Oregon’s Willamette Valley is a major hotspot for webs of mycorrhizal, or network-forming, fungi. These fungal networks help promote soil health and plant growth by moving nutrients between plants and soil. Researchers at the Society for the Protection of Underground Networks (SPUN) predict that nearly 90% of mycorrhizal networks around the world lie outside of protected areas, including those in the Pacific Northwest.
Scientists at SPUN say that this hidden, vital component of land-based ecosystems deserves more protection. But protection for these networks is different from typical land protection, since these fungal species are present in much of the soil in the U.S. Researchers say it’s important to find ways to protect this diverse fungi without keeping humans out of these areas entirely.
Kylie Mohr, a reporter with High Country News, wrote about the presence of these fungal networks in the West, and spoke with several experts who are imagining and calling for ways to preserve them. She joins us to break down the details.
Note: The following transcript was transcribed digitally and validated for accuracy, readability and formatting by an OPB volunteer.
Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. Nearly 90% of crucial fungal networks around the world lie outside of protected areas. That’s according to researchers at the Society for the Protection of Underground Networks. The group is known as SPUN. They focus on mycorrhizal fungi. These networks help promote ecological health by moving nutrients between plants and soil. Oregon’s Willamette Valley is a major hotspot for these buried webs. Kylie Mohr recently wrote about these networks and efforts to preserve them in High Country News, and she joins us now. It’s great to have you back on the show.
Kylie Mohr: Hey, thanks so much for having me.
Miller: What are mycorrhizal networks?
Mohr: So mycorrhizal means fungus root, and it basically refers to the relationship these types of fungus have with plants via their roots. So the network is basically a two-way symbiotic relationship where fungal filaments connect with plants’ roots, and that connection allows the exchange of nutrients and nurtures soil health, and it can even promote carbon sequestration. So, at the end of the day, these networks, they result in bigger, healthier plants, more productive soil, and are really crucial for aboveground benefits.
Miller: You based a lot of your reporting on a map created recently by this group I mentioned, SPUN, the Society for the Protection of Underground Networks. What did this map show?
Mohr: Yeah, so the map was really cool. It actually came out last summer in June 2025, and it basically shows expected mycorrhizal fungi biodiversity globally. So you can see hotspots that the researchers modeled based off of environmental DNA and a variety of other kinds of environmental data. And covering this story for High Country News, I zoomed in on the western U.S., which is the area we focus our reporting on and I immediately saw, oh, OK, there’s these spots that are showing a high concentration of this fungi, but it’s not in protected areas, it’s where there’s development, it’s where people live, it’s along road corridors. And I wanted to learn more and figure out what exactly I was looking at and how better understanding these networks is important for better conserving them and protecting them in the future.
Miller: What stands out in the Willamette Valley in particular?
Mohr: Well, I think in the Willamette Valley, that’s an area that you can kind of see the benefits of these networks firsthand, because it is such a fertile place, right? There’s so much agriculture there and that comes from what’s happening in the soil. So the Willamette Valley is really just a case study of the benefits of these fungal networks and why they’re so important for humans.
Miller: Right, so what’s lost when mycorrhizal networks are disrupted?
Mohr: Right. So, any sort of disruption of soil, especially topsoil, it severs those networks and it makes the soil less healthy, less productive. You’re not gonna see the same quality of plants, the same health of plants, the same carbon storage. It really just degrades the soil and therefore what the soil can offer to the plants that are growing in it.
Miller: So to go back to that headline stat that I mentioned at the beginning, that you just mentioned briefly, that 90% of hotspots for these mycorrhizal fungi, these networks lie outside of protected areas. What did you hear from researchers about ways to protect these networks without that kind of protected status and without keeping people outside of these areas altogether?
Mohr: Right, so one of the researchers, he acknowledged we can’t have national parks everywhere. That kind of conservation is not what they are necessarily saying that they want for all of this fungi, that would be impossible, but there is a lot that we can do that we haven’t done. So number one is you can’t really protect what you don’t know. And so that’s where SPUN comes in. They are both doing the research and also funding the research of studying fungi, identifying new species, learning more about them. What they do, why they’re important, and where they are. And then once you know that, there’s a lot that you can do.
So you can reduce soil disturbance. You can do no-till agriculture if you’re in an agricultural area. If you’re a land manager with the Forest Service, you can follow this principle of “let it rot,” which is basically this idea of leaving woody debris on the landscape, letting things rot rather than moving them somewhere, getting rid of them, even burning them, so that they can decompose into a food source for this fungi.
And then in your own life, just as an everyday regular person, compost is a great thing you can do. You can compost your food scraps, add that to the soil in your garden or your backyard. That’s helping feed mycorrhizal fungi. They love organic matter like that, and anything that you can do to kind of infuse the soil, give them what they need to thrive, is a step in the right direction according to the researchers.
Miller: And don’t put all of your leaves into the bin around leaf pickup either, for example.
Mohr: Yes, yes, that is a great example.
Miller: There are nurseries for raising threatened plants or collecting seeds, say, for native grasses. We’ve talked about that over the years. There are hatcheries for endangered salmon. We’ve talked a lot about that. Is there any analog for mycorrhizal networks, efforts to actually boost the production of these underground fungal networks?
Mohr: Right. I don’t want to speak definitively for global systems because I might miss something, but one of the researchers that I mentioned really made the point that we’re not even at that level when we’re thinking about fungi. We’re not at the level where we’re thinking about nurseries or hatcheries or kind of that level of intervention. We’re still at the point of merely identifying new species that we didn’t know exist. However, there are lots of resources and labs that are studying soil and trying to preserve soil samples and soil fungi.
One of them is at the University of Kansas, and at the time of my reporting, funding for that really important soil library was in danger of lapsing. So, again, it comes back to funding priorities, right? If we are going to put fungi on the same level as wildlife and plants and all the things that we know and love and try to protect above ground, then we need to also fund research to better understand what’s below ground and how to protect it moving forward.
Miller: Although you do know that protecting these organisms, it does seem fundamentally different than protecting things like native animals, or even not big charismatic animals, but like things like pollinators where it’s easier to see the possibility for public buy-in. What did you hear from researchers, and you have about a minute for this, about building that kind of buy-in for underground fungal networks, getting people to care?
Mohr: Yeah, I mean, I think they hope that this map is the first start because you can really see – it’s such a cool resource, I would highly encourage people to go check it out, zoom in on ecosystems that you care about – but having an idea of just what is going on under our feet, what is going on every time you look at a flower in your neighbor’s garden or a tree on your block, or a beautiful landscape in a national park, to think about what’s going on underneath the soil is really the first step. And because the world is changing at such a rapid clip, it’s important to protect fungal species even before we know everything about them. Let’s not wait until we’ve identified everything. Let’s protect them now, is kind of their message.
Miller: Kylie, thanks very much.
Mohr: Thanks for having me. Really appreciate it.
Miller: Kylie Mohr is a reporter for High Country News. She wrote recently about mycorrhizal fungi, mycorrhizal networks in the Northwest and around the world.
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