Wednesday, March 21, 2007

Should lions, cheetahs be introduced to the Great Plains?

By Kirsten Weir

Dreaming of traveling to Africa to see lions and elephants in the wild? Wait a few years, and you might be able to save yourself the international plane fare. A group of ecologists and conservationists hopes to "rewild" North America by introducing camels, elephants, cheetahs and other big animals to the Great Plains.

The scientists, led by Cornell University ecologist Josh Donlan, first announced their plan in 2005. The idea grabbed headlines, but not the support of many conservation groups. According to Donlan, "People jumped to a conclusion that we wanted to back up a van and let out a bunch of cheetahs, or that we wanted to take Africa's wildlife and raise it for them in North America. That's not the point."

The point, he says, is to actively transform a dysfunctional North American ecosystem into a functional one. To clarify their intentions, Donlan and his colleagues recently published a more detailed version of their proposal in the scientific journal The American Naturalist. And they're serious.

Once upon a time, some 60 species of "megafauna" (animals over 100 pounds) roamed North America. Mastadons grazed and saber-toothed cats hunted, contributing to the continent's biodiversity. Top predators and huge grazers often have a top-down effect on habitats, helping to shape the landscape and preserve biodiversity.

North America's big beasts weren't just an Ice Age anomaly. For hundreds of millions of years, all around the globe, huge vertebrates dominated most ecosystems. "Before 50,000 years ago, the distribution of the body sizes of mammals was roughly the same on all continents," Donlan says. As humans began to migrate across the planet, the distribution shifted. By the end of the Pleistocene era, around 10,000 years ago, North Am-erica's charismatic creatures had disappeared. "Whenever and wherever humans showed up," Donlan says, "all the big stuff went extinct."

He and his colleagues believe that by carefully and systematically returning large vertebrates to the American West, they can restore the fractured ecosystem to its pre-human health. As Donlan sees it, big species would be introduced to large, fenced-in tracts of private land on a species-by-species basis. The project would likely start with the introduction of camels using controlled, scientific methods. If all went well, cheetahs, elephants and lions could follow.

Those species aren't as foreign as one might think, advocates say. The so-called "African" lion is actually the same species that once roamed North America. The continent was also home to four varieties of camels, two types of American cheetahs and five mammoth and mastodon species—all now extinct. Asian camels, African cheetahs, and Asian and African elephants could act as ecological stand-ins. Asian elephants, in fact, are more closely related to mammoths than they are to African elephants, the scientists note.

An expert working group would be established for each species and start with a feasibility study, looking at issues ranging from captive breeding to sociopolitical hurdles. Social challenges may prove one of the project's biggest hurdles. How many landowners are eager to live next door to a pride of free-ranging lions, fenced or not? But, the ecologists say, the plan would also create social payoffs in the form of ecotourism. When South Africa's Kruger National Park was established, it was home to nine lions, eight buffalo and not a single elephant. Today, more than 2,000 lions, 28,000 buffalo, 7,000 elephants and 700,000 annual tourists—worth $26 million per year—roam Kruger National Park.

Could a Pleistocene Park be as beneficial for North America? Despite assurances that the reintroductions would be careful and scientific, some conservationists are concerned about using non-native species to act as understudies for roles played by animals that disappeared thousands of years ago. "You're not really putting back the animal that was there," says Sanjayan Muttulingam, lead scientist for the Nature Conservancy. "That's a dicey proposition."

Bringing back Ice Age stand-ins, Muttulingam fears, will only make conservation seem more elitist and irrelevant. "The reason that people aren't behind the conservation movement is because we haven't done a good job of saying it's relevant to real people dealing with real problems in the real world," he says.

Eric Dinerstein, chief scientist for the World Wildlife Fund, also takes issue with the plan. He agrees that some parts of America's central and western grasslands are dysfunctional. "How do we make things more natural?" he asks. "It's a genuine concern for a lot of ecologists." But introducing exotic species will only make things less natural, he argues. Dinerstein is working with other conservation organizations to restore parts of the American west. They've purchased thousands of acres for grassland reserves in Montana and have reintroduced genetically pure American bison. Instead of bringing species from Asia or Africa, Dinerstein says, why not restore American bison, pronghorn antelope, mountain lions, grizzlies—the big North American species that survived the Ice Age?

Other conservationists are coming around. Tom Gavin, a professor of natural resources at Cornell, was originally critical of the idea. Now Gavin says, "We're talking about introducing species that are similar but not the same into an ecosystem that is similar to, but not exactly the same as, it was 13,000 years ago. Do two wrongs make a right?" he wonders. "It could be catastrophic, or it could be really interesting."

Why should the conservationists simply manage extinctions, Donlan asks, when they can instead take steps to actively restore a wounded ecosystem? "We're talking about taking a proactive approach," he says. "We're affecting future biodiversity whether we like it or not. The idea of not doing anything is essentially as big a risk as taking these bold actions."

—Kirsten Weir

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