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sushibowl | 7 months ago

As far as I know, the science on this is far from settled. There is no consensus and the evidence in favor of a trophic cascade in Yellowstone came predominantly from two studies done by the same team/person. Later studies failed to replicate findings.

Do wolves fix ecosystems? CSU study debunks claims about Yellowstone reintroduction

https://eu.coloradoan.com/story/news/2024/02/09/colorado-sta...

A good story: Media bias in trophic cascade research in Yellowstone National Park

https://academic.oup.com/book/26688/chapter-abstract/1954809...

discuss

order

ricardobeat|7 months ago

That looks like a quite biased interpretation of these studies. Direct quotes:

> The average height of willows in fenced and dammed plots 20 years after the initiation of the experiment exceeded 350 cm, while the height in controls averaged less than 180 cm

> This suggests that well watered plants could tolerate relatively heavy browsing. It also shows that the absence of engineering by beavers suppressed willow growth to a similar extent as did browsing

They posit that the growth in control groups not matching the fenced areas is evidence of wolves reintroduction not having the effects they are said to have. It is a pretty unconvincing argument since there are so many other variables involved. They also prove that IF the wolves have indirectly lead to either the return of beaver dams, or reduced elk browsing, there is undoubtedly an impact in tree growth, which is a positive result regardless.

Their theory that things will never return to their original state, and instead will settle into a new alternate equilibrium is probably correct, but does not seem like the definitive blow to the wolf theory that it’s made out to be.

ChuckMcM|7 months ago

Both links are paywalled so I can't comment on what they say (positive or negative). That said, I did attend an interesting lecture about systems that looks a bit at the Yellowstone as a cautionary tale about extrapolating how a system works from observational data. Basically it came down to there are secondary and tertiary effects from systems variables that express visibly differently depending on both the magnitude of the system elements influence and the time where it it changes. Thus making "simple" conclusions like 'wolves did this' often insufficient to explain system behavior and sometimes outright incorrect.

However, the introduction of wolves did, incontrovertibly, add a system element that had not been present before. Exactly what that element was, and how it expressed is up for interpretation :-)

ForOldHack|7 months ago

Brilliant observation. Dynamic systems like this are rarely a cut-n-done. Like the study of ozone, with it's seven counter intuitive steps, it is all an evolving study.

It also proves the worth of just simple studies over a long period of time. Science used to do a lot of that, and it was very interesting, as many appear on hacker news, but now it seems that cut-n-done grab more popular news.

It also bears the question: what longitudinal studies are popular here besides this one, and retro computing?

GlibMonkeyDeath|7 months ago

And this one from the National Park Service web site, funded by NSF:

https://www.nps.gov/yell/learn/ys-24-1-the-challenge-of-unde...

TL;DR - the observed reduction of the elk herd correlated with wolf introduction, but also with an increase in cougars, grizzly bears, and even bison, all of which either reduce or compete with elk. Human hunting also added pressure, but that has been limited as the herd size reduced. It is complicated.

troupo|7 months ago

I also read it as "biodiversity is a good thing"