To define biome-scale hotspots of phylogenetic and functional mammalian biodiversity (PD and FD) and compare them with classical species richness (SR) hotspots at a global scale, we analysed 782 terrestrial ecoregions using distribution ranges of 4616 species. We applied a unified framework incorporating relative species coverage and built multifaceted diversity-area relationships to rank ecoregions while accounting for area effects, defining hotspots as top-ranked regions.
Ignoring species coverage produced apparent congruence among SR, PD, and FD hotspots, but areas rich in evolutionary history and functional diversity did not match SR hotspots, and PD and FD hotspots showed strong spatial mismatches.
FD and PD reached maximum values faster than SR with increasing area, suggesting they may be less sensitive to habitat loss. Incorporating species coverage reduced congruence among biodiversity facets, indicating that maximizing species number alone may overlook key phylogenetic and functional components, highlighting the need for a multifaceted approach to conservation.