Mapping the Invisible: Why 90% of the World’s Mycorrhizal Hotspots Remain Unprotected

Redacción HC
10/09/2025

Beneath our feet lies a vast, intricate network that quietly sustains life on Earth. Mycorrhizal fungi—symbiotic partners to over 80% of plant species—are nature’s hidden engineers. They help plants absorb essential nutrients, bolster soil health, and even influence global carbon storage. Yet, despite their critical role, a new global mapping effort reveals a stark truth: nearly 90% of the planet’s mycorrhizal biodiversity hotspots lie outside protected areas.

Published in Nature by Michael E. Van Nuland, Colin Averill, Justin D. Stewart, Oleh Prylutskyi, Adriana Corrales, Laura G. van Galen, Merlin Sheldrake, Kabir G. Peay, Johan van den Hoogen and the SPUN Mapping Consortium, this study marks the most comprehensive attempt yet to chart the “hidden half” of global biodiversity.

The Overlooked Architects of Ecosystems

Mycorrhizal fungi live in symbiosis with plant roots, trading nutrients for sugars and weaving vast underground networks that link entire plant communities. These connections—sometimes likened to a botanical internet—redistribute water and nutrients, enhance plant resilience, and influence entire ecosystems.

While conservation efforts traditionally focus on charismatic wildlife or visible habitats, fungi have been largely absent from protection strategies. Without detailed maps of their distribution, policy-makers have been unable to safeguard the biodiversity that thrives below ground.

How Scientists Mapped the Underground

The research team compiled an unprecedented dataset: 24,982 geo-referenced soil samples from global databases like GlobalFungi and GlobalAMFungi. These samples contained over 2.8 billion fungal DNA sequences, which were processed to identify arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) fungi.

Using machine learning models trained on this dataset, scientists predicted patterns of species richness and endemism at a 1 km² resolution worldwide. Environmental variables—such as climate, vegetation, and soil chemistry—helped refine the predictions. The results were then compared against global protected area maps to evaluate conservation coverage.

While the dataset was vast, the authors acknowledged limitations: uneven sampling (especially in tropical regions), potential underestimation of undescribed species, and the need to extrapolate predictions in underrepresented environments.

Where the Hotspots Are—and Why They’re at Risk

The maps reveal that AM fungi dominate many tropical regions, including the Amazon and African rainforests, while EcM fungi flourish in boreal and temperate forests. Mediterranean zones and cloud forests also host significant diversity.

Yet when overlaid with existing protected areas, the findings were sobering: fewer than 10% of these underground biodiversity hotspots are protected. Asia, for example, showed especially poor coverage for AM fungi. Even in regions with slightly better protection, like boreal forests, the safeguards are still far from adequate.

This disconnect suggests that conservation plans centered on above-ground species may fail to protect the microbial and fungal life critical to ecosystem stability.

Implications for Conservation and Policy

The study’s significance extends far beyond academic curiosity. Mycorrhizal fungi influence agriculture, climate resilience, and forest regeneration. By integrating fungal diversity into conservation planning, countries could enhance food security, mitigate climate change, and strengthen ecosystem services.

Practical steps suggested by the authors include:

1. Expanding protected area networks to cover fungal hotspots.
2. Targeted sampling in underrepresented regions, especially in the tropics.
3. Including soil biodiversity indicators in environmental impact assessments.
4. Using fungal diversity maps to guide ecological restoration.

Why This Matters for Everyone

Soil health underpins agriculture, forestry, and water regulation. Communities dependent on fertile land—such as smallholder farmers and those practicing agroforestry—stand to benefit from healthier mycorrhizal networks. Protecting underground biodiversity could be as critical to our survival as conserving forests, wetlands, or coral reefs.

By revealing the vast, unprotected fungal world beneath our feet, this research calls for a paradigm shift: biodiversity conservation must go deeper—literally.

Conclusion: A Call to Map, Monitor, and Protect

The story of mycorrhizal fungi is a reminder that much of Earth’s biodiversity is invisible, yet indispensable. Protecting it will require coordinated scientific, political, and community action. As climate change and habitat loss accelerate, these underground networks may prove to be one of our most valuable allies in sustaining life on the planet.

Topics of interest

Biodiversity