Madagascar’s dwindling biodiversity could take over 20 million years to recover : ScienceAlert

Madagascar’s dwindling biodiversity could take over 20 million years to recover : ScienceAlert

The risk of extinction for Madagascar’s mammals, including unique species like the lemur, faces a biodiversity crisis that would take more than 20 million years to heal, scientists warned Tuesday.

The southern island in the Indian Ocean has been cut off from the African continent for over 80 million years – a separation that has produced an extraordinary diversity of plants and animals, many of which are found nowhere else on earth.

But after humans settled on the island around 2,500 years ago, many species such as giant lemurs, elephant birds and pygmy hippos disappeared, and about 30 species of mammals have already become extinct.

In a study published in nature communicationPaleontologists from Europe, Madagascar and the United States have analyzed how long it would take for the large island nation’s mammalian diversity to recover to pre-human levels

If losses were halted now, it would take nature 3 million years to recover, with similarly complex mammalian species emerging to replace those already lost, they found.

But if the 128 mammals currently classified as endangered also went extinct, that recovery time would be dramatically extended to 23 million years

Researchers said the study highlights the urgency of protecting Madagascar’s biodiversity.

“If Madagascar’s endemic fauna and flora becomes extinct, ecosystems on the island will collapse,” said study co-author Luis Lima Valente, senior researcher at the Naturalis Biodiversity Center in the Netherlands.

“This will have a dramatic impact on the livelihoods of people in the region, leading to hunger and mass emigration.”

Extinction is gathering momentum

Madagascar is a biodiversity hotspot, meaning there is a large population of species not found anywhere else.

The researchers were surprised to see that Madagascar took less time to return to prehuman diversity compared to other islands, and attributed this resilience to the fact that human-caused extinctions began relatively recently.

However, due to high biodiversity, Madagascar would take much longer than other islands to recover if species extinction continues.

“Biodiversity hotspots are home to large concentrations of threatened species — they’re not necessarily more endangered than other regions, but they’re places of particular concern because there’s more diversity to lose there than in other parts of the world,” Valente told AFP.

The island also serves as an important measure of human influence.

The main causes of biodiversity loss in Madagascar include land use conversion for agriculture, habitat degradation, invasive species, climate change and hunting, according to the study.

According to a 2020 assessment by the International Union for Conservation of Nature (IUCN), over 100 Madagascar lemur species are threatened, while about 40 percent of the island’s original forest cover was lost between the 1950s and 2000.

“Even remote/inaccessible and relatively large patches of forest in Madagascar are beginning to experience the impact of habitat destruction and climate change,” Valente said.

To calculate how long it would take for the same number of extinct or threatened species to evolve again, the researchers looked at the evolutionary return time — or the time it would take for species in a region to return to a given level of diversity.

Valente said this “gives us a temporal perspective on human impact — it shows that our actions have impacts on temporal scales that are difficult to imagine.”

“At the same time, it shows that if we act now to protect species, we have a chance to save millions of years of evolution.” That is a powerful message.”

© Agence France-Presse

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