Can Humans Be A Keystone Species? 5 Inspiring People Making a Difference

Have you ever heard of a keystone species? In ecology, a keystone species is one that has a disproportionate impact on its environment relative to its abundance. In other words, the presence of these plants and animals creates a positive upward spiral so many other plants and animals can thrive. But here's a question we don't often think about. Can humans be a keystone species?

First things first: what exactly is a keystone species?

A keystone species is an animal or plant that plays a significant role in keeping its ecosystem healthy. If you introduce it, habitats regenerate. If you remove it, habitats start to fall apart.

Take oysters, for example. They might not seem like a very exciting animal, but you're going to love this. A single native oyster can filter and clean 50 litres of water a day. And oysters don't live by themselves. They create a living coral reef where hundreds of other fish and plant species can live, purifying the water and protecting coastlines from erosion. Then you've got the poster boy of keystone species; the wolf.

When wolves were reintroduced to Yellowstone National Park in 1995, they helped bring the ecosystem back into balance. Before that, there were too many elk, and they were overgrazing young trees and plants, especially around rivers and streams. Once wolves returned, they began hunting elk, which reduced their numbers and changed their behaviour. Elk started avoiding open areas where they were easy targets, giving plants like willow and aspen a chance to grow again. This new plant growth helped bring back birds, beavers, and other animals. Beavers, in turn, built dams that improved water flow and created new habitats for fish. Birds of prey came to hunt those fish. You get the picture! Wolves are a keystone species, so reintroducing them meant all these other animals and plants got a chance to thrive.

Can humans be a keystone species?

We often hear about the damage humans cause. It’s easy to wonder if the planet might be better off without us. But that’s only part of the story. Humans can also be a powerful force for regeneration and healing.

Around the world, people are making an enormous difference by restoring ecosystems, protecting wildlife, and stabilising the climate. These individuals act like keystone species in nature: they hold things together and help life around them thrive.

That’s what gives me hope. Imagine a world with billions of people each playing their part, helping to create a greener, more resilient planet. If more of us believed in our ability to make a difference, we could change everything.

The five people I’ll introduce below prove that humans can be a keystone species. Let’s dive in.

1. Boyan Slat – Cleaning Up the Ocean

At just 18 years old, Dutch inventor Boyan Slat turned frustration into action by founding The Ocean Cleanup, a non-profit organisation developing cutting-edge technology to rid the world’s oceans of plastic. While most people his age were finishing school or figuring out what to do next, Boyan was designing systems that could clean the Great Pacific Garbage Patch, one of the largest accumulations of ocean plastic on Earth. His solution? A series of passive, solar-powered barriers that float with the currents, gently gathering plastic waste for removal.

But he didn’t stop there. Realising that rivers are the main channels carrying plastic into the ocean, Boyan and his team developed “Interceptors”. These automated systems collect waste directly from rivers, preventing it from ever reaching the sea. So far, millions of kilograms of plastic have been removed or intercepted. His story reminds us that age doesn’t limit impact, and that innovation, persistence, and belief in solutions can drive massive change. Boyan’s message is simple but powerful: solving big problems starts with believing they can be solved, and then acting on that belief. In doing so, he’s become a keystone human, holding open space for a healthier ocean and a cleaner future.

2. Rajendra Singh – The “Waterman of India”

Rajendra Singh didn’t start out as an environmentalist. In fact, he trained as a doctor. But when he began working in rural Rajasthan, he quickly realised that medicine alone wasn’t enough. His patients were struggling not just with illness, but with the deeper issue of water scarcity. Crops were failing, rivers had dried up, and entire villages were being abandoned. What people needed most wasn’t more pills. They needed clean, reliable water. So he set out to solve the root of the problem.

He learned a traditional method for collecting water. With simple tools like spades and pick axes, people can create earth dams (johads) to collect and store rainwater in ponds. He started teaching this to his patients, and the idea spread. Over the years, he worked with villagers to build over 11, 000 johads. As well as filling pools with rain, some water trickled under the ground and filled up old aquifers so springs and rivers got recharged.

With pick axes and determination, the people in Rajasthan brought 5 rivers back to life!

Rajendra's work sparked what became known as a “reverse migration,” as families who had been forced to leave returned to their land and livelihoods. Wildlife came back too, as the landscape slowly healed. His story proves that you don’t need to start out as an expert to become a keystone human. You just need to care enough to act.

3. Isabella Tree – Rewilding at Knepp Estate

Alongside her husband Charles Burrell, Isabella Tree transformed their struggling farm in southern England into one of Europe’s most inspiring rewilding projects. Faced with poor soil and declining profits, they chose to stop conventional farming and let nature take the lead. They introduced free-roaming animals such as longhorn cattle, Exmoor ponies, and Tamworth pigs, which mimic the natural grazing patterns of wild herbivores. Without ploughing, planting, or pesticides, the land began to heal. What followed was remarkable: biodiversity flourished, and rare species like nightingales, turtle doves, and purple emperor butterflies returned. The landscape came alive with birdsong, wildflowers, and thriving wetlands.

Isabella shows that abundance can return when people make space for nature. But Isabella Tree’s impact goes far beyond one estate. Through her writing and advocacy, she has inspired countless others to reimagine what land can be. In that sense, she is a keystone human: someone who creates the conditions for others, human and non-human alike, to thrive. Her story is a powerful reminder that restoration is possible and that giving nature room to breathe can bring back life in ways we never expected.

I absolutely loved Isabella's book about rewilding the Knepp Estate. You can buy it here.

4. Chibeze Ezekiel – Grassroots Climate Justice in Ghana

Activist Chibeze Ezekiel led a successful grassroots campaign to stop the construction of a coal power plant in Ghana. While powerful interests pushed for fossil fuel development, Chibeze mobilised communities, educated citizens, and built pressure through local networks. Instead of coal, he championed clean, renewable energy solutions that met both environmental and social needs. His leadership helped shift national policy and earned him the Goldman Environmental Prize in 2020.

Chibeze’s story is a powerful reminder that ordinary people, when organised and informed, can challenge even the most entrenched systems.

5.. Nemonte Nenquimo – Defending the Amazon Rainforest

Nemonte Nenquimo, an Indigenous Waorani leader from the Ecuadorian Amazon, made history in 2019 when she helped win a groundbreaking court case that protected more than 500,000 acres of rainforest from oil drilling. The court ruled that the Ecuadorian government had violated the Waorani people's rights by failing to properly consult them before opening their land to extraction. This victory not only protected trees and wildlife, it also safeguarded a way of life and set an important legal precedent for Indigenous rights across the Amazon.

As co-founder of the Ceibo Alliance, Nemonte continues to defend her people’s territory and leads efforts to protect the forest through community-led conservation. Her voice is calm and strong, rooted in deep love for the land and a vision for future generations. Like a keystone species that helps hold an ecosystem together, her leadership supports both cultural and ecological resilience. Her story reminds us that Indigenous communities are not just protectors of nature, they are a living part of it. And so are the rest of us. No matter where we come from, we are all part of the natural world. When we recognise that connection and act on it, we too can play a vital role in healing the planet.

How will you be a keystone human?

These five stories are just a handful among millions. Every person doing their part, whether rewilding land, restoring rivers, rethinking fashion, or reshaping minds, is a vital thread in a global tapestry of change.

We may not all make headlines. But just like keystone species in nature, our everyday choices can offer support, spark inspiration, and create ripples that travel farther than we ever realise. Even small actions can strengthen the web of life around us.

So the question is not really: can humans be a keystone species? The real question is this. What kind of keystone human will you be? Instead of seeing a world full of problems, we can choose to see billions of opportunities. Billions of people, each with the potential to help build a vibrant, balanced, and beautiful world.

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