Saturday, July 15, 2017

The Age of Biological Annihilation

[Pacific Standard] Habitat loss, over-hunting, and climate change are just a few of the human-induced changes to the Earth that biologists say are driving the planet's "sixth mass extinction." Research has shown that we're losing two vertebrate species a year—a pace that's on par with Earth's other five extinction surges, including the most recent that snuffed out the dinosaurs about 66 million years ago.
But the wave of pressure on life is rippling far beyond the growing list of endangered animals closest to the edge of extinction, according to a new study. This "biological annihilation" is, in fact, decimating populations of thousands of other species and potentially threatening our own way of life, a team of biologists recently reported in the journal Proceedings of the National Academy of Sciences.
"We have to be very careful not to be alarmist on the one hand," said Gerardo Ceballos, a biologist at the National Autonomous University of Mexico and lead author of the study. "But now, the problem is so big and so overwhelming, the magnitude so huge, [that] not to mention it in this proper way would be irresponsible."
The loss of approximately 200 species a century might not seem extreme through the lens of one person's lifespan, but it's as much as 100 times faster than historical estimates, according to a 2015 study also led by Ceballos. He explained that under "normal circumstances," it might have taken as many as 10,000 years for that many animals to vanish.
The team also suspected that this outright loss of species might be masking a wider-ranging problem in which distinct populations are disappearing, so they decided to look beyond the animals classified as endangered by the International Union for Conservation of Nature. To get an idea of how animals' ranges—and therefore their populations—are changing, they looked at a sample of 27,600 vertebrates, which is roughly half the species that we know exist. Read More