On a tiny island north of Papua New Guinea lives a snail that dons an electric-green shell with a yellow stripe. In the 1930s, the world decided these shells would make some swell jewelry, so the people of Manus Island started collecting the gastropods to meet international demand. By the ’60s and ’70s, the shells had become so in vogue that they were sold in units of 500.
As scientists watched the market grow, they started to fear that Manus’ rainforests couldn’t possibly keep up with the world’s snail fever. For its part, the United States added the Manus green tree snail to the Endangered Species Act of 1973, making it the first invertebrate to be listed. Soon after, the U.S. Fish and Wildlife Service started cracking down on illegal imports and confiscating shipments of hundreds of shells at a time.
These early moves probably saved the species, says Nathan Whitmore, a Papua New Guinea–based biologist with the Wildlife Conservation Society. And yet, it took until June of this year for the International Union for the Conservation of Nature to render a near-threatened listing for the snail. Not because its population recently dipped below that threshold, mind you, but because it's only now that we have been able to take stock of how many remain—and doing so was only possible with the help of those who know the snails best: locals who live with them.
The basic premise behind the WOC method is that, while no single answer is likely to be perfect, the statistical mean that emerges from all the inputs is often crazy accurate.
Whitmore, who conducted the research that led to the IUCN listing (published in the August issue of Oryx), says we have to be realistic when it comes to which animals receive attention—and therefore funding. Something like nine million species reside on the planet, and we have limited resources. For every species we focus our time and money on, many others are neglected. “In a competition for funds,” Whitmore says, “tigers beat snails—even pretty [snails]—every time.”
But this doesn’t mean it’s time to write off all the blobfish and Gooty spiders of the world. It just means we need to develop new ways of approaching conservation, as Whitmore did with the Manus green tree snails. He was able to cut most of the expenses associated with surveying remote wildlife by simply talking to people who live with the snails. This is what’s known as the “wisdom of crowds,” or WOC, method.
In September 2013, Whitmore and four Manusian facilitators spent more than a week talking up shoppers, stall operators, and local residents at the Lorengau Market—a shopping area that serves as a meeting place for people from all over the island. More than 400 people answered questions and filled out forms, providing an island-wide snapshot of local knowledge of the eye-catching snails.
Turns out, Manus islanders know their snails—mostly. The WOC method revealed that the gastropods are more common in areas that still have intact forest, high elevation, and low human populations, all of which Whitmore predicted. But the locals also suggested that snail numbers have undergone a decline of about 20 percent since 1998. (By the way, 1998 was used as a starting date because it looms large in public memory—it’s the year the World Sea Kayaking Championships were held on Manus Island.)
Once Whitmore analyzed the data and submitted it to the IUCN, the group found it convincing enough to designate the Manus green tree snail as near threatened, removing it from the long-held limbo of a data-deficiency status.
Now you may be wondering, can we really trust the word of a few hundred people who by and large likely have no formal scientific training? Whitmore says the evidence suggests we can, but only so far.
The basic premise behind the WOC method is that, while no single answer is likely to be perfect, the statistical mean that emerges from all the inputs is often crazy accurate. But while the approach is excellent for gathering data—how many snails do you see each day; what were they eating?—Whitmore admits that it becomes less useful as you ask more complicated questions. For example, 37 percent of respondents said they could tell the difference between male and female snails—which is impossible, given that the creatures are hermaphrodites.
“It was most definitely a trick question,” Whitmore says. “People gave all sorts of answers, which clearly highlights that when using a wisdom-of-crowds technique, you want to be basing it on simple direct observations rather than phenomena that are open to interpretation.”
Obviously, the method isn’t perfect—but nor are traditional field monitoring techniques. (Remember how subjective orangutan nest counts were at estimating population size?) “There will never be enough money in conservation to get perfect knowledge,” Whitmore says.
That makes low-cost, easy-to-employ techniques like WOC a potentially useful tool for all the little, ugly, or boring species that might need help—like bugs and plants in general, and probably thousands of creatures most of us don’t even know exist.
The next thing that needs to happen, Whitmore says, is to test the WOC method on a larger scale. There’s no shortage of potential subjects: Thousands of species are listed as data deficient by the IUCN. One possible candidate he’d like to see studied is the coconut crab, found on far-flung atolls across the Pacific and Indian oceans. The gnarly looking crustacean’s data-deficient status is likely due, Whitmore says, to the fact that it’d take tens of millions of dollars to survey them.
Personally, I don’t know why no one wants to donate money to study what Whitmore calls a “gigantic mutated hermit crab” that can grow up to nine pounds, has been known to tear turtle hatchlings limb from limb, and may be responsible for scattering Amelia Earhart’s bones. But I guess there’s no accounting for taste.