Safeguarding evolutionary history in a biodiversity hotspot: downscaling the EDGE metric to a regional application

Abstract

In the face of accelerating biodiversity loss, phylogenetically informed approaches offer critical insights for conservation planning from an evolutionary perspective. The EDGE (Evolutionarily Distinct and Globally Endangered) metric combines phylogenetic singularity with extinction risk to identify taxa that represent unique evolutionary history under threat. In this study, we focus on the global conservation relevance of angiosperms native to a regional biodiversity hotspot, the Iberian Peninsula. Our aim was to identify areas with a high concentration of EDGE species and to evaluate how effectively the current protected area network encompasses them. Our findings reveal that threatened evolutionary history is primarily concentrated in mountainous and coastal regions. While several EDGE zones --areas containing unique and endangered evolutionary lineages-- overlap with existing protected areas, particularly in mountains, others harbouring few but evolutionarily unique and highly threatened taxa remain largely unprotected. This study highlights the value of applying global conservation metrics such as EDGE at regional scales. Our results provide a foundation for integrating evolutionary history into conservation prioritization in the Iberian Peninsula and offer a replicable framework for implementing the EDGE approach in other biodiversity-rich regions. Impact statementIn the Iberian Peninsula, there are 22 EDGE zones that account for over 90% of angiosperm threatened evolutionary history.