This post discusses an article published in PLoS Biology reviewing Cornell Ecologist Josh Donlan's idea of importing African analogs of extinct North American vertebrates like the American lion and the mammoth in the hopes that filling these niches will restore and stabilize lost ecosystems. Two questions from my end: Are these non-native organisms truly analogous to their extinct American cousins and is it too late to make such a bold move?
Ecologists have been debating about whether or not they know enough to begin rebuilding long-lost ecosystems by replacing extinct large vertebrates with analogs from other areas.
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 [2].
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.
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.
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.
- Log in to post comments
More like this
To me, such a plan is awfully nutty. Many seem to be enamored with the idea that if humans hadn't killed off much of the megafauna of North America, there would still be mammoths, saber-toothed cats, giant ground sloths, and other now-extinct mammals roaming about. Indeed, sometimes on my daily commute to Princeton I wonder what it would be like if mammoths were still around, and what if one decided it wanted to take an unexpected detour across Rt. 1 (given the damage a moderately-sized deer can do to a car, it wouldn't be pretty).
If such a reintroduction was made I honestly don't think it would go over too well, especially since the ecological makeup of North America is quite different from Africa, India, and South America; we can't just throw in some elephants and expect them to grow longer hair to deal with winter. What would they do? They could move south, but then you'd either have to deal with a migrating population of elephants or make sure all states (and Central American countries) were on board to protect the animals. Plus, there are already plenty of problems with coyotes, black bear, white-tailed deer, and other creatures making their comeback in urban/suburban environments; I can't see too many people being happy with the possibility of an elephant or lion dropping by when a group of unruly wild turkeys is enough to call the police.
Anyway, the view that Donlan seems to be espousing may be based upon the notion that human beings are solely to blame for the extinction of North American species in recent history, but the truth is that we lack a "smoking gun." Unfortunately I do not have it handy, but there seems to be some evidence of a tuberculosis epidemic among mammoths (tuberculosis can be studied in extinct mammals because it leaves osteological clues), and the ideas of climate change and hyperdisease (either together or separately) still are being batted around. Surely humans had some impact, but what if the death knell for many of these animals was because of an unfortunate combination of ecological factors, disease, and predation; would we be right to restore modern-day analogues (which have been evolving since, becoming adapted to their own habitats) into an ecology that wiped out their ancient relatives? I don't think so; if we're talking about restoring ecology there are plenty of displaced animals like the jaguar that need help, and I personally regard the establishment of ecological corridors or pathways to be the most important thing we can do to help wildlife right now.
Anyway, I didn't mean to ramble on for so long, but ultimately I think introducing lions, elephants, giant tortoises, giant birds, or other creatures that would be regarded as "alien" or "invasive" if they came here on their own is foolish and is almost an attempt to exhibit penance for what some perceive our ancestors did the North American wildlife long ago.
Whether the African lion is analogous to the extinct American lion is the least of the problems of this proposal. Look at the pressures on existing North American large mammals, like bears and mountain lions. How could anyone reasonably expect African lions (for pete's sake) to survive in the "wild" of North America? What are they going to eat? Hunters?
What a splendid way to introduce an armada of African parasites into the American ecology! This is no Trojan horse, this is a Trojan herd!
D'oh! I was wrong; it was mastodons (not mammoths) that tuberculosis has been recorded in (59 out of 113 individuals showed signs of it). There's the link and my own thoughts on the PLoS paper over at Laelaps (but most of it I already said in the above comment).
Look at our recent record: we're incredibly conflicted about letting bison, wolves, and grizzlies, run free with enough territory to sustain them. We're gonna accept wild elephants? I don't think so.
Meanwhile we have plenty of endangered species of our own to worry about. Grassland birds in particular are under a high amount of stress. What would introducing big flocks of large mammals do to their situation?