The Status of the World's Land and Marine Mammals: Diversity, Threat, and Knowledge

TLDR

Mammalian diversity knowledge remains uneven across regions and taxa. The study provides a comprehensive assessment of global mammal conservation status and distribution. The assessment draws on data compiled by over 1,700 experts covering all 5,487 mammal species, including marine mammals. The freely available data reveal that land and marine mammals differ in macroecological patterns; marine species face higher threats from accidental mortality and pollution, peak in northern oceans, and are poorly known, while both groups share common drivers of diversity and endemism.

Abstract

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.