Bahamas – Scientists found that human activity is more dangerous for species than climate change, after studying 11,000-year-old animal fossils found in the Bahamas.
In 2004, a retired military scuba diver named Brian Kakuk dived into the depths of a place called Sawmill Sink, a flooded sinkhole on Abaco, an island in the Bahamas. There he found a trove of bones from dozens of animals species that disappeared from the island —and many of them already extinct.
The bone collection contains more than 5,000 fossils from 96 vertebrate species: 13 fishes, 11 reptiles, 63 birds and 8 mammals, as 39 of them —the 41 percent— are gone from the island.
According to Kakuk, if humans had never reached this island, we could still see today animal species like Cuban crocodiles, Albury’s tortoises, and rock iguanas. A number of 22 species, including birds, reptiles and mammals, have disappeared since humans showed up in the region 1,000 years ago.
Islands are ideal environments for the developing and studying of species, as their isolation makes it easier to find the factors that contribute to the animal’s growth. The perfect example for this is the Galapagos Islands, where Charles Darwin did the most important part of his research.
Paleontologists often give credit to the Pleistocene-Holocene transition for the extinctions of numerous species like mammoths, saber-toothed cats, horses, camels and giant sloths, although there is an argue about the role of humans in the process.
The discussion about who is to blame for the species disappearance has been on the table for years. Some experts blame dramatic climate changes, as others point to the incursion of humans, to their hunting practices and their life habits.
As experts study the underwater fossils discovered in the island, they have been able to separate these two causes, finding that humans appear to be the ones to blame on the matter, as their incidence causes more damage than anything else.
David Steadman, the lead author of the study published in the journal Proceedings of the Natural Academy of Sciences, said that “In a way there’s some real irony here because any of the species that were alive a thousand years ago on Abaco when people first arrived were pretty darn resilient — in other words, they’re the ones that could handle the island getting smaller, the habitat changing and all that. But when people show up and they start burning the forest in the dry season and things like that, that’s a tough one to adapt to,” according to the LA Times.
Researchers believe that understanding how species were able to survive to natural and human changes could lead them to predict which ones are likely to continue on Earth in the future. Also, it provides a better understanding of the functioning of the ecosystem during ice ages, allowing them to compare to other fossils having the same age.
“If we’re losing that high of a percentage over a millennium, is anything going to be left by the time we get to the next ice age? If you start looking at it in longer time frames, an extinction rate of even 10 percent of the local fauna over 1,000 years is not sustainable in the long run,” concluded Steadman, according to LiveScience.
Source: Journal Proceedings of the Natural Academy of Sciences