Margaret Kennedy took a deep breath…and adopted her podium stance. ‘We have decades of environmental management experience. Yellowstone Park was the first wilderness to be set aside as a natural preserve anywhere in the world. Americans know how to do these things.

‘I agree,’ Shepherd said. The American experience with Yellowstone Park is very instructive. Professor Calderón. Take us through the background.’

‘Well the region around the Yellowstone River in Wyoming has long been recognized for its wondrous scenic beauty. Lewis and Clark sang its praises. Artists like Bierstadt and Moran painted it. And the new Northern Pacific Railroad wanted a scenic attraction to draw tourists west.

So in 1872 in part because of railroad pressure President Ulysses Grant set aside two million acres. The problem…unacknowledged then and later…was that no one had any experience trying to preserve wilderness. There had never been any need before. And it was assumed to be much easier than it proved to be.’

‘When Theodore Roosevelt visited the park in 1903 he saw a landscape teeming with game. There were thousands of elk, buffalo, black bear, deer, mountain lions, grizzlies, coyotes, wolves and bighorn sheep.

Yet within a few years the teeming landscape was gone forever. The park managers…charged with keeping the park in pristine condition…took a series of steps that they thought would preserve the park and its animals. But they were wrong.’

‘The early park managers mistakenly believed that elk were about to become extinct. So they shot and poisoned all the wolves and prohibited Indians from hunting in the park…though Yellowstone was a traditional hunting ground.

Once protected the elk herds exploded and ate so much of certain trees and grasses that the ecology of the area began to change. The elk ate the trees the beavers used to make dams so the beavers vanished. Beavers were vital to the overall water management of the region. When the beavers disappeared meadows dried up, trout and otter vanished, soil erosion increased and the park ecology changed even further.’

‘By the 1920s it had become abundantly clear there were too may elk so the rangers began to shoot them by the thousands. But the change in plant ecology seemed to be permanent. The old mix of trees and grasses did not return.’

Kennedy broke in. ‘That’s fine as far as it goes. But our knowledge has increased since then. These were early teething problems.’ Bill Shepherd raised his eyebrows. ‘I wish this were true. But you know this is a perpetual claim…that we know more today. But it’s not borne out by the facts.’ He nodded to Constanza to continue.

‘It became increasingly clear that the Indian Hunters of old had exerted a valuable ecological influence on the park lands by keeping down the numbers of elk, moose and bison. This belated recognition came as part of a more general understanding that Native Americans had strongly shaped the ‘untouched wilderness’ that the first white men saw…or thought they were seeing…when they first arrived in the New World.

The untouched wilderness was nothing of the sort. Human beings had exerted a huge influence on the environment for thousands of years…burning plains grasses, modifying forests, thinning specific animal populations and hunting others to extinction.’

‘Forbidding Indians from hunting was seen as a mistake. But it was just one of many mistakes by park managers. Grizzlies were protected, then killed off. Wolves were killed off then brought back. Animal research involving field study and radio collars were halted then resumed after certain species were declared endangered.

A policy of fire prevention was instituted with no understanding of the regenerative effects of fire. When the policy was finally reversed thousands of acres burned so hotly that the ground was sterilized and the forests did not grow back without reseeding. Rainbow trout were introduced in the 1970s soon killing off the native cut-throat species.’

‘So what you have,’ Shepherd said, ‘is a history of ignorant, incompetent and disastrously intrusive intervention followed by attempts to repair the damage caused by the repairs as dramatic as any oil spill or toxic dump. Except in this case there is no evil corporation or fossil fuel economy to blame. This disaster was caused by environmentalists making one dreadful mistake after another while proving how little they understood the environment they intended to protect.’

Margaret Kennedy turned to Calderón. ‘This is absurd. You know that perfectly well. To preserve a wilderness you just preserve it. You leave it alone and let the balance of nature takeover. That’s all that is required.’

‘Absolutely wrong,’ Shepherd said. ‘Passive protection…leaving things alone…doesn’t preserve the status quo in a wilderness any more than it does in your backyard. The world is alive. Things are constantly in flux. Species are winning, losing, rising, falling, taking over, being pushed back. Setting aside wilderness doesn’t freeze it in its present state any more than locking your children in a room prevents them growing up.

We live in a changing world and if you want to preserve a piece of land in a particular state you have to decide what that state is and then actively…even aggressively…manage it.’

‘But you said we don’t know how to.’ ‘Correct. We don’t. Any action changes the environment. Any change hurts some plant or animal. Preserving old-growth forest to help the Spotted Owl means Kirtland’s Warbler is deprived of the new-growth forest they prefer. There is no free lunch.’

…extracted from a Tavern Talk on Climate with Bill Shepherd