From "Restoring Nature's Backbone" by Henry Nicholls for PLoS Biology:
Rather than trying to simply ring-fence what wildlife remains, conservationists need to be restoring whole ecologies to something of their former glory, says Josh Donlan, an ecologist at Cornell University (Ithaca, New York, United States). Last year, he and a long list of high-profile conservation biologists penned a controversial commentary in Nature in which they laid out the case for rewilding North America seeding the continent with suitable stand-ins for species that went extinct thousands of years ago .Optimistic is an appropriate term. I can see the attraction of a program like this; conservation biologists are often ignored, and seem to be relegated to passive measures of protection. This seeding method is an active approach, where they can use their knowledge to manipulate ecological systems in order to save certain environments.
Donlan's world would see carefully chosen slivers of North America grazed by giant tortoises, horses, and camels; the stamping ground of elephants in place of five species of mammoth; and African lions in lieu of the extinct American lion that once stalked the continent.
The benefits, they argued, are obvious. It would restore ecological processes that have gone by the wayside, mend broken evolutionary relationships, create a back-up population of some of the planet's most endangered species, and raise huge awareness for the conservation cause. The obstacles are substantial and the risks are not trivial, but we can no longer accept a hands-off approach to wilderness preservation, they wrote of their optimistic vision.
But is there enough knowledge of these systems to be able to manipulate these environments effectively? Ecosystems are incredibly complex, and if their data are incomplete, if
one organism or mechanism in the system is missing from ecological models, manipulation enters a dangerous zone.
In other words, do we know enough about nature to rebuild it?
The same question can be asked of drug companies. How many pharmaceuticals are pulled from the market because of unforeseen consequences? And this comes after years of research and testing.
Administering drugs to the body is an inelegant process, like tossing a wrench into a car engine and hoping it will fix itself. I'm exaggerating of course, the body automatically distributes chemicals along certain paths, but the paths themselves are not fully understood.
My point is, there are trillions of chemical factors extant in one human being, and one person's chemical environment is sometimes drastically different from the next.
The same can be said of ecosystems. Each one runs analogous to another in certain ways, with different organisms filling certain niches, but there are certain distinctions that need to be fully understood before administering new organisms that never existed in that particular system before.
All I'm saying is this: Ecologists need to make sure that the African lion is truly analogous to the extinct American lion before the animal is introduced to the North American landscape, and the system that exists now, thousands of years after the American lion's extinction, can support such a predator.