For decades, researchers have debated what caused the extinction of a large number of animal species in different parts of the world at the end of the Ice Age about 10,000 years ago. Was it the rapidly changing climate? Or human activities that dramatically altered habitats? Now a group of researchers at the University of Florida have revealed that humans have been a greater threat to biodiversity than climate change.
The Caribbean’s first humans drove 22 species to extinction
Scientists led by Dave Steadman of the University of Florida recovered fossils of dozens of extinct animal species from caves on the Caribbean islands. Findings of the study were published in the latest issue of Proceedings of the National Academy of Sciences. The study discusses 39 species that no longer exist. Of them, 17 bird species disappeared due to climate change and rising sea levels at the end of the Ice Age.
Another 22 species of mammals, birds and reptiles endured the dramatic environmental changes, but started vanishing when humans first reached the Caribbean islands about 1,000 years ago. Steadman said the introduction of invasive species and human activities like habitat alteration could pose the greatest threat to Caribbean species. Figuring out why some species were more flexible than others in the face of human-driven and climate changes could alter the way we think about biodiversity conservation.
What mechanisms drove the two types of extinctions
The species that existed in the Bahamas up until humans arrived were survivors. They endured environmental changes over millions of years, but could not adapt to changes that occurred after humans showed up. Researchers believe that there could be “different mechanisms” driving these two types of extinctions. An earlier study by Steadman showed that the Caribbean’s first humans drove species as small as bats to the verge of extinction.
The latest study shows that species that survived climate change were lost to human activities such as hunting, wildfires, etc. But now we have a “perfect storm” where climate and human-led changes are occurring at the same time. Scientists said they would conduct further research to see whether there are genetic differences between Caribbean species that survived and those that went extinct upon arrival of humans.