IMAGING

There’s Fungus Among Us. But Where Exactly?

The world’s biological riches are not evenly distributed. Instead, much of Earth’s plant and animal life is concentrated in a small number of biodiversity hot spots — from the tropical rainforests of the Amazon to the alpine meadows of the Himalayas — that have earned enormous scientific and conservation attention.

Now, new research suggests that more of these critical hot spots could be hiding beneath our feet — undocumented and largely unprotected.

Using machine learning models, the scientists predicted that rich reservoirs of these fungi lie hidden in some unexpected places, including the Alaskan tundra and Mediterranean woodlands and scrublands. The dense Amazonian jungle did not stand out as a fungal biodiversity hot spot, but the neighboring savanna, the Brazilian Cerrado, did.

Using machine learning models, the scientists predicted that rich reservoirs of these fungi lie hidden in some unexpected places, including the Alaskan tundra and Mediterranean woodlands and scrublands. The dense Amazonian jungle did not stand out as a fungal biodiversity hot spot, but the neighboring savanna, the Brazilian Cerrado, did

“The Amazon of the underground is not actually in the Amazon rainforest,” said Michael Van Nuland, the lead data scientist at the Society for the Protection of Underground Networks, a research organization that led the mapping effort. “These patterns of diversity that we’re seeing are unique.”

Alarmingly, they found, relatively few of these critical hot spots are in ecologically protected areas.

The scientists say that more work is needed to confirm their predictions, which were published in the journal Nature, and to elucidate how these fungi function. But the scientists hope that the findings will usher in a more expansive view of biodiversity and conservation.

“This paper is wildly exciting,” said Rebecca Shaw, the chief scientist at the World Wildlife Fund, who was not an author of the study. “We’ve been studying aboveground biodiversity and its functioning for things that we care about — like water retention, carbon sequestration, productivity — for five decades. But we’ve made very little progress doing the same thing with belowground biodiversity.

” She added, “I’ll be looking to this group in the future to help me better understand: What do we protect?”

More than 80 percent of the world’s plants form symbiotic relationships with mycorrhizal fungi, which entwine themselves in the plants’ roots and spread thin filaments underground. But the fungi, which are often invisible to the naked eye, have not traditionally been well studied.

“We really had this aboveground bias, I think, as a society,” said Toby Kiers, an evolutionary biologist at the Free University of Amsterdam who co-founded SPUN (Society for The Protection of Underground Networks) and serves as its executive director. “How do we protect what we can’t see?”

Genomic sequencing has provided a new tool, allowing scientists to identify mycorrhizal fungi by sequencing the DNA present in soil samples collected across the world.

In the new study, the researchers mined several large global repositories of this fungal data, pulling together more than 2.8 billion fungal DNA sequences from 25,000 soil samples collected in 130 countries. They built machine-learning models to analyze this data, alongside a variety of environmental variables, such as the climate and elevation at each collection site.

The models then made predictions about fungal biodiversity across the entire planet, estimating both richness — how many species were present at a given location — and rarity, or how unique those fungi were.

“If we go to a place like Mongolia, are there really unique fungi that have unique traits that could be very helpful in the future?” Dr. Kiers said. “Are there fungi that have evolved a very high tolerance to salt or to drought?”

Some of the findings mirror other well-documented biodiversity trends. For instance, the map predicts that the biodiversity of one major subgroup of mycorrhizal fungi — associated with grasses, crops and many species of trees — is greatest near the Equator, a pattern that holds for many plants and animals. (Specific hot spots for these fungi included the Brazilian savanna and tropical forests in Southeast Asia and West Africa.)

But the opposite was true for another subgroup of mycorrhizal fungi that is associated with a select group of trees, including pines, spruces and oaks. The richness of these mycorrhizal fungi was highest closer to the poles, with hot spots that included forests in Siberia, Canada and the United States. And tundras — cold, dry habitats — were brimming with rare species of these fungi.

Indeed, extreme climates and isolated habitats, like mountaintops, seem to harbor more rare fungi, Dr. Kiers said. Preliminary data suggest that deserts may also serve as these kinds of hot spots, she added.

The researchers also found that just 10 percent of the predicted richness hot spots, and 23 percent of the rarity ones, were located in protected areas, potentially leaving them at risk. “It puts a number to what we’ve been saying for a while — that these are underappreciated systems or underappreciated organisms on the planet,” Dr. Van Nuland said.

https://www.nytimes.com/2025/07/23/ science/fungus-spun-atlas mychorrhizal.html