Expanding European protected areas through rewilding.

Rewilding seeks to address biodiversity loss by restoring trophic interactions and fostering self-regulating ecosystems. Although gaining traction in Europe and North America, the extent to which rewilding can meet post-2020 protected-area targets remains uncertain. We formulated criteria to map suitable areas for rewilding by identifying large tracts of land with minimal human disturbances and the presence of key mammal species. We find that one-quarter of Europe, approximately 117 million hectares (ha), is compatible with our rewilding criteria. Of these, 70% are in cooler climates. Passive rewilding opportunities, focused on managing existing wilderness, are predominant in Scandinavia, Scotland, the Iberian Peninsula, and notably in the Baltic states, Ireland, and southeastern Europe. Active rewilding opportunities, marked by reintroduction of absent trophic guilds, are identified in Corsica, Sardinia, southern France, and parts of the Netherlands, Denmark, Sweden, and Norway. Our mapping supports European nations in leveraging land abandonment to expand areas for nature conservation, aligning with the European Biodiversity Strategy for 2030. Nevertheless, countries with limited potential for rewilding should consider alternative conservation strategies.