NATURE - ONCE AND FUTURE GIANTS
BY SHARON LEVY
London - The only time I remember seeing a woolly mammoth, I didn’t study it too closely because it was threatening Raquel Welch and she was wearing a fur bikini and I was 15 years old.
But it’s entirely possible that, rather than relying on DVDs of One Million Years BC, in the not-too-distant future we’ll be able to see a real live mammoth.
Deep-frozen mammoths turn up regularly in Siberia and five years ago scientists sequenced the mammoth genome.
While DNA recovered from refrigerated mammoths is probably too degraded to be used to clone a live animal, it’s possible that substituting modern-day elephant genes for the missing bits could resurrect the mammoth. Some scientists believe it’s inevitable.
The mammoth is the most well-known of the megafauna, those giant animals that roamed the Earth during the Pleistocene epoch, the two-million-year-long Ice Age when glaciers covered much of the Northern Hemisphere and which ended about 13,000 years ago.
Sharon Levy’s fascinating book asks how these huge mammals vanished and what lessons can be learned from their demise for our world today.
Controversy rages over what killed off the big beasts.
Until the Sixties, it was thought climate change was responsible, with rising temperatures altering their environment, but then US scientist Paul Martin came up with the theory it was overkill by Stone Age hunters.
But how could people armed only with Stone Age technology wipe out a whole species of 16,000 lb giants? An answer lies in the mammoth’s modern relative, the elephant.
Large animals like elephants and rhinos breed very slowly. Elephants don’t calf until they’re 12 years old and produce only a single baby every four years.
The potential growth rate of an elephant population is 6.5 percent per annum. Such slow-breeding species are doomed if a new, efficient predator like man arrives.
Elephants, once common in North America, browse on trees, breaking them in the process and allowing grass to grow, which supports grazing animals.
When elephants disappear, so does the alternating cycle of forest and grassland growth, leading to soil loss and catastrophic effects on the environment and biodiversity.
Levy’s book demonstrates the knock-on results of species loss to nature. Take America’s Yellowstone National Park.
Early in the last century wolves and cougars were hunted there to protect deer, principally elk.
The consequences were devastating. The elk population exploded and they ate the young aspen trees that make up much of the park’s forest.
As a result, the beaver population plummeted, as beavers need aspen to construct their lodges and their dams to fish. Without beaver dams, which cause flooding, amphibians and other species dwindled.
The wolf is what’s called a top predator and the trickle-down environmental effect of a top predator on other animals and plants is known as trophic cascade. It’s estimated that restoring top predators worldwide would lock up 23 gigatons of human-released carbon now loose in the atmosphere.
In recent years, wolves have been reintroduced to Yellowstone from Canada, managing the elk population naturally — and the beavers are back. This kind of example is seized upon by proponents of so-called Pleistocene rewilding, whose supporters argue reintroducing extinct species will restore the ecology to a more natural and sustainable state.
Pleistocene rewilding is already underway in Siberia, where rising temperatures have begun to melt the ancient permafrost layer of the steppe. The frozen remains of prehistoric vegetation beneath contain more than double the amount of carbon of all the world’s rainforests combined.
If present trends continue and it’s released into the atmosphere as carbon dioxide, it will accelerate global warming dramatically.
The goal here, in what’s been dubbed Pleistocene Park, is to reintroduce vanished large mammals to mimic ice age fauna.
These large herbivores will encourage grass growth, protecting the permafrost from heat and stopping it thawing out.
The project is already showing some success from reindeer, moose and a thriving horse herd.
It’s hoped to add Canadian bison and musk oxen, too —although it’ll be some time before we see mammoths roaming free. - Daily Mail