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

Abstract

Madagascar’s biota is hyperdiverse and includes exceptional levels of endemicity. Here, 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, rates of species description and human uses, in addition to an updated and simplified map of vegetation types. We report a dramatic increase of records and species new to science in recent years, and yet 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 the majority of analyzed groups. We highlight humid forests as centers of diversity and endemism, due to 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 108 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 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.