Madagascar’s extraordinary biodiversity: Evolution, distribution, and use.

Madagascar’s biota is hyperdiverse and includes exceptional levels of endemicity. We review the current state of knowledge on Madagascar’s past and current terrestrial and freshwater biodiversity by compiling and presenting comprehensive data on species diversity, endemism, and rates of species description and human uses, in addition to presenting an updated and simplified map of vegetation types. We report a substantial increase of records and species new to science in recent years; however, the diversity and evolution of many groups remain practically unknown (e.g., fungi and most invertebrates). Digitization efforts are increasing the resolution of species richness patterns and we highlight the crucial role of field- and collections-based research for advancing biodiversity knowledge and identifying gaps in our understanding, particularly as species richness corresponds closely to collection effort. Phylogenetic diversity patterns mirror that of species richness and endemism in most of the analyzed groups. We highlight humid forests as centers of diversity and endemism because of their role as refugia and centers of recent and rapid radiations. However, the distinct endemism of other areas, such as the grassland-woodland mosaic of the Central Highlands and the spiny forest of the southwest, is also biologically important despite lower species richness. The documented uses of Malagasy biodiversity are manifold, with much potential for the uncovering of new useful traits for food, medicine, and climate mitigation. The data presented here showcase Madagascar as a unique “living laboratory” for our understanding of evolution and the complex interactions between people and nature. The gathering and analysis of biodiversity data must continue and accelerate if we are to fully understand and safeguard this unique subset of Earth’s biodiversity. Madagascar has been isolated from mainland Africa and Asia for more than 80 million years and has developed a distinctive flora and fauna, with more than 90% of its species endemic to the island nation. It is also home to the Malagasy people, with a population of about 30 million, and was first colonized by humans around the first century BCE. The island’s biodiverse wildlife is highly threatened, and much of its human population lives below the poverty line. In Reviews, Antonelli . and Ralimanana . characterize the biological history and diversity of the island and examine conservation status and actions required to protect biodiversity and improve living standards and well-being for the Malagasy people. —SNV A review explains that Madagascar’s biodiversity is the product of complex processes that produced remarkable life-forms, many remaining undocumented.