2014/02/17/how-wolves-
change-...](http://sustainableman.org/blog/2014/02/17/how-wolves-change-
rivers/)), and see that other have pointed out that the video also uses
uncredited video of English badgers and Slovenian bears.

The creator of the video responds "Hi, we “steal” footage from lots of sources
all in a non-commercial effort to raise awareness about sustainability.". The
removes most of the criticism I'd have toward Monbiot, and retargets it toward
Sustainable Man. The video is clearly more concerned with rhetoric rather than
accuracy. Regardless of the goodness of the cause, I think in the end this
sloppiness with facts will do more harm than good.

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finkin1
Wonderful and enjoyable video. It's sad that the accuracy of it is debatable:
[http://www.nytimes.com/2014/03/10/opinion/is-the-wolf-a-
real...](http://www.nytimes.com/2014/03/10/opinion/is-the-wolf-a-real-
american-hero.html)

~~~
swartkrans
That opinion piece says the impacts affecting the park are more nuanced and
complicated than the popular narrative of the reintroduction of wolves would
lead one to believe, it doesn't say it's entirely wrong.

~~~
akavel
Um, quoting exactly:

 _" [The aforementioned] study, which focused on willows, showed that the
decades without wolves changed Yellowstone too much to undo. After humans
exterminated wolves nearly a century ago, elk grew so abundant that they all
but eliminated willow shrubs. Without willows to eat, beavers declined.
Without beaver dams, fast-flowing streams cut deeper into the terrain. The
water table dropped below the reach of willow roots. Now it’s too late for
even high levels of wolf predation to restore the willows."_

and:

 _" When we tell the wolf story, we get the Yellowstone story wrong. Perhaps
the greatest risk of this story is a loss of credibility for the scientists
and environmental groups who tell it."_

~~~
akavel
Why -1? I'm quoting exactly from the article mentioned above in the thread. Am
I wrong in anything? Am I disrespectful? Please care to explain.

~~~
swartkrans
I didn't downvote you, I can't since you replied to me, but you are
selectively quoting the article, which may have been the reason. The article
also said the Elk population was reduced by the wolves, and that this impacted
plant regrowth but not as much as widely believed, and yes some areas haven't
been improved at all. It also said bear populations increased. It's a nuanced
piece.

~~~
waterlesscloud
I've read a few papers on this in the past, after having originally seen the
video. The ongoing research is indeed nuanced and complex, and as with a lot
of ongoing scientific research, there's disagreements among scientists.

Different papers use different methods to estimate predation risk in various
locations, for instance. Some base it on actual predation incidents, some on
landscape factors (which may model risk perception as opposed to actual risk).

There's also discussion about the way active predators such as wolves impact
an area, which is different from lie-in-wait predators. And there's an idea
that a constant background threat comes to be ignored, as opposed to a sort of
pulsing threat, where there are surges of predation.

Also worth noting that various studies take place in different areas of the
park, and in different seasons. Not to mention there's three main varieties of
trees under discussion (aspens, cottonwoods, willows), which have all seen
different recovery rates in different areas.

It's not a simple question, and from what I've seen in my sort of casual
reading on the topic, it's not at all settled.

------
swartkrans
For those that can't watch the video, aka tldr, the deers in Yellowstone
National Park were apparently very destructive, and the harm caused by them
was lessened when wolves arrived. The wolves also reduced the coyote
population. Forests recovered which lead to increases in population of other
species including eagles, beavers and bears, and there was less soil erosion
affecting the rivers themselves.

------
xamolxix
Reminds me about this TED talk
[http://youtu.be/vpTHi7O66pI](http://youtu.be/vpTHi7O66pI) where Allan Savory
speaks about the behavior of herbivores with/without predators and the impact
on flora.

Fascinating, really.

I hope the day will come when we understand the biosphere of this wonderful
planet we live on.

~~~
anon1385
Unfortunately, Savory is a con artist.
[http://www.theguardian.com/environment/georgemonbiot/2014/au...](http://www.theguardian.com/environment/georgemonbiot/2014/aug/04/eat-
more-meat-and-save-the-world-the-latest-implausible-farming-miracle)

~~~
xamolxix
Thank you. It looks like a well documented article. Makes me sad to find this
out.

~~~
kevinbowman
Also interesting is that the Guardian article is by the same person (George
Monbiot) as the OP video. Not saying that's good or bad, just worth noting.

------
TheMagicHorsey
You can see something similar in economies too.

Amazon introducing AWS has radically changed Silicon Valley.

Other IaaS services and PaaS services also entered the market.

The huge variety of different SaaS businesses around now is probably directly
related to the ease of leasing/running cloud servers.

Because start-ups need so little capital to get started these days, those
start-ups engage with VCs and Angels not at the powerpoint stage of their
business, but perhaps after the launch of their MVP ... or even after they
have a solid running business.

That has changed the nature of the relationship between start-ups and
investors, and the kinds of services the investors are expected to provide.

It has also made large-scale incubators like YC possible.

------
dpflan
This concept of "rewilding" is very intriguing. I first heard about it through
NPR's TED Radio Hour with a segment on George Monbiot. The show touches on
interesting connections within nature.

Here is a link to the show - Everything Is Connected -
[http://www.npr.org/2013/09/27/216098121/everything-is-
connec...](http://www.npr.org/2013/09/27/216098121/everything-is-connected)

Also, link to The Rewilding Institute -
[http://rewilding.org/rewildit/](http://rewilding.org/rewildit/)

~~~
e12e
Happens to be part of the plot of Kim Stanley Robinson's Nebula Award winning
"2312" as well.

------
ISL
Should I take away from the video that wolves are good for the environment or
that rapid and substantial change in the relative populations of important
species can have substantial impact throughout an ecosystem?

The idea that I take away from the video is less one of trophic cascade and
more of the connectedness of things in biology.

~~~
ahoy
The trophic cascade _is_ a manifestation of the connectedness of all things
biological.

------
enraged_camel
I think this is just one example of how little we understand nature's systems.
The food chain effect is well-documented in terms of numbers. For example, we
already know that if you decrease the number of predators in an ecosystem, the
species they normally prey on grow out of control. But the video shows that
there's a massive amount of complexity under the surface of this model. For
example, the wolves in Yellowstone changed not just the number of deer (their
prey) but also their _behaviors_ , which is one of the factors responsible for
the cascade effect. Similarly, the increase in beaver numbers resulted in the
creation of more niche ecosystems for other species.

~~~
drostie
> I think this is just one example of how little we understand nature's
> systems.

Oh, definitely. And it applies at a very broad sense of the word "nature." For
instance, weight-loss. As a physics guy I have a minor aneurysm whenever
someone, referencing the obesity epidemic, says something like "a calorie is
not a calorie". What they're trying to say is very important, but I dislike
the way that it's expressed, and it may be the reason why it's hard to get
those views more accepted.

What I'd say is: the _physics_ of weight loss is extremely well understood,
but the _psychology_ of weight loss is not at all. I can tell you about
thermodynamics but that doesn't really tell you, at the level you want, _why_
everyone and everything is becoming obese. For a personal example, once I came
from the Netherlands to the US Midwest, I rapidly gained a lot of weight,
going from "skinny for my height" to having trouble with some Men's X-Large
T-shirts. Is it because the portion sizes are in general much larger? Or is it
because there's more fat or sugar or chemical additives here? Or is it because
I'm not bicycling to work every day because distances are greater here? Or is
it because in the Netherlands I was expected to "have a sport" (in my case
ultimate frisbee) and I'm no longer able to maintain that time commitment in
my new phase of life? Or is it because of a shift in my religious and personal
priorities which made it harder to fast once or twice a week? Hey, maybe it's
none of these! Maybe it's just that I'm now in a relationship with a teacher
and her late-night grading causes me to get less sleep, but because I work a
programming job and solve cognitively-complex problems, I have to spike my
blood sugar constantly to maintain the same functioning. But maybe it's
something else, like the fact that satiety signals only get sent from the
stomach to the brain after 20 minutes, and here I just tend to eat more in
that 20 minutes than there.

All I can really tell you as a physicist is that my body will naturally find
some equilibrium where energy in = energy out, at which point weight will
become mostly stationary -- and I can in theory point to the idea that I can
change this by changing the situations that I'm in. In addition with a little
bit of knowledge about hormones like leptin & ghrelin, I can tell you that
when my fat cells eventually start to die, their equilibrium will signal
hunger to my brain, making it hard to work off this weight without a lot of
discipline about my food urges. (Another potential cause! I now have a
refrigerator so food is "always around".) But even the littlest things,
perhaps even getting an hour more sleep every night, could throw that whole
psychological set of triggers completely in a different direction.

Some things, especially seen in the outside world, just have ridiculously
complicated causal graphs. It's true of weather, ecosystems, biologies -- and
even when those graphs are generated by some really simple rules like energy-
exchange, their interactions can easily spiral out of control for how we see
them.

Software is the same way. If each line has a chance of interacting with one
other, that's going to be an O(n^2) causal complexity created by O(n) lines;
good modules and interfaces only reduce the multiplicative constants but don't
change the scaling. When you get to the 50+ million lines of Windows it's
hardly remarkable that it has some bugs in it.

~~~
graycat
On "a calorie is a calorie", a suspicion is that there can be two diets equal
in calories per day but very different in how they make the person feel, say,
in _energy level_ , and, thus, how many calories they burn or how much weight
they gain or lose.

In my own efforts at dieting and weight loss, I'm not sure I've seen any such
effect for the range of diet variations I've tried. Still, there are
suspicions that some such effect might be true, somewhat common in reality,
and significant.

------
VikingCoder
This reminded me of a NATURE episode I saw, where it was all about one Fig
Tree, and all of the species that live on it, nurture it, depend on it. It was
fantastic.

------
jcroll
What attributes make a species eligible for this type of ecosystem redefining
introduction? Do they have to have been there before (i.e. _re_ introduction)?
Because I just spent four months in Florida and I can tell you down there the
populace pretty much holds the exact opposite excitement level for the
introduction of pythons to their native habitats.

------
nojvek
While getting my advanced open diver licence, I did a dive with grey nurse
sharks. There I learn't how important sharks were. Where there are sharks,
there are more reefs, more other species. When the sharks are killed, the
over-feeding begins and over time the reef is depleted.

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boyaka
Must watch anime: Wolf Children (Ookami Kodomo no Ame to Yuki)

It's about a man that is also a wolf who meets a woman and they have kids, and
about their struggle to grow up and live with their human and wolf
personalities.

------
graycat
Ah, the amazing possibilities of a multi-variable predator-prey model, say, a
system of several ordinary differential equations!

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sgt101
Hmm - how well controlled is this as an experiment?

~~~
mapleoin
It's ecology in a really large national park. You don't get to do much
controlling there.

~~~
wuliwong
I'm sure he meant his comment with a little tongue and cheek. I believe the
point is, don't assume that the conclusions drawn in this article are
accurate. Do a little cursory "googling" and you'll find quite a few articles
warning caution or full rebuttals of the thesis in this video. Here's one link
[http://elyfieldnaturalists.wordpress.com/2014/02/27/do-
wolve...](http://elyfieldnaturalists.wordpress.com/2014/02/27/do-wolves-
change-rivers/)

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zubairismail
great video ever...never saw anything like this

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vincentleeuwen
I never would have guessed the Imp knows so much about wildlife :)

