Rewilding America, Pleistocene Style

Ever since Congress passed the Wilderness Act in 1964, defining wilderness has not been easy. What often looks wild or "pristine" has probably been altered by humans over centuries. And in recent years scientists have tried to coax nature back to some concept of an original state by bringing back long-gone species, such as wolves, the American elm, or prairie plants.

Now a team of ecologists proposes a radical step to recreate the pre-human wilderness of North America by reintroducing large predators like those that lived 13,000 years ago.

This eco-team, writing recently in the journal Nature, proposes a gradual "rewilding" of the continent with today's relatives of the large mammals that lived during the late Pleistocene era. Such a step is seen as necessary to restore the empty ecological niches caused by eons of human activity. The pronghorn antelope, for instance, still runs as if it's dodging the extinct American cheetah; its evolution may benefit by restoring that relationship.

Some 60 or so species of lions, horses, camels, elephants, and other animals were made quickly extinct after the earliest humans showed up. Many of their relatives in Africa and Asia could not only act as modern ecosurrogates in North America, but those facing extinction might flourish in a new but familiar environment.

This idea may be practical for animals, but is it meaningful to Americans? Do ranchers really want cheetahs around? Can elephants be contained in large parks, as proposed? Can scientists even accurately recreate the old "wilderness"?

This proposal deserves a serious look-see to help the constantly moving debate over wilderness in the US. At the least it provides an intriguing intellectual backdrop, and possibly a conservation benchmark if implemented in small degrees.

What is the proper role for humans in nature? What species are worth preserving at a cost to human activities? Such questions come up dozens of times a year across the US.

The Endangered Species Act of 1973, for instance, is up for renewal, and one bill would change it to provide a better balance for humans in nature's mix. A new federal law allows exploration for oil and gas in a seashore national park off Mississippi that includes designated wilderness areas.

The Wilderness Act itself called to preserve areas "where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain." About five percent of the US now carries that mystical label of wilderness.

The impact of humans, both ancient and modern, has left few North American habitats "untrammeled," and the removal of large predators was probably one of the biggest environment-shapers. Today's exploding deer populations testify to that.

A controlled experiment to set up a few fenced-in "Pleistocene parks," as the group proposes, could just revive the ancient ecology for North America's species, while saving a few endangered ones. It would also put a brighter spotlight on the lingering question of what is authentic biodiversity when humans aren't involved - if that's possible.