What’s a Keystone Species, and Why is It Important for You to Be One?

A keystone in architecture is a wedge-shaped stone at the center of an archway or vault that stabilizes all the other stones into position, allowing the archway to bear weight above it. Without the keystone, the building would crumble.

Our sacrum has a similar feeling of being a central support structure in the human skeleton – a keystone bone supporting the spine and pelvis.

In nature, a keystone species is a species that has a disproportionately large effect on its environment and the other organisms and animals living around it. These keystone species create habitats and living conditions for other species. Examples of keystone species are beavers, hummingbirds, sea otters, starfish, prairie dogs, gray wolves, grizzly bears, and sharks.

If you remove a keystone species, the ecosystem degrades and slowly unravels. As habitats disappear, so do the species that relied on food sources or shelter the habitat provided, and a complete rearrangement of the food web occurs.

Think of a keystone species as the glue that holds an ecosystem together.

You may have heard the iconic story about the reintroduction of gray wolves to Yellowstone National Park back in 1995? It goes like this:

Wolves in the park had been completely killed off but their reintroduction triggered a trophic cascade (when one species impacts the ecosystem from the top down) that ultimately restored balance across the entire ecosystem:

In the wolves’ absence, deer and elk proliferated and overgrazed all of the vegetation in the park, and with it, the habitats of many animals vanished, despite humans trying to control the size of the herd.

When wolves were reintroduced in 1995, they didn’t hunt the deer and elk to decrease their numbers – it was simply their presence that caused the herd to be on the move (rather than linger in areas where they could get trapped and hunted by the wolves). This presence and movement is what allowed the trophic cascade.

As a result, the park’s vegetation and other ecosystems regenerated, bringing back diverse species of plants, birds, and mammals.

Believe it or not, humans are supposed to be a keystone species, but we’ve become so disconnected from nature that we no longer can hold that title – not with any dignity anyway.

In fact, according to Lyla June Johnston, a scholar of the Navajo and Cheyenne lineage, “Indigenous people are trying to bring the human being back into the role of the keystone species, where our presence on the land nourishes the land and its inhabitants.”

What if humans could become a beneficial keystone species again?

To halt the devastating climate crisis, widespread focus on regeneration must take center stage, and humans are smart enough to create trophic cascades in the diverse ecosystems on the planet that bring habitats back to thriving.

Here are some ways you can be a helpful member of the human keystone species:

Support your local beyond-organic farms, particularly the biodynamic, regenerative organic farms. Join their CSAs, shop their booths at the farmer’s market, and tell all your friends about them. These farms are keenly aware of how to build and regenerate healthy soil which leads to healthy food, plants, and species diversity.
Donate to The Rodale Institute, an organization devoted to growing the regenerative organic movement through research, farmer training, and consumer education.
Rewild your garden by reading these helpful guidelines by Mary Reynolds, a landscaper and garden designer from Wexford, Ireland.
Donate to organizations working to preserve other keystone species, such as:
- WildAid’s shark program
- NRDC
Build healthy soil by composting at home! Read this article to get started.