As It Happens·Q&A

Scientists are mapping the world's underground fungi network to fight climate change

There is a global blind spot in the fight against climate change, says evolutionary biologist Toby Kiers, and she is on a quest to map it out.

'You can think of fungal networks as kind of the coral reefs of the soil,' says biologist Toby Kiers

Tiny threads of fungi known as fungal mycelium wrap around or bore into the roots of plants and exchange nutrients. (Yoshihiro Kobae)

Story Transcript

There is a global blind spot in the fight against climate change, says evolutionary biologist Toby Kiers, and she is on a quest to map it out.

Kiers is leading a team of scientists known as the Society for the Protection of Underground Networks (SPUN) to study networks of fungi across the world.

"We've documented their importance for decades, but this work has largely been inaccessible," she said.

The biologist says the overlooked organism sustains much of life on Earth by isolating carbon from plants, but through increasing land use changes, various types of fungi get destroyed.

Kiers spoke with As It Happens host Carol Off about her plans to create a global map of fungi. Here is part of their conversation.

Toby, why do you want to map the world's fungi?

They've been a total global blind spot in conservation and climate agendas. They're this ancient life support system [and] they need to be mapped the same way that ocean currents and global vegetation are mapped.

People who dig and garden, who know what the soil looks like, can [they] see these things?

They're just too small to see with the naked eye. They're thinner than threads of cotton. 

But what they do is they form these living nutrient highways between plant roots and the soil. So if you wanted to be able to see underground, you would see these plant roots become colonized by the symbiotic fungi.... Plants feed carbon to these fungi in exchange for phosphorus and nitrogen that the fungi collect out in the soil. 

This is what we're doing in my lab right now.... We see these nutrient highways that are full of carbon and phosphorus and other kinds of nutrients.

The fungi mycelium network is like a series of 'living nutrient highways,' says evolutionary biologist Toby Kiers. (Loreto Oyarte Galvez)

When you talk about mapping it ... how much territory does this cover?

If you hold even a handful of soil in your hand, that's about 100 kilometres of fungal networks. So they're incredibly dense. Like 50 per cent of the living biomass in these soils is fungal network. 

When we talk about mapping, what we're talking about is actually understanding who is where. The biodiversity of these fungi. So we have to go out and take those samples and extract the DNA and look for these fungal networks and look for the biodiversity hotspots.

You can think of fungal networks as kind of the coral reefs of the soil. They're the ecosystem engineers, but they're completely invisible to the naked eye. And so people haven't been focused on them as a conservation priority.- Toby Kiers, evolutionary biologist

Why do you think it's necessary for conservation that we should have a map of these networks?

These fungal networks are disappearing at an alarming rate. 

The destruction of the underground really accelerates climate change, biodiversity loss and interrupts all of our global nutrient cycles. 

You can think of fungal networks as kind of the coral reefs of the soil. They're the ecosystem engineers, but they're completely invisible to the naked eye. And so people haven't been focused on them as a conservation priority.

This initiative, I think it signals sort of an emergence of a new underground climate movement.

Toby Kiers, far left, and her team are embarking on a quest to map the world's fungi. (Seth Carnill)

What are the chief threats, then, to these networks of fungi?

Networks are really threatened by agricultural expansion, by deforestation, by urbanization. 

Urbanization, in particular with layers of concrete, it's very hard for these fungal networks to survive. And so one of the things we're doing is advocating, for example, for a living roof — the green roofs — because surprisingly, these fungal networks, they actually can disperse by spores in the air. And so if we have things like living roofs that form these corridors, it can help fungal networks survive big urbanization centres.

What you're saying is not just the urbanization of the planet, but also farming itself ... the use of chemicals and tillage, right? That's how most of our agriculture is done. So what needs to change, then?

There's really compelling data suggesting that pesticides and fertilizers are really disrupting the symbiosis between plant roots and their fungal networks. And this is bad for agriculture because if you have an agricultural system with a healthy fungal network, it can keep the nutrients in the ecosystem. But as soon as the network is gone, you have leaching. [There is] about 50 per cent more leaching in the absence of a fungal network.

A fungal network with reproductive spores containing nuclei. (Vasilis Kokkoris)

When you're looking at things like beautiful trees and rainforests or coral reefs, they are so lovely to look at. When you're talking about fungi, though, we can't even see it. It's underground. What message do you have for people [on] how to understand and to appreciate what you're talking about?

What we're saying to people is to try to switch our mentality about what it means to conserve … and not necessarily always focus on high-priority or high-profile plants and animals. 

Focus on things that we can't see as structures and flows.

We're developing some of the first visuals of what these fungal networks look like when they're underground. And they look like nutrient rivers.

They have very complex flows inside of them because ... this carbon and phosphorus and nitrogen and all of the organelles of the fungi [are] moving through. And it's a giant pipe system, and you can actually watch the behaviour of these fungi as they navigate [the] landscape. 

Watching the flows inside of them really changes people's perspective about walking on top of them.


Written by Mehek Mazhar. Interview produced by Kate Swoger. Q&A edited for length and clarity.

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