Science Friday - ‘Underground Atlas’ Shows How Vulnerable Fungal Networks Are

Episode Date: August 11, 2025

Fungal networks in the soil are arguably the basis of much of life on Earth, but they’re understudied and underappreciated in the conservation world. Scientists at the Society for the Protection of Underground Networks (SPUN) are trying to fix that. They just unveiled a global map of mycorrhizal fungal networks, which highlights how widespread they are and how little protection they have. Host Flora Lichtman talks with two of the SPUN mapmakers, Adriana Corrales and Michael Van Nuland, about the importance of fungal networks and why they need more protection.Guests: Dr. Adriana Corrales is a forest ecologist and scientist with the Society for the Protection of Underground Networks. She’s based in Bogotá, Colombia.Dr. Michael Van Nuland is an ecologist and scientist with the Society for the Protection of Underground Networks. He’s based in Portland, Oregon.Transcripts for each episode are available within 1-3 days at sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Hey, it's Flora Lickman and you are listening to Science Friday. Today on the podcast, the unsung hero of the underground. I think we sometimes give for granted that soils are just going to continue to exist and to give us all their functionality or the great services. When you think about the planet's top conservation priorities, you might think about biodiversity hotspots like the Amazon rainforest or the Galapagos Islands. Or maybe you think of animals like rhinos or right whales. But my next guests have something else in mind.

A kind of underdog in the conservation world, something that supports life on Earth but that most of us probably don't think about. An invisible ecosystem beneath our feet. Fungal networks. They say these underground fungal filaments are critically important to us and our planet, and we should pay them some. respect. Why? Here to tell us are my guests, Dr. Adriana Corales, forest ecologist in Bogota, Colombia, and Dr. Michael Van Neuland, ecologist in Portland, Oregon. Both are researchers with Spun,

the Society for the Protection of Underground Networks, which we're going to hear more about. Welcome to you both to Science Friday. Thank you for having us. Yeah, thank you so much for this invitation. Adrianna, let's start with you. Why should I care about the fungus underneath my feet? Wow, well, microized fungi or soil fungi in general are mega diverse. Soils are mega diverse ecosystems and microized fungi specifically, we believe they support life on earth because plants have, in many cases, an obligatory symbiosis with microized fungi. And plants wouldn't be able to really survive or have colonized terrestrial ecosystems without this fungi. So we just believe that, They are the basis for life on earth, basically.

They do all sorts of incredible things like Adriana was saying. They partner with the vast majority of plants. So any plant that you see from where you're sitting right now, there's a good chance that it has a fungal partner attached and wrapped around its root system. And the fungi is out in the soil building these high-fold networks and through their building of this fungal infrastructure, they're helping stabilize soil.

helping gather nutrients that the plant needs to grow and survive and reproduce. They're interacting with all the other diversity that's in the soil and helping soil food webs run. And in partnership with plants, they help draw down lots of carbon. As the plants are photosynthesizing, they're sharing those carbon resources with their fungal network. So they're also, we're realizing they're also becoming really critical to our global climate story and our global strategy to fund. climate solutions because of their potential for this large carbon drawdown. These fungi sound like givers. What are they getting from these relationships?

They are getting carbon, and they're also getting, you know, kind of a nice environment to live with a partner. You know, they could be out on their own trying to mine for resources and get carbon and sugars from the soil environment. But soils are a tough place to live. One of the co-authors on our new study, Merlin Sheldrake, described soils as a crowded rotscape. So they're not the most hospitable places to live. That is a good band name. It's crowded rotscape.

I was thinking about that the other day. It is a great band name. They're just harsh places to live. And so by partnering with plants and getting access to the carbon that the plants are photosynthesizing, it's a little bit of a shortcut. but it's a way for them to sort of live a little bit more comfortably in the soil and do some really amazing things. How should I imagine these underground networks? Can you kind of paint me a picture?

Yeah. One way we describe them as a circulatory system. So if you imagine sort of the veins and arteries in your body and how they are weaving their way down your arms or down your legs and sort of providing oxygen to key parts of your body, Fungal networks kind of are the circulatory system of soils. So they're these networks that grow through the soil matrix. They grow underground. They grow in these amazing branching patterns. And then not only are they visually very beautiful. Functionally, they're moving tons and tons of cellular material through these highway networks. So they kind of look like really complicated branching root structures underground. But they're not. not roots. They're fungal tissue. Are they microscopic? Could I see them with the naked eye? So some of them you can see with the naked eye. Sometimes they fuse together and create

these big, thick, fungal-rude-type structures. And sometimes if you're gardening or digging around in the dirt, you might peel back a layer of leaf litter or something. And you'll see these really thick white threads kind of weaving its way right at that surface. So that is a fungal network. That might not be a microisal one, but those are the types of networks that we're talking about. And just a mind-boggling amount of fungal tissue creating that network is underground at any one time beneath your feet. Spun, the Society for the Protection of Underground Networks just unveiled this huge map of these networks. Where did you find the hotspots?

Like the places that you thought were the most important. So we predicted hotspots of microizofungumutworks in these really interesting places and some unexpected places to us. And we found hotspots in lots of different tropical forests, but surprisingly not the Amazon rainforest. We actually found hotspots just outside the Amazon forest in the savannah, the Cerrado in Brazil and some of these hot, humid grasslands in South America. It was still really surprising to us that those were the hotspots for this type of micro-isol fungi and not places that we think of like the Amazon rainforest. One of the things that I am more excited about these maps is the tool that we design, the Underground Atlas, because that could be a great connection for everyone,

even if you are an ecologist or you are in the fungi or not, to really look at the diversity in your area. you living in a hot spot or not? What is the diversity of this fungi in your backyard? And if you are you are into mushrooms, how many of those species have you observed or not? So I think that that's a very cool tool that every person can use to really connect with these maps and explore the diversity in their local areas, for example. You can find a link to this on our website at Science Friday.com slash spun. So these hotspots are based on data collected from field biologists.

Adriana, take me into the field. What is it like to do this kind of field work? Well, yeah, it depends where you are located. Here in Colombia, for example, I have collecting locations in the Andes, in the Black Oak Forest, which is an endemic forest of Colombia, which is pretty remote, is, cloud forest. There are just small fragments of these forest that are remaining, so you have to fly there and go in these dirt roads to the top of this mountain sign and collect both the soils, but also the mushrooms, because this is the type of microrizo fungi that produce mushrooms.

So, yeah, it's pretty rewarding at the end to have the samples in your hand and come back with them. So Spun is advocating for the protection of these hot spots. What kind of threats are they facing? They face very similar threats to other organisms that folks are concerned about. So climate change is a big threat. The fungi in the soil are not immune to feeling those shifts in temperature, feeling those changes in soil moisture. And then beyond climate change, habitat loss is another key factor. Yeah, what is habitat loss look like for soil underground? Yeah. So habitat loss could be seen as deforestation in some cases, but also for, for example, this could look more like soil degradation or exotic species invasive. But I think one thing that could be transversal to all that is soil degradation, because

soil is going to suffer when the biomass above ground is destroyed and all these those host plants are destroyed, but also when, for example, we put fertilizers in the soil or things like that. So there are chemics spills in the soil. So those are super important also for soil organisms and sometimes are not super evident from the have a ground perspective. Yeah. How many of these hotspots are in areas that are protected? We estimate that less than 10% of overall hotspots that we predict are currently in protected areas. And when we compare that to animal diversity hotspots or tree diversity hotspots, it's about three times less for microisosophungi compared to those other protection levels for other organisms.

Hmm. Adriana, does that make you nervous? Very. Really? I mean, it makes me nervous because we are not aware that we are destroying these communities. And most people are not aware of the importance of this fungi for the functioning of our ecosystems. So I think we sometimes give for granted that soils are just going to continue to exist and to give us all their functionality or the great services of carbon storage or water regulators. or all those things that we use soils for. Do you feel like this is an issue on the radar of conservation groups or governments or activists? No. Generally no.

Maybe increasingly so. Certainly not governments, it feels like. Maybe activists a little bit more. I mean, it's hard, right? They are invisible organisms underground. Like they have two really big things going against them to sort of get them into that, into the same level of conversation that we have for other organisms that we can see and measure and hear. And yeah, that's just a big challenge.

Coming up after the break, the hard sell on why you should care about these underground networks. Understanding the underground is like diving in on something that is completely unknown. How do you conserve something that lives underground? The short answer is we don't know yet. So the research that we just did, we compared those hotspots to protected areas. But we don't know if you just set up boundaries and call it a national park. Is it a national park for fungi? We don't know the answer to that yet.

And we're racing to find out. This is a question for both of you. So, yeah, it's hard to make people care. what is your strategy to make people care? Adriana, let's start with you. I tell people and I used to tell my students, when you think of a plant, you have to think of fungi and microized fungi because the fungi are the microbiome of plants.

Oh, I love that. Yeah, of course. So the root microbiome has tons and tops of fungi and the plants wouldn't be able to acquire their nutrients without those fungi. So that's really eye-opening for people, that agriculture depends on this fungi to drive, and food security is going to depend on the diversity of this fungi and the ability of this fungi to also adapt to new environmental conditions. I mean, part of it is filling a data gap.

So folks who work in the conservation and restoration space have not really had the fungal data they need to help them make decisions about which ecosystems to prioritize for protection and those types of things. So that's one of the ways I feel personally motivated by just building bigger and better and sort of unignorable data products to allow them to. A lot. People can ignore data, Michael. I don't know if you've noticed. Yeah. But actually, it's apparently very easy to ignore data. Yeah, and maybe, yeah, that is probably too much of a white whale goal for me to

build the best fungal map possible that is unignorable. But as a something I should talk to a therapist about most likely, but part of it is filling a data gap, at least providing the data to the people who care, who will incorporate it and sort of measuring the impact of that. Can I offer a perspective on this? Yeah, absolutely, please. I mean, as someone who's worked to help the public care about science for the last two decades, I'll just add one more thing to your list, which is we tend to take action when we have an emotional response. I think you've got to make people feel something about all of this. Yes, I 100% agree. We don't care about what we don't know and we don't love what we don't know. So it's super important to just tap into that, the feelings.

And actually, many people are getting so excited about this fungi. Because for the the ones that produce fooding bodies, they are so beautiful and those eye-catching and people really love them. I have an emotional connection with fungi because I am obsessed with them and I can see how you. Well, tell me more about that. Why do you have an emotional connection to them? I just love them. I see them and I just talk to them and I collect them and I Once I'm in the field and I know a place I've been there collecting several times and you find a new species that you didn't see before. And it's like, oh my God, where were you before? I never seen you.

And it ends up being a new species for science or something. And it's just so, it's just the amusement of seeing these organisms that are just so different looking because they don't look like anything else. They just have their own shapes and colors, and they are just so striking. I think in the very beginning of this interview, Adriana, you said that it's the basis of life on Earth. So what would our world look like without these fungi? Oh, that's a big one. This is a cool because, of course, plants are primary producers, right? But, yeah, plants depend on microized fungi, and microized fungi depends on plants.

depends on plants and they cannot live without each other. So when we think about primary producers and just the first step in food chains, you have to think about fungi as well. Agriculture, trees, the plants that other animals eat, all of that. All of that. When you talk about protecting fungal networks and how important they are, It feels kind of existential. Like, how is studying them changed your perspective?

Starting fungi have changed the way I see plants, for example. I'm a forest engineer and I just learn a lot about plants and biomass and wood when I was in school. But understanding the underground and just the vast amount of species and carbon and other functions that are there that we don't really think very much about. It's like diving in on something that is completely unknown. There are under 200,000. Describe species of fungi, and we have predicted two or three million species of fungi.

So there is just so much unknown. And every little step, every little data set that I analyze, is just more information and more to be. to discover. Thank you so much, both of you, for joining me today. Thank you for having us. Thank you so much. Dr. Adriana Corales is a forest ecologist in Bogota, Colombia, and Dr. Michael Van Newland is an ecologist in Portland, Oregon. Both are scientists with the Society for the Protection of Underground Networks. Thanks for listening. Don't forget to rate and review us wherever you listen, but only if you like the show. It really does help us get the

word out and get the show in front of new listeners. Today's episode was produced by Rasha Aredi. I'm Flora Lichten. Thanks for listening.