Between 1,500 and 500 years ago, nearly all Madagascan megafauna, including the famous dodo bird, gorilla-sized lemurs, giant tortoises, and the elephant bird, which stood 3 meters high and weighed almost half a ton, disappeared. Were these creatures over-hunted by humans to extinction? Or was it because of climate change that they disappeared? Numerous theories exist, however the exact cause of this crash of megafauna remains elusive and fiercely debated.
The Mascarene Islands east of Madagascar are of special interest because they are among the last islands on earth to have been colonized by humans. What is fascinating is that the megafauna of the islands crashed within only a few centuries after human settlement. In a recent study published by Science Advances, an international team of researchers found that it was probably a “double blow” of increased human activity combined with a particularly severe drought throughout the region that could have been the downfall of the megafauna. The researchers rule out climate change as the sole cause and instead suspect that the effects of human colonization played a decisive role in the collapse of the megafauna.
Hanying Li, a post-doctoral researcher at Xi’an Jiaotong University in China and lead author of this study, compiled a detailed history of regional climate variability. The main source of this new paleoclimate record comes from the tiny Mascarene island of Rodrigues in the southwestern Indian Ocean, about 1600 km east of Madagascar. “[It] is an island so remote and small that you will not find it in most textbook atlases,” says Gayatri Kathayat, one of the co-authors and associate professor of climate science at Xi’an Jiaotong University.