Scientists look at why the numbers of caribou are declining.
Throughout history, people have repeatedly contemplated teeming herds of animals – or schools of fish, as the case may be – and thought, “Nothing we humans can do will ever put a dent in this bounty.”
They’ve repeatedly discovered the opposite: Humans can – and have – put a big dent in what they thought was nature’s limitless abundance.
That’s the story with cod off the coast of New England. The once seemingly innumerable fish have yet to recover from overfishing in the late 20th century. And that’s the case with the American bison of the Great Plains – by some estimates once the most numerous large mammal on earth. Then came the slaughter of the 19th century – an estimated 40 million bison gone.
Now, a study in the journal Global Change Biology sees trouble for a species historically considered so numerous – and so distant from human activity – that most assumed it was beyond human ability to affect it.
Caribou and reindeer, a single grazing species with regional variations, inhabit the northern reaches of Eurasia and North America, from Scandinavia to Siberia and from Alaska to Greenland. Yearly, their vast herds make the single greatest migration of any ungulate in the Northern Hemisphere.
But in what they characterize as the first worldwide caribou census, scientists at the University of Alberta, Edmonton, find that populations have declined by nearly 60 percent in the past three decades.