High-resolution range mapping of mycorrhizal fungal species reveals systematic biases in their protection

Mycorrhizal fungi are essential to ecosystem functioning but have been overlooked in conservation agendas due to data limitations and a historical focus on plants and animals. We present the first global, species-level assessment of the area-based conservation of mycorrhizal fungi. Using 16.5 million site-by-taxon presence–absence records, we created high-resolution range maps for 189 arbuscular mycorrhizal and 2,669 ectomycorrhizal species hypotheses. By intersecting these range maps with protected areas, we show that arbuscular mycorrhizal fungi are less protected than expected by random chance, and both guilds are less protected than terrestrial mammals. We explored the Species Protection Index (SPI) as another conservation metric and found it sensitive to predicted range size. Nonetheless, the SPI framework can be used with our maps to monitor and inform mycorrhizal fungal habitat protection. Our findings highlight the value of species-level spatial data in fungal conservation planning to mitigate extinction risks associated with habitat loss.