It seems like such a nice, tidy way to explain the rebirth of Yellowstone National Park — that after wolves were reintroduced in the mid-1990s, they changed the ecology of the park, including the way rivers flow.

But nature is never tidy, as Colorado State University scientists explain in a recently published paper that debunks the popular notion that wolves were solely responsible for park changes.

I was certainly duped.

A few weeks ago, I wrote a column about a popular video featuring a stirring TED talk by British writer George Monbiot, who explained how the reintroduction of wolves changed Yellowstone’s ecology.

A natural predator to elk, wolves came back and reduced the number of elk that were destroying the park’s willows and aspen, Monbiot says. As trees grew back, songbirds and beavers returned, he says.

“The dams (beavers) built provided habitats for muskrats, otters, ducks and fish and reptiles and amphibians,” Monbiot says in the video, which now has more than 3.7 million views.

Monbiot’s talk was focused on the concept called “trophic cascade” — when predator species suppress their prey, thus alleviating pressure on that animal’s food source.

Monbiot points to river banks growing sturdier with vegetation and rivers becoming less meandering, creating pools that attracted more wildlife. “The wolves changed the behavior of the rivers,” Monbiot says.

Well, not so much, say researchers at Colorado State University.

“It has been popular and convenient to tell the romantic tale that wolves have restored Yellowstone, but our findings prove it is not so simple,” said CSU professor Thompson Hobbs, who co-authored the paper.

Researchers looked at 30 years of riparian willow growth and also the annual precipitation, stream flow, growing season length, soil moisture and abundance of elk.

Their central finding was the relationship between elk populations and willow growth cannot solely be attributed to the reintroduction of wolves but also is dependent on geography, climate and water supply for the willows.

“No single force explains the patterns of plant establishment and growth in Yellowstone over the past three decades,” Hobbs said in a press release.

A 2013 CSU paper found beaver dams’ impact on water levels were as responsible for the health of vegetation as elk. In other words: science, not romance.

I contacted Chris Agnos, who produced the video of Monbiot’s talk for his website, Sustainable Man. Agnos said the video was never meant to suggest other factors weren’t at play.

“You can’t attribute any one effect in nature to any one cause in nature,” he said. “Everything is connected to everything and it all matters. That was the moral of the story.

“Perhaps some of the other causes of Yellowstone revival were omitted from the video, but if we were to identify every micro cause of Yellowstone, we would literally have to analyze every single action that every being has taken on the planet, since every action affects everything else, even if ever so slightly,” Agnos added.

“This does not take away from the impact the wolves have had; it only more accurately reflects the knowledge that there is no separation and that everything we do affects the entire world.”

E-mail Jeremy Meyer at jpmeyer@ denverpost.com. Follow him on Twitter: @JPMeyerDPost