Back in the Roaring Twenties, while the human world celebrated a decade of economic prosperity and the birth of Jazz, the animal world in America’s Yellowstone National Park was instead facing a tense standoff with death. Yellowstone’s top predator, the gray wolf, had become extinct and the impact of its disappearance was not so much trickling down as pouring down to the Park’s other inhabitants. First, the gray wolf’s prey – moose and elk – shot up in number, and that led to a decrease in the distribution of aspens and other trees they ate. Then the lack of vegetation destroyed habitat for migratory birds and for beavers. Ultimately, the entire ecosystem of the Park started crumbling because of the absence of the wolves. Desperate ecologists decided to reintroduce the wolves to the Park, and finally breathed a sigh of relief as over the next few years Yellowstone’s ecosystem slowly settled back down to normal.
80 years later, a dozen prominent scientists, old and young, gathered together in a small ranch in New Mexico to mull over conservation schemes. And as they debated amongst themselves, an audacious new idea began to grow and take form. It seemed completely outlandish, but it was one of those plans, they felt, that was so crazy it just might work. They called it Pleistocene Rewilding.
The vision – the brainchild of the scientist, Paul Martin – was to reintroduce to North America the many large predators (called megafauna) that had once been at the top of the food chain but were now extinct, mainly due to human interference. For tens of millions of years, these large predators had dominated the globe, strongly interacting and co-evolving with other species and maintaining ecological balance in nature. But starting roughly 50000 years ago, the overwhelming majority went extinct, sparking a chain of reactions in the natural world that culminated in the collapse of entire ecosystems. Now, it was time to restore these ecosystems to their former glory by bringing back the megafauna.
But animals such as the woolly mammoth, the ground sloth, the American mastodon, the Saber-toothed cat or the aptly named Terror Bird hadn’t dwelt in American since the Pleistocene era. How were scientists to bring them back in the first place? It was impossible to bring back these long-extinct species, and still more impossible to resurrect dinosaurs that had lived on the earth 80 million years ago. What they could do, instead, was introduce substitutes. Since the Pleistocene mammals existed far more recently than the dinosaurs, close relatives of them can still be found surviving elsewhere in the world. For example, the enormous mastodons and mammoths of the Pleistocene era have close genetic links to the African and Indian elephants of today. The powerful American cheetah, that chased antelopes across the grasslands of America for millions of years, now only survives through its African kin. Camelops, a late Pleistocene camel that used to roam in the frigid landscape of Montana, could find a modern proxy in the Bactrian camels living in the Gobi Desert.
Conservationists who support Pleistocene Rewilding dream of vast, secure ecological history parks in Northern America encompassing thousands of square miles, where camels, bison, zebra, elephants and large carnivores could roam freely. But to get to that distant point, certain challenges need to be faced.
Remember the tall, eccentric scientist named Ian Malcolm in Jurassic Park? The one who opposed the reviving of the dinosaurs because he argued that no matter how much man tries to control nature, it can never be kept in check because sooner or later life finds a way. Malcolm tried to convince the others that since the dinosaurs had come from a habitat that humans have very little idea about, there was no way they could fully predict just how the animals would cope with an ecological system many millions of years after their time. Malcolm said that sooner or later, the dinosaurs were bound to take the humans by surprise; they would act out in random and unpredictable ways and suddenly the humans would lose any semblance of power they had over those fearsome creatures. And he was right.
The trouble with the concept of Pleistocene Rewilding is along the same lines. Most opponents of the idea assert that bringing back an ecosystem that existed so many thousands of years ago is just not feasible. Habitats have changed over the millennia. The lands have evolved without these animals for thousands of years so we can never know for sure how exactly the animals would fare in these altered environments – the likelihood of unanticipated ecological consequences and unexpected (perhaps unsafe) interaction with neighbouring human communities is great. Lion cubs are so very cute – except when they wander into your backyard and eat your dog. Elephant families running free under big skies might sound romantic – until they trample entire villages, and destroy fields of crops. Then there’s the possibility that the new animals might be unusually susceptible to diseases present in the ecosystem, or worse, they could bring with them novel diseases that scientists will not be able to cope with.
But scientists are still hopeful that these challenges won’t prove to be insurmountable. Pleistocene Rewilding deserves serious debate because the indisputable fact remains that the natural world needs our help urgently. Scientists challenge the assumption that if we let things stay the way they are, everything will be fine. Even in the largest national parks, species go extinct without active intervention. And human encroachment has shown alarming signs of worsening. It was human intervention that led to the demise of large animals, which has thrown ecosystems out of balance. Even if humans decided now to leave these ecosystems alone, they are too far gone to recover on their own. The Prairie would revert not to its Pleistocene glory but to a scraggy weedland.
Conservation has always been a business of ‘doom and gloom’, a struggle merely to slow the loss of biodiversity. Here is a chance to remedy that, an opportunity for us to be proactive instead of merely reactive. Pleistocene Rewilding may be controversial, but it is nevertheless a daring new step in the right direction. And perhaps it will help us to make amends for the centuries of destruction and havoc we humans have wreaked on the natural world.
Donlan, C. Josh. Restoring America’s Big, Wild Animals. SCIENTIFIC AMERICAN India (June 2007)