9.5% of mycorrhizal richness hotspots fall within protected areas

The unit is land area

Michael E. Van Nuland and colleagues compared models of mycorrhizal fungal distribution with World Database of Protected Areas boundaries. In their Nature analysis, protected areas overlapped 9.5% of predicted fungal richness hotspots overall. The separate values were 5.1% for arbuscular mycorrhizal fungi, AM, and 13.9% for ectomycorrhizal fungi, EcM.

These percentages describe model-defined areas. They do not mean that 90.5% of fungal species are threatened, or that every unprotected location is currently being destroyed. Those statements would require different evidence.

How the comparison was defined

The authors identified richness hotspots above the 95th percentile of predicted values. Their models use samples and environmental variables; the map is not a complete census of every fungus in every grid cell. Uneven sampling and extrapolation remain important limitations. The published data and code make it possible to examine how the results were obtained.

Richness and rarity are also different metrics. This chart concerns concentrations of taxa, not areas containing especially rare lineages. The corresponding values should not be exchanged simply because both kinds of map look similar.

A boundary does not measure effectiveness

Protected areas differ in their objectives and management. Spatial overlap alone does not demonstrate that soil moisture, plant hosts or habitat continuity are being maintained. The indicator helps identify a planning gap, but it needs field knowledge and monitoring alongside it. The practical question is therefore both whether an area has protected status and which conditions its management preserves for fungi.