When Birds Overshadow Snails -- And Why That's a Problem
May 9, 2005 — -- When bird enthusiast Bobby Harrison realized he had spotted an ivory-billed woodpecker, once thought extinct, he "put his face in his hands and began to sob," according to his fellow searcher and Cornell University ornithologist, Tim Gallagher.
When Jeff Garner, Alabama's state mollusk biologist, collected two snails that were thought to be extinct, it took him a while to figure it out.
"I really just got a bag of snails from the river bottom and brought them up to the boat. Then I noticed the little pointed ones," said Garner, who made the discovery last summer in Alabama's Coosa River.
Both discoveries were announced in the last two weeks and, needless to say, Garner's snail find was a little less dramatic and greeted with much less fanfare. Still, many scientists would say that the finding of the cobble elimia and nodulose Coosa River snails is no less significant than the spotting of the majestic ivory-billed woodpecker.
In fact, some argue the differences in reactions to the discovery of these very different kinds of animals reveal an underlying problem when it comes to conserving species and determining when they're extinct: Big and pretty animals get all the glory. And this might mean we're often not even aware when we're losing species.
"Scientists are as susceptible as anybody to the biases that give us a fixation on mammals, birds, other vertebrates and flowering plants," said Mark Burgman, a botanist at the University of Melbourne in Australia. "Everything else is a long last. But then everything else makes up more than 90 percent of all living things."
Not Knowing What We're Missing
Of course, finding any species once thought to be extinct is positive news. In the case of the ivory-billed woodpecker, the bird's discovery was a sign that efforts to restore the bottomland hardwood and swamp ecosystem in Arkansas have been making a difference. The snail finds, meanwhile, show that clearer waters and currents have been restored to the Coosa River.
The recent rediscovery of another snail by Stephanie Clark, of the University of Alabama, was more welcomed than news that another river in that state, the Cahaba River, has been cleaned up.
But the fact is there are likely many more people looking for rare birds than rare snails.
"We don't have the faintest notion if the vast majority of species are extinct or not because we don't look," said Burgman. "And if we don't look, we assume they are OK."
Not only may unappealing species be disappearing, some may remain completely undiscovered.
So far, biologists have named a total of about 1.7 million species and each year about 13,000 more are added to the list of Earth's known organisms. But Harvard University biologist Edward O. Wilson has suggested that vast numbers of species -- particularly the smaller, less glorious ones such as snails and insects -- remain undiscovered. Some estimate that up to 100 million species have yet to be found.
"There are a great number of species we don't even know about so some of those may be going extinct and we're not even aware of it," said Michael Bean, a legal expert specializing in the Endangered Species Act for the nonprofit group Environmental Defense.
Some might wonder -- what's the big worry if a small snail or insect or bacterium disappears over time? Clark, who recently rediscovered the Cahaba pebble snail in Alabama's Bibb County, says the point is we don't know what the effect might be.
"It's like a stack of cards," she said. "How many cards do you need to take out before they all fall down? Because we don't know the answer, it's better to just have all the parts."
Clark, an Australian snail specialist who began research at the University of Alabama last year, didn't know what she had found at first as she waded in the Cahaba River. She only knew the small, cone-like shells were unusual. It turns out the Cahaba pebblesnail hadn't been seen since 1964 and had since been dismissed as extinct.
"People may have looked for it, but they didn't look hard enough," she said.
No Solid Rules on When to 'Throw in the Towel'
Bean explains that there are no solid guidelines when it comes to determining whether a species is extinct. Instead, the judgment is made by a rough "rule of thumb" whereby if a species isn't seen in about 50 years, it is declared extinct.
Declaring a species extinct, however, can have broad implications, including pulling back on efforts to restore a threatened species' habitat. So some argue the process of declaring an animal extinct should be made more scientific.
"There's no way to ever prove beyond absolute doubt that an animal is extinct because it is proving a negative," Bean said. "But instead of a 50-year rule of thumb, you might consider variables such as how conspicuous it is, how many people are looking for it and how long we've been looking. From that you can draw an inference on how likely it is to be extinct and have a better idea of when it may be time to throw in the towel."
Depending on the popularity of a species, officials may take more time to declare an animal extinct. For example, the ivory-billed woodpecker was never officially declared extinct, even though it hadn't been seen since 1944. Instead, it remained listed as endangered and this may have helped its survival, since people continued looking for it and working on restoring its (and other animals') habitats.
But for Burgman, who specializes in little-known rare plants, the rediscovery of the ivory-billed woodpecker in Arkansas was somewhat bittersweet.
"It does annoy me a little when we report people weeping for joy on rediscovering a bird," he said. "We could expend a tenth of the effort to learn a great deal more about 10 times as many insects. Trouble is, no one weeps for joy over insects."