One of the world’s remaining biodiversity hotspots will take millions of years to recover from extinctions, scientists predict. A new study suggests more than three million years of evolutionary history have already been lost on Madagascar. The researchers are calling for urgent conservation action to prevent another wave of extinctions. The island is known for its unique fauna and flora. It is home to wildlife such as ring-tailed lemurs, the long-tailed cat, the fossa, spiny hedgehog-like mammals called tenrecs and nocturnal primates known as aye-ayes. The researchers used computer modelling to predict how long it would take for new species to evolve naturally to replace those lost – something known as the evolutionary return time. The figure exceeded 3 million years for lost and recently extinct mammals. But if all currently threatened mammals were also to go extinct, that number would rise to more than 20 million years, suggesting an even more severe impact on biodiversity could be imminent.