Fossils Show Humans, Not Climate, Affected More Caribbean Island Creatures

Bahamas animal species were the ultimate survivors until one thing happened: humans showed up a mere 1,000 years ago, according to a new study of nearly 100 fossil species from a cave on that Caribbean island, according to a release.

A team from the University of Florida recently published their findings on that in the Proceedings of the National Academy of Sciences. In them, they concluded that human activities, and less so human-driven climate change in current days, are a threat to island biodiversity's future.

In the study, 39 of the species examined no longer exist on the Bahamas' Great Abaco Island. Looking at those 39, the researchers say that 17 species of birds probably succumbed to climate changes and increasing sea levels near the end of the Ice Age, around 10,000 years ago. More importantly, they say, 22 other species of birds, reptiles and mammals stayed on the island through dramatic changes in environment, only to disappear after humans' arrival on the island 1,000 years ago, said the release.

It will be helpful to continue to look at why some species can make adjustments in response to climate and human-caused changes, especially considering that changes in habitat and invasive-species introduction currently seem to be large threats to island species, noted Dave Steadman, ornithology curator, Florida Museum of Natural History, at University of Florida, in a release. "What we see today is just a small snapshot of how species have existed for millions of years. 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.

"So, there must be different mechanisms driving these two types of extinctions. What is it about people that so many island species could not adapt to? That's what we want to find out," Steadman pointed out in the release.

The scientists will work further on that question later in 2015, when they go into more caves on Caribbean islands.
"The answer could help us predict what animals will be affected most by a changing climate and humans," Steadman said in the release.

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