If centuries of archaeological research and fossil finds are accurate, the Earth has experienced periods of global climate change and major die-offs of many of it’s mammal species several times before.
According to a recent study by UC Berkeley and Penn State University researchers, however, humans might have helped to bring about the planet’s sixth mass extinction even faster thanks to habitat destruction, pollution and now global warming.
The study, which looked at over 30 million years of archaeological record, found that between 15 and 42 percent of the mammals in North America disappeared after humans arrived.
Compared to extinction rates demonstrated in other periods of Earth’s history, this means that North American species are already half way to to an epic extinction, similar to the one that eliminated the dinosaurs.
“We are seeing a lot of geographic range reductions that are of a greater magnitude than we would expect, and we are seeing loss of subspecies and even a few species,” Anthony Barnosky told the San Francisco Chronicle. “So it looks like we are going into another one of these extinction events.”
Although human beings weren’t around to contribute to the dissolvement of the other extinction periods, scientists have found that exponential population growth and the systematic destruction of vital wildlife habitats are helping this mass occur long before it was expected.
The historical record shows that while many species have been able to withstand these environmental changes in the past, and maintain healthy numbers. It was only when humans start to reproduce rapidly and swallow up the natural ecosystems with buildings and farms that the numbers started to decline at an unnatural rate.
The SF Chronicle article pointed out that “at least 50 species went extinct in North America soon after humans arrived on the continent 13,000 years ago. Among the mammals that disappeared were California tapirs, peccaries, lions and cheetahs, llamas, ox, horses, mammoths and mastodons.”
Depsite the bleakness of the findings of this study, scientists stressed that it is still not too late to curb the negative effects of human society on North American mammal species.
“If we redouble our conservation efforts, we can stem the tide of extinctions and have those species around in the future,” Barnosky said. “There is a bit of urgency here. By demonstrating that we have already lost 15 to 42 percent of mammalian diversity, the question is, do we really want to lose any more? I think the answer to that is pretty obvious.”
Polar bears, corals, sharks, and tuna are all in danger of extinction, yet international trade of these rare animals continues, often unregulated. Please consider taking action on behalf of wildlife and the environment by signing one of these Care2 Petitions today!
Image Credit: bcsengage.wikispaces.com
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