A brown mouse lemur, one of the world’s smallest primates, found only on Madagascar. Credit: Chien C. Lee/Field Museum
Key points:
- Madagascar is at a tipping point that needs to be addressed within the next 5 years.
- Of the 219 known mammal species on the island, more than 120 are endangered.
- If all the endangered mammals went extinct, it would take 23 million years for evolution to achieve a similar level of evolutionary complexity to now.
About 90% of the plants and animals on Madagascar are found nowhere else on Earth. But these plants and animals are in trouble, thanks to habitat loss, over-hunting and climate change. For example, of the 219 known mammal species on the island, including 109 species of lemurs, more than 120 are endangered.
If these species go extinct, evolution is not a quick process. In fact, according to a new study in Nature Communications, it would take 23 million years for evolution to replace Madagascar’s extinct mammals.
To study the looming extinction of Madagascar’s endangered mammals, an international team of researchers built a dataset of every known mammal species to coexist with humans on Madagascar for the last 2,500 years. The scientists came up with the 219 known mammal species alive today, plus 30 more that have gone extinct over the past two millennia, including a gorilla-sized lemur that went extinct between 500 and 2,000 years ago.
Armed with this dataset, the researchers built genetic family trees to establish how all these species are related to each other and how long it took them to evolve from their various common ancestors. Then, the scientists were able to extrapolate how long it took this amount of biodiversity to evolve, and thus, estimate how long it would take for evolution to “replace” all of the endangered mammals if they go extinct.
According to the study, it would take 3 million years to rebuild the diversity of land-dwelling mammals that have already gone extinct over the past 2,500 years, and 23 million years to rebuild if all currently endangered mammals were to go extinct.
Even worse, the researchers say the 23 million years is only to achieve a similar level of evolutionary complexity as now. It does not mean evolution will recreate the same animals.
“It would be simply impossible to recover them,” said coauthor Steve Goodman, field biologist at Chicago’s Field Museum and Scientific Officer at Association Vahatra in Madagascar.
According to Goodman, Madagascar is at a tipping point for protecting its biodiversity.
“There is still a chance to fix things, but basically, we have about 5 years to really advance the conservation of Madagascar’s forests and the organisms that those forests hold,” he says. “Madagascar’s biological crisis has nothing to do with biology. It has to do with socio-economics.”
Information provided by Chicago Field Museum