Global Biogeography of Multidimensional Marine Biodiversity Hotspots

Abstract

Efforts to curb marine biodiversity loss have gained momentum through new global agreements extending protections across both national waters and the High Seas [1,2]. However, it remains unclear how to best capture the full multidimensionality of ecological features encompassed by the term “biodiversity” and, more importantly, how and where to prioritize conservation efforts to account for this complexity. Here we show, using AquaMaps 2.0 species distribution models for 31,426 marine taxa[3], that hotspots defined from the upper five percent of species richness (taxonomic diversity), range-size rarity (extinction risk) and phylogenetic distinctiveness (proxy for evolutionary uniqueness) identify largely complementary conservation priorities rather than a single shared geography. These hotspots span benthic/demersal and pelagic assemblages in EEZs and the High Seas, forming a continuum from shallow coastal habitats to deep-sea systems. Overlaying hotspots with cumulative human impact and marine protected area layers shows that exposure and protection are uneven: Asia and the Americas contain the most pressure-exposed hotspot areas, human impacts are concentrated mainly within EEZ hotspots, and only a small fraction overlaps high or fully protected MPAs[4–7]. These results establish a conservation- and management-ready framework at scales suitable for locating, comparing, and protecting the most irreplaceable concentrations of marine life.