Invertebrates Are Forgotten Victims Of 'Sixth Extinction'

Some 95 percent of catalogued Hawaiian land snails could already be extinct, and similar rates of invertebrate extinction could be happening around the world. Christopher Intagliata reports.

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When you think endangered species, which come to mind? Tigers? Pandas? Gorillas? I'm guessing what probably does are Hawaiian land snails. Yet a new analysis in the journal suggests that some of known Hawaiian land snails could already be gone. [Claire Regnier et al, ]

"That's a horrible level of extinction." Robert Cowie, a biologist at the University of Hawaii. 

Cowie and his colleagues came up with the 95 percent figure by convening the world's foremost experts on Hawaiian land snails—that is, the dozen or so scientists and naturalists who study the creatures. Through a series of interviews and hundreds of field surveys of the islands, they took their best guess as to whether each of the 325 documented species still existed. They think only 15 are still alive, leaving 310 in the "probably extinct" category.

There an organization that officially counts this stuff: the International Union for Conservation of Nature. But the Union lists only 33 of the 325 species as extinct—a gross underestimate, in Cowie's view. And therein lies the problem, he says. Invertebrates, including snails, make up the lion’s share of the world's biodiversity. But there's hardly anyone to catalogue it. 

"It's a tiny, tiny number of people relative to the vast extent of invertebrate biodiversity." And to get an organism onto official endangered lists, you need data to document its disappearance. Data that just aren't there for many invertebrates, due to the labor shortage. "In my more cynical, negative days I throw up my hands and say, why do we even bother? Because we're not going to be able to halt this, to turn around this process. But if you care about this you just can't give up." 

And this approach, he says, an almost folkloric reconstruction of what's out there, may be the only way to fully understand the species we're losing. Before they're known only from fossils.

—Christopher Intagliata