22 Caribbean species survived the Ice Age, then went extinct when humans arrived

Crooked Island Bahamas
© Fossils in a flooded cave reveal the impact of human activities on biodiversity. (University of Florida)

Reptiles, birds and mammals in the Bahamas survived climate change, habitat change and rising seas … only to succumb when man showed up.

Nearly 100 fossil species were recently removed from a flooded cave in the Bahamas by a team of researchers from the University of Florida. And what those fossils reveal is really pretty profound. In a study detailing their findings, the scientists warn that the biggest threat to contemporary island biodiversity may not be human-driven climate change, but direct human activity itself.

Thirty-nine species (of the 100 fossils) found on Great Abaco Island no longer exist. Of those, 17 species of birds appear to have succumbed to climate and rising sea levels around the end of the Ice Age some 10,000 years ago. But the 22 other species? They survived dramatic climate change, habitat change and rising seas. But when humans arrived to the island 1,000 years ago ... that was too much for them.

"What we see today is just a small snapshot of how species have existed for millions of years," says lead author Dave Steadman, ornithology curator at the Florida Museum of Natural History on the UF campus. "The species that existed on Abaco up until people arrived were survivors. They withstood a variety of environmental changes, but some could not adapt quickly or drastically enough to what happened when people showed up.”

A study in January of this year co-authored by Steadman showed that the first humans to arrive in the area depleted small species like bats; this latest research shows that other species were lost to human activities like hunting and human-ignited wildfires.

Why some species were more adaptive in the face of climate change remains a mystery that Steadman and colleagues hope to unravel later this year. They are planning on returning to the Bahamas to solve unanswered questions about which species were lost when humans arrived and why.

"What is it about people that so many island species could not adapt to?” Steadman asks. “That's what we want to find out."

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