DATE: October 6, 2020
SNIP: Though some believe prehistoric humans lived in harmony with nature, a new analysis of fossils shows human arrival in the Bahamas caused some birds to be lost from the islands and other species to be completely wiped out.
The researchers examined more than 7,600 fossils over a decade and concluded that human arrival in the Bahamas about 1,000 years ago was the main factor in the birds’ extinction and displacement in recent millennia, although habitat fluctuations caused by increased storm severity and sea level rise could have played a role.
Many spectacular species, such as a colorful parrot, a striking scavenger called a caracara, and a number of hawks, doves, owls, and songbirds, were still found as recently as 900 years ago, and may have overlapped with people by a century before disappearing or retreating to only one or two islands in The Bahamas. “No other environmental change could explain their loss,” said study co-lead Janet Franklin, a distinguished professor of botany and plant sciences at UC Riverside.
Full results of Franklin’s study were published this week in the Proceedings of the National Academy of Sciences.
For example, the Abaco parrot is now only found on two islands in the Bahamas. There are many islands in between the two where the parrots now live that have the same habitat.
“We wondered why those parrots aren’t found in the middle islands,” Franklin said. “It turns out, they were, not that long ago.” Franklin and her collaborator, ornithologist David Steadman of University of Florida, found Abaco parrot fossils were on all the islands until 1,000 years ago.
The study was also able to identify losses of bird species that lived in the Bahamas since the end of the last ice age, more than 10,000 years before people arrived. These species included a giant barn owl and giant eagle—predators whose prey also disappeared from the islands after people arrived.
More than two thirds of the 90 bird species identified in the fossils that date from the end of the last ice age. Either they have gone altogether extinct or now only persist outside of the Bahamas.
Furthermore, the researchers note in the study that “the related futures of biodiversity and humanity perhaps never have been at a crossroads more than now. The transfer of a zoonotic disease from wildlife to humans, which has resulted in a global pandemic, is directly linked to biodiversity loss.”
In other words, as humans increasingly take over wild habitat, particularly rainforests, there are more opportunities for diseases to jump from wildlife to people.