Global hotspots of mycorrhizal fungal richness are poorly protected

Using more than 2.8 billion fungal sequences sampled from 130 countries, we worked with GlobalFungi, Fungi Foundation, the Global Soil Mycobiome consortium, and researchers around the world to predict patterns of fungal richness and rarity across biomes from the Amazon to the Arctic. This work allowed us to identify predicted hotspots of biodiversity and endemism for both arbuscular and ectomycorrhizal fungi. This marks a major breakthrough in how we understand and visualize life beneath our feet.

The world’s richest hotspots of mycorrhizal fungi (which are vital for plant growth and climate stability) lie largely unprotected and overlap with human pressures, leaving critical underground biodiversity at risk.

This matters because mycorrhizal fungi live in partnership with most plants, helping them take up nutrients, grow better, and store carbon in soils. These underground fungi are crucial for healthy forests, food security, and climate stability. But unlike plants and animals, we know little about where the greatest diversity of these fungi is found—or whether those areas are being protected.

We gathered the largest global dataset of soil DNA to track where different kinds of mycorrhizal fungi live. We then compared these “hotspots” of fungal diversity with maps of protected areas like national parks and reserves.

We found that the richest fungal hotspots are in tropical and subtropical regions like the Amazon, Congo Basin, and Southeast Asia, as well as some temperate ecosystems, and that very few of these hotspots fall inside existing protected areas. Additionally, many overlap with areas of intense human activity such as farming, logging, and land clearing which makes them especially vulnerable.

This is important because mycorrhizal fungi are invisible but essential for ecosystems and agriculture. Yet most of their diversity is left outside of conservation planning. Protecting fungal hotspots alongside plants and animals would help maintain soil health, biodiversity, and climate resilience.

SUMMARY

Mycorrhizal fungi form symbiotic relationships with most plants, underpinning ecosystem functioning, carbon storage, and biodiversity. Identifying where fungal richness is concentrated—and whether those areas are protected—is essential for biodiversity conservation strategies.

We compiled the largest global dataset of soil DNA records for mycorrhizal fungi, integrating amplicon sequencing data with environmental and geographic variables. We mapped global richness patterns across arbuscular, ectomycorrhizal, and ericoid fungi, and overlaid these maps with existing protected area networks to assess conservation coverage.

Findings:

Richness hotspots occur in tropical and subtropical regions (notably South America, Central Africa, and Southeast Asia) and in certain temperate ecosystems.

Current protected area networks cover only a small fraction of these hotspots, leaving most mycorrhizal fungal diversity unprotected.

Human pressures (land-use change, agriculture, deforestation) overlap strongly with unprotected richness hotspots, further threatening fungal biodiversity.

Conclusion
Mycorrhizal fungi are critical to plant health, soil function, and global carbon cycling, yet they are largely excluded from conservation planning. To safeguard these hidden biodiversity reservoirs, conservation frameworks must explicitly include fungi alongside plants and animals. Protecting fungal hotspots could strengthen ecosystem resilience and sustainability under global change.

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