Experts document remarkable transformation in Yellowstone National Park after bringing wolves back: 'The power of predators as ... architects'

If you want a glowing example of how interwoven ecosystem elements are, take a look at Yellowstone National Park. A recent study revealed that even wolves and willow trees depend on one another there.

Though it's now a symbol of the park, the gray wolf was absent from Yellowstone for nearly 70 years. The species was hunted to eradication by around 1926, leading to ecosystem chaos in the region. Without predators to maintain balance, the elk population surged, leading to overgrazing, particularly of riverside willows.

In the decades following the eradication of the gray wolf, conservationists gained a stronger understanding of both how fragile and how crucial a balanced ecosystem is. By the mid-1990s, it was agreed upon that reintroducing wolves to Yellowstone would restore that much-needed balance.

Should we be actively working to kill invasive species?

Absolutely

It depends on the species

I don't know

No — leave nature alone

Click your choice to see results and speak your mind.

The aforementioned study was designed to gauge the impact of the "trophic cascade" of the wolf reintroduction over a 20-year period. According to the study, trophic cascades are "the indirect effects of predators propagating downward through food webs" and "play a critical role in shaping ecosystems."

To gauge this trophic cascade, researchers measured the crown volume of riverside willow trees. In 2001, the average crown volume was 0.3 cubic meters. When the study concluded in 2020, they were 4.8 cubic meters. That's a 1,500% increase.

"Our findings emphasize the power of predators as ecosystem architects," lead researcher William Ripple said. "The restoration of wolves and other large predators has transformed parts of Yellowstone, benefiting not only willows but other woody species such as aspen, alder, and berry-producing shrubs."

Watch now: Giant snails invading New York City?

Giant snails invading New York City?

0 seconds of 41 secondsVolume 0%

00:00

00:41

This study perfectly highlights nature's delicate balance and shows us that caring for that balance is not always intuitive. Long ago, wolves were eliminated in certain areas to protect human settlers, but while there was logic to that decision, it wound up doing more harm than good. Studies such as this one offer us the wisdom to avoid those mistakes going forward.

Other conservation efforts have had similar success in allowing both individual species and ecosystems to thrive. A Caribbean project revived 12 species on the brink of extinction by removing invasive species. In Pakistan, conservationists have reversed decades of damage done to mangrove forests.

Each of these success stories offers both a roadmap and sense of hope to others seeking to protect our planet's inhabitants and their ecosystems.